Best ways to clean up a blade after heat treat

[koyote]

1. Cut Blade Out
2. Drill all holes
3 Stamp my Name in using a press
4. Mill if I need to
5. Heat Treat the Steel
6 quench in oil and hold there.
7. Put back in oven and Temper the Steel
8. surface grind the hold knife.
9. Hollow the blade or flag grind
10. Hand sand the blade starting with 120 to 2000 grit.
_______________________________

Steel I use is 1095 - 1084 - 52100

VERY helpful. I'm using the 1095 "like" steel, haven't been doing it quite like this, so far after 4 my pattern is roughly.

clean, anneal (recycled steel)
draw, cut, grind, normalize
rough shape what I can and file smooth
heat, quench, temper
draw file, file, put on the edge bevel (not hollow ground, but thin enugh blades so far)
sand sand sand sand by hand and then some more
handle work
wrap it up tight
form sheath
sharpen.

man, a belt system would help. I wonder how usable the delta belt/disc combos are, since I'm not getting a big belt grinder anytime soon.

 

[David Wesner]

I mean cleaning up as in finish sanding. I have encountered scaling and pitting but to me that means re-grinding then starting the heat treat over again from the beginning.
Excellent question because cleaning up will probably mean different things to different folks.
Chris

OK Chris That makes it easier. If my blades come out looking good I use my Diprofil (reciprocating polisher found in many Mold shops) with polishing stones(diemaker type stones, some are called edm type) up to 600. Then I pull silicon carbide paper (trying to avoid the fishhook problem) from one end to the other in one smooth motion up to 600 for utility type blades and 2000+ for blades I'm trying to squeeze Hamon out of ( Don H. is a master at this & can tell you more than I ) Very few of my knives see much buffer time if any. The biggest reason I don't grind after heat treat is, like I said, its a b*tch @ 60 HRC and more importantly my grinding isn't at the W.C. Davis or Steve Johnson level yet. It comes out looking better for me by doing my grinding & benching in the annealed state, get it looking good, and using either foil or PBC to maintain that finish through heat treat. I do finish grind my thin Bird & Trout knives, my little BT6, and 1 or 2 hunters I make after heattreat to avoid any decarb on very thin edges. Thats it though. Not much surface area to deal with if some need a little extra "help" I make so many BIG knives that until my grinding gets better this is what works best for me on them. I keep saying "me"/"I" because IMHO, everyone has to find what works best for them. I can have the exact same equipment W.C. Davis has, same belts, etc. and he will smoke me on the grinder. I'm working very hard at perfecting all of my skills, everyday, as I'm sure most of you are. Getting a great looking finish straight off the grinder like some can is still eluding me I spent so much time and $$ looking for that "easier way" (haven't found it yet), I am getting better though (I can feel it) . I would give my eye teeth for a day or two watching and listening to Davis or Johnson or that Hanson dude My method isn't something I can take credit for, Terry Primo is the guy that turned many of us onto the "do it before heat treat" method using PBC, me included. I wish I could give you a magic method Chris, everything that I had to give......... you got

 

[Barkes Knife Shop]

VERY helpful. I'm using the 1095 "like" steel, haven't been doing it quite like this, so far after 4 my pattern is roughly.

Yes alot of work. Did you check out my site and see my setup. I use the 2x72 for hollow grinding. Sometimes I put on the 10" wheel or the 14" wheel. One thing I know is one has to love making knives. Thanks for your post and have a great day. ---------------:thumbup:

 

[jdm61]

2 important things when using the anti-scale. First, don't let any bubbles form. that makes for instant piting. Second, when you quench, have some water boiling. After the balde is cooled down, put it in a pan or the sink and cover it with the bopiling water. If you didn't have bubbles, the stuff should pop right off.

 

[Rob!]

I agree with the concept of finishing (almost) in the annealed state. More and more, I'm taking knives to 800 - 1200 grit before HT and just buffing the oxide off if there is any. Blades done right in foil come out cleaner than salt. Of course, that only works for air quench steels - and only if you plate quench in the foil. Before I got plate quenching figured out, I used to go to 220G before HT and back to 220 and beyond after HT. I still do that with oil quench blades.

Rob!

 

[nivejuncky]

How do you keep bubbles from forming in the pbc?

 

[cmd]

OK Chris That makes it easier. If my blades come out looking good I use my Diprofil (reciprocating polisher found in many Mold shops) with polishing stones(diemaker type stones, some are called edm type) up to 600. Then I pull silicon carbide paper (trying to avoid the fishhook problem) from one end to the other in one smooth motion up to 600 for utility type blades and 2000+ for blades I'm trying to squeeze Hamon out of ( Don H. is a master at this & can tell you more than I ) Very few of my knives see much buffer time if any. The biggest reason I don't grind after heat treat is, like I said, its a b*tch @ 60 HRC and more importantly my grinding isn't at the W.C. Davis or Steve Johnson level yet. It comes out looking better for me by doing my grinding & benching in the annealed state, get it looking good, and using either foil or PBC to maintain that finish through heat treat. I do finish grind my thin Bird & Trout knives, my little BT6, and 1 or 2 hunters I make after heattreat to avoid any decarb on very thin edges. Thats it though. Not much surface area to deal with if some need a little extra "help" I make so many BIG knives that until my grinding gets better this is what works best for me on them. I keep saying "me"/"I" because IMHO, everyone has to find what works best for them. I can have the exact same equipment W.C. Davis has, same belts, etc. and he will smoke me on the grinder. I'm working very hard at perfecting all of my skills, everyday, as I'm sure most of you are. Getting a great looking finish straight off the grinder like some can is still eluding me I spent so much time and $$ looking for that "easier way" (haven't found it yet), I am getting better though (I can feel it) . I would give my eye teeth for a day or two watching and listening to Davis or Johnson or that Hanson dude My method isn't something I can take credit for, Terry Primo is the guy that turned many of us onto the "do it before heat treat" method using PBC, me included. I wish I could give you a magic method Chris, everything that I had to give......... you got

