Hello all,

I am trying to figure out how to make an internal 3/8-4 double lead acme thread. I have tried getting help from large company's like Sandvik, Vargus, xactform, etc, but have not had any luck. The part I have to thread is around 3/4" long. Everyone I talk to says this cant be done, but I have the part in my hand that is currently being made. Any help is appreciated. The material is similar to D-2. It is a 29 degree thread.

Made, how? Thread cutting, thread milling or tapping?

I think that size two start would be a serious challenge to thread cut. Figure out the maximum diameter possibly for the shank of the threading tool; I think it would be less than 0.25" which would be awful bouncy at 3/4" long.

Thanks Geof,

I dont have a preferred way. I only have a sample from our customer. I would prefer to tap but nobody will make it. I agree the shank diameter is way to small. If only one pc was needed I could probably cut the thread in several different passes, but the qty's for this job are around 25,000, so I need a solid process. Someone is making it now somehow, but they will surely not tell me :)

Thanks for the help.

By the way, somehow I posted this in the wrong forum. Sorry about that.

http://www.newmantools.com/taps/acmetap.htm


They claim to make dual lead acme taps.

Thanks Ironlung29, I will check it out.