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Lathe repair part needed [ Bradford MetalMaster]

taildrager

Aluminum
Joined
Nov 5, 2012
Location
Ft Valley Ga.
I am in need of some advice on where i could find this part or have it made .
It is part of the rapid thread chase and is missing about 3/8 inch of thread on the end plus the out side is warn down about 40 thousands
The acme thread is a double start thread and even if my lathe was not down i do not have any experience with internal threads not to mention double start acme .

Thanks in advance for any help with this
Donny
 

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It does not need to be precision since its sole purpose is to get out of the cut quickly. Is your assembly not working, or what?
 

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This out-fit makes generic nuts that you can machine to fit. Green Bay Manufacturing They also make acme screws that you machine to fit too. Or look around your area for a small job shop and have them make you one or there are plenty people on here who could do it for you I am sure.

John Your knowledge and collection of manuals is such a valuable tool this forum has.

Rich
 
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The lathe did not have the taper att. on the machine when i got it . The bar was broke right over the rapid chase i have welded it and am installing it back on the lathe .
There was a few days of head scratching figuring out how it worked . I was unaware that the acme threaded shaft was keyed . Mine was jammed all the way in with a nearly sheared key so there has been some trauma .
There were signs of there being more threads on the end . As it is now there is not enough threads to hold the nut on . The ware on the out side is enough that you can not lock it down if you want to use it as a thread chaser
 
Tell us more about it taildrager?

OD of two start Acme?
Apparent pitch (which will be half of lead)?
Minor diameter inside the bronze?
Length of threaded portion inside bronze?
What's available for sending off for "go-bys" to prospective helper-outers?
 
Thanks for your interest John . Here are some more photos maybe you can make some sense out of them .
The way it clamps requires some closer tolerances than what i have now . Its kind of a weird design it does not have any springeeness to it .
It looks like when you are though using it and back the set screw off it would not be a bad idea to take a screw driver and open it back up .
I am not familiar the term Go-Bys fill me in .

Donny
 

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Here are a couple more pics
 

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A go-by is something to look at while you are making a replacement. Its what you need when there is no drawing.

That is a little bitty part. Single pointing a two start Acme thru that little hole in a lathe is likely not in the cards. I'll bet Bradford had a series of taps to do that job.

I'll guess the screw is 5 TPI pitch 2 1/2 TPI lead and maybe .812 OD. This would make the thru bore about 5/8.
 
I have considered silver soldering a tail on the end then adding the threads on the outside and not worrying about the internal threads on the extension . Also forget about using the thread chaser since with the out side wear it will no longer allow it to clamp on the brass part .


Edit This is not what i prefer but if John is right in his assumption what other options do i have ??
 
Well i made my repair today . I think it turned out ok ! I silver soldered a piece on and built up the out side with silver then turned it down and cut some new threads
 

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