Thread: Build your own grinder

After finally scoring a motor for free (!), I'm about to start on my grinder-building adventure. After spending an hour tearing the thing apart, I can honestly say this is the most fun I've had with a treadmill.



Getting the motor was the main thing, but a bunch of steel, electronic bits, a linear actuator (possibly to use with a standing desk if I ever get around to building it), and a small pile of nuts, bolts, etc., was a nice bonus.

Originally Posted by Cangooner

After finally scoring a motor for free (!), I'm about to start on my grinder-building adventure. After spending an hour tearing the thing apart, I can honestly say this is the most fun I've had with a treadmill.


Getting the motor was the main thing, but a bunch of steel, electronic bits, a linear actuator (possibly to use with a standing desk if I ever get around to building it), and a small pile of nuts, bolts, etc., was a nice bonus.

Very nice. Are you following Bruno's plans? If so, how much was it for all of the steel cut to spec?

Originally Posted by Butzy

Very nice. Are you following Bruno's plans? If so, how much was it for all of the steel cut to spec?

I haven't decided on a design yet. First I want to see if I can make use of the steel that made up the treadmill frame. If I can, that would be great. But if not, then I'll start costing things out. Fingers crossed...

I had heard that the tread mill motors could be used but never actually spoke to any one that has used one. Please let me know how it works out.
Thanks
Ray

Originally Posted by wmrayt

I had heard that the tread mill motors could be used but never actually spoke to any one that has used one. Please let me know how it works out.
Thanks
Ray

No problem. I still haven't built it as I've been *very* slowly accumulating the bits and pieces, but I'm hoping that this weekend I'll actually get it going. There are three resources you should check out:

1) if you're a facebook user, there is a group dedicated to building 2x72 grinders. Check out the files section for plans, etc: https://www.facebook.com/groups/847488865357217/

2) Dan Comeau (who is part of the FB group above) has his own site with *tons* of info about building grinders, as well as other knifemaking-related stuff: DIY Knifemaker's Info Center

3) If, like me, you want a more elegant solution for controlling your motor speed that a janky re-using of the treadmill control board, check out this video. I have caveman-level skills when it comes to electronics, but followed this and got mine working just fine. I followed the advice of others one the FB group to upgrade the bridge rectifier to a beefier model. For a few bucks, it's probably good advice.

Just be aware that a treadmill motor is typically not very strong. You can use it to build a sander but be careful to not bog down the motor too much because that will burn out the coils. As long as it doesn't slow down, you're good. But if you are slowing down the belt, that's when you need to lighten up the pressure.

never mind, I miss read

Originally Posted by Bruno

Just be aware that a treadmill motor is typically not very strong. You can use it to build a sander but be careful to not bog down the motor too much because that will burn out the coils. As long as it doesn't slow down, you're good. But if you are slowing down the belt, that's when you need to lighten up the pressure.

Absolutely. I think I lucked out with mine as it's 2.9hp peak, and 1.75hp continuous (DC). From what I understand, that should do the trick.

I *finally* have a grinder-shaped object in the shop.

It isn't mounted yet, but after a tremendous amount of tweaking, my "belt" (72" of webbing) is tracking well. I have a flat platen to start with, and still need to make a work rest and set up a wheel for hollow grinding. But it's on its way.

Other things that remain to do: Mount grinder and box o' controls; build a shroud for the motor (it is not enclosed and so will die a quick death from metal dust/grit if not protected) that will include a fan for cooling and to encourage dust to go where I want it.

My first order of belts should be waiting for me at home when I get home from the office, so fingers crossed I'll be able to do a test run.

Odds of me sneaking away from the office early tomorrow if at all possible are very, very good.

Excellent!

That is looking great, nice build.

Joe Calton, has some super ideas on sealing the tread mill motor from the dust.