Home-Made Slow-Speed Grinder

[Dr.Al]

-Thanks Dr Al, and welcome back! Amazed nobody haven't commented on this build yet.
Really clever and nice build, and thanks for the link to the excellent description on your site.
Your flat and parallel, adjustable honing surface is a first for me - haven't seen that one ever...

Q: Given the neodymium magnet disk hold, do you get any residual magnetism in & grinding dust sticking to the disks after use?
How far below the disk surface did you set the magnets? Did you cut your gears by conventional mill/ dividing head methods?

Sorry for the slow reply - I somehow missed that anyone had replied to this thread until today. In answer to your questions, yes - there's a bit of grinding metal dust sticking to the discs, but I generally find it just wipes off fairly easily, so any residual magnetism is pretty weak. The magnets are flush with the surface and yes, the gears were cut with a dividing head and some Chinese gear cutters. I've cut gears using Mike Cox's method before but decided in the end that it was worth buying some cheap module 1 cutters.

I've scored a cheap n cheery (BG) set of disks myself, intending something of the like:
merely 3 "drive dog" 3 mm dowel pins (120 degs apart)
protruding 1,5 mm and giving the 1/2" centre a 2,5 mm stick-out
for easy placing/ turning the disk into its magnetic hold position.
Incidentally I've already dumpster-dived a 150W 24V sealed DC motor from an electric kickboard,
a 20A cheapo PWM controller
and a 30VDC 7A PSU of the same ilk as yours for my Zero-cash backburner grinder project.

Just a few thoughts and questions - thanks again for sharing such an inspiring build!

ATB

Johan

I'll look forward to seeing what you come up with - that sounds like a good project.

What is the power source?

OOPS! I should have asked: "what motor is the grinder powered with?" . I looked at the info on the link and found the answer. I"m thinking of using a variable speed motor off a treadmill that I bought for $25. I will post results "when I get around to making it".

It looks like you've figured out the answer to that, but for anyone else who comes looking it's a 250 W 24 V permanent magnet brushed DC motor. I think it was originally designed for a lorry windscreen washer system or something like that, but it had been repurposed by the company at which I worked for one of their products. At the end of the product development cycle, a load of motors that had been used for testing got chucked out. I got three of them and this is one.