Bailey Steam
Engineering Designs

Fowler B6 Road Locomotive Tender

A recent project was to manufacture and build a tender for a Fowler B6 road locomotive. An original full size drawing obtained from the Rural history center at Reading university was provided by the customer. This drawing was re-drawn full size using AutoCad. This allows easy scaling to any size required for the present and the future. Even full size if required. Selected items were copied and scaled to half size for the six inch engine tender. Where possible all holes were added to the tender sides, floor and reinforcing plates. The drawings were e-mailed to our Laser cutting sub-contractor. Several day's later we received a pre-cut set of parts.

Bitmap of the drawing created in Autocad that was used for Laser cutting. Note the fold extensions added!

Fowler designed tender and Belly tanks using various methods. Some Tender's had flat sides with the flange radius on the tender wrapper, others had flanged sides with a plain flat wrapper as commonly used. The early B6 tender's had this type of tender. The bend radii is 1.5 inches. Quite a large radii to fold, forming using the coining method in a brake press was not acceptable due to the fact that the finished radii would have an appearance similar to a twenty pence piece! Special radii forming tools were made to allow the brake press to cold form the radii to the correct dimensions.

Bunker top extension and the spare radius parts used for construction

After forming the flanges the corners needed to be added at the correct radius. For parts that are visible internally and externally you need to provide a good finish both on the inside and outside. Flanging the plates is the obvious method but formers, heat distortion and hammer marks in the finished product render this a difficult choice. To overcome this solid steel billets were turned in the center lathe. A radius gauge was made from the pre-formed tender sides. The radii were machined into the billets using the home made radius gauge as a template.


Laser cut and formed Tender sides with added radii parts!

Tender tank front plate. Only the external radii is visible on this plate!

For instances where Radii or filled sections are used I choose to use a wire frame method to produce the filled in sections. I use 6-mm diameter steel rod. This is easily formed to the correct radii, tack weld both ends. Each part that is added is at a slightly smaller radii. Then you have to weld along the rods both on the inside and the outside until the whole corner is one solid part, the heat generated during the welding leaves a nicely annealed, solid corner radius. Care full use of an angle grinder to dress the welds will prepare this into a nicely formed corner. See below!

During manufacture and after dressing made up radii

Partially assembled B6 Tender

During manufacture it is important to keep checking progress and the fit of each part into the assembly. I find this gives vision to progress and allows thought into what needs to done next. The photo above is where I trial fitted the front of the tank. This part has a large radii in the vertical plane that blends into the 1.5 inch radii of the tender side. Quite tough to get it all lined up correctly! Note the tender reinforcing plates are pre-attached before final assembly of the tank!

Draw bar fitted to the rear of the tender for spacing the wrapper rivets

One of the problems we face during construct is the need for another part of the assembly that is needed to allow progress. In this case the Draw bar assembly is need to allow the rivet spacing to be determined. Seen here on one of the many trial fittings. But the final dimension of the Tender is required before the draw bar can be made. Chicken & Egg situation.

This tender is of fully riveted construction. Riveting a large assembly that weighs around 75 Kg's can be a tough job. Here I am reaching down inside to rivet the front lower edge rivets.

View of the riveted tank construction

Mr Heath and Mr Robinson here again!

Supporting a large assembly and the rivet snap in a position that allows you to move and manipulate it during riveting can be difficult to arrange. This method allows me to lift the tender tank and loose rivet carefully over the rivet snap without pinching my fingers to many times. Also it is possible to damage the metal surface if you are to rough with handling. Care needs to be taken! In this view the right hand side panel is being riveted to the tender wrapper.

Fitting half round Beading to the Bunker

The half round beading is 3/4" x 1/4". I bend this to the correct radii by heating it carefully with a Welding torch, when it is just becoming red hot it will form easily to the radii. Take care with the heat, it is very easy to melt the brass. I fix the brass to an edge at the begriming where the beading starts. Then by clamping and moving around it is possible to get a nicely formed beading. The beading is attached with equally spaced rivets.

Completed Tender

It is difficult to write how to make and assemble, the main things to be careful with are to get everything as square as possible, Side plates and wrapper distances need to be equally spaced. Rivet spacing need to equal and in nice straight lines. Always assemble;e with several bolts. Check square ness then proceed to add more holes as you go. Finally riveting the whole assembly together.

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