Bailey Steam
Engineering Designs



6" Mc Laren road Loco build by Andy Smith

Mclaren Build Diary Part 1

First of all a big thank you to Colin Dix for a) getting me started on this project b) for all the help and friendship and finally for offering to host the build diary on the Bailey Steam site.

So where did it all start and how did I get myself into this mess? Like many others I have more than enough projects on the go in the workshop already! 2004 was the year we returned our 6” Wallis to the rally field after and absence of 15 years or so and thoughts turned to missing our Aveling & Porter 5 ton GND tractor 7898 that we owned up until 1997. With the escalating cost of another full size engine out of reach thoughts turned to the possibility of building a half size 3 speed road loco.

There are now many good steam sites on the Internet and one good one that I came across was the Bailey Steam Services Site run by Colin Dix up near Ross on Wye. I had spent many a lunch break following Colin’s construction diary of his own engine so decided to give him a call, after a long chat Colin invited me up to see his engine however it did come with a warning! “if you come up and see it you will fall in love with it and want to build one”

That fateful visit was to be the start of so many things (little did I know at the time), we were made most welcome by Colin, Julie and the boys and enjoyed viewing the engine in the workshop over a cup of tea and cakes etc. Colin provided me with an overview of his build costs and I plugged in my own numbers with updated prices from Double B who supply the castings for this engine in 3”, 4” and 6” scales. Colin provided me costs for machining that was outside my equipments scope as this was an essential factor in whether the project got the green light!

Jan 04 – The fateful first visit to Bailey Steam!

The build so far has not been straightforward and I nearly gave up early on out of sheer frustration at not being able to get castings. On return from Colin’s we ordered a set of drawings from Double B and when these duly arrived I immediately made the regulator lever as this was the first bit we made for the 6” Wallis. Many nights were spent studying the drawings and we decided to go ahead ordering the rolling’s for the chimney, smokebox and front wheel rims and all the castings for the front end of the engine in May 2004. It became clear early on that casting supply was going to be an issue so I busied myself making the smokebox door hinge, lamp brackets, perch bracket assembly etc.

The first part “Regulator lever”

The project effectively then went on hold waiting for castings, chasing the castings almost on a weekly basis before being finally promised castings just before Christmas only to be put off yet again. At this point I was close to scrapping the whole project. Colin came to my rescue again with an offer to come up over Christmas to steam his 6” Mac and go for a road run around the local villages. This was just the tonic I needed and with renewed vigour and after some more chasing we got a date of 17th Jan to collect the first batch of castngs, exactly one year to the day of my first visit to Colin’s. The trip was once again on and off right up until the last minute and even on my arrival having driven some 140 miles to Sudbury we were told all the castings are not here! There had been a mistake by the foundry as they had cast the front hubs without any coring out but on the plus side there were lots of other castings available so we cleared out all the 6” scale stock in one foul swoop.

The Front end rollings July 04

Castings delivery to the Workshop!

The Double B casting supply issue seemed to resolve itself once the new foundry came on line and the castings were come thick and fast and my bank account was shrinking at an alarming rate!

We now have 95% of the castings although I still do not have a cylinder block, this being the last real key casting. The front end is now nearing completion and will be ready to stand on her wheels once I have finished off the last bit of machining on the hub.

The hubs are effectively cones with 9 degree angle faces so allow the spokes to come straight out without bending at the hub. I did consider machining them conventionally but the hub inners and outers are cast with the angles on them leaving insufficient material to clean up flat and still support the spokes.

Machining the hubs has had its challenges in that there was insufficient travel on the top slide of the lathe to do it in one pass so we had to take two bites at it. Ideally the hub inners and outers should be machined at the same setting but this was not possible so careful setting up was key to success!

The hub outers came from two different foundries and one pair were glass hard and even tip tools did not want to cut! This was eventually overcome but added to the problems. The next problem is how to machine the slots for the spokes on the cones. Colin machined his by packing up his rotary table at 9 degrees but this was a precarious set up that could have moved part way through machining. I have devised a more solid set up with a tilting machine vice and an indexing head. This will allow the hub to be clocked up in the flat and then tipped up and clocked in exactly before machining the
six slots in each face. I set it all up on the big mill at work with a digital read out only to find that there is insufficient clearance under the head! Believe it or not my small Taiwanese mill at home has much more clearance so the set up should work there?

Front Hub machining setup

Front hubs prior to spoke slotting

The final drive gears and pinions are all 12 module and I have no way of cutting the teeth or machining the big gears as they weigh near on a 1cwt each. I machined the two pinions and delivered them along with the raw castings for the two spur wheel to Colin. Colin machined the spur wheels although once again the curse of the foundry struck again with a large “slag” inclusion being found at the rim that only showed itself after machining was nearly finished. This of course was the one from the “old” foundry but to Double B’s credit they replaced it with a new casting in a couple of weeks. The 12 module gears were cut at AG Prout Engineering as this was outside the scope of Colin’s gear cutting machine.
The two small pinions have been cut but the larger ones were delayed as they have to be cut as a pair and with one defect casting this has slowed things down.

Finished final drive pinion with square drive hole cut

Final drive spur wheel prior to machining

I have deliberated over the chimney as no clear clues are available as to whether Mclaren’s had lapped and riveted or but strap and double riveted chimney’s or even if they were riveted at all ?

A friend of mine Richard Morris who I met through this project is restoring 8HP 3 speed Mclaren No 1295 and he traveled over to South America to photograph the sister engine. Fortunately this is still fitted with its original chimney and clearly shows a double riveted butt jointed chimney with rivets at a larger than “normal” pitch so I have copied this. I now have to decide whether to fit a spun brass cap or go for a more original cast iron version that sits down inside the chimney?

