What's new
What's new

Has anyone here built a work holding electro-magnet from scratch?

Thunderjet

Hot Rolled
Joined
Jun 24, 2019
We have a grinding job where we have to surface grind a small steel part. 350 dia x .100 thick.
I've already made the fixtures, utilizing neo-dot magnets, and they're doing a great job....too good of a job.

Between cleaning them and getting the parts off of the magnet plate, it's a MAJOR PITA.

I'm wondering if it's feasible to build you own custom magnetic chuck for a certain part.

Has anyone tried this?

It would be awesome to simply turn the bloody thing off , gather the parts up, blow off the chuck and move on.
 

Bobw

Diamond
Joined
Feb 8, 2005
Location
Hatch, NM Chile capital of the WORLD
I tried it for a lathe job. Through the spindle wires, brushes, even wound it myself
(I actually has somebody else do it).. Had to unwind it and go from a long single wire
to 4 shorter wires..

It worked.. And I don't remember why, but it didn't work well, so I actually made
9 magnets to go around the ring, instead of one giant round magnet.. And then the
owner decided it was taking too long, and sent the damn thin floppy piece of shit
out to be blanchard ground, like I had been telling him every single day for MONTHS.

you also know they sell magnetic chucks that turn on and off with the flip of a lever, right?

I don't know if this is the proper way to do this, but that same part up above needed to
go on the mill for some more BS.. Bought a round magnetic chuck, and then made a nice
"Jig" I guess you could call it out of aluminum. Put the jig on, drop the part on, its located,
turn the plate on. Remove Jig. Machine. Worked pretty darn well.
 

Thunderjet

Hot Rolled
Joined
Jun 24, 2019
I tried it for a lathe job. Through the spindle wires, brushes, even wound it myself
(I actually has somebody else do it).. Had to unwind it and go from a long single wire
to 4 shorter wires..

What did you use for a power supply?
Adjustable?

The reason I want to go with an electro-magnet is the ability to turn it on/off.
 

Bobw

Diamond
Joined
Feb 8, 2005
Location
Hatch, NM Chile capital of the WORLD
What did you use for a power supply?
Adjustable?

The reason I want to go with an electro-magnet is the ability to turn it on/off.
A chopped up power supply cord, and a $6 rectifier from radio shack to produce DC current.
Plugged into the wall.

Bolted the rectifier to an aluminum plate because it got HOT!!!!!

The magnet power still pulsed a little.. Probably could have used a capacitor to
even out the current flow.

You can find all the formulas online, and you can buy magnet wire to wind your own,
its just copper wire with a very very very thin coating of some kind of clear insulator.

It was so long ago, that I made my own electro magnet.. Been there.. Done
that, Got the T-shirt.. No plans on ever doing it again, so I couldn't tell you all the
details, and it was a LONG time ago. And I think this is the first time I've told anybody in the
last 15 years that I made my own rotating electro magnet.. And it actually WORKED!!!!!
 
Are you just flat grinding them?
Or something more complex?

As has been mentioned (more or less) above, you can just bore a grid that is thinner, to contain the parts; and block it on the regular chuck. I've done that with steel.
Have also drilled/milled/bored magnetic transfer blocks for some small parts, and blocked those as well.

With your idea, or with milling/boring the mag-transfer blocks an issue can be how flat/parallel is the bottom. A steel (magnetic) swiss cheese grid on the regular magnet avoids that problem.

smt
 

Comatose

Titanium
Joined
Feb 25, 2005
Location
Akron, OH
Why an electromagnet? If you're getting good results with the neodymium magnets, all you need is a piece of shim stock between the magnets and the work being held.
 

Thunderjet

Hot Rolled
Joined
Jun 24, 2019
Why an electromagnet? If you're getting good results with the neodymium magnets, all you need is a piece of shim stock between the magnets and the work being held.
Because I want to turn it off to retrieve the parts.
The neos are making it very difficult to demount the pieces, and they are very hard to get clean for the next load.

I don't understand how shim stock will help me.
 

Kingbob

Hot Rolled
Joined
Dec 1, 2009
Location
Louisiana
yeah if the permeant mags are working why change. Copy a mag base indicator where the actual magnets are internal and can be raised and lowered via cam. Lower the magnets for cleaning. Or like comatose said just use shim stock or foil or a film between the parts and magnet so you lift away all the trash/swarf with the parts; leaving behind clean magnets for the next set.
 








 
Top