Cutting HSS Lathe Bit Stock

[Downwindtracker2]

I was not pleased with my attempt at a compound angle on the top so I cut it off. I used a Zip Cut. I think that overheated. What's a better way to 3/8" stock ?

 

[David]

HSS has to reach a very high temperature before it loses temper. Unless it was glowing red it's just fine.

 

[MrWhoopee]

HSS does not lose it's hardness by "overheating". That's what makes it special. It has to be heated above the critical temperature (~1850 deg. F) and cooled very slowly to anneal it. There aren't too many ways to cut it other than abrasive.

 

[Susquatch]

I was not pleased with my attempt at a compound angle on the top so I cut it off. I used a Zip Cut. I think that overheated. What's a better way to 3/8" stock ?

What @MrWhoopee says.

Not a chance you will ruin it. I only cool it so I can hold it without branding my paws. Ignore the blue colour when it cools or grind the blue colour off when/if you hone it.

 

[mbond]

I think that maybe you are _trying_ to cut off the end, but the saw you used didn't work. That would not be a surprise. Even among those with machine tools, actually cutting HSS is almost impossible. Grinding is just about the only way.

So if you have messed up the grind, just grind it some more

 

[Art M]

I almost always rough in HSS blanks with a zip cut then grind to finish works quick

 

[pdentrem]

Wire EDM works! I have used a thin edge impregnated diamond wheel on our surface grinder, but now the EDM is number 1.

 

[Dan Dubeau]

I use a zip wheel.

 

[Susquatch]

I use a zip wheel.

Gez, do I ever feel dumb.....

I have only ever used a bench grinder to shape the whole damn thing. And I've done some pretty amazing grinds!

It's no wonder the RCMP think I'm the only guy in the world with no fingerprints.

 

[Downwindtracker2]

I basically melted my way through, friction cutting. I use Walter Zipcut discs, structural/ stainless . I guess I'll try another brand.

 

[gerritv]

wire edm is nearing afordability for home use. https://rackrobo.io/ all open sourcre

 

[Dan Dubeau]

I basically melted my way through, friction cutting. I use Walter Zipcut discs, structural/ stainless . I guess I'll try another brand.

Easy up on the feed an let the disc cut, moving it along the cut line. Walters should have no problem with it, I love those discs. Use them a lot at work, but don't have the $$ to buy them for home. They aren't cheap. I used to buy dewalt brand from TSC when they went on sale for $1. Have about 80 left, and they should last a while before I need to find another source now that TSC is no longer.

I know I'll get some flak back from this, as it's not supposed to be technically possible, but in my experience HSS will absolutely soften if you grind it so much that it turns red hot, or just under. I've seen it happen too many times with drills getting dull, and grinding toolbits to believe otherwise. When I grind, I quench often and never let it get too hot. Good HSS will probably do this less or not at all, but with cheap import HSS, it absolutely will soften and ruin your drill/toolbit. Shouldn't be possible right?

 

[PeterT]

wire edm is nearing afordability for home use. https://rackrobo.io/ all open sourcre

Now that would be a cool tool. I hope you are in the que! LOL

 

[Susquatch]

Good HSS will probably do this less or not at all, but with cheap import HSS, it absolutely will soften and ruin your drill/toolbit. Shouldn't be possible right?

All things are totally possible WITH CHEAP IMPORT HSS! Could be anything! Might not even be HSS.

FWIW, I have ground good HSS till it was red hot. I don't like to do that, but it happens when you are holding it with Visegrips and trying to remove a lot of metal. I've never been aware of any subsequent change in the HSS performance.

But you raise an excellent point. Not all HSS is created equal. THIS IS PARICULARLY TRUE OF DRILL BITS!

 

[Downwindtracker2]

Sasquatch on a 3/8" blank, using CBN wheels, the coarse wheel is 180grit, I dip the tool bit twice, maybe thrice, per face. I don't have rough tough hands.

 

[Downwindtracker2]

I have had issues with chop saw discs, some simply don't cut, too hard . I had to toss a new one and break down and buy a Walter.

That 3/8" blank had KMS packaging, so would be of questionable quality.

 

[Susquatch]

That 3/8" blank had KMS packaging, so would be of questionable quality.

I have never purchased from KMS. But I would trust KBC for something like that.

 

[Downwindtracker2]

What would you expect if welders were doing the machine tool purchasing choices ?

KMS got it's start by importing US Granger Speedaire compressors and selling them cheaper than anyone else. They did that by having a local engineering firm doing the CSA certification. They have gotten too big to have really great deals now. They have to spread the stock over a lot of stores.

 

[ChazzC]

It's no wonder the RCMP think I'm the only guy in the world with no fingerprints.

My wife was/is an RN for 40 years before getting a 100% desk job. When she started volunteering at a local school she needed to get fingerprinted to get a background check: two different agencies tried and gave up: multiple hand washings with antiseptics took a toll on her hands.