Thread: My first go at hollow ground

That is some seriously beautiful grinding and finishing.

VERY nicely done!

What type of grinder/sander are you using and what wheel diameter are you running?

They are all amazing but I especially like the creative blade guard...

What a great triplet of razors. The fixed one looks so aggressive, but has a real medieval look to it.

Beautiful work....sheesh....I'm re-reading Frank Herbert's, "Dune" right now and looking at that blade, the Litany Against Fear starting going through my head, "Fear is the mind killer. Fear is the little death...."

Gulp!

Hi mgilndo,

I'm manly using 01 tool steel once its been heat treated and oil quenched three times it holds it's edge really, really well.
Up until the last one (the fixed blade) they've all been wedges but I've got a new toy for the workshop so I can now do some hollow grinding, the fixed blade looks more like a quarter hollow to me.

Drew

Originally Posted by 3Drew101

Hi mgilndo,

I'm manly using 01 tool steel once its been heat treated and oil quenched three times it holds it's edge really, really well.
Up until the last one (the fixed blade) they've all been wedges but I've got a new toy for the workshop so I can now do some hollow grinding, the fixed blade looks more like a quarter hollow to me.
Drew

Nice. What hardness are you shooting for?

Mike

Originally Posted by mglindo

Nice. What hardness are you shooting for?

Mike

After tempering for 10min at 150c (350f) it should come out at around C62 but I've never sent a piece off to be tested so I'm not 100% on that, but it should be pretty close. I do use an off cut of the bar I'm working with, heat treat and temper it along side the blade I'm working on at the time, then once its sat for a couple of days put it in a vice and just give it a tap and if it breaks off nicely and has a good crystal structure I'm happy that its a good piece of steel and the heat treat has worked well.

Drew

with a proper "soak time" in the o1 you could be hitting 64 after tempering at 350f. not sure about that 10 min tempering time though, can you point me to the info where you got that? if 10 min does it then I temper way too long! haha

The place I get my steel from recommends the following for tempering

Tempering:
150C (300F) Rockwell C62
200C (400F) Rockwell C60 - 61
232C (450F) Rockwell C58 - 59
290C (550F) Rockwell C56 - 57

Hold at tempering temperature for about one hour per inch of thickness


so figure for 4mm thick temper time = 9min
5mm = 12min
6mm = 14min

so as I use mainly 5mm that has lost a little width while I'm working on them I'd go for 10min, if i'm wrong please tell me so i can adjust accordingly.

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!