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projectnut
07-03-2011, 02:30 PM
Yesterday I picked up a Brown & Sharpe model 510-1 permanent magnet, magnetic chuck. It's in good shape and seems to have plenty of holding power. I intend to use it on my horizontal mill when working on irregularly shaped parts.
It will be used on an intermittent basis so most of the time it'll be setting on the shelf. Since it's my first permanent magnet chuck I'm not quite sure of the proper method of storing it so the magnet will retain its power. Should it be left in the on position with a steel plate magnetized to the surface, or should it be left in the off position with nothing on the surface?

I have a couple magnetic balancing tools and the manufacturer says to put a plate over the magnets so they will retain their power. In the case of the chuck I'm not sure if that's the proper method of storage. I don't want to permanently magnetize the surface plate but on the other hand I don't want the magnets to weaken either. Any input would be appreciated.

tdmidget
07-03-2011, 02:38 PM
What your balancer manufacturer is talking about is commonly called a "keeper".A bar full length of your chuck would do the job.
I think you will be very disappointed with a magnetic chuck on a mill. In any case don't stand downstream.

Dr Stan
07-03-2011, 02:41 PM
In any case don't stand downstream.

Amen says the choir. :eek:

winchman
07-03-2011, 04:34 PM
When you move the chuck handle to the "off" position, it's the same as putting a keeper on the magnets. That's all you need to do.

Carld
07-03-2011, 05:28 PM
Yep, I am thinking you will get a surprise using a magnetic chuck on a horizontal mill but try it and let us know what happens.

If you undercut the cutter may chase the part across the table. If you climb cut, well, that may be interesting to watch, from a distance.

madman
07-03-2011, 05:53 PM
I been in Machine Shops and Grinders for over 38 years NEVEr EVER saw a Keeper xcept on small 1 inch dia magnets BUT what we always did (Most of the Guys) was to keep a very light Layer of oil on the Magnet if it sat for a while, I used ATF on mine I have a few of them very very old never had demag Problems.

duckman
07-03-2011, 09:16 PM
I have machined more gibs than I can remember using a magnetic chuck on a BRPT we drilled and tapped the end where you clamp it down to the table put set screws in the holes and use them to tilt the chuck put something under the screws so you don't mark the table, just remember to use side and end bars to keep it from moving out of position. Mostly used a fly cutter, have even used the chuck on our open side planer always cut from the small end to big just in case it decided to catch, it would just move down and not ruin the gib.

Jaakko Fagerlund
07-03-2011, 11:46 PM
If it has rare earth magnets, they will loose their power over the years but if it has neodymium magnets it won't and doesn't need a "keeper". I would not store it with the magnet "on", as that could be dangerous near metal objects.