How to flat grind with a disk grinder?

T

Timy

Well-Known Member
Do you have it setup vertical or horizontal?

I just came across and am very fascinated by the idea. Love the idea of getting my flats flatter.

Also can you set it up with a single phase motor? I have a spare leeson 1hp motor that I am toying with the idea of getting a 9" disk from beaumont.

Apologies if this has been asked before, my search fu is lacking.

Thank you for your time.
 
I've got my disk horizontal.

The problem with single phase is it will not be variable speed or reversible.

For grinding on bevels this means that on one side it'll be throwing sparks right in your face or you'll have to grind one side of the blade edge down which is very awkward.

Even a 1750 RPM motor is way too fast for a disc grinder IMHO. I've typically got mine running 50% speed or less.

You'll be FAR FAR ahead to go with a VFD and 3-phase motor or DC motor and a speed control IMHO.

I believe if you threw a disc on your spare Leeson you'd never use it or at least not the way you think you would.

Those are my thoughts on the disk.

-Josh
 
FWIW, single phase motors can usually be reversed, but this is best done with a drum style switch, which, IIRC, is not usually cheap.

I agree that 3 phase with a VFD is definitely the way to go. Anymore, it can be done fairly cheap if you shop around.
 
I have the disc grinder that Trugrit sells, and I have a Baldor 1140rpm motor with a built in reverse switch. It works well for me, but I don't use it to grind on blades.
 
The qualities you get from a disc grinder are increased 100 fold when you can use it at variable speeds (IMO).
I didn't have one for years and sprung for one from Rob. Id be lost without it!

Good Luck and God Bless
Mike
 
Honestly I think once funds allow Ill be getting the one that rob sells. Variable speed sounds like where its at.
 
Well I have one from Rod, Rod Nielsen that is. It has variable speed, reversible,with the magnetic hub . It allows me to have different grits of sand paper on separate discs so you don't have to change the one disc for a different size. He sells the magnetic hub and discs as a separate part so you can attach to your own motor. It does help a lot in the work I'm doing. Frank
 
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I do all the primary bevel grinding on a 2x72 belt then move to the horizontal disc to get them flat. The belt grinder does not grind the surface of the blade flat, there are usually slight dips and swirls in the surface. The variable disc does a good job of getting the surface true. The small "work post" at the edge of the disc is used to stabilize the blade against the disc surface. I rest a finger or the edge of my hand against it; makes the grinding go a lot easier. The vertical fence is removable, there are wing nuts under the table surface which are used to attach it to the horizontal plate.This is a Rod Neilson magnetic disc. The motor is reversible as well as variable speed.

DSC01090.JPG
 
I also have a couple of Rod Neilsens remove able disc system with vfd. I rarely run mine over 30%. I would be lost without them as well.
Jim
 
Awesome guys thank you for all the info.

Fred fantastic picture, thank you for sharing.

If anyone could post a video or series of pictures just roughly showing how you do the flats? I have never used or seen a disk sander and I am terrible curious
 
Check out my web-site and Rod's web-site at http://www.nielsendesigndiscgrinder.com for the Nielsen Interchangeable Disk System. I have the systems in stock and will have them at Quad State in two weeks. I can also supply the motor and VFD and my wiring kit and my one page instructions for wiring and setting up the VFD and motor. Watch the Video on my web-site for more information.

And you can use your Bubble Jig with the Disk Grinder.
 
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