Author Topic: Single pointing a small ACME nut  (Read 3477 times)

Offline steamer

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Single pointing a small ACME nut
« on: December 27, 2012, 02:24:37 PM »
In another thread, I described how I cut a ACME nut...and there was interest in pictures of this....so here ya go

I needed a new nut for ...wait for it....a Lathe Rebuild! :lolb:....and not the Southbend....A Waltham Toolmakers lathe.

She's a rare bird.....I've only seen 1 other in the wild...in about 17 years of looking....

She came without the cross slide...which as you can imagine...is unobtainium.

However I did get hold of a BC Ames lathe of similar size and construction and was able to repurpose the cross slide for the Waltham as the AMES is clapped out beyond all recognition!

It desperatly needed a new cross slide nut.   The screw is .354-10 LH ACME....and no there isn't a tap for it...

Here's some photo's of new /old and process





Here's the worn out nut...the theads were wearing right through the side of the nut...and the nut had twisted in it's mount


Here's teh single point tool I made with boring bar.  The tool is .0625 diameter HSS and is clamped in the .25" dia boring bar with a #4-40 screw


The tool is much narrower than the thread.   There was no way to single point to full width as the boring bar was not up to that task...so the plan was to cut the thread too narrow, but to depth.   Then using the compound which was preset to be parallel to the axis of the work...widen the thread until it fit the screw.

Here's the leadscrew being used as a gage.



and the nut blank on the screw next to the old one


IT TOOK A LOT OF PASSES to cut that thread...and if a tap had been available...I'd a used it....but no such luck.

About this time, I got the SB...so I still need to finish the cross slide....but most of the scraping is done



That was painfull    there were hard spots in the casting that gave me fits!

Dave


« Last Edit: May 26, 2015, 12:11:23 AM by steamer »
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Offline Don1966

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Re: Single pointing a small ACME nut
« Reply #1 on: December 27, 2012, 05:17:36 PM »
Awesome Dave, you just got to love buddy. I have such a long way to go to be even thinking about doing something like that

Don

Offline smfr

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Re: Single pointing a small ACME nut
« Reply #2 on: December 27, 2012, 05:55:58 PM »
Great post. I'd like to do this to replace the chewed-up nylon cross-slide nut in my Emco, but I don't have a second lathe or spare leadcrew, so it would be a long process of repeated dismantle/reassemble!

Simon

Offline steamer

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Re: Single pointing a small ACME nut
« Reply #3 on: December 27, 2012, 10:57:00 PM »
Hey Guys

Thanks for  the kind comments guys!
Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline steamer

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Re: Single pointing a small ACME nut
« Reply #4 on: January 17, 2013, 05:20:31 PM »
Simon,

Make up a duplicate short length of the leadscrew thread, make sure it matches perfectly!...then use it as a gage to cut a new nut.

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!