Grinds not even

dirtyphil

dirtyphil

Joined
Mar 19, 2014
Messages
165
having a problem that I didn’t have when I was new...when I was new to knife making my plunge lines had a nice “L” shape to them (though the blade left a lot to be desired overall!) Now, on my left side I get a nice “L” but on the right I get a long sweeping “U” shape. I try and concentrate, use the force, telepathy, etc on placing my blade perfectly on the grinding belt on both sides and still get the L and U. I know it’s muscle memory but my memories are different on each side! Tips?
 
I feel your pain, I didn't grind any knives for over a year and I just got back into the shop and my grinding...well, I need to put some time in front of the grinder to get back to where I was.
Things that I can think of to check if you are using a flat platen.
Make sure the belt is not hanging off the edge of one side of your platen.
Check to see if your platen is worn.
Use a heavier backing on your belts. Stiffer belts give crisper lines.
Good luck, I hope you get it figured out soon.
 
Thank you sir. I do have a light dish in my platen and just got glass to replace it. I was thinking a tilt in my wrist maybe or canting the blade differently on each side. Back to practicing.
 
Two suggestions:
1) Carbide shoulder jig
2) File in the pluinges with a #2 or finer file for perfect 90 degree plunges. Some folks use a small chain saw file to get rounded plunges.
 
dirtyphil said:
Thank you sir. I do have a light dish in my platen and just got glass to replace it. I was thinking a tilt in my wrist maybe or canting the blade differently on each side. Back to practicing.
Click to expand...

If the dish is on the edge of you platen it will give you a rounded plunge. And that's fine if that's what you want but the other side has to match. If you want rounded plunges hang your belt off the other side so try and match the two.
 
I would think that a rounded or sweeping plunge line would be stronger then a hard 90* one due to less stress concentration points but have yet to see a knife brake right at the plunge line because of it

So, it likely comes down to preference. I like the sweeping plunges so I run my belt slightly over the edge. Also as belt tension seems to play a large part in keeping both sides the same. At least on mine
 
It happens to the best of us.

You need to break down exactly what you are doing on both sides. You are changing pressure, angle, motion etc.

To eliminate some variables and figure out what is changing you can use a steady rest, make sure the level of the edge is same when doing both sides, make sure hand and figure placement is the same, be sure the location of your body is in the same location etc.

Rest the spine on the steady rest with the grinder on a very slow speed, ride spine on the rest and try to exacty the same on both sides.

You will find out what is changing side to side, also be sure to hang over the belt the same on both sides to have the same sweep at the plunge.
 
Seems to me the "L" shaped plunge would produce stress stress cracks, being a sharp angle.
 
Are you grinding thinner stock than you used to?
Thin stuff tends to warp if you mostly grind one side first, wreaking havoc on side two. Check for straightness before switching sides.
 
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