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One more question on my 1937

RonRock

Active Member
Active Member
#1
More questions on my 1937 assembly.

How do I install the Shifter Rack so that it positions the Back Gear in the correct position?

There is a dimple on the outer end of the shaft that I am sure has something to do with install (like a timing mark) but I don't know where to place it. Should I be setting the Shifter Rack so that when pulled out in Back Gear position the gear goes to it's highest position?

I read the post on adjusting the shaft for back gear, But there is no mention of initial setting, I'd like to get it set correct if possible.



Should there be end play on the gear when the Eccentric shaft is locked into place with the set screws?


I also posted on the Yahoo group, but I am sure some here have gone through this so thought I'd ask here also. I'm at a standstill until I figure this out. Don't want to set the headstock to the lathebed until I am sure the eccentric bushings are set properly. Can't get to the set screws after that.
 

CluelessNewB

Active Resistor
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#3
The only dimple I remember on the outer end of the shaft was the mark left by the set screw in the collar that keeps the rack shaft from pulling all the way out.

If you have the spindle installed in the headstock you can just follow the directions, the headstock doesn't need to be mounted on the bed to do this.
 

RonRock

Active Member
Active Member
#4
Thanks,

Yes I read the explanation given by Scott first thing. But as mentioned the directions to adjust the shaft don't discuss the initial install of the shaft and rack.

I don't have the spindle installed yet.

Here is a couple photos of the end of the shaft as seen from the outer end of the headstock.

20170320_164842.jpg 20170320_165152.jpg

After more thought I have concluded that the "dimple" was likely from when the shaft was turned. It relates to the eccentric when the gear is at it's lowest point. I'd guess that they used it when the lathe was assembled, as a reference.

The black mark on the bushing in the first photo is a marker spot that I did trying to determine how to properly set up the rack.

I've gone ahead and started mounting the headstock. I figure I can use the instructions given to adjust as necessary after the spindle is installed. I wanted to start with some confidence that the shaft was in the general ballpark before I installed the spindle and all that will be in the way with it.


I left .002" of endplay on the gear when setting the bushings. Leaves a little room for the gear to move up and down when going in and out of backgear.
 

CluelessNewB

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#5
"I don't have the spindle installed yet."

Well that's easy, don't install the rack until you have the spindle installed. :)

I think you may be thinking this is more difficult than it really is. It might be slightly easier with the headstock not attached to the bed but with a little ingenuity you should be able to rotate the gears on the eccentric.
 
Last edited:

Chuck K

Active User
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#6
You could save yourself some grief adjusting it if you mill a slot in the end of the shaft where the dimple is. It allows you to rotate the shaft with a screwdriver when you're trying to get your rack started on the correct tooth. As clueless said, it's a lot easier with the headstock on the bench but you can certainly do it when it's on the bed.
 

Nogoingback

Active Member
Active Member
#7
I adjusted my back gears recently on a Model 200 headstock. Chuck's suggestion of slotting the shaft is a good one, but it also can be done by rotating the shaft by prying on the
gear with a screwdriver. I suggest just putting it together and working with it. I had to fiddle around with it for a while, but in the end it went together fine. If you just go for it, you'll
figure it out, (and Scott's instructions do work).
 
Last edited:

eeler1

Dang, buggered that up too!!
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#8
yeah, this shouldn't be that hard. Ive done it a bunch of times and yes, it's annoying, but not complicated either. should be a collar on the rack shaft sticking out the back of the headstock, as mentioned, there is a 'dimple' there for a set screw to hold the collar on. you take the collar off when setting this up. it's just iterating different locations mating the rack to the eccentric back gear until they engage and dis-engage properly, i.e., you find the sweet spot. if they dont align right, try again, until they do.
 

MBfrontier

Active User
Active Member
#9
I used a Dremel Tool with a cutting disk to cut a screwdriver slot in the end of the back gear eccentric shaft similar to Redlinemans Rescue thread. The slot is cut on the gear box end so you can access the screwdriver slot after removing the reverse gear bracket. Works like a charm.
 

RonRock

Active Member
Active Member
#10
Pulled it and cut a slot today. Perfect fix to an annoying issue.

Should have been done in the factory.

Thanks for the help.

Ron