Weak magnets in cylindrical square- Re-energize, or replace?

BuffDan · May 13, 2020

This cylindrical square has weak magnets, barely enough to hold it in place.
Can I re-charge them, or replace them?

Thanks.

Richard King · May 13, 2020

You should contact these guys as they make them new. I see they have a repair dept that could possible sell you new magnets. Those 3 holes probably are there to press out the old magnets. The square looks like it needs a reconditioning, so maybe you can send it back to them.

1-888-647-8665
E-mail: [email protected]

BuffDan · May 13, 2020

Thanks for your reply Richard... They make fantastic products.. But I cant justify their cost for this piece.

gbent · May 13, 2020

Knock the old magnets out and buy appropriately sized new neodymium magnets. Study the old magnets to see how they were made. The outer steel shell makes each magnet into a horseshoe magnet, bringing the other pole around to the face. The brass is just a separator. Get a couple of sizes, neodymium magnets are so much stronger than the originals that similar sized magnets may make it nearly unremoveable. You won't be able to grind the face of the magnets, so make sure you recess them at least .0005".

BuffDan · May 13, 2020

gbent said:
Knock the old magnets out and buy appropriately sized new neodymium magnets. Study the old magnets to see how they were made. The outer steel shell makes each magnet into a horseshoe magnet, bringing the other pole around to the face. The brass is just a separator. Get a couple of sizes, neodymium magnets are so much stronger than the originals that similar sized magnets may make it nearly unremoveable. You won't be able to grind the face of the magnets, so make sure you recess them at least .0005".

Thanks for the input... The magnets have 2 brass shells and 2 steel for the magnet.. I'll have to get one out, hopefully intact..
Not sure if I need to replace with magnet that has outer brass shell, or just the inner one..

gbent · May 13, 2020

You have to make the brass shells. The outer is to keep from shorting that pole to the cylinder square. This gives better pull, and keeps the magnetic poles in a small area.

pavt · May 13, 2020

I would be tempted to try and just knock out the magnets themselves first. Just the innermost part. Then shop around for some fresh ones. These guys are good, I've bought from them before: Neodymium Magnets For Sale - Rare Earth & Top Grade Neodymium Magnets now at CMS Magnetics

FWIW (not much) I spent the winter lapping in a cylinder square for myself mostly with diamond plates. I started with an NOS piston pin. Ended up with +- .0001 over 5 inches, after about 2 weeks. Total cost less than $30 plus a lot of time.

dazz · May 14, 2020

Hi
You don't need to use brass. It only acts as a magnetic insulator. You could use expoxy glue (not JB weld. It contains metal) if the magnets are wedged away from the steel. You could glue in loose fitting brass sleeves. Glue avoids the need for precision fits.

Dazz

Mike1974 · May 14, 2020

Do you know the square is 'good'? It doesn't look like it is in good shape from the pictures..

Cylindrical Square | 57-020-263 | Travers Tool Co., Inc.

Maybe just buy a new one...?

TGTool · May 14, 2020

Mike1974 said:
Do you know the square is 'good'? It doesn't look like it is in good shape from the pictures..

Cylindrical Square | 57-020-263 | Travers Tool Co., Inc.

Maybe just buy a new one...?

And put one huge effing magnet in it??

BuffDan · May 14, 2020

I haven't used it because the magnets don''t hold it in place very well.. I have cleaned it and painted since the attached photo.. I view this as a project, learning, etc. I believe it can be a useful reference for my shop.. And I like challenges. I haven't bothered with lapping yet as I want to replace the magnets first..
Thanks for the inputs guys.

TGTool · May 15, 2020

I have no particular advice on magnet replacement, but refurbishing as a square should be doable. Lap or hone the cylinder and it can be tested for size and straightness. Then check squareness and lap the base as needed. You should be able to get it as good as the limits of your measuring equipment.

BuffDan · May 15, 2020

The magnets popped right out, they were a press fit.
They sure are weak..
I ordered some neodymium 1/2x1/8 magnets.. They will fit inside the inner brass shields. I will probably have to dust the bores in the brass..
So a 1/2x1/8 Neodymium rates at 5# pull.. I didnt need them that strong, but I'd have to get some really thin ones to lower that.

ratbldr427 · May 15, 2020

To bad they didn't make the base so you could turn the pull off & on.I refurbed a cheap mag vee block with rare earth magnets.I think I ended up with three 50lb mags.Very impressive!
Another advantage, rare earth mags don't need a keeper and will last a long time.
I found mine on E-Bay.The low power ones you want are pretty cheap.

dian · May 17, 2020

BuffDan said:
View attachment 288692
The magnets popped right out, they were a press fit.
They sure are weak..
I ordered some neodymium 1/2x1/8 magnets.. They will fit inside the inner brass shields. I will probably have to dust the bores in the brass..
So a 1/2x1/8 Neodymium rates at 5# pull.. I didnt need them that strong, but I'd have to get some really thin ones to lower that.

just space them deeper from the surface.

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Weak magnets in cylindrical square- Re-energize, or replace?

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