new cootes grinder, help

Got my xmas present set up, 2x6x72 grinder (3 step pulley) with a 1 1/2 hp motor(4 step pulley). Started on my firt practice blade...what a flop. Ended up warped (? too much heat), plunge line all messed up, grind lines not even. So, I cut the blade off and tried using the handle for a neck knife. A little better attempt, but still the same, tip heated up, grind lines and plunge lines a bit better, but still ugly.

On my first knife, hand filing the master blade bevel took time, but my lines were kept fairly even. I am half tempted to grind the outline of the blade and finish it with a file
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Opps sustained: knuckle touched moving belt (1/4" deep abrasion), neck knife got away from me (went between the grinding platform and the belt, then slammed to the ground, ripped my new belt
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).

Loveless makes it look so easy in his book "How to make knives".

I can tell, it is going to take practice. How many knives did it take before you got good at symmetry in grind lines and plunge cuts?
 
Crayola

Crayola

Joined
Sep 23, 1999
Messages
3,831
I take a VEEEEEERRRRRRRRRRRRYYYYYYYY long time to make each blade (I've made 4 and the first was with a file.) I have thrown out two blanks. People will tell you here that practice makes perfect. I know that each knife has been an improvement for me. You may want to call ALlen Blade and order his grinding videos. They are inexpensive and he shows you how to grind a blade from scratch and tells you how to keep lines even, hot to make that plunge area look nice, etc.

You may want to pick up some mild steel (you should be able to get some from hardware stores) and practice with that. I hear that you can grind many blades out of that with one belt for practice. Mild steel DOES NOT make a good knife, or any knife for that matter. You can't harden it nearly enough for what a knife needs to be. But it is cheap practice.

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"Come What May..."
 
Welcome to knifemaking...hehe! Crayola has given you some good advice. Additionally, I would recommend grinding freehand. I tried grinding off the rest when I first started and it turned out poorly. When I started grinding freehand with the proper techniques, my grinding improved 100 percent within an hour. Find some scrap steel (preferably free) to grind on for a while. I have a small box of botched attempts in my shop. Expect 40-50 attempts before you start to get the hang of it.
 
I just picked up my practice steel. 20' of 1 1/2 x 1/8" mild steel. Only cost me $5. That'll give me about 30 or so practice blades
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I never thought I would get an even grind.Alot of good steel ended up bad steel.But once you get the feel of freehand grinding it becomes second nature (almost).Practice, practice and practice.
 
If it was easy everybody would be doin it.
Throw away the rest or just use it for profiling. I grind barehanded if the metal is hot enough to burn you it's to hot ! Dunk it in a pail of water that you have next to you.
I ran accross some saw mill bandsaw blades and acquired enough of them to see me through most of the trial and error stages.I hope.
Next thing is I always start out grinding a big knife.You can always make them smaller.
I hate to use practice metal. What if you get it right the first time??
Just do a lot of grinding, take a look after each pass and see what happened.
Super glue over those gouges in your hide make a pretty good bandage.
Take Care
TJ Smith
 
Congrats on the Coote and a good setup too!

Find something easy to grind for pratice. I use plexiglass because it's free. Some have warned about breathing the particles so take approiate steps. You can also use wood or other soft substitute for steel.

The advantage to using fast grinding stock is in seeing your mistakes instantly. Wood on a 50 grit belt will show mistakes before you know you've made them.

Later, Lynn
 
I did the opposite of most of you guys...I had a 2" X 48" Jet grinder to start with, and got a bunch of fully hard D2 planer blades.
Bought 24 grit CZ belts, a big bucket of water, & went to work.
After getting that half-bassed right, I moved to annealed stuff & it seemed to grind like a dream.
Whatever floats yer boat....
FWIW, make sure your platen is a skosh narrower than your belt, raduius th edges a trifle so they ain't so square, track the belt to the side of the ricasso you're grinding, kill the edge ofthe belt a mite with a piece of hard steel or a crock stick, and keep Crazy Glue handy....haven't had a stitch in 6 years(knock on wood)... but have glued up my share of belt boo-boos!!!!!
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Dear exsanguinate:

There are a lot of tricks you can use to get even grind lines and avoid warping. It's hard to get too specific because you didn't say if you're hollow grinding or using a platen. And, the length of the blade can make a bit of a difference on how to set yourself up. (Don't start with broad swords!)

Try laying out your bevels. You can scribe "railroad tracks" on the edge of the blade if you are grinding with the edge up. Use a fine Sharpie pen and a square to mark the bevels' perimeter if you're grinding with the edge down. Both methods allow you to see where to stop while you're grinding.

Most materials warp when cut due to stress relief. (Even wood!) Heat adds to the effect. One way of reducing the heat, by dipping your blade in water, has already been mentioned. You could also reduce the speed of your grinder and attach a "heat sink" (i.e. piece of bar stock) to the back of the blade. I find that makes it easier to control, as well (kind of like shooting a carbine vs. a target rifle).

Remove even amounts from both sides, switching often from side to side. Leave a little bit on the bevels to clean up with grits finer than 220. The last few passes with real fine grit are just to achieve the final finish - not to correct mistakes. If the belt is clogged or too dull, the cut won't be accurate and the blade will heat up faster.

Don't try to do what some of those magazine photo's suggest - seeing how big a shower of sparks you can make. (Notice how a lot of times the guy is simply pushing the end of a piece of bar stock into the belt!) Take your time and keep the blade cool. Use a "push stick" just to balance and control the cut - not to force the blade deep into the belt. If you get yellow discoloration, it's getting hot. Blue means, at some point, you've reached 500 degrees! (Not good on you or the blade.) Orange/red usually occurs at the thinnest part while grinding and should always be avoided.

and....... Practice! Practice! Practice!

Ask 100 guys and you'll get 100 techniques. I hope some of these work for you!


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Tom Anderson
Hand Crafted Knives
 
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