The stainless double riveted chimney, final riveting will take place after the chimney cap is fixed in place

The summer season does not usually leave much time for model engineering and the summer of 2005 was to be no exception although we had no idea what lay ahead! We attended the Welland rally with the Wallis during the last weekend in July, this is an excellent friendly 3 day rally set to the backdrop of the Malvern Hills and run by the Ross-on-Wye club. The Friday started off well with the ground drying nicely and a normal day of ring events and running around. Instead of Saturday dawning dry and bright per the forecast we were awoken by the sound of rain on the tent roof, and the day remained wet with the ground turning into a sea of mud that was to last well into Sunday. Despite all this we had a wonderful weekend with friends camped alongside the Dix family with “Hogwart”. This was the first time that the two engines had met and the Mac is certainly a big engine somewhat dwarfing the Wallis despite them both being 6” scale.

“Hogwart” and “Tiger” at Welland before the rain came!

We were scheduled to attend the Kemble rally the following weekend but this was not to be as my mum sadly passed away on the Friday following a long battle with cancer. Mum was a great support to my late father Les Smith and attended early Andover rallies with him in the late fifties and early sixties with various models and always supported our engine activities both full size and modeling. Needless to say all engine activities came to a grinding halt for several months. Colin came to my rescue again with the offer of having “Hogwart” for a couple of days at he GDSF and we did not need to be asked twice! We had a wonderful time trundling around the play pen and it really made me glad that I am building the Mac, it truly is a fabulous powerful engine.

We left off last time pondering the chimney cap and things went from bad to worse! I had settled on a brass cap from Double B per the 4” version and again after lots of chasing they eventually turned up but made of copper instead of brass and to completely the wrong shape! Action was clearly required so with help from Richard Morris who provided a drawing of a proper Mac cap and my friend Mark Money in Tasmania who provided a template from his 10HP road loco we were able to validate the shape. My dad always considered the cap as the crowning glory of any engine and so many models are spoilt by ugly appendages that bear no resemblance to there full size counterparts, I was therefore determined to get it right. The 6” drawing was provided to Double B and about three weeks later the caps turned up, I am delighted with the final result and it really sets the chimney off.

Finished chimney cap and chimney

October turned out to be a busy month as the cylinder block was also successfully cast by Crayford Castings in Kent. Despite being fully cored out it came in at 185kgs and took two of us to lift it out of the car!

The Cylinder block with ports cast in

A couple of week’s vacation was followed by news that the boiler was complete and tested ready for collection. The boiler was made by Bell boilers near Stonehouse in Gloucestershire and I planned to co-ordinate the collection with Colin so that we could take it up to Alan Prout’s yard and machine of the stay ends on his Kearn’s borer to ensure a nice flat parallel surface to bolt the hornplate’s to.

Colin machining the side stays on the Kearn’s borer

The allotted day dawned cold, frosty and foggy and we set of early to collect the boiler at 9:00, it took about 2 hours and the windscreen washers had just about thawed out by the time we got there. The boiler was loaded without issue and then we headed off to Alan’s where the job went smoothly but I have never been so cold in my life, it took a least a day to thaw out properly! The boiler was safely unloaded with an engine crane but it was certainly on its limit!

The cylinder block was dropped of at Colin’s at the same time as the boiler stay machining ready to go up on the big Kearn’s borer at Alan Prout’s. The block was completed and collected just before Christmas 2005 and is now somewhat lighter as I was able to lift out of the car on my own! Clupet piston rings have also now been sourced but I am still trying to figure out how they make them!

“The finish machined Cylinder Block”

Other work has been the machining of the trunk guides and final drive gears. The Trunk guides needed a lot of cleaning up and many hours of careful filing to put the radiuses on the edges of the trunk guides to blend in nicely. The foundry fettler had also been a little over zealous and this required additional cleaning up etc.

Much thought and discussion took place over the crankshaft to determine the best method to produce ranging from fabrication, machine from solid or SG iron casting? After much review the machined from solid option was chosen as this is a very powerful engine and with a 1cwt flywheel hanging on the end it just didn’t feel right as a casting, an order was placed with Custom Crank and Engineering in Wolverhampton.

Some feverish work over the Christmas holidays saw the building of the front wheels completed and this enabled the whole front end to be assembled on New Year’s Day, quite a moment and a good feeling for how big it all really is.

“The front end all assembled on New Year’s day 2006!

Next job was the hornplates, belly tank brackets and ashpan brackets. The hornplates were laser cut with all the bearing housing bracket holes but still heavy and awkward to mark out and drill al the dummy rivet / stay holes. The third shaft bearings and back axle bearings were also machined and bronze oilite bushed fitted ready to ensure alignment when fitting the hornplates to the boiler sides.

“Hornplate ready for riveting”

The rear wheel rims have sat in the garage since the summer and just looking at them did not seem to make them any smaller or lighter! The first job was to grind the welds on the T rings back ready for filling after vulcanizing the tyres on. The brake rings were supplied un-welded so these were fitted, welded and then welded into the rims on the inside of the rim. The rear hubs are substantial to say the least and the double lobe hub is just about as much as I can carry when fully assembled. Colin lent me his wheel building jig and fly press for bending the spokes and this was used on the front wheel as well. The rear rim was lifted up onto the jig with an engine crane and the whole wheel has to be moved around and turned over using this as it’s the only safe way.

“The first rear wheel completed 12” wide x 39 ¾” dia!”

One rear wheel is now finished and the second one is on the jig and I have started to fit the spokes. All the wheels will have to be dismantled for the tyre vulcanizing as it sends everything red rusty. The wheel rims are shot blasted after vulcanizing so will need a coat of primer before reassembly and riveting. The finished crankshaft was collected in March and I am very happy with the results.

