©Charly, all rights reserved. Click for full size.
This was the first iteration of my belt grinder. I built the whole thing out of scraps and it was completely ad-hoc process – piling stuff upon other stuff as it seemed appropriate at the moment. The base is a piece of thick particle board – specifically the piece I had cut out of new kitchen counter for the sink. Further I used a few other cuts of particle board I had lying around and an old 1,5 kW motor from old pump. The tracking wheel, the drive wheel and the platen I got from a cheapo 60,-€ belt grinder that I bought specifically for those – I expected it to be useless and I was correct. The guiding wheels I have built each out of two ball-bearings, a piece of threaded rod, a piece of metal tube as a spacer between those bearings and a stainless steel furniture leg as a shell. The furniture leg did not pass tightly over the ball bearings but I was lucky enough to find for 10,-€ a plastic tube that filled the difference perfectly. The guiding wheels were then fixed between two scraps of plywood together with the platen in hard belt + slack belt configuration.
©Charly, all rights reserved. Click for full size.
The tracking wheel was a major headache for me. I had everything done but I still did not know how to do that part. As I was mulling it over in my head I got the idea one day whilst driving home from work. I have used a garden gate hinge (a new one, because there was no suitable one in my scrap pile) on which the wheel is fixed to the short wing and the longer wing can rotate. The angle between the hinge wings can be adjusted by a screw going through the long part and pushing against the part that holds the tracking wheel. The force for tension was supplied by a spring from an old bed. The spring ws too long so I had to bend it around a strange wheel of unknown origin.
It has worked reasonably well, after all I made two knives on it and I ground the basic shape of a machete. But mainly it was a proof that I can do this and that it will work. The machine as seen on these pictures does not exist anymore. I have completely rebuilt it and only the base and frame have stayed unchanged.
Never having owned a belt grinder, or used one since school (far too long ago to mention), what’s the advantage of this over a grinding wheel?
…and my curiosity out-voted my politeness, and I never mentioned that that’s a damned impressive piece o’ work. I’m so sorry.
I’d guess the 1,5 kW motor is fairly lightly stressed in this application. Did you have to do things to get the belt speed right? (Asking out of curiosity.)
And, concurring Daz, it’s an impressive machine.
A splendid piece of work, I would say!
(I do wonder, what Marcus will think of it)
What a splendid machine! Such an interesting grouping of odd things that work together. I did have a chuckle, though, over your explanation about using a new hinge. You sound almost apologetic that you couldn’t find a used one in your stash. I am now imagining your shop filled to the brim with strange and wonderful bits and pieces.
Lovely work! Intelligent improvising is a craft in itself.
The idler adjustment is really clever.
There are so many people who post on the knifemaking 101 list(s) “I can’t afford a grinder” … I don’t think I’ve seen anyone make a serious grinder with a plywood frame, before. That’s a great idea.
avalus@#5:
(I do wonder, what Marcus will think of it)
It’s way nicer than what I started with, and the first grinders I built were nowhere near as complicated or well-designed. I’m glad that I can just get top of the line gear made for me, without having to put my lack of welding skills on display for the whole world to see. I’ve been noodling on a design for a grinder for hollow faces and facets, but I plan to design it in inkscape and take it to the fabricators in Clearfield and have them cut the frame out of a 1/2″ steel plate. The way I see it is that we all decide where we’re going to work and where we’re going to be lazy.
Thank you all.
@Daz
There are several.
1) It allows to grind true facets against the platen. On grinding wheel you are stuck with concave facets with the wheel’s radius.
2) It allows quickly change belt and therefore quickly go through a set of finer and finer grids to polish a surface.
3) It is possible to have attachements for belt grinder that allow for hollow grinding like on grinding wheel, but with a scale of different radii. And the wheels can be made soft for better grip on the surface of the worked piece.
4) The slackbelt allows polishing lenticular blades and convex surfaces without faceting them or scratching them.
And probably some more that I cannot think of in early morning stupor.
@Charly
Thanks!
My grinding needs are much cruder than yours. The occasional axe or drill bit to sharpen or a burr to clean off, basically. (I use a butcher’s steel for knives.) I just whacked a medium grade wheel onto the spindle of a washing machine motor. But it’s good to know what can be done, should the need arise.