Roll form tapping questions

[stebanski]

Does anyone know how large of a thread can be roll form tapped and how well does it work in cold rolled steel and stainless and brass for that matter?

I have used roll form taps in the past but only in aluminum and sizes less than 1/4".

I also wonder about using them in a comp/ret tap driver in my VF-2.

I'll bet at least one of you guys has experimented with all of the available options.
I'm trying to first elminate digging chips out of blind holes, and second, cut down on tap breakage. Seems like I heard somewhere that roll form taps take less torque and provide a better thread.

Any experiece in this area would certainly be of help.


Thanks
steve

[dertsap]

they can be used on steels ,
never tryed brass , but i can t see why not

[gsrmmeza]

at work we tapped 1 inch x 12 tpi in steel.
we had to make a sleeve for the tap an put
it into a 1 inch cat 40 holder. there is a hole
in the sleeve for the set screw and a flat on
the tap. we have tapped thru 2.5 inches thick
without problem. the only special thing we do
is mix grease with tapping fluid an coat both the
tap and the hole. since we have to make the
threads to a class 2b tolerance we just have
to keep an eye on the compression/minor diameter.
we have a vf2 with a geared head.

[drewmeister]

i have never used roll taps, but I have thread milled before with very good results. You can go as big as you want and are very easy to program.

[taylors]

95% of the metal I machine is 304L stainless. And roll form tapping is all I will do. It is virtually maintenance free when set up right. Here is a link for a Balax tap catalogue. It has some very usefull info in it.

http://www.balax.com/catalog.pdf

[stebanski]

Thanks you guys. And Taylors, I've saved the link for future use, looks like it should answer all my questions.

[Rekd]

I've done brass, it works good. I made a small (and free) program to calculate tap drill sizes, and it includes form taps.

Be careful, some customers don't allow form taps on certain parts.

[eljam2000]

We are roll form tapping a 1 1/6-10 into steel and going completly thru the part which is 6" long , im currently searching for the best speed for that application, and we are doing this on a lathe.

Any advice would be taken.

Thanks,
James

[KenFoulks]

How big is the material?
How much does it weigh?
How well are you holding it?
What type of steel?
Who manufactures the tap?
What coating does the tap have?
What coolant are you using?
How much coolant are you using?
Are you currently experiencing problems?
What size lathe do you have?

[eljam2000]

Originally Posted by KenFoulks How big is the material? How much does it weigh? How well are you holding it? What type of steel? Who manufactures the tap? What coating does the tap have? What coolant are you using? How much coolant are you using? Are you currently experiencing problems? What size lathe do you have?

The Material is only 1 5/8 dia. and we are holding it in a collet chuck with serrated jaws and material is 4140 steel. Tap is an OSG tap with a coating but not sure which it is, and we are using Consultant Lubricants Full Synthetic at a 8 on the refracometer. This is currently working just fine and we are using a Doosan 2500, only lathe we had with enough umph and holding force.

[KenFoulks]

OSG only carries taps up to 3/4". They do make custom taps, here are their recommendations, based on coating:

Premium 25-30 SFM
Standard 20 SFM

The Doosan 2500 only has 20hp, the same as a Haas ST-20.