# ACME 7/16-10 left hand thread TAP



## Richard Tymko (Mar 3, 2020)

Does anybody have an ACME 7/16-10 left hand thread tap?  I need to make a new cross feed (slide?) nut for my south bend 9 junior?

suggestions?

Thanks

Richard


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## YYCHM (Mar 3, 2020)

I got my 1/2"-10 ACME LH from these guys.  https://mpitools.com/product-category/acme_taps/  $58 CAD landed. They ship to CA, you have to email them.  I paid via PayPal and shipping was fast.  I got it in less than a week.

They list a 7/16-10 LH for $30 US.


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## Tom Kitta (Mar 3, 2020)

If it is 1 off and the nut is not very wide, can you thread on your lathe? LH thread is just moving from head to tail and you can grind a HSS form tool. 10 thread pitch is not something exotic so should be available from standard gear changes... of course if your lathe is not operational buy a tap.


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## Brent H (Mar 3, 2020)

https://www.ebay.ca/itm/RDG-HSS-ACM...505755?hash=item5210a4101b:g:mqUAAOSwnQhXoJFi


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## Richard Tymko (Mar 4, 2020)

Tom Kitta said:


> If it is 1 off and the nut is not very wide, can you thread on your lathe? LH thread is just moving from head to tail and you can grind a HSS form tool. 10 thread pitch is not something exotic so should be available from standard gear changes... of course if your lathe is not operational buy a tap.


I am pondering that idea, do think I am that skilled... thinking maybe on my CNC?


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## Tom Kitta (Mar 4, 2020)

Well, I did LH inside thread for my Tool Cutter grinder - but it was not an ACME. Here is someone doing ACME





Not sure whatever CNC will be of help - you need a tool to make the cut - once you have the inside cutter of proper shape most of your work is done. It would also be interesting - I think - to program CNC machine with custom made HSS cutter for threading. 

You can buy a tool - https://www.amazon.com/Micro-100-SA...QF8WF6676DY&psc=1&refRID=KDPMFEKEYQF8WF6676DY

but I only found solid carbide ones == expensive. Also pitch of 10 is not available in such a small size as 7/16. 

Come to think of it I have some tiny bits like on the picture from Amazon - I wonder whatever I actually have some ACME thread making tools without even knowing about it.


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## Richard Tymko (Mar 7, 2020)

Tom Kitta said:


> Well, I did LH inside thread for my Tool Cutter grinder - but it was not an ACME. Here is someone doing ACME
> 
> 
> 
> ...


_________

So under further inspection i noticed that the hole for the ACME thread is not concentric with the hole for the bolt to lock it into place, which is odd but maybe it is to compensate for the spacing that the gib takes up?...  Maybe?  I think I will try to make a cutter and follow the video.  Unless of course, someone has a tap that can thread it for me???


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## Richard Tymko (Mar 7, 2020)

YYCHobbyMachinist said:


> I got my 1/2"-10 ACME LH from these guys.  https://mpitools.com/product-category/acme_taps/  $58 CAD landed. They ship to CA, you have to email them.  I paid via PayPal and shipping was fast.  I got it in less than a week.
> 
> They list a 7/16-10 LH for $30 US.


I should have read this more clearly.  I guess I will email them...  Thanks.


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## YYCHM (Mar 7, 2020)

Richard Tymko said:


> I should have read this more clearly.  I guess I will email them...  Thanks.



You did see this one that Brent H posted correct?

https://www.ebay.ca/itm/RDG-HSS-ACM...505755?hash=item5210a4101b:g:mqUAAOSwnQhXoJFi


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## Richard Tymko (Mar 7, 2020)

YYCHobbyMachinist said:


> You did see this one that Brent H posted correct?
> 
> https://www.ebay.ca/itm/RDG-HSS-ACM...505755?hash=item5210a4101b:g:mqUAAOSwnQhXoJFi


Thanks,  No I did not notice that.  Shipping from the uk is more expensive than the US.  I think I will go with the MPI tool.


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