“The finished crankshaft machined from a solid billet”

Having completed the wheels it was time to consider the options on rubbering them, fork lift tyres were considered but in the end vulcanizing direct onto the rims was chosen. Colin was also looking to get the full size Ruston wheels done at the same time and we found a company in Birmingham who offered a very competitive price compared to some of the other quotes we received along with a 4 week delivery. I decided to strip the wheels down and just send the rims up as they have to go into an autoclave to cure the rubber and its sends everything red rusty. The rims were shipped up to Leakes and they were as good as their word and they were ready for collection four weeks later. I am very pleased with the results and now have three wheels back together again ready for riveting.

“The finished front wheels”

“A finished rear wheel”

Unfortunately things have taken a turn for the worse on the work front as we have had to move offices and have lost the use of the big mill in the workshop “how inconsiderate of them”! This meant some feverish activity to try and get all the big machining done and out of the way before the opportunity was lost. This has however diverted me away from target of getting her up on her wheels. I have now purchased a large mill for the workshop at home along with a phase converter so hopefully this loss has now been overcome.

“Gear blanks all machined ready for gearcutting”

I have finished machining all the gear blanks and delivered them to Colix at the end of June to have the teeth cut and the squares broached in and these were collected from Colin at the Midlands ME Exhibition in October

“Some of the completed gears”

“ Machining on the chamfers on the rear axle carrier”

The pile of bits in the workshop is now building fast and some assembly is planned over the Christmas holiday to reduce this pile and have something that starts to look like an engine!

With a couple of weeks off over Christmas 2006 it was planned to start assembling the ever increasing pile of bits in the workshop onto the boiler in the garage. I don’t know about you but I find that however much space I have it seems to get filled up with “stuff”. The arrival of the full size Ruston project has not helped matters but it’s a good job that it came flat packed “IKEA style”. Space is tight in the garage with the 6” Wallis in there but this is all part of the challenge!

The boiler was already set up on blocks in the garage ready to receive the hornplates and although the hornplates were all finished I still needed to fit the dummy rivets. The drawings show ¼” rivets but as they would have been at least ¾” in full size I opted to go for 3/8”. Richard Morris had already provided me the pitching info to allow the holes to be positioned correctly which was a great help. Although I had a large bag of ½” long 3/8 rivets they all needed to be shortened and with several hundred to do it was very boring time consuming job.

I elected to do the riveting in the mornings so as to cause minimal disruption to the neighbours. The belly tank mounting brackets and ashpan brackets also had to be riveted on at the same time. I cannot believe how heavy / awkward ½ size hornplates are to move around on the rivet dolly and swinging that hammer really was an arm acher. My wife informed me that she could hear the banging over the television from the workshop which is about 140 feet away down the garden………………

The boiler side stays had already been machined flat and parallel so I thought fitting them would be a doddle, how wrong I was! I started with the flywheel side as it has cutouts for the injector clack and two washout plugs. The hornplate was clamped on and lined up with the cutouts, bottom of the firebox and checked for squareness with the throatplate and boiler crown. The holes were spot marked through and then the hornplate removed to check alignment with the 8 large stays needed to be drilled and tapped, all were nice and central so they were drilled and tapped. The hornplate was then bolted on with button headed cap screws (the allen key holes will be filled before final painting to simulate stays). All the bearing housings were then bolted onto both hornplates before offering up the second hornplate.

The second shaft and rear axle carrier were fitted to ensure alignment before clamping the hornplate in position. It did not seem to matter where I fitted it either one would line up or then they would’nt, the drain plug bosses were holding it off so it was take it all off and then back down the workshop with the hornplate (now even heavier with all the bearings fitted) and get it up onto the mill to open out the holes to clear the bosses and allow more adjustment. It did’nt help that the hornplates were not dead flat but by clamping the front and spectacle plates in postion I managed to get it all set up correctly but a much longer job than originally envisaged and not helped by the cramped working conditions. It was a case of check, adjust, check again etc etc.

“The hornplates bolted on”

The weather over the Christmas period can only be described as “wet” so I could not get the Wallis out enable the front end to be fitted, this was rather frustrating as it was all ready to fit on. I decided that to ease the working conditions and allow more maneuverability I would fit some heavy duty castors on the back end so I busied myself fitting those in anticipation and hope of some dry weather.

The smokebox and front end had already been assembled so once the smokebox was on it would be fairly quick to build up the rest. The smokebox is quite heavy and I knew it would be a tight fit, the spacer ring was fitted onto the boiler with countersink caphead screws so that I could drive the smokebox on. The chimney base was left on as guide to squareness / level and it had to be adjusted several times during the fitting as I did’nt want a “wonky” chimney! Like all rollings it was not truly round so I had to revert to a hydraulic ram to open it out to get it started on and drive it on with a hardwood block and sledge hammer, it really is a good fit. After a double check for squareness half a dozen holes were drilled and rivet bolts now hold it in place.

The addition of the perch bracket, axle, wheels and chimney only took an hour after that and it was a great feeling to see it start to look like an engine, I had to wait another week for the weather to improve before rolling her out on the drive to get a look in daylight.

“JYNX” meets “TIGER”

It’s such a huge boost to your enthusiasm to see it all start to come together and for several evenings I just had to go and keep looking at it in the garage.

I have now fitted the spectacle plate and cross stays that go between the hornplates on a Mclaren, fitted the firehole door and machined the crankshaft and secondshaft bearings. The crankshaft was dropped in and rotates freely without any play or adjustments to the bearings so I guess hornplate fit cannot be too bad. The secondshaft and three speed gearing on the crankshaft and second shaft were fitted on Sunday, first gear was engaged and it turns over very sweetly without an ounce of backlash in the gearing. The pile of bits in the workshop is also definitely much smaller now!

“The Crankshaft and second shaft installed”

We have not even steamed the Wallis this year and our first rally is not until Kemble in August as I just have not had the time with heavy travel / work commitments etc.

