Belt grinder Gear ratio's

[Bryce]

Well I have been telling myself its time for a new grinder But I am unwilling to fork out the big bucks for a fancy beast. I have a Brand new 1 Hp 3250 rpm motor I got for free I understand that 1750 rpm is ideal but I have what I have What Kind of gear ratio would i need to run a 4" drive wheel like Rob frink sells? At a good belt speed (Btw how fast am I shooting for?)
How thick of plate are you guy's building your grinders out of?

Bryce

[george tichbour]

To get the proper reduction with a 4" drive wheel you should be using an 8" contact wheel.

An alternative is to mount the contact wheel on a lay shaft and drive the contact wheel with a belt...again the motor pully should be exactly 1/2 the diameter of the lay shaft pully but you are now able to use whatever diameter contact wheel you like because the lay shaft will be turning at 1750 all the time.

My homemade grinder is the lay shaft variety with a driven contact wheel on a 1/4" thick steel plate base.

The advantage of the driven contact wheel on a lay shaft is that you can use the machine either as a grinder or as a bufffer. Make sure that the contact wheel overhangs the edge of the plate for clearance.

[Bryce]

George Thats really what i was thinking of the shaft I should have specifyed that. what I Really was asking is what size of pulleys should i be using on the lay shaft and motor to get the shaft to be turning 1750 with my 3250 motor The way I am building is with a 3 wheel set up one as the drive wheel probley the 4" wheel rob frink sells. and for the tracking wheel the 2 inch one frink sells for tracking. a 10 inch contact wheel A large castor wheel untill I can afford a real one. So tell me if a am wrong I should use a pully twice as big as the one on the motor on the shaft and i will have the corect speed right?

[george tichbour]

The two to one ratio will really give you 1625 RPM but it is close enough because it will take two revolutions of the motor to turn the other pully one rotation.