Home build grinder

[colson]

I like to get some advice on a motor I am thinking of using on a grinder I am planning to build.
Being in the industry I am I have a lot of access to 1.1 hp and 1.5 hp 220v AC Motors with a
a average rpm of 1200.( motors are designed to pull 2 tons at a 90% duty cycle)

After a few calculations I have found I can step up the rpm and get about 3000sfpm
by adjusting the size of the drive wheel (200mm)and using some step pulleys to adjust it further.
I would love to buy a grinder but it is just not a option (funds) and I have access to pretty much all
the materials I need and am fairly proficient at welding and fabrication.

Being very new to knife making ie a hobiest I would rather grind slow and carefully and adapt the grinder
that I could swop out motors in the future .
Has anyone tried using similar motors and would the speed be sufficient. Here in rainy South Africa all our
Power outlets are 220v so I don't have any worries there.

Any advise would be appreciated .
Col

 

[Alfazulu]

I am in the process of building a grinder, too. I will be going with either a 2hp or 3hp 240V motor running at 1800rpm. I think a 1.5hp motor would be fine. I was planning to use a 1.5hp motor until recently, when I read a thread about how much is too much. Basically, the answer was always there isn't too much, but there is too little. I can get a 2hp or 3hp for about $30-40 more than a 1.5hp, so it's a no-brainer for me.

While I don't yet have a GOOD grinder, I have ground about 10 knives. From that limited experience, I can tell you that "grinding slow", as you said, is better done by reducing pressure, not speed. From what I've read, most belts are designed to run at a certain speed. You can grind slow by changing to a finer grit belt or using less pressure.

 

[colson]

Thanks for advice , I come across quite a few motors in my line of work and for free.
The electronics supporting them blow out or they get upgraded to quicker DC motors with backup
battery units.

Pretty much done all my knives using hand tools as I have not wanted to work harden the steel.

Thanks again for the advice I am here to learn and take in as much as I can.

Col