Tender Trucks

Making the wheels and axles

This is the first construction on the Pennsy A3 switcher. Kozo suggests the wheels on the tender are a good place to start. So I sat down one Saturday and ordered all the material. I like the pay as you go plan!

Here is the pile of material to build the trucks. The only thing missing (I think) is the wire to make the springs. Kozo uses a lot of brass and I am staying true to his design. There have been builders who have successfully used all stainless steel.

Hard to believe (for non machinists) that this chunk of 12L14 steel contains more than eight tender wheels! The cost per wheel will only be about $0.75 each. But wait, I am just getting started.

Here starts the first group of "action" shots. A chance to put the bandsaw into a real workout. Let me say I would have never got the first slice cut if I didn't have the saw. The slices will all be 1/2 inch. The band saw never struggled with this assignment!

Here is a little trick to keep the vise from binding. Throw one of the disks in behind and it will keep the jaw straight. A good trick to use on the mill vise too.

There's all the blank disks. A couple of inches of stock left over for something else.

This first facing will make this side parallel to the back.

This is the end cut from the suppliers saw. It is the worst of the bunch. About half of the face has been missed by this first facing cut.

The lathe is running in this picture. I am making a small dimple dead center with a small center drill so I have a place to center the dividers.

There may be "newbies" who think you can do this with the lathe running. Not on my life! I am turning the chuck by hand with the lathe safely off.

Lathe running and I cut between the lines. When I get to the proper depth, I stop the lathe and check with the dividers to see how much I might have to trim to get to the line. This is not a critical dimension, but I want them all to look the same.

Half done with part of it, ready for a clean-up. This was actually the very last wheel of the group.

Some people think I never get my machines dirty. This is evidence that I do! I bought them to do work, but that doesn't mean I have to keep them dirty. Ha!

Here is the end of the first chucking. All nice and sparkley!

That's it for one day. Boy! What A fun time!. I have to admit I am really hyped about this project. When I hold one of these steel disks in my hand I am just in awe that this is going to be a tender wheel. The size of this engine just has my juices flowing. I know it is not big by some folks standards, but it is every bit as good as I imagined. I love making parts of this size!

I am measuring the thickness after the first chucking. This was one of the fattest in the group. It needs over 0.050" faced off.

I cleaned the face of the jaws of chips and made sure the first wheel face was firmly against the jaws. A light tap with a small plastic mallet would be good here as suggested by Kozo. Before I started, I also confirmed the jaw faces are all equal in height by bringing the tool point up to the jaws and rotating the chuck by hand.

This is the set-up before facing. I like indexable carbide tools and use one here for facing. Note that if I back the cross slide out too far, the tool will hit the jaw. Machining requires a wide awake mind and careful planning of all moves

This is the second facing pass on the way down to the proper thickness. The lathe is running and some of that gray stuff is smoke. I must be a tiny bit of a masochist (a misspelling of machinist?) as I actually like the feel of the tiny burns from the hot chips hitting my bare arms. Maybe that's why I like welding too?

Facing is done and I applied blueing so I could scribe circles like in the first chucking.

Here is a closer look at the special round nose tool bit I made (per Kozo) for turning the wheel plates. The tool cuts in both directions. No rake but it works great!

Next is the center drilling (without un-chucking) and through hole drilling. This keeps at least this side concentric.

Final is a ream at the lowest lathe speed. Finished axle hole id 5/16". The US measurement system sure keeps me jumping back and forth between fractions and decimal inch conversions.

End of second chucking. This is a full days work for me. I goof off some, and rest my legs, but this is fairly constant effort. Sure looks good at stage two. Even this simple work creates a lot of pride. What a hobby!

I made a mandrel for all the rest of the turning required on the wheels. The stub on the mandrel is the axle size, 5/16 inch. I threaded the end 5/16x24 then had a heck of a time finding a brass nut that size. There are a couple of old time type hardware stores near me and the first one I went to had the nuts. Not so, for the big name stores.

Here is a movie I made as I was turning down the wheel to overall diameter. Each cut was 0.010 (0.020 total) at a fairly high speed. I was using a carbide indexable tool and carbide likes high cutting speed. This was not all the passes needed but enough so non-machinist can see and hear the action. Note how the O.D. trues up on the second pass. The first pass was just a skim. Click HERE to download. (size about 8 Meg)

I have switched to my home made HSS tool and am about to turn down the tread to raise the flange.

This is the set-up to turn the 3 degree taper on the wheel tread. Look close and you can see that I have a bit more to go before getting to the flange. Kozo suggest cutting left to right and that is a good idea. This prevents going too deep and loosing the tread diameter.

I am now set-up for the 10 degree taper (or 80 degree depending on your view) of the wheel flange. This is done on both sides of the flange. There is an amazing amount of set-up for all the various cuts with every cut done eight times. The corner chamfers were another three set-ups. What a great time!

All the machining is done! These eight wheels have been polished, so the next step is to de-grease and then paint the wheel plates. Then a final polish on the outside rim. Total working time about three days.

This is 3/8 inch TGP steel rod. They have all been cut to slightly over 4 3/4 inches to make the axles. I then faced them to exact length on the lathe.

Here I am setting the length for the end first turning. The cutter is in focus in this picture but the dial is a bit soft. I loose resolution when I size the pictures down for web publication. You can see I am using the point of the cutting tool for setting the measurement.

Now you see why I made the carriage stop. I want to use the carriage feed for cutting to be absolutely certain the turning will not be tapered. The compound angle is set at zero (0), but I can't be certain without trial cuts. I only have to set the stop once as I then use the compound feed in all future cuts to set the length with the carriage against this stop. Each time I re-chuck an axle, the length is reset with the compound feed. That way I don't constantly reset the carriage stop. I just have to be sure not to move the compound feed when making the cuts.

Ah! The measuring tool I most love to use. There are wonderful mental gymnastics when turning down a shaft to a precise measurement on a lathe and measuring with a micrometer. I cheat occasionally and write it down, but I will never tell anyone that... ooops!

I have just removed the micrometer from the shaft and am reading the results. The little knob on the far right is a clutch so you do not overtighten the micrometer against the work. This is a very accurate (0.0001) measuring tool. Not a C-clamp.

Most manual micrometers are scaled on 0.025 increments. That is where the head math starts. I am not going into a lesson on micrometer reading here. The reading in this picture is 0.3116. The lever where is says "MADE IN CHINA" is a setting lock so you don't loose this type of accuracy when move the micrometer away from the part. Yeah, that's my cheat sheet. Once you get the "hang" of this thing, it is great fun to use and compare actual cuts against your lathe dials.

This is the end of one axle before cutting the relief groove at the shoulder line on the left. Collet accuracy is so nice for this kind of work.

These are the finished axes with the wheels stacked in the rear. If you look close, you can see the relief grooves I mentioned above. The end of each axle is also center drilled, although in my case they were never between centers. This is done in case they need to be turned that way at a later date. (Not during original construction.)

Man! What a beautiful sight. I don't know how and old grown man like me can get so emotional about the metal parts he has made. Well, yes I can. It's the reason so many of us enjoy this hobby. If you're still lurking, buy some tools and get started!

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