5/8 Inch 8 Tpi Square Tap

[yooper]

5/8 inch 8 tpi square tap or modified tap. any one know where I could find one? I need to make a new cross feed nut for a Hamilton lathe. Any help would be appreciated --- Rick

 

[Ebel440]

Are you sure its a square thread?. That is a standard acme size I believe. You could always single point it on the lathe itself. You need to know exactly what type of thread it is before you can buy a tap. And even acme taps are pretty expensive.

 

[Andre]

You will most likely need a left handed tap as well.

 

[yooper]

Thanks, I have a 5/8 x 8 right hand acme tap, but its not acme. I also thought about it being left hand but it is a right hand thread. The 5/8 x 8 acme wont work. I used an acme thread gage and its not a true acme. Then I checked with an older machinist who was in the business since being in the navy in WWII and he said it was probably a modified thread, just by looking at it. Thanks for the help , I will keep looking

 

[4GSR]

If you have a follower rest for your lathe make you a new cross feed screw with an Acme thread. Then you could make a nut nut to fit the new thread.

Most Acme threaded taps out there for sale as new will not cut a thread with a close fit as needed for a cross feed screw. That's why most of us out here single point threads so we get that close fit needed.

I highly doubt you will find a new square threaded tap, even one with a modified thread. I have some OLD square thread taps, but nothing to fit what you need.

 

[yooper]

Making a new cross feed screw was going to be my next choice. I think I will try that seeing that I already have the acme tap.

Thanks for all the replies

Rick

 

[Ulma Doctor]

if you were so inclined, you could turn your own tap from medium carbon or tool steel and harden it pretty easily.

i recently made a set of wood taps (in 60* v thread) from mild steel 12L14 hex
you could do the same in med carbon (1040,4130) or (01 or W1) tool steels