# Logan Cross Feed Screw & Nut



## mjhenks (Mar 5, 2014)

Need some ACME tap help. 

As mentioned before I have to replace my cross slide nut.  My screw major diameter (OD) measures @ .441" and the Minor (ID) is .336"  The old nut Minor ID measures @ .341"  

I believe and a quick search seams to confirm that ACME is measured on the Major diameter so I figured I had a Left Hand 1/2-10 screw.  

 Got a 1/2-10 left hand tap today and it is bigger than my screw and will not thread into the old nut.  It Major measures .526" and the minor about .417".

What am I missing?


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## hvontres (Mar 5, 2014)

Well, checking the table on page 1609 in my 24th edition Machinery Handbook shows that a 7/16 Acme has a Major diameter of 0.4375-0.4325. My Cross feed measures 0.490 Major, which is only 0.005 under the minimum 
I'll bring in my nut tomorow to compare.


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## mjhenks (Mar 6, 2014)

Thanks Henry.

Turns out that Left hand 7/16-10 ACME taps are not that common.  Especially two stage ones.  I know the Southbend guys have the same issue.

Anyone have one or know where to get a two stage unit?  www.tracytools.com in the UK has single stage as does a seller on Ebay.


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## stevecmo (Mar 6, 2014)

Have you seen Jim Shroeder's excellent post on using Acetal for nuts?  That's the method I'll be using as I work my way down my "to do" list.

http://www.hobby-machinist.com/showthread.php?t=11166&highlight=acetal+nut


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## mjhenks (Mar 24, 2014)

I ended up finding someone who has the right tap and having them tap some blanks for me to later mill to size.

See post #73 in the below thread for details.

http://www.hobby-machinist.com/showthread.php?t=20631&page=3&p=190586#post190586

Matthew


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