We have despite all the above made some significant progress since the last update. The next process was to finish off the diff assembly and 3rd shaft gearing and then the two final drive assemblies. Things are all getting a bit big now and I am really glad of that extra 6” in the mill table length as the third shaft only just fitted to mill the square on the end. The length and diameter of the shaft would not fit in my lathe and we don’t have a steady for the lathe at work (will have to fix that!). Colin came to my rescue again by allowing to use his lathe to centre and face each end and then turn down the diameter and put in the retaining groove, a round trip of 160 miles but a good chance for a chat and Ruston discussions ……………. over a cuppa.

Machining the square on the 3rd shaft

The diff gears and bevel pinions were already cut so to finish the diff assembly I just needed to make the pinion shafts and drill the mounting bolt holes for the gear ring and put in the oil pipe hole etc, the finished assembly along with the final drive pinion are quite a lump but it was very rewarding to see it all come together and more importantly fit the shaft I machined up at Colin’s. The assembly is held on the shaft by a split collar that drops into a groove in the shaft so this was made and fitted next. My measurements on the length of the shaft worked out perfectly so when the square was cut it all fitted perfectly with just a small amount on end float.

The assembled diff unit

The winding drum and final drive centre had already been machined so again just needed final assembly and the bearings made and fitted. The offside gear bolts directly to the rear of the hub so both gears were put up on the mill and the holes pitched out and then transferred to the hub / drive boss followed by reaming for fitted bolts. I could not lift the assembly off the mill so had to assemble on the floor, more big bits ready to be fitted on once the rear axle goes in.

Final Drive spur gear / rear hub backplate

The cylinder block has also now been finished off with all the stud holes etc being added and all the covers/ trunk guides fitted. Drilling the valve chest stud cover holes proved to be a real challenge as the block would not fit under the quill on the mill. Mr Heath Robinson was called in and we overcame the problem!

Mr Heathrobinson at work!

I have also had lasercuts made for the belly tank ends, rear spring hangers and gear change sliders, this process works on steel up to 14mm thick and saves a tremendous amount of time. While on belly tanks I decided to have a pattern made for the water lifter hose bracket and this was done along with several castings by Alan Davenport, Richard Morris lending his original to help get it right even down to the casting number, the end result is very pleasing. Colin also decided to build a toolbox for the belly tank so we did two with Colin getting these folded up. Richard Morris once again came to the rescue with pictures and dimensions from his full size version.

Water lifter hose brackets (pattern and castings)

Laser cut / folded bellytank ends

Folded toolbox prior to welding

The finished toolbox with owners plate

With the block all finished it was time for assembly, the following pictures sum up the current build status as of July 07.

The finished cylinder block

Lifting on the cylinder block

Drivers view!

Side view

Starting to look like a proper engine!

Diary Update 15/08/2007

None of the two 6”Macs finished so far have been fitted with rear spring gear although Colin did make most of the components ready to fit on his engine. Having driven Colin’s engine on numerous occasions it really is not necessary and only has very limited movement anyway but in an engine of this scale I felt that I should include it.

The drawings are a bit sketchy in this area so I went ahead and produced some ACAD drawings of the springs and associated parts and these were used by the laser cut company to make some of the parts although the “T” pieces were CNC flame cut.

“T” piece flame cuts

I decided to get the actual leaf springs made professionally as they need to be hardened and tempered to maintain there “spring” in use. I sent the drawings out for quote with numerous responses ranging from not interested to extortionate ……….!

Laser cuts for the spring gear

I finally found a company in the midlands who were recommended and at a fair price so got these underway while I was making the rest of the parts. The springs were duly delivered as agreed and I have to say I was really disappointed when I opened the parcel. The leaves were all different leaves, the centre buckle looked like it had been hewn with an axe and then they were dipped in what I can only describe as tar! To be fair the vendor did offer to collect them and remake at their cost but by this time my confidence in their ability to do them to an acceptable standard had evaporated so we agreed a large partial refund of the cost and I got on with putting them right! This involved stripping each spring and re-machining the centre buckles and then adjusting the length of every leave, the worst job was actually get the black tar off as it seemed to get everywhere!

Finished rear spring assemblies ready for fitting

The spring troughs and stirrups were fairly easy fabrication work with the laser cuts saving a huge amount of time. The “T” pieces were machined and the oil and stud holes put in ready for a trial assembly. This is where it all started to go wrong again as the leading edge of the “T” pieces fouled on the fire hole door hinge and the back head while the stirrups fouled on the rear boiler washouts! A bit of investigation with Colin revealed that he had similar issues with his “T” pieces but he had not encountered the washout problem having never fitted the rest of the spring gear. Another builder I am in contact with reported that he had exactly the same issues as me so at least I was not alone.

Assembled onto the engine

I have overcome the problem by machining the front of the “T” pieces away on both sides, adding a radius to the door hinge and dropping the stud size down to ½” as there is no longer room for ¾” nuts. The reduced stud size has also provided clearance for the washout plugs but this makes access extremely difficult with the spring gear on.

- Progress Update 04/09/2007 -

With the spring gear done and fitted I decided the next task is to get the cylinder block finished off. All the machining has already been done and covers temporarily attached etc but I had been putting off making all the studs as it is such a boring job.
Another one of my pet hates is studs sticking out of nuts all different lengths and not finished off nicely on the ends so I have made sure that all the studs were identical and the finished result is very pleasing. At the same time as the studs I have also finished off glands for the regulator, slide valves and piston rods, all went smoothly with the exception of the HP slide valve as the flange of the gland fouls on the trunk guide. The trunk guide is machined off flat on one side anyway as per full size to I just need to adjust the gland to allow it to fully enter the block

Pictures of block with studs fitted.

