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uute
10-22-2005, 12:39 AM
Working on a roughing tap for 1/2" - 10 tpi ACME thread. I cut a 10-tpi Vee thread, then cut out the root w/ ACME form tool (ground for 8-tpi).

Sound reasonable?

Better way?

uute

ERBenoit
10-24-2005, 11:50 AM
If you start with a 60* thread, full depth may not allow the acme thread to properly form. You will have to stop roughing with the V before nearing the width of the flat at the crest. May not remove much metal at all.

Dont' know if it is a "better" way, but you can buy a tap that will rough and finish with the same tap in one pass. They known as Acme Tandem Taps. Drawback: pricey if only for single use.

Not trying to be a smart a**, if you are looking for 10 TPI, why then cut out the root w/ ACME form tool ground for 8-TPI?

[This message has been edited by ERBenoit (edited 10-24-2005).]

uute
10-24-2005, 11:47 PM
Thanks for the reply ER!

This was meant to be like the front half of a tandem tap, the roughing portion. So I cut the root w/ an 8 TPI tool so tap would not remove too much material from root (internal crest?) of hole - leaving some for the finish tap to clean up. Same reason the crest was cut to 60*. I'll try some pics later if I can.

uute

http://photobucket.com/albums/v300/uute/?action=view&current=ACMETap.jpg

and

http://photobucket.com/albums/v300/uute/?action=view&current=ACMETap-2.jpg


[This message has been edited by uute (edited 10-25-2005).]

[This message has been edited by uute (edited 10-25-2005).]

[This message has been edited by uute (edited 10-25-2005).]

[This message has been edited by uute (edited 10-25-2005).]

uute
11-05-2005, 10:07 PM
Finised them up.

Look OK, we'll see when I try to use them if the thread forms are too tight!?!

http://photobucket.com/albums/v300/uute/?action=view&current=ACMETap-3.jpg