Driving axle box lateral

[Dale Grice]

I am working on a RR Supply Mikado. The drawing calls for a 12" radius of the surface of the driving box that rides laterally on the frame. See attached pdf. I would assume this is for uneven cross elevation of the track. A 12" radius is going to be hard to accomplish. I saw one build where they just but a small taper in place. Any other ideas or thoughts on the subject?

Thanks,

Dale Grice

[Bill Shields]

This does allow for axle tilt without binding

I just put in a small taper...maybe 3-4 degrees and call it a day. The exact taper is based on suspension travel..but generally this dimension works.

And only put flanges on the outside of the boxes.

I did build one where I put in a dowel pin in place of the ears..worked ok but was more work than the ears.

[Fender]

Yeah, not many of us have a 24 inch faceplate on the lathe or a 24 inch rotary table on our mill.

[cbrew]

i personally machine my journals flat, and that locomotive has zero issues on some of the roughest track at Train mountain.

[KarlKobel]

Dale,

I built the Railroad Warehouse version.
Here is how I accomplished this task.

Just make sure to take light cuts an only in the 'conventional' direction.

Karl
www.karlkobel.com for other details on the major portion of the build (I stopped updating it after a while - preferring to spend my time machining - and running).

[Dale Grice]

Yes, with my rotary table, that is how I envisioned it. But that hangs it way out there and was not sure it would work. After all the time I spent on these, did not want to mess up.

Dale

[Bill Shields]

My question is why a 12" radius?

If the distance between flanges is 7.25" (approx)...why does the radius need to be significantly greater than that?

If you assume that one wheel is fixed and is the pivot point then why a greater radius?

[rmac]

For what it's worth, I've done something similar with success. The picture shows the setup before clamping the actual part (the little aluminum block) to the angle. As Karl said, take it easy and no climb cutting.

-- Russell Mac

[FKreider]

Make a paper or cardboard template and then file the radius by eye checking with the template once in a while.

Its amazing what can be done with a little bench work.

[Asteamhead]

A radius isn't necessary to allow the axle to follow uneven track! A lot easier to mill, some slight tapers will do .
When milling the axle boxes, you may mill tapers to flanges on both sides in the same action.
A typical angel left/right of 2 to 3 ° is recommended. I prefer to let remain a small area of about 1/2 "in the center without taper.
Good luck!
Asteamhead

[hoppercar]

I put 3/16ths total lateral in mine...which is way more than the drawings call for, you will need it... The lateral clearance on those mikado drawings are way to tight

[Harold_V]

Yes, with my rotary table, that is how I envisioned it. But that hangs it way out there and was not sure it would work. After all the time I spent on these, did not want to mess up.

Good thinking!
Make sure the extension piece used offers the required rigidity (don't use a thin piece of material), and DO NOT TAKE ANY CLIMB CUTS. The mechanical advantage of the extension is a guarantee that you'll fail if you do either.

H