It’s really nice now that as I make bits they can be fitted straight onto the engine. With the trunk guide studs all done and the oil pump sitting in the drawer it was tempting to make the mounting bracket and get that on as well. Having studied all the pictures the 8HP engines seem to have the lubricators mounted directly above the HP valve chest on studs but this is all cored out on the 10HP engines leaving no area for the studs so they seem to have them fitted on the top of the trunk guides. Armed with pictures on Boadicea’s mounting bracket we had this knocked up in short order along with the threaded fitting for the block. I have not fitted the pipe yet as I am going to fit a secondary non-return valve in the line.

Picture of the fitted oil pump.

The purpose of pushing on with the block is to enable me to get it permanently fitted to the boiler, I do mine by assembling the connecting rods / crossheads / pistons to line everything up and check for free rotation as well as allowing for boiler expansion (calculated to be 0.080” in this case). So with this in mind the crossheads and piston rods were next on my list. Having read Colin’s build diary and the need to add bronze slippers I was very careful in measuring everything and it became clear that the crossheads have very little machining allowance on the diameter that fits in the crosshead. I also decided to deviate from the drawings at this point as the single cross pin to take the load / drive did not seem adequate. On full size Mclaren’s the crosshead is screwed onto the piston rod and then fitted with a locknut. The piston rod is cross drilled through the crosshead and long dome headed bolt and nut are fitted.

The crosshead castings were carefully set up in the four jaw chuck and faced / drilled and tapped for the piston rod. The piston rods were then made up over length and the crossheads fitted on and the locknuts tightened. I machined the OD to fit in the crosshead like this to ensure that the diameters remain concentric. Once the desired fit was achieved and checked on the engine I drilled the cross holes to ensure that they would always go back in the same place after finishing off the other machining operations.

Picture of turning the crossheads

The crossheads were then removed from the rods and had the side cheeks milled and the little end holes put in, then the rears were machined and the inside cheeks cleaned up as well as the two locking bolt holes that prevent the little end pins from rotating in the crossheads. Another measure up once assembled to determine the finished piston rod length and the job is completed, pistons and slide valves are next on the list!

Pictures of finished crossheads.

- Progress Update 25/09/2007 -

The slide valves on the Mac are supplied as gunmetal castings all nicely cored out to allow free steam movement but like all things in life nothing is that simple! The ports on the Mac block are all cast in and if the sand cores move during assembly of the mold or during the actual casting process then the ports can move. This was the case with my block but being worse on the HP side, needless to say that after squaring up they don’t match the drawing dimensions on either side! Fortunately the slide valve castings are on the small side internally so I have after discussion with Colin opened them up on the inside to ensure that the ports are not blocked / obstructed and just cleaned up the outside edges. I may have to adjust these once we get to setting the valve timing. The rest of the slide valve machining is very straight forward.

Picture of slide and valve rod

I positioned the slide valves in the block and then inserted a piece of ½ dia bar with a pointed end on through the gland / block to mark the position of the hole. The hole is then drilled oversize on the rod to allow some float to let the valve move off the face in the event of priming.

The assembled slide valve in the block

I have made the valve rods from ½ dia stainless and left them over length until I have made the rest of the valve gear, the locknuts will allow easy adjustment of the valve timing at ether end of the valve rods.

The block with fitted crosshead and slide valves

- Progress Update 15/10/2007 -

They say a little of what you fancy is good for you! So instead of pushing on with the connecting rods I decided I fancied building the belly tank as I have been looking at the laser cut and bent ends sitting in the corner of the workshop since the summer. I had already sourced some strip to roll up for the radius flange so I rolled this up to just sit on the edge of the radius leaving a natural weld prep. Now welding is not one of my strengths but I have to say it came out quiet well and after dressing back the result was pleasing. I had some off cuts of 1 ¼” diameter boiler tube left over from the 6” Wallis and these were cut to make fill in pieces for the corners and once again after welding and dressing back to leave a perfect 5/8 corner radius.

Picture of welded up belly tank end

The strengthening pad that also provides the fixing at the front was also welded in at the same time and I will mark this out and drill the fixing holes once the belly tank is trial fitted after assembly. I clamped the rear belly tank end onto the engine to mark the position of the mounting holes. The end was adjusted to be both central and level to the horn plates before marking the holes, the positions were then checked for position and one set of holes drilled before remounted to double check before drilling the other side.

Picture of trial fitting for fixing holes

I deliberated on how to make the wrapper as it’s a big piece of steel to bend as per original plus the need for access to the inside to rivet it. I eventually decided to leave the boiler radius as a separate panel (as per Colin did) but to fit a separate flat base again as per original with a central manhole in the underside for access. The company that laser cut and bent the ends were also able to fold the wrapper ends and laser cut base with manhole rings so I provided them with a finished end to act as e template and the results are excellent.

Picture of laser cut bits

Before starting to drill any holes I assembled the pieces to see what it would all look like and check for any major errors in my plan!

Picture of mock-up

The drawings called for ¼ rivets at 13/16” pitch but once again after mocking up this did not look right. Richard Morris once again came to my aid confirming rivet sizes in full size of ½ “ and 1 7/8” pitch making ¼” and 15/16” pitch. The two end wrappers were carefully marked out and the pitching worked out perfectly avoiding a rivet right on the corner where it would be almost impossible to get to. The holes were all piloted before opening up to ¼” dia and I am now putting in all the holes for the water lifter, toolbox, hose bracket etc before the mass riveting exercise begins. I have enlisted the help of a friend to help with manoeuvring the tank around and we will have to pick a weekday to do this to minimise the impact on the neighbours with all that banging!

Picture of drilled belly tank end

The fitting of the ends is now complete and all the fittings are made and fitted prior to assembly. Unfortunately my plan for help went wrong as he decided to go away for the weekend at the very time I was ready for riveting so my son was enlisted to help along with an engine crane and I was able to do this on my own once it was all set up!

