taper vs plug taps

Harold, I mentioned in a previous post that I tap 304SS with form taps. So there. I started doing this when I had to make a bunch of parts to make from 304 that had a 10-32 tapped hole. This hole needed to be bottom tapped. Using a high spiral tap worked OK for a while but tap breakage destroying the part happened too many times. I did use all the advice and direction from the tap makers but tap life was still too short. Switching to form taps greatly reduced breakage. It eventually turned out that the material itself was the reason for poor tap life. Switching to 304 from a different supplier helped a bunch. But I still use form taps in 304 when tapping blind holes ERS

Greetings DoN, I have a 2nd edition, a 21st and 26th. It's amazing how much info in the second is still in the 26th. I wanted an early edition because I remembered reading an old one that a fellow machinist had that detailed how to join leather belts. That old info still comes in handy now and then. ERS

I have a 16th and a 20th that I don't need any longer. Do you know anyone that would like to have them for a few bucks? ...lew...

This is covered in both the 13th and 22nd editions which form my library. Gerry :-)} London, Canada

Yep, you did, but didn't mention the degree of satisfaction.

Understand that I'm not challenging you-----I am just curious about the performance they provide in tough materials. Stainless, with it's well deserved reputation for work hardening, could prove challenging----especially if you had to go back in the same hole because you didn't achieve proper depth. Assuming you get good and proper deformation in the process of forming the thread, it should be superior to a cut thread, just as rolled A threads are superior to machined threads. I'm a strong (mental) fan of thread forming, just inexperienced.

Harold

Greetings Harold, I am satisfied with form taps in 304. You need to watch carefully the load on the tap. With the proper high pressure tap lube it's the way to go for blind holes. Even so, I will tap the holes as soon as possible in the part making process because form tapping 304 is right at the limit. And when I don't pay attention I break taps. ERS

Thanks, Eric. That's what I was thinking, but had no experience to confirm my hunch.

Harold