Author Topic: Bending High Speed Steel  (Read 858 times)

Offline 10KPete

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Bending High Speed Steel
« on: July 26, 2018, 04:40:25 AM »
Well, I had to try it. The only 3/32 parting blade I have turns out to have been bent sideways about .04" (1 mm)! I was having trouble with it being square with the work when all the other tools were square....never entered my mind the blade would be bent! So how to straighten it? It won't bend cold so it must bend hot. Nothing to lose, I gripped about 3/8" in the vise and put the O/A torch to it while 'coaxing' with pliers at the end. Heating slowly and feeling for yield the color (dim room) just started to have some red when it was bendable. So, went along heating and 'coaxing' until it looked straight.

Now the answer I had sought all these years..... it's still as hard as when I started!!  :cartwheel:
Put it in the holder and attacked a piece of mild steel about 1 1/4" dia. Went through just like it should.

Next, I think I'll find a square tool bit and try to bend it...  :noidea:

Pete
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Retired, finally!
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Online Kim

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Re: Bending High Speed Steel
« Reply #1 on: July 26, 2018, 05:00:35 AM »
That was a pretty nice repair job there, Pete!  Saved yourself a few dollars on a new parting blade, hard to beat that! :)
Kim

Offline zeeprogrammer

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Re: Bending High Speed Steel
« Reply #2 on: July 26, 2018, 05:00:52 AM »
Next, I think I'll find a square tool bit and try to bend it...  :noidea:

Pete's gone round the bend.  ;D

Another item for my reference book!  :ThumbsUp:

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Offline 10KPete

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Re: Bending High Speed Steel
« Reply #3 on: July 26, 2018, 05:24:03 AM »
Round the bend, ehh?  Way past that and into the triple loop!!!  :facepalm:

 :lolb: :lolb:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Online steamer

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Re: Bending High Speed Steel
« Reply #4 on: July 26, 2018, 10:59:47 AM »
M2 HSS has a Yield point of 500,000 psi, and a Tensile strength of 550,000 psi.    Yup   Heating it is you only hope.

I used a M2 HSS drill blank in an extrusion press, and I had to test the part to destruction  ( late 80's)  I got 26,000 pounds on a 9mm blank that was 3" long before it collapsed..or more accurately stated..exploded into dust  ( in compression) .     Damndest thing!


Dave
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Offline gbritnell

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Re: Bending High Speed Steel
« Reply #5 on: July 26, 2018, 12:40:32 PM »
Hi Bill,
I believe it's Young's modulus of elasticity that states a metal will bend and deform at a certain point.
If that metal is hardened it will break at that same point it bent at.
All the cut-off tools I have ever used have been through hardened and have shattered when stressed too far. I have never had one bend.
gbritnell
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Offline Zephyrin

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Re: Bending High Speed Steel
« Reply #6 on: July 26, 2018, 04:44:55 PM »
I did something similar to give a little offset to a 3mm dia HSS round bar to "forge" a tiny lathe boring tool... I was amazed that the tool keeps all its hardness, even after some "overheat" in the grinder.
doing the same with carbon steel gave ruined tool !

Offline Hugh Currin

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Re: Bending High Speed Steel
« Reply #7 on: July 26, 2018, 04:59:54 PM »
I'd probably wrap a wet rag around the cutting part of the tool, keep the heat down there. Then heat the portion to bend. With luck the cutting edge would hold its heat treat.

Or, re-heat treat when done. More trouble but should work.

Thanks.

Hugh
Hugh

Offline Ramon

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Re: Bending High Speed Steel
« Reply #8 on: July 26, 2018, 06:40:40 PM »
Hi Guys - I can add a little here if I may

HSS will retain its hardness at red heat and that property made it a revolutionary cutting tool when superseding Carbon Steel tools so many years ago. It can, as Pete has discovered, be heated to red heat and its shape altered to a degree without any loss of hardness. As said by Zephyrin do that to a carbon steel tool and it will have to be re-heat treated.

I ran a small machine shop where we manufactured parts for progression press tools and we occasionally made items from unheat treated HSS. We would do all our own heat treatment save for these parts - they would have to be 'put outside' due to the quenching temperature which if I remember correctly was about 1200C and our ovens would only go to 1100 or so. Most of our hardened components were made from general tool steel - Arne BO1 or GFS though we did use quite a range of heat treatable steels.

The HSS was very tough to machine as was two other steels - Sverker 3 and Sverker 21. These we could heat treat but only just at a 1050 C I think - I do remember they would exit the oven a very bright yellow.

So Pete - you should have no problem bending a piece but you might have a job hardening some with average home methods ;)

Hope that's of interest

Tug
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