Belt Grinder info

galadduin

galadduin

Joined
Dec 25, 2004
Messages
1,363
I am bored of my bench grinder and am making my own belt grinder. I collected 3 HP motor and 2 wheels, constructed them and yes it is working.

Just for a 1 day labor and here is the new year present for my smithing shop.

BUT wait it is revolving too fast, i can't control it damn. :confused: . However, the wise guys in thesse forumssss will tell me whatss wrong, how we can control the speed, wont they my preciousss.. ;) ..

ps. I think i have to change the wheel diameters, but i dont know to reduce the speed do i have to reduce or enlarge the diameter of the first wheel connected to motor and at which scale does this change affect the pace.
 
It's like a bike. You reduce the wheel on the motor to go slower. First, I'd figure your FPM (Feet per minute) take the diameter of the wheel, multiply by pi (3.14) this gives circumfrence. Multiply by the RPM (rotations per minute) of your motor. Then divide by 12. (Assuming your wheel is in inches :eek: ) The formula is like this: (D)(pi)(RPM)/12=FPM
you could also reverse this to find the size wheel you need. Take the FPM you want, times by 12, then divide by the RPM and pi. This will give you the diameter of the wheel in inches.

[(FPM)(12)/(RPM)]/(pi)=D

Hope this helps. I am not an expert, just used some basic algebra :barf: to help out.

I have heard that for knives you want the belt to run between 4000 and 6000 FPM. Maybe it was 3000-6000.

If Yall find anything wrong with my formula or FPM suggestions, please correct them, I am NOT a professional knifemaker.

Hope this helps.

~Brian
 
A smaller wheel connected to the motor will make the belt go slower. To figure out the exact speed of the belt, you need to know how fast the motor spins and the circumference of the wheel.

The motor RPMs are hopefully printed on the side of the motor.

To find the circumference of the wheel you can measure with a flexible tape measure. If you don't have one, measure the diameter of the wheel and multiply it by pi (approximately 3.14159) to get the circumference.

Once you have those two values, simply multiply them together, so if the motor spins 1750rpm and the wheel is 50cm around (about 15cm in diameter), you multiply:

1750 revolutions/minute * 50cm/revolution = 875m/minute

because the surface of the wheel goes 50cm every time it goes around and it goes around 1750 times every minute.

You can also make your speed adjustable with stepped pulleys like you can see here:

http://beaumontmetalworks.com/kmg-base.html

-Allin
 
Cool Brian, I can never remember that formula. :D

Another thing to consider is a set of step pulleys, which will allow you to vary your belt speed.
 
I ran across the formula while searching for homemade grinder plans. I forgot it too, and had to figure it out all over again :rolleyes:! That took a little thinkn. But, it looks like my algebra is finally paying off! :p

The step pully idea is a good one. I'd forgotten about that. If you can, I would just do that and forget about the wheel size, that way if you want to cut faster/slower. My little craftsmen is nice, but I have wished for variable speed, so it will come in handy.

~Brian
 
Thank you all.
It was too big i figured..
You saved my life; i will buy a stepped pulley. It will be cool..

We love you my preciousss..

:cool:
 
You must log in or register to reply here.
Back
Top