Picture of fitted up tank end

The ends were riveted first with the bolts holding everything in line and these were removed once enough rivets were in place to hold things tight and I only had to remove one rivet that got misaligned on the snap leaving a nasty unsightly mess. The corners dressed nicely in as well once the rivets had pulled the joint in and I am very pleased with the results so far.

Picture of riveted belly tank end

Picture of riveting setup

I have decided to fit a separate bottom plate to the tank (once again as per original) and the removable top section allowed this as it would be very difficult if not impossible to rivet without this access. I have also added in the manhole and strengthening angle iron brackets where the steering brackets are mounted. The bottom edges of the ends need to be “scarfed” down to a knife edge to allow the bottom to fit snugly so these were ground back and pull up nicely with bolts but this will need careful attention when riveting up.

Picture of belly tank prior to fitting the base.

Picture of bottom assembled prior to riveting in position.

- Progress Update 29/11/2007 -

Having fitted up all the bottom of the tank, bolted in place and drilled / positioned the strengthening plates it was time for my favourite job of welding! The bottom was removed and the strengthening ring and steering shaft supports bolted up tightly and after careful tacking all still looked good, that is until I had finished the welding and the based had bent like a banana! Time for a cuppa but having left it all to cool down it did not look any better! Careful bolting down soon pulled everything into line and I could at least sleep knowing I only had several hundred rivets to put in.

Picture of Finished tank bottom

I had a tidy up / move round in the workshop until the belly tank could be sat over a sturdy bench at waist height with the rivet set in a suitable vice and by careful adjustment of the support blocks the belly tank could be levered up and the manoeuvred over the snap. This et up worked well but I found I needed a third hand at times and I only managed to drop the tank with my finger between the snap and the tank a couple of times! I had to have several goes at the riveting spread over a couple of evenings as it was noisy work and I didn’t want to upset the neighbours. The end result is very pleasing and it was great to be able to bolt all the bits back on and see what it looked like although I still have the top section to roll and fit.

Picture of bits bolted back on the tank

I decided to do the steering brackets next as I had already fitted the bolts in the tank and it would be easier to set up with the tank off the engine. The castings were not as easy to machine as they would not fit in the vice on the mill so I had to add an angle plate and some clamps for additional; support. The steering shaft comes through at an angle in a split bearing on the 10HP engines which are different to the 8HP and smaller engines. The cap is part of the casting and needs to be sawn off before machining and then refitted with studs to put the shaft hole in and a bronze bearing. I had been up at Richard Morris’s the weekend before and he very kindly provided a couple of large 3/8 split pins for the ends of the shaft, this seems to be a Mclaren special as despite having the worm wheel keyed in place it still has the split pin at right angles to the key.

Picture of steering shaft machining

Picture of shaft fitted to tank

The steering brackets and shaft fitted straight onto the tank so it was now almost ready to fit onto the engine. I made up two hardwood spacers ½” thick that slip in between the tank and the mounting brackets on the horn plates to allow the tank to slide up into the front mounting bracket. It was necessary to get the engine out to fit the tank and it was a simple job to slide the tank under the boiler on a trolley and then pack up with wooden blocks until the correct height was found and the bolt holes lined up. The pre fitting obviously worked as the tank bolted straight on and is nice and square so now I just have to fit the front mounting bracket.

Picture of belly tank being fitted

Having got the tank on and subsequently fitted the shaft underneath it seemed sensible to make the steering shaft and fit the worm and the steering wheel, only problem was I could not find the casting! After a bit of searching it was located and also realised that I have very few castings left to machine now. A study of the drawings also showed me how many are complete now so I guess I must be making some progress.

The steering wheel is a straight forward machining operation but how I hate those over zealous foundry fettlers who had attacked the rim! The handle was turned up from stainless and both ends of the shaft turned to fit the bearing, worm and wheel with the final length being determined by a test fitting. I cannot make the top bearing yet as it bolts on to the gear case and I may have to machine a little off the top of the steering shaft bearing housing to lift the assembly up as it comes a bit to close to then final drive pinion.

Picture of the steering wheel fitted

I really must get on with those connecting rods next!

- Progress Update 08/01/2008 -

When I originally did the major machining on the front plate I deliberately left out the two outer holes for the gear change shafts thinking it would be easier to mark them in position from the engine. Having fitted the gear change castings it became clear quite early on that one side lined up perfectly and the other side was miles out! I have been pondering this for a while as to how to overcome it as the shaft really has to go through the centre of the boss to both look right and line up with the gear change pin.
I made up a marker from a piece of 9/16” dia bar with a nice cone turned on the end, simple to pop this in the housing and then tap the end to mark the hole position. The near side marked dead centre but the offside really was about 3/16” out of position so the only choice was to machine part of the bear cap / gear change housing and move it all over as far as I could and make a spacer up to sort the gap this generated.

Picture of middle gear change

While the front plate was off for machining the holes I put in the drain cock and simpling valve holes and drilled and tapped the back of the regulator stand for the pressure gauge support. I had already machined the middle gear change so this just needed the two 3/8” stud holes drilling and tapping. The gear and racks have different numbers of teeth in different positions these were first sorted out into sets per gear and then machined to length / turned down to allowing fitting of the selectors. The selectors had previously been laser cut so just needed a clean up and marking / drilling for the fitting hole and lubrication holes.

