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Jonny C

Bevel advice

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Hello! I’m trying to finish the edge on a knife I’ve made but I don’t have a belt grinder, just a 4X36” sander and my brand new file won’t cut it, the blade has already been heat treated and tempered and I left the edge 1/16” thick , any tips or recommendations on affordable equipment would be appreciated! P.S I do have a bench grinder and angle grinder but I’d prefer a nice clean bevel and plunge line, thanks!

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I bought a dayton 2x48 belt sander for a decent price if you can afford it I would suggest getting a 2 x 48 or even a 2 x 72 the 4 x 36 ones well yea.  If you have the ability to do so I would invest in a better belt sander.  As far as the bevels I'm sure others will chime in.  I find that forging the first bevels works much better than having to grind them in.

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I forged the bevel but didn’t get a nice crisp line, kinda turned into a wedge shape that I was able to grind before I heat treated, Guess it’s time to invest in a proper grinder, thanks for your input

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It can be done on cheap sanders, it just takes more time.

Start with a low grit belt, lowest ive found for a 4x36 is 80 grit, then go to 120 and hand sand after that. Should be like a 4 hour thing.

First grind the edge at around 45 degrees to establish the centerline of the blade, the rest of the grinding is creating a bevel and thinning the edge. With the sanding belt coming at the edge of the blade press down on the edge where you want material removed, material is mostly removed where there is pressure, with a big thick blade that doesnt flex while grinding you can hold the tip and the tang but you wont feel the blade getting hot. If you havent ground any knives before they can get hot quick, you can overheat the edge in a few seconds if the blade is still so always keep the blade moving on the sanding belt and keep water nearby to cool the blade, if the blade is just warm you can cool it in water and it take off a second from the blade heating up. if its too hot to hold cool it in the water, the very edge is what overheats easily, like 1/4" of the edge, your fingers wont be that close to the edge so you have to be a bit cautious with the very edge. I cool my blades every couple passes or more if needed, it can get monotonous but ive sat in front of a slow cheap sander for six hours, its sort of relaxing.

I have trouble letting myself relax sometimes though. If you want to go faster you can use the drive wheel of the sander as a contact wheel, im assuming you have the harbor freight 4x36, this takes more skill. The wheel has less contact area with the blade than the platen does, this means it can dig in a little deeper, and that means it can dig in too deep and the wheel will stop in the groove its created and it will overheat the edge. But, with the centerline established, the length of that tiny 45 degree bevel will show you the thickness of the blade relative to the rest of the blade. So if the bevel is the same all the way the blade thickness is the same all the way. Just do long steady swipes with the 'contact wheel'. After some of that you need to go back to the platen to get everything flat.

The wheels on the 4x36 are not simple cylinders, the middle is slightly thicker and it tapers down to the edge. This means that if you place a blade on the wheel with the edge facing the center of the wheel the edge will be ground more, if the spine is towards the center it will be ground more. The middle of the wheel will do a sort of hollow grind, dont use the middle of the wheel. 

It looks like a fun knife, I would sand the edge down to 1/32 and that should be thin enough to then sharpen the blade, id test it on a nice juicy pineapple.

Now I feel i can say that I am a fairly qualified operator of a barely functioning machine. 

Dont file hard steel!

If you can you should get a nice grinder, if you dont want to jump in all the way the harbor freight 1x30 is the bare minimum, like the 4x36 its a sander not a grinder. The motor is still weak but its fast and shaky, the wheels can be trued up and that helps a bunch. Its like the 4x36s brother, same low power but it does stuff a little different. Im not going to recommend it, but its out there and it beats hand sanding for thinning a blade and getting an edge after hardening and tempering. A few people use the dayton 2x48, listen to them, a 2" belt is worlds beyond a 1" belt.

 

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