Belt grinder build questions

T

Trevor51

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Jun 24, 2015
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I was originally going to buy a small belt grinder but I decided I will build my own 72 x 2 belt grinder. I am just wondering if there is any other options for the drive wheels when building one. maybe long board or skate board wheels? Also should I just have one drive wheel right on the motor shaft or should i have the motor with a v belt going to the grinder itself? Thanks any advice is much appreciated.
 
I can't really provide input on alternative wheels for the grinder, But I have picked up some stuff from previous posts like this concerning direct drive v.s a pulley system. My understanding is you should really only use a direct drive system if you have a Variable Speed Drive hooked up to the motor. Otherwise, you would just be stuck on the same speed (not ideal) the whole time you are using it. Different speeds are necessary for different grinding processes like finish work, rough grinding, profiling, etc. Assuming you don't have a VFD, get yourself a couple of 3 step pulleys (2", 3", and 4" dia.) and set your grinder up to run on a pulley system.
Hope this helps!
Tanner.S

Here is a picture of my 3-step pulley system. May be hard to see the pulleys but you get the picture (badum-tsss);
 
Step pulleys are a good way of running a grinder without the expense of a VFD. Larry
 
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Just to clarify something about having a VFD attached to a pulley set up .. You don't just have one speed . It is fully adjustable. My KMG has a pulley set up with VFD and works perfect .
 
Why would you need pulleys with a vfd? Direct drive gives solid torque, less vibration and parts, and instant speed control.
 
Not all grinders are direct drive.
The kmg isn't. I have pulleys and a vfd as well.
 
If you want a direct drive, you'll want to go with a VFD if you want more than one speed. Keep in mind this requires a 3 phase motor. VFDs will range anywhere from say $100 for an open (needs an enclosure and/or filters to keep dust and debris from destroying it) to about $450 for a TEFC. Then there's a motor, which will vary depend on where you source it. I've found 3 phase motors for $50 to $100 before.

If you go with a belt and pulley system, you can still use a VFD, but instead of needing step pulleys (will give you 3-4 speeds on a single speed motor) you can get by with just a single pulley on the motor and one on the shaft.

Now, I'll just add that there is less power loss due to friction and other factors with a direct drive vs a belt/pulley system. with a 2hp or 3hp motor, this may not really be an issue though.

As for drive wheels, there are plenty of economical options on eBay, and you can get a decent aluminum wheel for $35 or so that will be much better than any skateboard wheel, caster, or similar. Same for trackng and idlers.
 
Ok thanks I happen to have to three step pulley from a old Briggs and Stratton motor from a lawn mower. Also Where is the best place to buy belts and drive wheels that will ship to Canada. Thanks for everyone's help I really appreciate it.
 
Oregon Blade Maker on ebay sells a decent set of wheels and will ship to Canada. Supergrit has a large selection of belts and also ships to Canada.
 
I got mine made locally by a guy who has a lathe. I just supplied him with bearings and aluminium. They work perfectly. Same with the drive wheel. I just glued rubber on it and it works without problems. I use a VFD too and I can highly recommend it if you have the money (check for used ones. Will save you money!).

So I would say that if you know someone with a lathe, ask them if they can make you some wheels.

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Just chiming in on the conversation, I'd highly suggest you go for a VFD. It lowers your energy cost significantly. And gives some electronic protection for your motor. Moreover minute adjustments to speed is just a button away. You won't have to shift pulleys. I build industrial machines for people and we use inverters(vfd) for every single motor because of the above reasons.
 
what thickness of steel will I need to make a 1 1/2" x 1 1/2" square tubing fit inside a 2" x 2" square tubing to make the adjustment portion for the platen.
 
mrlocchoc said:
Treadmill motor is a good option. It is easy to find and come with speed controller.
Click to expand...

I heard that they have very little torque even though they are rated at fairly high horsepower. I found a 1/2 motor in my shed so I'm just going to use that with some step pulleys. I know it will be under powered but it will work for now untill I can find a 2hp for cheap.
 
Treadmill motors are designed to run a very wide belt capable of supporting hundreds of pounds. Seems like the torque should be sufficient for a 2 x 72.
 
Stay away from skateboard/longboard wheels!! I just made another platen and i tryied those wheels: they have the bearings offset to the side and the realtively soft wheels deforms in the "unsupported" side due to the belt load.
Fortunatly i had transpallet's spare wheels, those did the trick, but those are heavy casts so you may yet stumble in unbalanced wheels and those could create whobbling.
 
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