the heel and tip of my grinds are often too thick, what am i doing wrong?

C

clockworkfish

Joined
Dec 1, 2010
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so i only have a 1X30 belt sander and i find that the heel of the blade as well as the tip often end up being like twice as thick as the center area of the blade. is there anything i can do to minimize this outside of just taking that area down carefully with needle files post heat treat and before final hand sanding?
 
I may be completely wrong here BUT... Assuming the angle of your grind is the same throughout the blade then you will notice the height of the grind raises as you grind deeper into the steel. My point being is that you are most likely just not grinding deep enough in those areas.
 
That plain and simply means you spent more time in the center than the ends. Were you using the platen or unbacked area of the belt when grinding? I'm not a big expert, but I still did a ton of grinding after quenching, left my knife way too thick. I ended up just grinding with bare hands(in order to detect heat) and once the piece got absolutely too hot to hold, I would dunk it in ice water to cool it. I took the reasoning that tempering is usually done at over 400 degrees, and I think that the metal was getting to about 130 degrees if it's too hot to hold, therefore the 130 degrees for an hour of grinding wouldn't hardly do anything to the hardness of the steel. In fact, I only tempered for about an hour after quenching, so I welcomed any softness in steel gained. So I would recommend just using the belt sander with bare hands. Steel never turned color for me as long as I kept moving a bit.

Why would you use needle files and not just regular sized files?
 
are you applying consistent pressure? for me i find that i unconsciously ease up pressure as i end and begin getting on the belt. Also if you are flat grinding try pulling the knife striaght pass the grinder instead of following the curve.
 
Oh, I just run my blade straight across the platen with no pulling up or down like ken says. Try that, that should do it.
 
Perhaps you are only using one grind line for a guild? Go to two if you are and it will help you maintain the same thickness all along. Frank
 
Jeremy is right, I had the same problem on my first knife, If your grind lines are uneven and assuming you are keeping a consistent angle then the problem could be you are just grinding more in some areas than others. Where the grind is lower, grind there for a little bit longer and slowly bring the lines back to where you want them.
 
With a little 1 x 30 and that small platten it would be tough to get a nice even grind, you can work on the thick areas more, I always go the full lenth of the blade but use light pressure and move faster over the areas that dont need much work, this help prevent the edge of the belt causing a mark and also blends the grinds together. I spend a little time , look at the blade and then decide what Im going to do and how to achieve it, make a couple of passed and look again
 
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