My slow speed diamond disc lapping machine, the beginning

[Janderso]

Hey Jeff,

Back in post #69 on page 7, @OCJohn asked the same thing I was wondering:


Thanks,
Brian

I have four rare earth magnets
It is rock solid.

 

[brino]

Thanks Jeff!

 

[homebrewed]

This is a good thread, thanks for sharing your work!

Here's a 0-90RPM gear motor for $99. Nice with the speed controller, but it would need a different mounting system. More like a stepper.

Speaking of steppers, I've been using a "spare" stepper motor + driver for a similar application (but not implemented nearly as well). I'm generating the step pulses using a 555 timer circuit I built for the purpose. But all the pieces now would cost more than $99, especially if you have to buy a power supply for it. On the flip side you would get a _lot_ more flexibility in terms of the RPM range.

I've used 4,000 grit diamond to hone carbide scrapers. It produces a mirror finish on the scraper. Too bad my scraping results don't "reflect" the tool

 

[Boxless]

I have four rare earth magnets
It is rock solid.

How does the runout perform when you switch from one grit coarseness disk to another? Still good?

Cool project BTW.

 

[Janderso]

How does the runout perform when you switch from one grit coarseness disk to another? Still good?

Cool project BTW.

Yeah, no difference

 

[Janderso]

This is a good thread, thanks for sharing your work!

Here's a 0-90RPM gear motor for $99. Nice with the speed controller, but it would need a different mounting system. More like a stepper.

Speaking of steppers, I've been using a "spare" stepper motor + driver for a similar application (but not implemented nearly as well). I'm generating the step pulses using a 555 timer circuit I built for the purpose. But all the pieces now would cost more than $99, especially if you have to buy a power supply for it. On the flip side you would get a _lot_ more flexibility in terms of the RPM range.

I've used 4,000 grit diamond to hone carbide scrapers. It produces a mirror finish on the scraper. Too bad my scraping results don't "reflect" the tool

I just saw this.
Way over my head.
4,000 grit aught to put a mirror finish on those blades

 

[Boxless]

Yeah, no difference

Great. I think I might try something like this. Thanks!

 

[Boxless]

Janderso, My project is slow moving, but I bought an aluminum disk for my project and I'm starting to think about how to affix that disk to my arbor. I have a couple questions about what you did.

First, I can see the key on your motor shaft and the associated slot in the hub you made, but I cannot see how you held the hub onto the shaft. I'm assuming there's a setscrew hiding on the back side of the hub that just never showed up in any of the pics?

And second, about the screws you used to clamp the disk to the hub... It looks like you threaded both the hub and the disk? In this pic, there are threads below the countersink?

Did you ream the threads out of the aluminum disk when you were done?

 

[Janderso]

Janderso, My project is slow moving, but I bought an aluminum disk for my project and I'm starting to think about how to affix that disk to my arbor. I have a couple questions about what you did.

First, I can see the key on your motor shaft and the associated slot in the hub you made, but I cannot see how you held the hub onto the shaft. I'm assuming there's a setscrew hiding on the back side of the hub that just never showed up in any of the pics?

And second, about the screws you used to clamp the disk to the hub... It looks like you threaded both the hub and the disk? In this pic, there are threads below the countersink?

Did you ream the threads out of the aluminum disk when you were done?

I used a set screw on the keyed coupling. I made sure I had a tight fit for accuracy, it probably didn't need the set screw.
No, no reaming.
As said before, the slow speed output is the tough part. Trying not to break the bank.

 

[Boxless]

Thanks again. As for the speed, my (potentially flawed) plan is to use a DC motor to drive a belt coupled grinder arbor.