Flat grinding tips needed!

G

Guy Thomas

Joined
Feb 1, 2000
Messages
1,370
Help, I tried flat grinding a small 1/16" thick kitchen knife on my 4"x36" grinder and failed miserably. I ended up with a convex grind half way up the blade instead of a nice flat grind to the spine. I also burned the delicate tip right up!
Obviously I lifted up too much on the handle during the early stages of grinding but the flat grind seems to elude me. Do you lay the blade flat on the grinder and then apply pressure towards the cutting edge or do you try to hold the blade at the 1/2 or 1 degree incline and then lower it onto the belt?
Thanks for the tips in advance (I'm suspecting that it might actually be harder to grind very thin blade stock than the heavier blades!)-Guy Thomas
 
Guy,

The problem you describe sounds exactly like the problem I was having when I started (not that long ago, so you will be surprised what you can do with good techniques). I was trying to cut the final angle of the bevel from the beginning. I also used a rest, thinking that grinding would be easier that way. I had no feel for the grind when using the rest. Blade hold is also critical. There are, of course, many methods used by many users. Here is mine.
Try cutting in initially at about 30 degrees. Use an old belt for the initial cut since edges are hell on belts. On 1/16" stock this should take it close to the scribe lines real fast, so be careful. If possible, run your grinder vertical with the blade edge up (belt running down). Start decreasing the angle, keeping the pressure off of the edge. This will slowly move your grind line towards the spine, while maintaining you edge thickness fairly well. Do a little at a time and look at your work often. The further you cut the bevel in, the more you will feel it when you are 'on angle', so to speak.
As for the tip, you may find it easier to blend it in after the bevels are mostly ground. When 'pulling' the handle, pull less than would normally be needed. You will still be putting the bevel on, but will leave the tip and edge near the tip thicker.

[This message has been edited by Kaos (edited 05-16-2000).]
 
Kaos, thanks for the tips! I can see where starting at a higher angle would give you something of a starting point, the "groove" I've heard about, eh? This is how I've been practice hand filing bevels, I don't know why I didn't apply it to the grinder also!-Guy Thomas

[This message has been edited by Silent (edited 05-16-2000).]
 
Bob, if you ever use a disk to flat grind, you will never go back to a belt. I have a
home made 9" grinder with a 1 1/2" variable speed. It is also reversible. I use a 1"
square push stick with a 1/8" lip (Thanks Kit), to help hold it square. With a disk,
you will not have that durn 2" dip you can get with a 2" belt. I use 9" X 11" wet and
dry sand paper. I use 3M 777 spray adhesive on the back of the sand paper. After I
place it on the disk, I use an old pair of scissors to cut of the extra paper. I start with 80 grit (for folders) and go up to 400 before heat treating. After heat treating, I go back to 400 and on up to 1200. I slow the grinder down to about 20% of power. After the 1200 grit I hand sand, starting with 600 grit.

If you are going to make sheath knives, then the disk should have a one degree taper on it. I got mine from Ronny R.W. Wilson.

------------------
A.T.
http://www.customknives.com
AKTI #476


 
You must log in or register to reply here.
Back
Top