# Logan 820 rear take up nut



## vincent52100 (Aug 9, 2018)

Does anyone know the dia. and thread pitch for the spindle back up nut (the nut on the back side on the spindle on a Logan 820. I think it’s to set the tension on the spindle bearings.). Or the same info for the spindle itself. S/N is 33206  Any help would be greatly appreciated!
Thanks


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## Norseman C.B. (Aug 9, 2018)

Personally I would grab a mike out of my toolbox or, my calipers and
measure the OD, then get out my trusty thread pitch gauge and find the pitch...
Just sayin'...........That is if you have the part and tools available to do so........


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## vincent52100 (Aug 9, 2018)

Funny you should mention that. I have calipers but there is not an auto store or hardware store etc in this town that carries a thread gage. The older gentleman at Auto Zone said that they got rid of all the “old stuff” that we used to be able to find in any auto store. It was hard to find anyone that knew what a thread gage was. They wanted to sell me a feeler gage. So I ended up ordering one.


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## wa5cab (Aug 9, 2018)

Yeah, a lot of older people here might be surprised at what can't be bought at so-called auto parts stores these days.  The number of people around who can still overhaul/rebuild an engine, gearbox or front and rear axle is much smaller than it was even 20 years back.  I don't recall right now what the tool was (and I still haven't found the one that I once had) but I got the same sort of answer recently from a guy who runs a parts store that mainly deals with garages, not the general public.


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## Campfire (Aug 9, 2018)

Let me go out and dig around around my old headstock. I should have one that I can measure, and post up in a few minutes.


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## Campfire (Aug 9, 2018)

Here we go, (disclaimer) done with Mitutoyo digital guestimate caliper. 

Spindle shaft threads OD = 1.288" and the OD of the threads (depth) = 1.253" 
Thread pitch = 20 TPI
Nut ID = 1.237" with an OD of the spanner surface of 1.684"
And these are the measurements of the nut on the spindle shaft on the RIGHT SIDE of this picture...


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## vincent52100 (Aug 9, 2018)

Thank you! Just what I needed. Really appreciate it.


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## MathewsLG (Dec 16, 2020)

This was perfect. I have a Logan 820 that I am working through, and the current take-up nut is too large to fit through the gear cover. Planning to make a new take up nut so that it will fit under the cover.


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## wa5cab (Dec 16, 2020)

That sounds like a lot of unnecessary work just to avoid removing the cover.  Remove the cover, set the bearing pre-load to factory specs, and reinstall the cover.  Check the preload maybe annually.


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## MathewsLG (Dec 16, 2020)

wa5cab said:


> That sounds like a lot of unnecessary work just to avoid removing the cover.  Remove the cover, set the bearing pre-load to factory specs, and reinstall the cover.  Check the preload maybe annually.


I think this was for me. It is a lot of work, but also good practice on threading and practice in general (which I need). As far as removing and installing the cover, the take up nut that came on my lathe does not leave space for the cover to be on at all. It's a great big ghastly thing that I should replace.


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## wa5cab (Dec 17, 2020)

OK.  Then that is different.  Since you didn't explicitly say that the nut wasn't original, and it wouldn't be unusual for the designer to intend that covers be removed for what would be rarely done, I just assumed that it was.  Despite what some of us seem to think, most of us really aren't smarter than the original designer.   










o


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## Nogoingback (Dec 21, 2020)

wa5cab said:


> That sounds like a lot of unnecessary work just to avoid removing the cover.  Remove the cover, set the bearing pre-load to factory specs, and reinstall the cover.  Check the preload maybe annually.




The Logans don't have a provision for preload adjustment since the preload is built into the chuck-side bearing.  The only
reason I can think of to remove the nut would be to replace it with a spider.


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