Wheel building can be quite a heavy task. Some
model engineers like to get some help with the wheel assembly.
This information is an example of a customer who had pre-machined
the wheel hubs, prepared the spokes ready for assembly and
infact had done a lot of the work to getting a set of wheels.
The task detailed below is for the wheel rim preparation and
Rolled sections were obtained from a commercial
section rolling company. Rolling flat on edge requires a special
machine and a skilled operator. The sections require welding
and dressing before the inner rings are welded in to the wheel
cylinders. To ensure a strong wheel the tee ring is ground
to a combined angle of 60 degrees on both sides. A small flat
is left on the inside to maintain the radius. I usually clamp
the tee section in the vice and weld the inner and outer edges
first to keep the rolled section in line. The main weld are
best welded last!
Tee ring weld photo
(inner & outer)
After welding the welds are ground back to the
tee surface and inspected for finish. Any irregularities are
filled with weld and ground off to give a clean finish. A
final finish with a file adds a nice blending radii with the
rest of the ring.
The wheel outer rolling is also treated in the
same fashion. Again the aim here is to get a good strong butted
weld that will not be visiable after the wheel is complete.
Wheel Outer Rolling
tack welded only as delivered from Section benders
A tee ring is then placed inside the outer rolling
and set to the correct depth. The rim is positioned by adding
small tack welds both on the inside and the outside until
the tee is supported in the correct position. As you may be
aware welding pulls the parts close together as it cools in
the same fashion as hot riveting. An uneven pull will cause
distortion. If this weld tacking procedure is not done the
tee section may pull during welding and not be perpendicular
to the rim.
Tee ring placed in
rim for welding
The main welding is done in a similar fashion.
Do short welds of about two inches long both inside and outside
the tee rings alternatively. Rotate the rims 180 degrees and
do the next runs opposite the last. This helps to distrubute
the weld pull and heat stress evenly and keep the risk of
distortion low. Some builders try and get a weld radius to
represent the radii in the finished rim. I prefer to use a
smaller radii weld (dressed too if required) then fill the
welds to produce a nice acurate radii.
Filler applied to the
welded tee rings
The filler is best put on with your finger a
small bit at a time. If the rims are still warm the filler
is set quickly and you are able to start sanding. I use a
coarse grade of paper to remove the filler that squidged out
past the finger on application and to make the radii. Adding
a a small amount of filler may be required after to fill any
small irregularities. When the rim is finished to satisfaction
a coat of primer is a must to prevent the posibility of rust.
Front rim, Welded,
Filled and ready for assembly
Cutting out spokes can be a labourious task.
I prefer to use laser cut spokes. Some builders leave the
laser cut finish on the spokes and this is quite good. A better
finish can be obtained if the cut edge is dressed. A belt
sander is the best method of removing the cut finish because
it can be quite hard. Always add a small chamfer to the spoke
edges and indeed any edges that will be painted because it
is hard to get a good thickness of paint on a sharp corner.
I have not detailed the manufacturing of the hubs in this
document but it is worth ensuring the spokes are a good fit
into the hub spoke slots after dressing to make the wheel
strong! Front spokes can be pre-drilled before assembly because
of the single tee ring. Rear spokes have to be drilled on
assembly through a drilling jig because they usually fit on
the inside of the tee.
One corner of the spoke palm end will need a
large radius to allow it to fit into the rim radius. I have
included a section of an original Fowler works drawing as
an example of how it was done!
Add copy of spoke drawing from reading
Wheel building can be done on a wooden board,
I use a 1/2" thick steel plate for my assembly jig. Angle
brackets are bolted to the plate at 90 degree positions. This
angle brackets have adjustable position clamps to allow easy
centring of the hub to the rim. The hub is positioned in the
centre of the jig on a mandrin that is secure from below.
The mandril is perpendicular to the plate surface.
Wheel Assembly plate
with angle and centre adjuster
The hub is fitted on the centre mandril with
a spacer to position the hub to the correct position within
the rim. The rim is placed on to the jig and centred with
a tape measure. The adjusters are lightly tightened to hold
the rim. A pointer is then attached to the hub with an engineers
clamp. This pointer is adjusted to inspect the centring of
the hub to the rim. Carefull adjustment of the centring screws
will allow the hub to be positioned acurately within the hub.
The pointer is then adjusted to check the hub to outer flange
run-out. This can be corrected if required by adding thin
packing below the rim in the required position. The centring
has to be re-checked if packing is added! Finally lock the
adjusters in position.
Piece of bent metal
used to centre the wheel and check for wobble
The palm end of the spoke is bent to allow the
spoke to fit flat against the tee ring in its correct position
and just touch the edge of the hub at the bottom of the slot
that has bee pre-cut.
Bending spokes, note
the try square to set the spoke square before bending
Mark the edge of the hub on the spoke. This
end is then bent to the correct angle. I use a small fly press
(above) to bend the spokes. Get them square to the tool and
you get parrallel bends. Another way of reducing unknown distortion.
Mark the spoke length to cut off the excess off but leave
it longer than required by around 1/16" of an inch. File
the end of the spoke to match it to the slot radius. I believe
method supports the spoke (as well as the fastner) and makes
a really strong wheel.
Spokes fitted into
the hub and drilled
Finally trimming the length until the palm end
is in the correct position. Finall check the bending is correct
by pressing the spoke each end. If the spoke lifts out of
the hub slot or there is a gap below then it is best to correct
this and get a good alignment. The more accurate the spoke
is laid on the rim and in the slot the better. This will allow
an assembly that is not being pulled by uneven stress when
the wheel is rivet or fastened into the hub.
Using the drilling
Secure the hub end of the spoke with counter
sunk screws and pull them down tightly. Clamp the spokes to
the tee ring with as many clamps as possible. Then turn the
wheel over. Drill the palm end through if it is a front wheel
or through a drilling jig for the rear wheels. A drilling
jig is required here because the tee ring has to be drilled
in the correct position to line up with the spoke. This is
also held with a clamp or Mole grips!
Well the front wheels are a little easier to
build on most models. On the Foster both spokes are mounted
on the outer edge of the tee ring. This means the rear spokes
have to bend a lot to get where they need to go. Getting the
length correct can be tedious. I have added a couple of views
if the completed wheels.
Front Wheel in Build and Complete
Complete set of wheels
Well nearly, they need riviting and rubber tyres
fitting. Still the job is nearing completion at last.
Click on the link below for
with Wheel Build or Enquires