Hardening O1 Tool Steel - What Am I Doing Wrong?

Forget the oven one time. Make another small piece ¼” x ¼” x 1 ½”. Find some junk pliers and a map torch. Holding the test piece with the plies heat just one end to a bright red then into oil. File test both ends and see if they are different or same hardness. And maybe try clean water instead of oil.
 
chips&more said:
Forget the oven one time. Make another small piece ¼” x ¼” x 1 ½”. Find some junk pliers and a map torch. Holding the test piece with the plies heat just one end to a bright red then into oil. File test both ends and see if they are different or same hardness. And maybe try clean water instead of oil.
Click to expand...

Good idea. I'm trying that in a few minutes.

The two test pieces are in the temper right now. It is a separate oven.

Put the file to both of them after the dunk and before the temper. It's not looking good. Looks like the problem is me. Although bot pieces came from the same supplier on the same day but even that would be a stretch that they messed them both up. I'm apparently doing something wrong.
 
Okey Doke. I tried the suggestion above but don't think I got it hot enough.

I have some results from the two pieces I did in the last test in the oven. Only differences from the other tests is I let it soak at 1200º for an hour before cranking it to 1490º and let it soak there for and hour before quenching. Tried the kitchen oven instead of the toaster oven for the tempering. Both pieces came out the same and they're both the same as the other tests :frown:.

Then I had a bright idea. I've been using a small wood shaper blade in the lathe to make some shaped parts and it's been working fine so maybe I should compare the blade I made to that and compare the difference in the way the file acts. They're pretty similar! So I compare against a piece of mild steel. The file takes almost no effort to dig into the mild steel but with the piece I made and the shaper blade I can just get it to bite a little but it takes way more effort. Now I'm wondering if my piece is actually hardened and I just didn't know it. I expected the file to slide off and not leave a mark while the hardened steel laughed at it. Have I been expecting too much? Am I so stupid that I've probably been complaining about it not working when it actually was all along? I'm a dope.

Before all this filing though, I was sulking over my tool I made when my wife asked what my problem was. I told her the details she needed to know and she said "Did you at least try the tool to see if it worked" :dejected:. No I did not. I don't care if it's the consistency of butter as long as it works. I'll be trying it tomorrow.

Then I came across this video and my test sounds almost exactly like his. You can just barely see a small indentation at 1:13-1:14 where his file dug in a little and it looks exactly like what I'm seeing on my pieces.



Hey George, do you have a hardness tester? You're pretty close to me and if you're willing I'd love to see what the hardness is of the part I made. Would be nice to meet you too. There's only one other local hobby machinist I know that's local.
 
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I had a real nice Versitron hardness tester at work,but no longer have access to it.

HSS is not as hard as you might think. There are many types,but a common hardness that I tested was usually about 63 RC.. That is too hard for a file to cut.

FOR PETE'S SAKE!! That English guy must be trying to ruin his file!! He needs to ease up on the back stroke,and he doesn't need to keep SAWING at the hardened steel bearing race. A little,short stroke will do perfectly well.

He doesn't mention it, but a fine cut 8" mill file is a good file for testing hardness. That is what he is using. The 8" Nicholson is labeled "bastard" cut,but it is actually a pretty fine cut file. A fine cut file will cut hardened steel better than a coarse tooth file. There are more teeth per inch on a fine cut file. The smaller the file,the finer the teeth will be for any designation of tooth size that is stamped on the file.
 
Get the book "Heat treatment,Selection,and application of Tool Steels" by William E. Bryson.
I find it invaluable.
I was put on to it a couple of years ago by postings on this forum. Great book!
 
ecdez said:
I have some results from the two pieces I did in the last test in the oven. Only differences from the other tests is I let it soak at 1200º for an hour before cranking it to 1490º and let it soak there for and hour before quenching. Tried the kitchen oven instead of the toaster oven for the tempering. Both pieces came out the same and they're both the same as the other tests
Click to expand...

If I remember right from the book above... You can soak all you want at 1200 with out consequence and you can temper at your tempering temp all you want with out consequence.
But you can over cook at the high temp and on 0-1 if I remember right it is 5 minutes per inch of cross section after the oven arrives at the high temp.
Off the top of my head 20 min. at 1200 then turn heat to 1500 (ok 1490) once oven reaches 1500 wait 5 min. and then quench. If the part is 2x2 wait 10min 3x3 15min etc etc.
Once temp has dropped to 150 immediately temper. And he was a stickler about the tempering happening immediately.
Small parts usually get a hole drilled in them and a piece of stainless tie wire tied to them to be used as the handle for quenching.
That way you don't get a soft spot from grasping the part with pliers.
 
That book does look interesting, pricey, but interesting.

Interesting point about the pliers making a soft spot. Hadn't really considered that but I guess it's possible.


SO THE FINAL VERDICT IS IN!!

I guess it's hard; or hard enough at least. Took the cut like a champ. I thought the two little tangs would break off but they stayed put. Even stalled the spindle and I only took maybe a thou at the long flat area. I don't think I had it going fast enough. I know it's not the best shape to use a forming tool and all that, I'm just getting my feet wet. Best of all, the tool did not break! I'm a happy camper right now!!

Thanks to everyone for the input and guidance!


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Hi
"Thanks to everyone for the input and guidance!"
I think you should thank your wife. :foot in mouth: :big grin:
Jeff
 
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