Thread rolling on a B&S 2G?

[klpauba]

How feasible is it to roll 3/8-16 threads (3/8" long) on 5/8" 12L14 hex stock using a B&S 2G machine? I plan on forming the "working face" and chamfers as close to the spindle as possible to minimize deflection due to the force involved.

Will the load on the front cross slide be too great to make decent threads?

All responses are welcome, especially from those who have attempted something similar.

Thanks!

 

[Limy Sami]

New one on me - using a thread roller box on the turret yes, ..but not a single roll off the cross slide, and most definitely not 16tpi in any steel.

But I stand willing to be corrected

 

[FredC]

Sounds like a lot of pressure to me, also. To get good quality on rolled threads you need to control the blank diameter pretty close. That is probably done easy enough on a B&S. Before spending a lot of money on a turret mounted rolling head, look to have the threads rolled by some one like Rolled Threads Unlimited. Make the blanks and send them out to be rolled.
There are straddle rolls that can be applied from the side, but I think they are almost as pricey as the turret mounted ones. I think they are a little finickey also, plan on a learning curve.

 

[klpauba]

Thanks for the replies, folks!

I kind of expected the conclusions you provided. I'm trying to avoid the roller box (axial) because it'll require another chucking of the part -- I would prefer to thread on the spindle end. The cost of the pinch roller (CJ Winter pneumatic type) is $4500+ and I don't see any on ebay!

I'll get some quotes on having a shop do the rolling for me.

 

[Milland]

Thanks for the replies, folks!

I kind of expected the conclusions you provided. I'm trying to avoid the roller box (axial) because it'll require another chucking of the part -- I would prefer to thread on the spindle end. The cost of the pinch roller (CJ Winter pneumatic type) is $4500+ and I don't see any on ebay!

I'll get some quotes on having a shop do the rolling for me.

If there's any "body" to the rest of the part you're making, and it's not thousands, just drill/tap/Loctite in a stud or setscrew. Vastly stronger than rolled 12L14, no questions on precision, and replaceable if the stud breaks anyway.

 

[klpauba]

Milland, that's a good idea but it probably won't work on the part in question. I had planed on additional drilling operations that would be concentric with the formed threads. There is also the hope that I'll be making thousands of the part.

Camscan, it's good to hear that you've done this operation. In my case, I don't think the threads need to be high quality. I'm figuring a Class 1A fit is acceptable. Might you have any good design references (or links) to roll threads on a screw machine (I had located a document on the internet a year or so ago but haven't found it again).

Thanks!

 

[Limy Sami]

Would it be possible to screw cut that on a B&S 2G Camscan?

 

[DDoug]

Would it be possible to screw cut that on a B&S 2G Camscan?

Yes, I am a bit cornfused here.

The OP wants to thread roll from the crosslide much like
"bump knurling" ?

With a single roller or 2 rollers ?

How does the roller(s) move lengthwise when they engage the
workpiece ?

Why not a die or roller head from the end turret instead ?

 

[klpauba]

The part is a short length of hex (about 3") that has a v-size hole drilled about 2/3 of it's length and a smaller diameter hole the last 1/3 of the length. The end with the smaller hole is formed to roll the 3/8-16 thread. If I were to thread with an acorn, button or roller box on the turret end, it would require a separate operation (manually loaded into the chuck). If I'm able to use a single thread roll on the front or back cross slide, all of it could be done in one chucking

The roll will be a few threads wider than the length of thread required (3/8") and it doesn't need to move along the workpiece.

I often forget all the stuff that I leave out ... hopefully this will make it a little clearer. Thanks for all the responses.

 

[FredC]

Sure it can be done but a lot will depend on the quality of the thread you are looking for. You must have an undercut either side of the thread before rolling.The thread chamfers need to be 30 degrees along the bar.

When you put it that way with chamfers on either side of the thread bed the pressure will certainly be reduced. Simple bump threading certainly looks attractive especially in light of post 11 where this is going to be done behind a shoulder.

 

[klpauba]

Sorry this follow-up post is long delayed.

I ended up getting a Reed B13 thread rolling head and have had great success using it.

Thanks all who replied!