# Supermax 1338 crossfeed acme?



## sasanifab (Feb 3, 2021)

I think I found my problem with my dro, i have a lot of back and forth movement in my crossfeed nut , like I can physically pull back the top slide forward and back. I can make the nut , I just can’t figure out what size it is ? It’s 8 tpi , it’s the diameter that’s crossing me up.


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## Jim F (Feb 3, 2021)




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## sasanifab (Feb 3, 2021)

Jim F said:


>


I’ve watched every video from that fine man, like I said , making the nut isn’t the problem, I can even make another cross feed screw , I’m just wondering if this is some non standard size


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## Jim F (Feb 3, 2021)

Metric ?


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## sasanifab (Feb 3, 2021)

Jim F said:


> Metric ?


The diameter is 15.63mm plus or minus and 8 tpi? Have no idea


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## benmychree (Feb 3, 2021)

15.63 is pretty close to 5/8" (.625")


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## sasanifab (Feb 3, 2021)

benmychree said:


> 15.63 is pretty close to 5/8" (.625")


I have a 5/8-8 tap , having trouble getting it to cut threads.  I tried 1/2inch starting hole but the tap just spun. I think it needs to go slight under that


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## jocat54 (Feb 3, 2021)

Your DRO shouldn't care about any backlash--it should be reading the actual movement of the crosslide


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## benmychree (Feb 3, 2021)

sasanifab said:


> I have a 5/8-8 tap , having trouble getting it to cut threads.  I tried 1/2inch starting hole but the tap just spun. I think it needs to go slight under that


Is it a left hand tap?  for a crossfeed screw, it needs to be left hand.


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## Jim F (Feb 3, 2021)

Acme thread,also.


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## sasanifab (Feb 3, 2021)

benmychree said:


> Is it a left hand tap?  for a crossfeed screw, it needs to be left hand.


The crossfeed screw is left hand and you want a left hand nut correct


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## aliva (Feb 4, 2021)

As said above it's more than likely 5/8 left hand. Acme stepped taps are expensive. 
you could buy some 5/8 LH acme rod and make your own tap. I did this while making a new nut for my lathe. I had a piece of acme rod.


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## DAT510 (Feb 4, 2021)

Mcmaster Carr sells Acme lead screws and nuts that you can cut and machine to meet your needs.









						McMaster-Carr
					

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.




					www.mcmaster.com


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## sasanifab (Feb 5, 2021)

DAT510 said:


> Mcmaster Carr sells Acme lead screws and nuts that you can cut and machine to meet your needs.
> 
> 
> 
> ...


 It was 5/8-8 ..... made a new one today , 1 thousands backlash


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## sasanifab (Feb 9, 2021)

Finished .... 0 backlash


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