Thread: My first go at hollow ground

Those are some NASTY razors (in the best way possible) Super cool looking I love them.... but

With the tempering process, I understand your math, but the tempering process is to "relax and align" the steel after the stress of a heat treatment (which I also have a question about). 10 min wouldn't be nearly enough for this process to take place fully, heck, probably takes a solid 5 min for the steel to get up to that temp alone. I always temper for a minimum of an hour one time no matter what steel I'm using. But it usually ends up being a couple one hour sessions or one two hour session.

Next question, aiming for 62 HRC seems a bit hard IMO, not only would it be more difficult to hone, but I have found sometimes if I don't temper it enough and leave it too hard the edge chips out. How many shaves have you put into your razors that have that hardness? Typically if a blade is too hard, or too soft it just won't stay sharp long, ie chips out or rolls over.

Lastly, if I understood you correctly, you triple heat-treat them? What do you mean by this? Because taking it by word just doesn't make sense to me why one would do this?

But over all they look great, and most importantly, regardless how you got there, if they continually give you good shaves over and over... that's really all that matters!

Tempering for 10 mins seems a bit short.
As it is intended to relieve stresses, longer is better. I use at least 1 hour.
Also, 62 is a bit too hard for comfort. Most people go for 60-61 because that allows for a very fine edge that it not too brittle, and not too hard to hone. 64 would be silly. It would make honing truly onerous, and result in an edge that would chip out almost by looking at it.

Originally Posted by Bruno

Tempering for 10 mins seems a bit short.
As it is intended to relieve stresses, longer is better. I use at least 1 hour.
Also, 62 is a bit too hard for comfort. Most people go for 60-61 because that allows for a very fine edge that it not too brittle, and not too hard to hone. 64 would be silly. It would make honing truly onerous, and result in an edge that would chip out almost by looking at it.

Agreed,
A good temper is as much a function of time as it is temperature regardless of how small the section is. I start with an hour and have never had to go to two. If I struggled to hone I would temper for a further 30 mins to 1 hour. Some guys go straight for two hours in the oven.

Joe

Originally Posted by Bruno

Tempering for 10 mins seems a bit short.
As it is intended to relieve stresses, longer is better. I use at least 1 hour.
Also, 62 is a bit too hard for comfort. Most people go for 60-61 because that allows for a very fine edge that it not too brittle, and not too hard to hone. 64 would be silly. It would make honing truly onerous, and result in an edge that would chip out almost by looking at it.

Bruno-I was talking about "as quenched" hardness up to 64 with a proper soak in o1, not suggesting to aim for 64 as an end result. and Bruno- the statement on tempering as a stress relief- i agree wholeheartedly. its not just a matter of reducing the hardness, its about equalizing internal stresses as well. I do think ease of sharpening is better for anyone interested in maintaining their own blades. it seems a lot of folks have become obsessed with highest degree of hardness rather than ease of maintenance. it doesn't take an ultra hardened blade to achieve keenness and edge holding. sometimes its more a matter of ingredients in a particular steel that affect the ability to achieve keenness. sometimes its the manner of heat treat that means the most. will the particular steel benefit from multiple quenches or not in order to refine the grain size? lots of factors, but as hipsley said, if it takes an edge and shaves successfully then the proof was in the pudding. optimal does not mean essential by any means. the shave and ease of maintenance are the test of any blade.

Originally Posted by silverloaf

Bruno-I was talking about "as quenched" hardness up to 64 with a proper soak in o1, not suggesting to aim for 64 as an end result. and Bruno- the statement on tempering as a stress relief- i agree wholeheartedly. its not just a matter of reducing the hardness, its about equalizing internal stresses as well. I do think ease of sharpening is better for anyone interested in maintaining their own blades. it seems a lot of folks have become obsessed with highest degree of hardness rather than ease of maintenance. it doesn't take an ultra hardened blade to achieve keenness and edge holding. sometimes its more a matter of ingredients in a particular steel that affect the ability to achieve keenness. sometimes its the manner of heat treat that means the most. will the particular steel benefit from multiple quenches or not in order to refine the grain size? lots of factors, but as hipsley said, if it takes an edge and shaves successfully then the proof was in the pudding. optimal does not mean essential by any means. the shave and ease of maintenance are the test of any blade.

Precisely,

This is why I go only for a 1 hour temper to start. Its because I can't be sure how optimal the hardening has gone. The hone always informs me. This is purely a practical consideration over theory. If I get a very hard edge, one hour would not be enough and would relinquish more martensite. Chippy edges are another real problem if they are too hard, I can vouch for that.

Joe