Wobbly and Eccentric

[R.K. Maroon]

I got diverted into working on the chassis of a friend's Varney Ten-Wheeler this week. I had to dig mine out as a reference:

Varney Ten-Wheeler chassis.png (340.85 KiB) Viewed 4668 times

The model this goes with arrived as a project and has never made it to the front of the queue, but once I had it on the workbench I decided to do a bit of maintenance on it. Four of the drivers were loose. In removing the valve gear to tighten the driver capture nuts I found that one of the eccentric cranks is really wallowed out and is wobbly on the crank pin:

Wobbly Eccentric.jpg (857.73 KiB) Viewed 4668 times

The crank is held in place by a retaining pin that goes in the hole in the side (as can be seen in the photo). The pin was sheared on this one and that jammed the eccentric crank on the crank pin, but by wedging carefully from the back I was able to eventually work it off:

Eccentric Crank.jpg (1.19 MiB) Viewed 4668 times

I have some ideas on how to restore this piece, but I thought I would see what others would do before proceeding. The first idea I had was to drill it and sleeve it. The inner bore is not a bearing surface though, and it would be simpler just to build it back up with a bit of JB weld or similar tough epoxy and then redrill. I could epoxy it in place but I want to be able to remove it again if needed.

Thoughts, opinions, ideas? It is a bit of a mystery how the crank got wallowed out -- it bears no load worth speaking of. The wobble was there before I removed it, so working it off was not the culprit. The other side is a mild interference fit -- somewhere between a slide and a press, which seems right.

Jim

[bob turner]

Most wobble. Consider blue Loctite. It releases with heat. Check the crankpin itself - it is held with a nut similar to the axle nut. You don't want these things slipping. That is how the pin gets sheared.

In fact, maybe the pin is designed to be frangible, just in case . . .

[sarge]

I'll be contrary and say bore it for a bushing.

Loctite and all that sort of thing is too compliant and you can't take it apart without heating nor put it back together without cleaning it all out and regluing it. Bushed and pinned can be taken apart, the bush replaced if ever needed, just do it right rather than cobbing it with glue. Its just nicer...

[Jay Criswell]

Yeah, I'd be inclined to go with a bushing after cleaning up the hole. If it's not right nothing else will be either.

Just my 2 cents,

Jay

[rrjjf]

I am sure I have some extra All Nation Eccentric Cranks. If all else fails I can send you a new one. AS bob said above make sure the crankpin is in tight. When I assemble these drives I use removeable Loctite 242 on the crankpins and axles.

Joe

[R.K. Maroon]

Thanks to all for the input. It would be very convenient if I already has some brass tubing that is the right size (or a little under) to use as a bushing. I will investigate and report back. Special thanks to Joe for offering to send a replacement if I manage to booger this one up beyond service -- that takes the pressure off and allows some experimentation.

And, yes, I will check the crank pins. I have not yet noticed any problems with these but I haven't thought to check. More later.
Jim

[Rufus T. Firefly]

And here I thought this - Wobbly and Eccentric - might some personal commentary regarding my behavior,

[robert.]

Is the second drivers axle bent?

[E7]

And here I thought this - Wobbly and Eccentric - might some personal commentary regarding my behavior,

Rufus,

We will concede eccentirc, but the wobbly depends on how many shots of "Old Stump Blower" bourbon you have consumed!

Rich

[R.K. Maroon]

Is the second drivers axle bent?

That's a good question, Robert. The outer drivers turn true, but the center drivers have some out-of-plane wobble. It's not awful -- no worse than many of my old doorstop steamers. The side with the wobbly eccentric crank is worse than the other, but the wobble in this driver is much less than the wobble in the eccentric crank. My first inclination was to think that the driver itself was out of kilter. But it could be that the axle end is bent. This wasn't my first guess as the axle is steel and the driver is Zamac, aluminum, or some other white metal. Also, I noticed on inspection that the axle seems a little loose in its brass bushing. It's hard to say for sure without a complete tear-down, in part because the axle bushing floats a bit vertically in the chassis -- which I surmise is a feature allowing equalization? I don't for sure about any of this -- As common as the Varney/GMC/All Nation steamers are, I don't have much experience with them.

Jim

[R.K. Maroon]

I am going to create a bushing for the eccentric crank. I have some thick-wall 5/32" aluminum tube stock in hand. The bore is about .120", which is near perfect, as it needs to be 0.125". If I drill it with a 1/8" drill though then the hole is too big. I don't have a ream, so I am going to see if I can bore it using a small lathe (the club-owned Unimat, as it were). This required grinding a very small boring bar. I have some near-scrap pieces of tool stock and a 3" bench grinder, and after about 30 minutes I had the boring bar. The cutting edge is to the front in this first photo:

Boring Bar 01.PNG (377.99 KiB) Viewed 4514 times

Boring Bar 02.PNG (497.72 KiB) Viewed 4514 times

Boring Bar 03.PNG (514.17 KiB) Viewed 4514 times

The tool cuts very nicely, leaving a smooth finish in a quick test cut. I will take a stab at turning the bushing tonight.

Jim

[bob turner]

You are indeed ambitious. If the wobble bothered me I would have inserted shim stock while the Loctite was curing.