Carbide vs steel

L

Larry Wilkins

Guest
Hi all, to those who make little number nines while threading the tube.
Question?? What is the best explaination regarding carbide vs steel cutting points??

After a long time sharpening and forming my theading points at the Gunsmith School at Northern Ca. I thought about not having to re-do the edge and getting some carbide ready cotting tools, but had to leave the class. So please continue my education on thread cutting points if you will Thanks

Cheers

Larry
 
Larry:
A big part of your question revolves around what your time is worth.

There are threading inserts for every thread form known to man, in every coating to match up with every material. Good, laydown, three point inserts run anywhere from $6 to $9 a point. Internal, external, full form, partial, etc., etc. Tech reps at any of the companies that make the inserts can help you get started. You will need to suck up the initial cost of a tool holder of your choice. Make sure you get one with interchangable anvils so you can match up with the helix (leade) angle you are cutting.
I bet it's been 30 years since I last ground a threading point.

HTH,

Alan
 
HSS vs Carbide

With a HSS cutter, you can cut at lower speeds than carbide. Very nice when cutting to a shoulder. Carbide dosen't cut well at slow speeds and tends to tear.
 
If time and consistancy mean anything, get carbide. Without a precision jig and surface grinder a HSS bit will never be right. 200 RPM's and Moly D get me a pretty good finish. To slick and they might gaul if stainless to stainless.

Dave
 
I agree, for consistancy there is nothing like a coated carbide. I have used for many years now the Kennametal topnotch external and internal setup. The best part is that with just a turn of the allen key, you can replace the threading insert with a grooving insert to do the thread relief in a couple of different forms or even parting off up to about eighth inch wall thickness.

Tony Z.
 
What is this Moly D ??

200 RPM's and Moly D get me a pretty good finish.

A search for this got me nothing, Who makes it, where to buy?

Thanks
 
Castrol Moly-Dee tapping fluid

1-800-645-7270

MSC #00259515

I get a better finish and less chip weld on the insert.

Dave
 
I started threading with the same top-notch inserts Tony Z talks about, and agree that these Kennametal inserts (both threading & grooving) are a good way to go. I just used a reground grooving insert yesterday to turn grooves into the surfaces of several bedding pillars.

I've also got Iscar internal & external bars for the laydown inserts. AG60 partial profile inserts will cut threads from 8-48tpi, so a single 5-pack should cover the needs of most of us, and last a very long time.

I generally don't thread any faster than about 180 rpm (slower when recutting/truing internal receiver threads), and use Mobil Omega cutting oil (dark, sulphurized oil) with both types of inserts. I think the topnotch tool gives a slightly smoother finish at these low speeds, but there's really not much difference, and either type of insert will cut very servicable threads. Getting the right insert coating for your application is probably more important than worrying about which cutting oil to use.
 
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