UNJF EXT THREADMILL

[So not a Guru]

We have a job that is going to require us to threadmill an external 1/2-20 UNJF 3B thread on a rod 2-1/4" long. Does anyone know of a good source to get the specialty threadmill from? An inserted cutter, with a shorter LOC would be fine, as long as the shaft will allow us to reach the full 2-1/4" thread depth. It has to have the UNJ root geometry ground due to being an external thread.

[crazy^millman]

Advent Threadmills. Want to get a skip tooth insert and one that is an integrated CAT 40/50 shank style for rigidity.  that is 8X stick out sorry sir, but you will be dancing the chatter dance to mill those thread I wish you all the best and not sure who you made upset with you to even agree to do such insanity and will pray they quit giving you the impossible to do.

[MIL-TFP-41]

In the past for a one off part I used a top notch boring bar for a lathe in a toolholder. It was slow, but got the job done. Over that length...its going to be a PITA

[jaydenn]

You may want to consider thread rolling.

It may be a custom tool for the length you need, but you'll get a perfect thread everytime and you can make rolls in any thread configuration you like.

J

 

[So not a Guru]

I suggested we outsource this one. We don't have any turning centers here, just a cheap Jet manual lathe for in house aids. 

5 hours ago, C^Millman said:

Advent Threadmills

I was not aware that they made any UNJ profiles. I'll check with them, if we're forced to do the job.

5 hours ago, C^Millman said:

not sure who you made upset with you to even agree to do such insanity

We are required to quote everything that comes in, but we are allowed to suggest outsourcing as well as putting in the true hours we believe it will take to get it done in house. Sometimes you have to lose on a single job to keep the profitable ones coming in.

[mkd]

Iv'e used an opening die-head on a manual turret lathe back in the day.

similar what jayden posted up, but not quite as amazing

3 internal HSS insert prolly won't be cheap, but they work pretty slick. Stopping in-feed make them snap open.

[robk]

Xactform should have what you are looking for as a standard item.

http://catalogue.xactform.com/usa

[So not a Guru]

2 hours ago, robk said:

Xactform should have what you are looking for as a standard item

Thanks!

[CEMENTHEAD]

On 1/17/2018 at 3:21 PM, So not a Guru said:

Advent Threadmills

Use caution, they (Advent) make special inserts for external threads, Don't use internal thread inserts on external threads.