Tapping 304 Ss Help

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.
 
I've always had good luck with Guhring and Emuge taps. For hard steels, I've used TiAiN, TiCn and Cobalt/TIN. Msc has pretty good prices on some these taps.
Would I spend $70 for one tap? Only if I was making a part that cost hundred or thousands of dollars, or something very near and dear. :)
Good luck.
 
This was recommended by a member,for me it seems to work.So for myself combined with OSG tap it work for me,but just did acouple holes
$_57.JPG
 
I'm going to try the Tap Magic first. Then maybe try the Anchorlube. I have several people requesting the same part, but with different exterior shapes. They all take a m12x1.25 internal thread.

They're simple shift knobs. While there are several companies that sell knobs for this application, the designs wanted are not produced. And all mainly stainless steel for the weight. My next order of SS will be the 303 grade. So I get to offer my friends a unique knob and get paid!
 
That's a good plan,if us all could break even then that would be a profit.And its fun----kroll
 
I don't want to say how much they're paying for each knob. But in the end, I will have made enough to easily cover the materials, tools used and some for my time. I'm doing this just because I can, not trying to make a killing with side jobs. It is fun though, plus gives me a valid reason to be in the shop, in my wifes eyes haha.
 
Plain old fashioned cooking lard, and add a coupla drops of kerosene for tapping. A pound at the grocery store or wife’s baking supplies. I have the kind that does not need refrigeration(Armor brand)
 
Took delivery of my Guhring tap today......I'm blown away! This is the first time I've used a quality tap. I hardly had to apply any force. It just seemed to cut the threads in this 304 like a hot knife thru butter! Needless to say, I will be buying more quality taps like this. WELL WORTH THE MONEY!
 
You get what you pay for with Guhring. Wait till you try one of their Drill bits.

"Billy G"
 
Back
Top