- Joined
- Jul 26, 2011
- Messages
- 4,142
I just did a job all in 304. WHAT tough stuff that is!! I had to tap a 1/4-20 thd. hole in each piece. I used "Tap Magic" cutting fluid. I only used NEW HSS drills and NOS taps. I found a CARBON STEEL NOS tap,and actually managed to tap both holes with it after drilling with a new #7 drill. Some how the NOS carbon tap seemed to cut better than a NOS HSS tap!! Using a carbon tap sounds crazy,but it worked. Carbon gets just as hard as HSS. (HSS gets about 63 RC.) Just not as durable. But it lasted for the 2 holes,and still seems perfectly fine.
The carbon steel tap is probably from the 40's or 50's. I certainly would NOT recommend using a brand new carbon steel tap!
Understand,I am NOT recommending that you use a carbon steel tap for 304. It just happened to work the best for me in this particular case.
The trouble(among other things) with 304 is,every time you hesitate during cutting it,it will work harden.
The carbon steel tap is probably from the 40's or 50's. I certainly would NOT recommend using a brand new carbon steel tap!
Understand,I am NOT recommending that you use a carbon steel tap for 304. It just happened to work the best for me in this particular case.
The trouble(among other things) with 304 is,every time you hesitate during cutting it,it will work harden.