Venturing into turning stainless - what do I need to know?

[Carl Fisher]

Seems to be a black art with so many different grades of stainless rod, turning tools, speeds and feeds. Looking for someone to help demystify the process.

So for the use, I'm looking at trim rings, couplers and maybe into a few front sections, etc... Pen parts basically.

I've got a small set of triangle carbide inserts that I use most of the time right now because honestly no matter how many times I try, I can't seem to figure out how to correctly grind HSS cutters. I'd like to stick with the carbide inserts if at all possible. I've also got my boring bars and parting tool for their respective operations.

So where do I go from here?

 

[Paul in OKC]

What lathe? If a 7x? it willbe slow and steady. Stainless can be 'gummy' material to work with. Lubricate liberally when drilling. Otherwise just goingt ohave to jump in and try a few things and see what works for you. I tackle stainless like any other steel as a whole, but.....it will make stringy swarf instead of chips on small machines, usually. Not much, but hope it helps....some!

 

[Carl Fisher]

Yes, it's a 7x (currently 7x16)

What grade of stainless for both the machine in question and final use for pen components? Looking at online metals they have an entire page dedicated to all of the different grades, but when I see phrases like "machinable with the right techniques" that tells me that there is more to it than I may have at my disposal.

At best guess, I'm thinking 303? 304 claims to be the most common but has one of the machining disclaimers I mentioned above. 303 states to have most of the qualities of 304 but is machinable and just not weldable which is fine by me.

 

[skiprat]

My golden rules for working stainless are;

1. Lowish turning and drilling speed. 300 - 400rpm
2. The tool must ALWAYS be cutting, let it idle or dwell at your peril :redface:
3. Good quality tools. DIY cheap drill bits etc are a waste.
4. Don't hang about when drilling. Get in and get out.
5. Be careful what lube / coolant you use. Flammable stuff like WD40 is not fun when superheated. I rarely use lube / coolant. But when I need to, I use my soluble oil coolant pump system. Messy though....:wink:

Here's the big one.....

6. The long strings of swarf are hotter than the hobs of hell and sharper than fresh razor blades on steroids. Never ever try and remove them while a machine is running. ( Trust me, you will try once...):redface:
When clean the long swarf from under the bed and between the ways, use gloves as one of them will always snag on something and slice you badly.

I love working with stainless, but I have learnt to respect it...:biggrin:

Good luck and be carefull...:biggrin:

Looking forward to seeing what you create.:wink:

 

[skiprat]

Carl, most of the stuff I use comes from old stainless threaded rods or bolts. Either A2 or A4 grade. If I have to buy, then I get 304 just cos it's a fraction cheaper than 316.
I've only ever come across one piece of stainless that defeated me. I have no idea what grade it was as it was a freebie. I now use it solely as a test bar for lining up my tailstock etc.
I have never had issues machining 304 or 316, or the old bolts for that matter.

 

[steve worcester]

Carl, most of the stuff I use comes from old stainless threaded rods or bolts. Either A2 or A4 grade. If I have to buy, then I get 304 just cos it's a fraction cheaper than 316.
I've only ever come across one piece of stainless that defeated me. I have no idea what grade it was as it was a freebie. I now use it solely as a test bar for lining up my tailstock etc.
I have never had issues machining 304 or 316, or the old bolts for that matter.

this might be a good start
McMaster-Carr

 

[Harley2001]

Thanks good info

 

[attie schoeman]

When working with stainless, keep the following in mind: the 300 series i.e. 303,304,316 are "work hardening" steels. As mentioned by Skiprat, when you cut or drill, make sure your tools are sharp and get on with it. The longer you carry on with a blunt drill for instance, the harder the material will become. This is of course an excellent means of hardening parts if you wish

 

[mecompco]

I've got a small set of triangle carbide inserts that I use most of the time right now because honestly no matter how many times I try, I can't seem to figure out how to correctly grind HSS cutters.

I watched a lot of videos--angles, formulas, blah blah blah, made little sense to me. Got my gunsmith friend to stop by and got a quick tutorial. Now I just hit my HSS cutter on two edges with a 120 grit belt on the belt grinder for a few seconds and it cuts great.

I've not done any stainless yet. I'm sure you'll investigate the recommended speed/feed for the material you settle upon.

Regards,
Michael

 

[Rockytime]

<SNIP> Got my gunsmith friend to stop by and got a quick tutorial. Now I just hit my HSS cutter on two edges with a 120 grit belt on the belt grinder for a few seconds and it cuts great.<SNIP>
Regards,
Michael

I've been sharpening my HSS on a belt sander for years. I only use a grinder to shape my blanks and maintain them on the belt sander. Your gunsmith friend gave you good advice.