This really is a wealth of good information, no magic expected :thumbup:

 

[Fred.Rowe]

This thread shows how many different approaches there are, in tackling this problem.


Before hardening:

• Have ricasso at a 320 or 400 finish.
• Have tang shaped and drilled. Cut shoulders.
• Finish spine, false edge etc.
• Grind flats on disc grinder to make sure they are flat.
• Make sure edge is ground evenly from ricasso to tip[same thickness]
• Grind blade flats to 220 finish.

Borax works well as a heat treat coating to protect the blade. Just make sure it is not lumped up on the blade surface. You can smooth it out with a few light strokes with a wire brush.
I have used the PBC coating with success also.
Using a clay coating, also, has a protective value.

If you take time to do many of these task before heat treat there is much less to do after heat treat.

After heat treat.

• Temper asap
• Use the edge of a brass rod or sheet to scrape scale from blade surface.
• Enjoy this time, where, all your hard work comes to fruition.

If there weren't any struggle; or if it didn't take a huge effort to make a great knife, a great knife would have little real value and we all know that is not the case.
Go ahead and make a great knife, Fred

 

[Rick Lowe]

After heat treat I've got about 3-5 minutes on the grinder to get to 400grit before hand finish. This takes care of any scale on the blade. To remove scale on the choil area or tang, just put 'em in a jar of vinegar over night. Use a wire brush for what might still be there. Windex will kill the acid and a little soap and water finishes it up.
Rick

 

[koyote]

Yes alot of work. Did you check out my site and see my setup. I use the 2x72 for hollow grinding. Sometimes I put on the 10" wheel or the 14" wheel. One thing I know is one has to love making knives. Thanks for your post and have a great day. ---------------:thumbup:

I looked at your site and drooled!

I'm currently working on a filing jig, might save my money and not get a belt/disc sander and try to get a belt grinder someday. When I get better- I'm probably learning some really valuable lessons doing it by hand.

Spending a work week in a shop like yours would do wonders for my thinking on tools, I'm sure- maybe I'll find someone close enough sometime.


prioritizing purchases is hard. I'm guessing a belt grinder should be pretty high on my list, but. Well, starting from a 6 inch grinder, drill guide (I turned it into a press with clamping areas last night), torch forge/oil quench, oven, files and sandpaper- what would you recommend as the next purchase?

 

[cmd]

Why would you have to heat treat all over again after re-grinding

"Most" knife makers grind their blades leaving the edge slightly thicker than finished size, heat treat, then grind the blade to desired thinness and hand finish. It doesn't get much easier than this.

Edit to add, I also know a few makers who heat treat a blade blank and do all grinding after but most don't.

Yeah, I leave my edges thick before heat treating too, then refine it down afterwards.

Doing all of the grinding after heat treating a blank doesn't seem like a good idea to me, but if it work for them that's fine. I'm definitley no expert.

The reason I would do a heat treat all over again after re-grinding is that when I get into serious removal of stock (36 grit, fast, heavy preasure) I don't worry about letting the metal get really hot. When I do finishing on the grinder after heat treat I am very careful not to let the metal get very hot.

Perhaps I am being too cautious about this but I wouldn't feel right about a knife where even part of it got really heated up after heat treatment was done.

Chris

 

[cmd]

This thread shows how many different approaches there are, in tackling this problem.

Absolutely Fred. This part of the process has always seemed a little less well defined, at least to me. It really is interesting to learn how different people approach this task.

Chris

 

[David Schott]

I never worry about overheating when grinding post-ht because i never wear gloves. Keep your fingers on the blade opposite where you are grinding. HT wont be affected until at least tempering temps, and if you can hold onto a 400+ degree blade with bare hands, you are a better man than me!

I use sharp belts, dunk often, and have never had any post HT blades ruined by overheating. One reason why i insist on post HT grinding is due to decarb, as well. I havent used PCB or foil and often do hamon work that i wouldnt know how to use PCB with the clay. As a result i get a thin section of decarb during HT. I visualize taking a thin layer of skin off the whole blade to get to the good center steel.

My process:
-Heat treat and temper
-Grind all exposed surfaces with 120 grit belt until an etch in FC reveals no decarb or scale (these will etch at a much different rate and color than hardened steel)
-Grind blade to final thickness, being careful to not toast the heat treat by being a lazy-ass and trying to grind too fast or too hard.
-Once at 220, I switch to hand sanding and take it up to my desired finish.