Need advice on keyway for train wheel

On the real ones, there is no key or splines. 36" wheel, roughly 9" bore with 8 to 10 grand fit. They push on with 150 to 200 tons. We do them from time to time. Some wheels are 40" and 42" on the newer ones.

Jason

+1 what Jason said. Probably the easiest and most effective way is to turn new axles with a slightly larger diameter and press the existing wheels on with an interference fit. Or You can put the new axles in the freezer to shrink them half a thou and heat up the wheels to red hot on the BBQ and slip them right on, if you get the axle tolerances within a thou or two.

I've just done something similar with old, double flanged turntable wheels - the old 1" roller bearings were rusted into a solid mass, so turned 2 1/2" shafting down to fit the wheel ID. Then pressed the axle blanks into the core of the wheel, and am now furthe turning down the axle ends to fit 1" OD flange bearings. Here's a photo or two.

No reason you couldn't make new wheel sets the same way...



Glenn

Just my 2 cents, if all else fails, another option is using a shear-pin. Bore the axle and wheel hub and install a bolt or roll pin. Crude but effective and easily made and serviced.

Old school way is with a file. If you are only talking about 2 wheels, and your mill is capable of cutting the axles, I would guess that less than an hour of careful filing would complete the other part of the keyways on the wheels.

I've cut many keyseats using a lathe and boring bar. Grind a HHS cutter to size, slot using the crossfeed for depth of cut and carriage handwheel to drive the cutter.

You could press it on with a shrink fit and then use a scotch, (dutch) key to lock it

Cheers Phil

There are several approaches available. To me, without actually seeing the project, I would press the wheel back on and drill a small hole in the joint between the end of the axle and the hub of the wheel. Starting at 1/8 inch and working up to maybe 5/16'. The 5/16" could be offset in the future with a square key but a round key will stand up to a lot of force. When you figure out how to make a good cut on your mill, and a broach for the wkeel you can make a square key if you needed it. Maybe a light knurling on the axle to give a "force fit" if it was loose. Didn't sound like it was, but loose on one job is tight on another. Depends on the service...

A round key was often used by railroad people a hundred or more years past. It wasn't right, but it worked well enough to get the job done. If it were me, I would use a roller from an old bearing as a pin and leave a little sticking out to get to later if I needed it off. There are several ways to do this key-ing, this seems to be the simplest and quickest so you could get back to the right-of-way debate.

By the way, I have some 7-1/2" stuff that I'm working on now and again. The small scale stuff (H-O) now, that's where most of the work is these days as I age.

Lots of alternative ideas floating around here, perhaps you will find the optimum one to use. Good luck with the old equipment, that stuff is a bear. An additional thought that night pay off someday is the way I make wheels. Too small for your stuff, but ya never know. Take a disk brake rotor and cut off the disk, leaving just enough for a flange. The hub would have to be large enough to make a wheel, of course. May save your butt one day. Bill Hudson NMRA 2125(Life)

Otherwise known as a scotch key Bill

12bolts said:

Otherwise known as a scotch key Bill

Click to expand...

Bill, I've used Scotch keys for years to hold wheels in place. I did not know the method had a name til I read your post.
First time I used it was to hold locomotive wheels in place. Loctite was supposed to do the job but one wheel continually slipped. I was going to try to cut a keyway in the hub and axle. I set the parts up in the mill and first bored a 1/8" diameter hole 1"deep thru the hub and axle . It occured to me that a roll pin or any rod would work well to keep the wheel from turning. I then reamed the hole to .126 and pressed the rollpin in. Did not need Loctite as the rollpin went in tight. I then repeated this with the rest of the wheels.
mike

Thanks. The Scotch or Dutch Key sounds good. The filing might take a lot of work since there's 3.5" to file (unless just a partial keyway is made. Lathe and boring bar would work except the diameter of the wheel is several inches larger than the 9" swing of my SB9A lathe. Broach and press sounds good. I'll have to think about all the options.

That turntable wheel looks pretty cool btw