42000+ tracks on pre 42000 JD 2010 sprockets

[robotmaker]

This is pretty much aimed at you Lavoy, but figured it could help someone else out so that's why I am posting. Hope that's ok. Background:
I have a JD 2010 #42193. A previous owner has installed a pre 42000 set of rear sprockets and tracks on this unit. I am completely out of adjustment and need to re-pin and bushing my rails along with putting a new set of bottom rollers on it as you already know. As I have found out, new pins and bushing are going to cost as much as purchasing a new set of rails for a 42000+ unit since the early model pins and bushing are like hens teeth. I have also found out that the pin to pin center distance is different for the two of these. The new rails have a 5 1/4" pin to pin center distance. I machined up two 1 3/4" diameter pieces of round stock (diameter of 42000+ bushing size) and placed them in the very root of my sprockets and measured the distance. It measures 5 1/4". It should allow the new rails work ok, right? Any other cautions I should be looking for here? Stand by for an order for new rails and my old rails to go on sale here shortly.
Thanks again for all your help Lavoy.
rj

[robotmaker]

OOPS... it's 5 3/4" pin to pin center distance on 42000+ rails.

[Tigerhaze]

My understanding is that you can't use the later number rails/pins/bushings with the early sprockets; however I'm sure Lavoy will clarify if that is not the case.

[Lavoy]

The pitch is the same on both rails, the difference is the bushing and pin diameter. Below 42,000 is 1 9/16" bushing, above is 1 3/4" bushing diameter. If your sprockets have at least 3/16" of wear, you will be okay. The problem occurs when there is not that much wear on the sprocket, or as the new rails wear, the pitch gets longer.
You might think that 3/16" is not that much difference, and it isn't, but the effect is cumulative. If the first bushing in right on the money, the next one is off by 3/32, the next by 6/32, and the next by 9/32, so you can see where the problem occurs.
Years and years ago, Deere restored or had someone restore one of their 420 crawlers. Whoever did it, put all new 350 rails on it, but used 420 sprockets. The manager of the Collector's Center at the time was a friend of mine and he called me because the crawler would not drive. It would go just a little, then everything would bind up and it would start snapping as the rails climbed the sprockets. I rebushed a set of original 420 rails and shipped them to Moline. They installed them, and end of problem. If you ever stop by the Collector Center, as far as I know, the crawler is still on display unless it got moved to the world headquarters.
Lavoy

[robotmaker]

It appears then, that I need some way to measure my wear. I have asked Deere for this information (distance from bottom of one tooth to the one directly across) but am not getting anything from them at all. They just want to sell me 350 sprockets. They will not fit at all as the center hole is a different diameter and the bolt circle diameter where it bolts up to the axle is also different. Any leads on where I can get this information to determine if my sprockets are worn enough to get a late model set of rails to work?
Thanks again.
rj

[cat10til2]

if all else fails, maybe you can take your old centers and cut the rim off then have a new rim welded on the outside to make new chains work properly.

[robotmaker]

I have already looked into this. Unfortunately, nobody makes the 42000+ sprocket parts, no where, no how. I have not stumbled across any used sprockets either. I have not looked everywhere, but darn near.

[Tigerhaze]

RJ-

I tried going down the route you are looking into now; the only hope would be to find post 42,000 sprockets or else stay with the early S/N track setup.

I wish there was enough demand on 2010s to have these Korean companies make the post 42,000 sprockets, but it doesn't seem to be there.

[Tigerhaze]

Double post- sorry.

[robotmaker]

If I could just get the mechanical data for an original pre 42000 sprocket, I could machine the thing to fit the 1 3/4" bushings. Deere won't get off the dime about this. Won't even send me enough information to tell how worn mine are. What's up with that? They don't make them anymore so why is it such a big secret? Does anyone know where we can get some drawings of these parts? I am about to start reverse engineering these things, make and sell them.

[robotmaker]

What I am finding is that the cost to have my rails re-pinned and new bushings (1 9/16") will be as much as a new set of rails for the 42000+ 1 3/4" style. I just can't pull the trigger on this when my rails are at the end of their life. Who is the guy with the tag line "There is no such thing as a cheap crawler ?"

[Lavoy]

Okay, nobody get your hopes up too high, but I spent a half hour today talking to a guy that has, or at least had a pattern for making 2010 sprocket rims. This is going back 20 years or more, but he believes he still has it. IF he can locate it, I MIGHT be able to get some 2010 rims done.
He is also of the opinion that he has or had the pattern for complete sprockets. BUT, even with a pattern, it would appear that complete sprockets are a no go unless you get well into the stupid money category, so no sense pursuing it any further.
Might be a while before I know any more, but we'll see what turns up.
Lavoy

[robotmaker]

Lavoy,
I finally convinced my local Deere guy to send me the drawings for both sprockets yesterday. They are part numbers T19007 and T13294. Let me know if you need to pursue anything about this whatsoever.
rj

[Tigerhaze]

Hi Lavoy-

We appreciate you looking into this- I know that it is a hassle but it would help out all of us 2010 owners in the long run if it pans out.