Advice for grinding thin blades

[David Mary]

I am about to grind my first blade in a stock thickness under 1/8". I plan to make some small edc knives and a filet knife out of 1/16" thick AEB-L. I had planned to cut and grind the blanks with an angle grinder and a 2 x 42 belt grinder, then send the blanks for away for heat treatment. I noticed that the annealed 1 1/2" x 12" pieces I have flex very easily, and don't spring back, so I am wondering exactly how I am supposed to go about this without creating a crooked knife?

I wish I could think of all the right questions to ask here, but I am hoping that someone who has gone through this learning curve can point me in the right direction and hopefully fill in the gaps.

Thank you.

 

[A.McPherson]

Get em profiled out, then heat treat em, then grind the bevels.

 

[David Mary]

Thanks A.McPherson , just that simple after all. And I guess I can just straighten them in my vise between two pieces of thick G10 before I send them?

 

[DevinT]

Straighten before heat treat with light hammer blows and bending and twisting if necessary. Use a backing board if they flex too much during grinding after HT. Use sharp abrasives.

Hoss

 

[David Mary]

Thanks D DevinT !

 

[AVigil]

I take a dead blow hammer and whack the high side. You can do it on the garage floor for flat surface

A couple of whacks and it will be flat.

 

[Stacy E. Apelt - Bladesmith]

TIP:
Tape the blades to a piece of plywood when shipping out for HT. This prevents them getting bent in shipping .

 

[JTknives]

Tip: Do not grind any edge bevels befor heat treating.

Tip#2: just have me cut your blade blanks, heat treat and ship to you.

 

[Backyard]

Grind with lots of water / cooling so as to not ruin the temper. Be very careful of the tip as it will overheat quickly

 

[Lee Hester]

I'm not great at grinding yet, but I think one thing that might help you here when you're grinding the bevels (post-heat treat as others have suggested) is the "push stick" method. Basically, use something to push the blade against the grinder's platen from behind as you pull the blade across the belt. Nick Wheeler uses this technique in this video. I've seen lots of other makers use this technique (Travis Wuertz uses it here). I think one of the things it will help with in your situation is it will stop the temptation to apply pressure to the belt through the handle of the knife, which can bend it and cause problems with your grind lines and potentially bend your knife. You do need to be careful about the temperature of the blade, because you're a bit more insulated from it with this approach. Also, I've found wood push sticks "stick" more to the blade, especially if you're dipping your blade in water to keep it cool, which can make it hard to pull the blade across the grinder with an even speed. I think something made from plastic (G10 or micarta would work) is a better option for this reason.

 

[David Mary]

B Backyard , yes, I at least know that much! Thank you kindly.

L Lee Hester - Why wouldn't I just continue using my ungloved hand to push the blade into the belt? Best possible temperature monitoring, and feels natural. It's how I do it now, and I don't know of any disadvantages. When I grind pre-heat treat, however, I sometimes use whatever pieces of scrap I have lying around as push sticks.

 

[PEU]

aeb-l, sandvik 13c27 and 14c28n tend to curve themselves I cycle them 850C-room temp 650C so they are without tensions and soft.
Harden between aluminium slabs with a heavy weight on top, I mean heavy!
check straightness, I prefer to harden again to deal with straightening after tempering
grind post hardening
fresh belts are a must if you are learning
one grind/one dip in water/loop
evaporation on your side of the blade is a very good indicator of how heated the blade is, you have a fraction of a second to dip it in water again.

Pablo

 

[Natlek]

B Backyard , yes, I at least know that much! Thank you kindly.

L Lee Hester - Why wouldn't I just continue using my ungloved hand to push the blade into the belt? Best possible temperature monitoring, and feels natural. It's how I do it now, and I don't know of any disadvantages. When I grind pre-heat treat, however, I sometimes use whatever pieces of scrap I have lying around as push sticks.

I use square piece of tube as jig to grind thin blade .I simple glue blank with CA to jig .On picture is 1.5mm thick hardened steel /64 hrc 1.2519 / glued with CA glue to jig , jig take are lot heat from blank .I never, never overheated edge grinding this way .. . .