Picture of low speed gear change

The actual gears had the selector grooves left out at the original machining as we were concerned about cracking during the broaching process for the drive squares so each of the three gears had to be set up and clocked in before adding in the grooves, this was straight forward on low and top but on the middle speed the casting has the ring left off of it to allow it out of the sand as a straight pull for casting. This requires the outer square to be turned down and then the selector ring / groove either shrunk or loctited into position. I favoured the shrink fit option so having turned down the casting a ring was machined up 0.001” per inch dia undersize, this was then gently warmed and dropped on and it won’t be coming off in a hurry! Even though it was only 0.003” shrink fit it closed down the square so that it no longer fitted onto the shaft but a bit of careful fitting soon overcame that problem

Picture of middle gear change

This now leaves the three actuating handles to complete the gear change so I am hoping to get these finished off over the Christmas break

Picture of all three completed gear changes

Having completed the belly tank my attention now turned to sorting out the laser cutting / bending for the tender so this could be going on in the background while I worked on the gear change. Both Colin and Ken Knight kindly provided me with the electronic drawings for the tender and I modified these to suit my own needs and then sent them out as dxf files to the laser cutter which saves both time and money. The parts were collected about a week later and once again I am really pleased with the results.

Picture of the tender bits

Picture of drawbar laser cuts prior to welding

I have already fitted the brake shaft casting and drilled all the fixing holes and have fitted the manhole and put in the rivet holes for the floor and front tank fixing, next job is to finish off the angle and fit them to the horn plates to transfer all the bearing mounting holes.

Picture of the floor angle fixing

I guess those connecting rods are going to have to wait!

- Progress Update 22/02/2008 -

Progress on the tender has gone very smoothly with riveting the angle iron onto the tender sides and I found I could do this on my own by careful balancing of the tender side on the rivet set! It was a fairly easy job to clamp each tender side onto the horn plates using the rear axle bearing housing as the location and ensuring all was square, that is until one slipped off and landed on my big toe!

Picture of finished tender side

I followed the same process as I used on the belly tank ends and welded in infill pieces for the corner radius and then dressed back with the angle grinder. The tender floor is in two pieces allowing removal for internal access so an angle iron
framework needs to be welded in place to support this in the middle and at the front and rear. I drilled and tapped all the holes in the plates first and assembled the tender and then tacked the joints before removing the plates for final welding ensuring everything remained nice and square.

I already had the steel pre-cut for the coal tubs. Which just needed rolling into shape, I say just but it was damn hard work! I managed to get some off cuts of angle for the tender from our local fabrication company and when I was there spied a nice set of rolls in the corner so asked if they could roll the coal tubs? They quickly agreed and I delivered the steel planning to collect it a few days later but after several visits and no activity I concluded it was not going to happen! Colin again very kindly and probably foolishly allowed me to go up and use his while at the same time borrowing his lathe to bore the ends of the brake shaft tube as we did not have a steady for the lathe at work. I went up for the day between Christmas and New Year despite not feeling my best as I was really not very well. After several hours of winding the handle of the rolls between us in cold weather we got the job done and they have come out superbly so thank you Colin, we were both exhausted at the end of it though and I had muscle aching for several days after that.

Picture of the tender with coal tubs on

The coal tub bases were made in the same way with a rolled ring welded onto laser cut disc and then dressed back to give a nice radius. The drawings called for ¼” rivets but these just did not look right so I changed them to 3/16” and increased the spacing on the top strengthening ring and they now look spot on compared to the original photos that I have. The brake gear was tackled next and I decided to drop the brake hand wheel down inside the coal tub to allow two people to comfortably drive the engine, not quite correct but a case of practicality over authenticity and it works really well on “Hogwart”. Ken Knight very kindly donated a length of square 4TPI threaded rod for the brake shaft that was left over from his build so this was an easy job for a change!

Picture of fitting the tender on

With everything on the tender completed it was time to wait for some nice weather to get the engine out and fit the tender on. We did not have to wait very long and took advantage of the fine dry weather last weekend. The tender fitting went without a hitch other than one rogue rivet that prevented the tender from sliding into place on one side. Some quick work with the angle grinder soon solved that and to my delight all the holes lined up perfectly with the only exception being the offside 3rd shaft bearing housing where there is not room for the fixing bolt heads so I will have to modify the diff bevel wheel to provide some clearance.

Picture of the fitted tender

Starting to look like a real engine now!

Another momentous event happened just before Christmas with the arrival of the spark arrestor which had been on order for almost three years. The good news is it’s a superb job, fits the chimney perfectly and looks really good. I have also collected the 6” scale transfers from Richard Morris and they are absolutely superb, Richard has made a fantastic job of these and they will really finish the engine off.

- Progress Update 01/04/2008 -

With the tender now on space in the garage has become a premium and with all the big bits done its time to start working on the details. I personally find this the hardest time to keep enthusiasm going on any project as it feels like you do a lot of work and don’t have much to show for it. The rear axle carrier had to come out to fit the tender so I decided to do the rear axle oilers as these have long pipes that are threaded into the carrier so a good time to get this done while it was all dismantled. The original oilers have tapered cocks allowing you to turn them on and off and stop the oil siphoning out of the oilers when the engine is standing. Richard Morris kindly lent me one of his full size ones for me to copy and it was simple enough job to make these up along with the pipes and they both fitted nicely on the engine.

Picture of finished rear axle oilers

I had been putting off making the three gear change levers for a while but these also needed doing and I managed to find some suitable rectangular bar. I milled the main profile and bored / reamed the main holes in the flat stock as it was easier to hold and the use of the digital readout on the mill made this really easy to get all the profiles equal around the centre hole. The handle section was a simple turning job between centres and then the radius profiles and fixing bolt holes added to complete. I have not put the flats on the shafts yet and won’t until I finally get the gear changes all set up properly.

Picture of finished gear change levers

The water gauge frames have been sitting in the drawer for a while so I decided these should go on next. The boiler has bosses welded in place to accommodate the frame extensions so these needed to be drilled out and tapped to suit the extensions (this would have been much easier to do with the horn plates off). The extensions were made from some large section hexagonal steel bar suitably relived in the middle and are screwed straight into the bosses.

