I have got to the stage of machining the wheels and axles on my Speedy and given the fixing a lot of thought.

1. Broach a 1/8″ key way in line with the intended crank pin position in the bore of each wheel.
2. Make the crank pin drilling jig with a key way grove in line with the crank pin drilling hole.
3. Drill and ream the crank pin holes keying the wheel and jig together. Making the crank pins can be done later.
4. Turn the axle ends to give an interference fit of between 0.0000″ and 0.0003″.
5. Machine the key ways in axle ends 90 degrees apart.
6. Use Loctite 638 to glue everything together with the key in place.

This solves the difficulties with quartering. I would be interested in comments.

Bob, I hope I have not hi-jacked your topic. I guess it is too late to use a proper square key but you could use a Dutch key (a screw in a tap hole between the axle and wheel).

JA

Hi Bob,

In response to  some of your points ->

So now I need to re-quarter the wheel/axles.  All stripped down and I have material to make a quartering jig, but I can’t find information of showing the correct angular displacement.  I know that it is 90degrees (or there abouts) so long as all axles are the same, but 90 degrees forward or backward?

Looking on the right-hand wheel and the crank pin at 3 o’clock, (looking through the spokes of the RH wheel and seeing the back of the LH wheel) does the LH wheel crank pin sit at 6 o’clock or 12 o’clock.

From this viewpoint that you outline above, i.e. viewing from the right side of the locomotive, the left-hand wheel crankpin will lie at 12 o’clock while the crankpin of the right wheel lies at 3 o’clock..

If you consider the wheels fixed on the axle and rotating as they would if the locomotive was running forward, the right-hand cranks would be ‘ahead’ of those on the left by 90 degrees.    That is to say 90 degrees in-front of, i.e. preceding, those on the left as the wheels rotated to allow forward travel.

Thus ‘right side leading: the conventional arrangement.

If you got it wrong, would it make a difference ?

No – provided all wheels on each side set at same angle and same relative position in direction of rotation.

The locomotive would run with left side leading and crank-pins set at 89 degrees!  As an ideal you should aim for 90 degrees, any serious variation from this will affect smoothness of drive and exhaust draughting, and give you audible ‘uneven beats’.

Nearly done, but should I pin the wheels afterwards ?

As the wheels have already come loose once that might suggest that your axle/wheel gapping is perhaps a little larger than the ideal (tho’ there can be other reasons for this state of affairs!).  Pinning once securely glued will ensure that the wheels will not move again.  End-milling a small hole along the axle to wheel interface carefully at relatively slow speed to keep local temperatures down and gluing-in an appropriate length of tightly-fitting round steel rod will do the job adequately.  If you prefer you can thread the hole and screw-in a small (self-made?) grub-screw which will be easier to remove and allow one to free the wheel should you ever wish to do-so.

Regards & best of luck,

Phil

This is how the big boys did it
<p style=”text-align: left;”>http://ibls.org/mediawiki/index.php?title=Quartering</p>
Holes for crankpins machined after the wheels were pressed on. I’d forget keyway, just use loctite. If you must, drill and fit a roll pin after you know it’s all OK