Techniques for bench grinders

M

Marcus

Joined
Oct 4, 1998
Messages
622
I`m giving knife making a try and I`d like to use the equipment I have now to get started. I have a 1/2hp bench grinder and a variety of fresh grinding wheels from 36 to 120 grit. I also have various hand grinders and sanders. I`d imagine it would be a good idea to make a few bolt on guides to keep things even but I`m not sure exactly how I`ll make them yet. Is it okay to use the sides of the wheel to produce a flat grind? Any ideas or hints on using the bench grinder,best grit for different jobs,making guides etc. would be very helpful. Marcus
 
I think you'll have an uphill battle trying to make knives with wheel type grinders - specially ones that aren't water cooled. Most people use belt grinders or large, disk sanders.

I don't think it's a good idea at all to try and use the side of a fast moving grinding wheel to grind anything. If the grinding wheel shatters while it's turning you'll be in a world of hurt.

Be sure and wear heavy protection: face, eye and breathing. I's also rec. you read Bob Loveless' book on knifemaking as well as David Boye's knifemaking book. Both are in print and can be found by searching Amazon.com.

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You are taking a big chance grinding on the side of the wheel. Grinding wheels not made for side grinding can explode from the side pressure. I would get a disk grinder with a variable speed motor for side grinding.
Or buy a surplus gear motor and put a disk on it to slow it down ... (cheap way)..


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Hmmm,food for thought. In years of using a bench grinder in fabricating work I`ve used the side of the wheels many times but never for long or with any real force,mostly to true an edge that`s already very close to flat. However you fellas do a whole lot more grinding than I do so I`ll take your word for it and keep myself out of trouble (in that respect anyway). Thanks for the tip. OTOH I still want to use the bench grinder for this project,too many times I`ve sunk $ into something only to realize later that I don`t wanna do it *that* bad. The EDMF Bowie I bought from Dale Sandberg was made almost entirely on a bench grinder (albeit bigger than mine) using clamp on guides having the same contour as the blades edge that slide along an adjustable bolt projecting from the front of the grinder under the wheel. He uses this to keep the grinds depth and angle uniform. There`s a pic of this setup in the issue of Tac. Knives that featured his stuff. Of course this only works to grind a hollow ground edge,I`ll have to figure out how to make it more of the flat type saber grind I want. The grinds on my bowie are real nice so it must work,I`ll just have to science it out. If I like knife making I`ll invest in a belt grinding rig. Any other tips? (Other than to quit banging my head against a wall and get the right grinder now.
wink.gif
) Thanks, Marcus
 
You have all you need. Dress the wheel at 45deg to keep the blade away from the motor.
Clean up with a disc grinder and files.
Be very careful.
Ed Fowler and Wayne Goddard bolth started this way.

ED
 
I`ve been playing with bench grinding techniques with some success. I made up some adjustable guides that allow me to grind the blade stock evenly. I set it to grind at 3 different distances from the edge so that the hollow grinds overlap. This leaves 2 slight ridges along the length of the stock. I use a 4 1/2"angle head grinder to remove most of these. Final shaping is done with a sharp mill file,using a straight edge to check my progress. This technique allows me to achieve a pretty nice flat grind up to 1 1/2" from the edge. Some mods on the guides will allow 2" from the edge. The only problems so far are that it`s time consuming and to get the grind right from plunge cut to tip the spine must be parallel to the edge all the way to the tip. I`ve been cutting the blanks out like this,doing my bench grinding with the guide,then cutting the spine to the profile I want and finishing the edge grind with the hand grinder and file. Final finishing will be done with a variety of air sanders. Seems to be working out okay,the test pieces I`ve made so far look pretty good (for a beginer) it`s just very slow. I`m having lot of fun though so I may have to invest in a belt grinder at some point to make the job easier. Marcus
 
Marcus,
After thinking about what your doing this might work.
Buy a snag wheel with the right size whole and dress it with an angle. This will let you go in and out and I think they are built to take the force from the side you will be grinding on.

Dressing at an angle as discussed above sounds good to .



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I`m in the process of making my first *real* knife with the bench grinder. I decided to make a 4" bladed utility for my 1st project. Blade stock is 5160,blade is 1 1/2" at it`s widest and had a distal taper from 1/4" to a point at the tip. I`ll be drilling large holes in the handle to achieve the balance I want before putting the grip scales on. I used the technique I described above to eventually make a flat grind. It came out pretty good
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but it took a looonnnngggg time. I have about 3 1/2 hours in the blade so far. I`m guessing it would`ve been MUCH faster on a belt grinder. After I get the balance right I`m going to try heat treating it myself as 5160 seems easier than most. Marcus
 
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