Picture of fitted gauge frame

I have decided to start work on finishing off the crankshaft and needed to fit the middle speed gear, centre balance weigh and all the eccentrics. The balance weight had already been machined earlier in the build and I had successfully managed to thread it over the crank webs for a test fitting but it still needed the large U bolt and special nuts that clamp it into place. I worked out the length on the U bolt and threaded both ends of a piece of 5/8 diameter bar. The bar was then heated to red heat and bent around a piece on 3” bar, it sounds easy but it took numerous heats to finally get it into shape and also not damage the thread but we got there in the end.

Picture of U bolt and special nuts

I have had the steel ready for the eccentric sheaves for a while and these are different from the HP to the LP and also on a 10HP Mclaren the pump drive comes of the rear of one of the LP eccentrics, this eccentric being extra wide. The sheaves themselves are a straight forward turning job with the holes being bored in with the offset in the four jaw chuck.

The straps took much longer that I originally though and some tricky machining to get the fits just right, all the special studs and fixing bolts along with the oilers but they are now done and ready for fitting onto the crankshaft. The eccentric rods are rather delicate and again different lengths from HP to LP so I have decided to machine these from the solid from 2 ¾” dia bar but to save time I am having these CNC turned for a very reasonable cost leaving me the ends to machine and the offsets to complete.

Picture of finished eccentrics

- Progress Update 11/05/2008 -

While waiting for the eccentric rod blanks to arrive I decided to remove the crankshaft from the engine and fit the balance weight, eccentrics and gears etc. I had already machined the balance weight and fitted it on the crankshaft (this is no easy job as it needs to be jiggled over the crank webs) so it was an easy job to fit the pre made U bolt and then drill and tap into each crank web for the two additional bolts and spacers that secure it . The next job was to fit the dummy shield to the middle speed gear and add keyway clearance and a nice radius to allow it to fit snugly against the crank web. This gear is keyed in place and a tight fit on the shaft to careful fitting was required. The eccentrics were only fitted loosely in place as I will be coming back to the timing once the rest of the motion has been fitted.

Picture balance weight and eccentrics installed on crankshaft

The crankshaft is no light weight but I was able to lift it out on my own and carry it down to the workshop. Its reinstallation was somewhat different the added bits (especially the balance weight) make it really heavy so required a trolley to transfer it back to the garage. My son was enlisted to help lift it back in position and it is great that he is both willing and able to help now its getting so big and heavy.

Picture of finished crankshaft assembly installed in the engine

The reversing lever was next on my list of jobs to do. The drawings leave a lot to be desired in this area so armed with dimensions and pictures (again from Richard Morris) I have been able to create an accurate version of Mclaren’s distinctive reversing lever. The actual quadrant was laser cut but everything else being machined from solid including the bottom latch with its distinctive shape.

Picture of fitted reversing lever

The eccentric rods arrived last week so I now have these on the mill machining the rectangular sections at either end prior to slotting and putting the pin holes in. The rods are different lengths each side as the HP eccentrics are smaller than the LP ones and each end has a different offset so will definitely need to measure twice and cut once!

Picture of eccentric rod machining

- Progress Update 26/06/2008 -

The eccentric rods are now finished after a lot of machining and the dustbin man was seen limping away after emptying the bins with swarf! The rods are quite delicate on the ends and I am really glad that I machined them from the solid. I carefully reamed all the pin holes 3/8” diameter only to find that the holes in the link are oversize so they will need to be opened out a little and the pins made oversize although the die block holes are spot on 3/8 so not sure what went on there. The rods have been fitted onto the engine and they line up nicely on the HP side and as per drawing the LP side will need to be bent to line up with the link so allowed this in the length before putting the pin hole in. I will carry out the bending once the block and motion bracket have be finally positioned and fixed down.

Picture of eccentrics rods with links

The lifting link arms are quite a visual feature on a Mclaren being turned from round bar with a nice taper and spherical balls on both ends and it is important that all three are exactly the same length so as not to affect valve timing. It seemed like and ideal test piece for the new CNC XYZ lathe at work! After a test piece was done I ended up with three identical arms on a nice stub ready to hold in the dividing head to put the flats on holes in. Once completed the only remaining job was to put in the clamp screw holes and broach in the keyways.

Picture of machining lifting arms

The lifting links on a Mac are just flat rectangular bar section so easy to make and then with spacers on spindles with nuts on each end. Colin had machined his lifting links from solid with the spacers with the view that this would give a larger bearing surface and be less affected by wear but it was not until Richard Morris sent me some pictures of his stepped spindles that I figured out how it goes together! The spindle is a larger diameter where it passes through the link so the spacers and lifting links are effectively clamped up against the shoulder on the shaft so they are solid with the shaft. In this instance the oversize holes in the link allowed me to follow full size practice and I just need to add in the split pin holes in the nuts before I harden the shafts!

Picture of lifting link assembly

The motion bracket had already been machined but it is amazing just how much finishing off work there still is. The weyshaft is located sideways by two annular grooves and clamp bolts so these were drilled and tapped along with the two boiler stud mounting holes and the four bolt holes that locate it onto the end of the trunk guides. The weyshaft spindle itself was turned up and the annular grooves and keyways added in., slots broached in the lifting arms, valve spindle guides and bushes made and fitted and the whole lot assembled ready to go back on the engine.

Picture of assembled motion bracket

I have now set myself a target to get her running on air and have generated a to do list of 48 items which I am slowly crossing off as I make progress! Some of the jobs are not really related to running but the need to fit the flywheel etc is driving the need to get the rear axle and wheels on as the weight is so heavy now the castors are becoming ineffective and it is almost impossible to move around! A couple of smaller jobs to help this has been the machining of the rear axle spacer and steam manifold. I have also added in two holes to the face of the flywheel to simulate those cast into the original for faceplate mounting as they will both look correct and make suitable lifting points when fitting the flywheel on.

Picture of axle spacer and steam manifold

"And yes the connecting rods are now underway as well so watch this space!"

Aye, likely story Maaaatttteeee?



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