Diamond wheel grinder.

[sacc51]

I’ve had a small motor hanging around the shed for a while, rather than throw it out I bought a $12 diamond grinding wheel off ebay, welded together a frame and mounted wheel and motor on the frame. I use it for honing bits after rough grinding, gives a nice sharp edge and makes the bits cut just a little better, also does a pretty good job on drill bits. The motor is only a 1450rpm low hp unit but with the pulleys probably spins some where just north of 2600rpm. Not fast enough I know but I don’t have any bigger pulleys and it does the job as is.

The vice you see behind is a freebie if anyone's interested, details here: http://www.woodworkforums.com/showthread.php?t=193300

[KBs PensNmore]

Looks good, nothing like recycling old motors and steel to make a useful item.
Kryn

[BobL]

Goo wrk there.
Is it just me or is the tool rest upside down?

[sacc51]

Upside down> Not sure what you mean, it's adjustable and at an angle in the picture. That what you mean? Anybody know what rpm these diamond wheels are supposed to spin?

[BobL]

Upside down> Not sure what you mean, it's adjustable and at an angle in the picture.

In the picture it looks like a round bar is above the steel plate tool rest. Or maybe the round bar is the tool rest?

Usually the tool rest is a flat plate like this?
http://www.woodworkforums.com/attachment.php?attachmentid=342168&stc=1



Anybody know what rpm these diamond wheels are supposed to spin?
Max RPM is wheel dependent (should have been provided with the wheel) and ranges anywhere from 6k to 10+ k rpm
4 - 7 K are are the sorts of numbers I've see on various T&Cutter grinders
Im far from a pro user but I believe 5-6k rpm is often used.
Just swapping motor out for a 2850 rpm motor should see your setup well in the range

My home bake setup uses a flat cheap 6" diamond wheel on the side of a CBN wheel on a 3Phase grinder with a VFD drive
Details here http://www.woodworkforums.com/showthread.php?t=188429
I use it 90% of the time for HSS on the CBN wheel and run at around 2000 rpm for a well controlled grind.
I can crank it up to 70Hz (4200 rpm) - It could go faster but I have a green ceramic wheel on the other side and that is limited to 4500 rpm.
I was thinking of removing the green wheel and getting a cupped wheel like yours for the other side.

[sacc51]

Ahh, I see what you mean. The flat plate you see is welded behind a 10mm rod. The 10mm rod is drilled and tapped as a hinge point so regardless of the rest angle the distance between rest and grinding wheel remains static. Had I welded the plate on top of the rod the wheel/table distance would change depending on table angle and that would have necessitated another in out adjustment. It was just a simple honing grinder so I didn't want to complicate the design.

I used the dished wheel because it provided a flat grind surface which made measuring the table angle easy.

No info was provided with the wheel, can't expect too much for $12 I suppose. I have a 2850rpm motor, but at 2hp, might be a bit of overkill for this grinder.

The motor I've used (hp???) should handle a larger motor pulley which could possibly raise rpm to around 3500rpm, anything over might be pushing it I think. The physical size of the pulley would be a limiting factor as far as available space goes though. But like I say, it was just something to use the motor for and it works as is, I wouldn't be trying to remove too much material with this wheel. Can't remember the grit rating but it was very fine.