Newbie Question - finishing ?

7

724wd

Joined
Dec 29, 2006
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435
ok, i see a lot of guys talking about finishing their blades after heat-treating - grinding and what not. how close do you finish your knives before heat treat? do you leave the last 10% and just make sure you don't get it too hot? do you do the outside shaping 100% and touch up the surface finish? how much grinding do you do on hardened blades? if you harden a finished blade, there's scale buildup, correct - and that needs to be removed.... oh hell, you guys just want to give me a little bit of info and shut me up? :D
 
I think a lot of personal preference goes into the process of grinding and finishing. It also depends a little bit if you use an oil- or air-hardening steel.
I finish all my blades to grit 400 or 600 before heat treat and it works quite good for me. After heat treat i clean the blade with a grey scotch brite belt and then i go on satin finishing it by hand to 800-1200 grit.
I wouldn't want to grind out 120 grit scratches on a hardened D2 blade with my hands. :D
My beltgrinder has no variable speed, so machine-grinding with finer grits after heat treat is not recommended.
 
Finish to around 400 grit prior to HT. Leave the edge about .040" (to allow for decarb removal and final shaping).Leave NO grinding marks or deep scratches to "take out later". They will be hard to get out and could cause a crack in the blade during HT.After HT, start sanding at one grit below where you were prior to HT (220,eg.).
Stacy
 
I never know what to do sometimes...

There is the idea that you dont want your cutting edge to be too thin as the heat of the torch or forge is bad for the steel there.

The main problem I have now is that at the plunge line if I have deep scratches left before the Heat-treating, they are nasty hard after....

I have been thinking about taking Bruce Bump's advice and just doing that stuff later on...
 
724wd said:
ok, i see a lot of guys talking about finishing their blades after heat-treating - grinding and what not. how close do you finish your knives before heat treat? do you leave the last 10% and just make sure you don't get it too hot? do you do the outside shaping 100% and touch up the surface finish? how much grinding do you do on hardened blades? if you harden a finished blade, there's scale buildup, correct - and that needs to be removed.... oh hell, you guys just want to give me a little bit of info and shut me up? :D
Click to expand...

Design the pattern of your knife. Cut out, drill, stamp, Heat treat, Temper, surface grind, to removed the scale. Then grind the blade leaving at least 10 to 20,000 on the edge. you will need to work up through your grit to get to that stage. Hand Rub, finish, and buffer to a mirror finish if desired. That's up to you as the maker., If you grind your knives before heat treat you may encounter warping of the knives. That's why I do it after heat treat. it is one way to control the outcome of the process. I hope this was of help to you. If you need to you can call me on the phone. God bless and have a great knife day.

Barkes :thumbup:
http://my.hsonline.net/wizard/knifeshop.htm
When I leave this world I would like to be known by the one who make his knives from start to finish.
1.812.526.6390
 
I only grind up to 120 or 220 before heat treat then I go to 220, 400, and sometimes 600 after. Then I clean it up with the scotchbrite wheel and polish it on the buffer if I want a mirror finish. I just keep my bucket of water under my grinder and dip the blade often to keep it cool. works for me.
 
As Barke says: you may encounter warping from the heat treating. I just rough grind before HT and after the blade is hardened and tempered its just a matter of regrinding to straighten out and true it up. Then just go through the finishing grits on the grinder until you can clean it up by hand sanding. Fresh sharp belts make all the differance in the world. Old belts cause frustrations, not to mention overheating and softening an otherwise perfect heat treated blade. heres my formula: "New belts nice! Old belts much cussing!"
 
I only go as far as 220 grit prior to heat treatment. I also drill all the holes for the handle and strike my name stamp into the blade prior to HT. There is always some scale after HT even with the foil wrap and a sliver of wood placed inside the foil pouch with the blade to help absorb oxygen. After HT then I take off the scale and finish the blades up to the 400 grit level before satin finishing and satin finish belt- those work really well. If I am going mirror polish then there are several more finishing belt grits up to 15 micron- 9 micron before going to the polishing wheels. For the mirror polish it is a 3 step process with the rouges, black, green chrome, and fine white aluminum oxide using different buffing wheels for each, and a heap of concentration and patients to make it all work out right.
 
Bufford said:
I only go as far as 220 grit prior to heat treatment. I also drill all the holes for the handle and strike my name stamp into the blade prior to HT. There is always some scale after HT even with the foil wrap and a sliver of wood placed inside the foil pouch with the blade to help absorb oxygen. After HT then I take off the scale and finish the blades up to the 400 grit level before satin finishing and satin finish belt- those work really well. If I am going mirror polish then there are several more finishing belt grits up to 15 micron- 9 micron before going to the polishing wheels. For the mirror polish it is a 3 step process with the rouges, black, green chrome, and fine white aluminum oxide using different buffing wheels for each, and a heap of concentration and patients to make it all work out right.
Click to expand...


Bufford's got it down. That's pretty much what I've been doing and that's how the guys I know do it too.:thumbup:
 
I do most all smaller blades. I cut rectangles and have those HT'd, same for slipjoint springs. Then surface grind and all belt grinding and drilling of blades and springs after HT. May be slower, but its the way I do it.
Down side is need solid carbide drill bits for the blades and springs' holes....but use 3/32" and 1/16" bits for slipjoints and solid carbide reamers of 0.0945" and 0.064" respectively....don't need alot of different sizes in carbide.
Oh, and while belt grinding, never operate without a finger or more on the steel....do alot of dipping to cool (steel and finger tips, both) so am not concerned about messing up the temper. Also grind with fairly slow speed... my grinders are all variable speed.
 
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