Thread: Eclipse magnetic Chuck

Hi.

Not sure what would cause them to loose there magnetic holding capacity but suspect it wojld be for the same reason why dismantling a PM DC motor woild reduce its HP by damagjng the magnets by sliding the armature past the magnets.

I have two mag chucks a 18"x6" and a smaller one. They both have stamped on the bottom not to be disassembled as it will cause damage. Im dying to do just that but since I cant afford to replace them I think they will stay assembled!

Well at least until I learn more....

I downloaded the Eclipse owners manual which I will read tonight.

Simon

Ps. Take yours apart so I can learn! Go on, what could possibly go wrong?

http://www.youtube.com/watch?v=cG-01vY36W0

Dale, I had a similar problem with an Eclipse magnetic chuck. I did all the googling and tried the easy fix first, ie turn the chuck upside down for a day or 3. Something to do with redistributing the lubricant or whatever is inside the chuck. I think I only came across one reference to this 'repair' method.

And so help me it worked, I now have a powerful chuck.



I like the youtube video, to me its the best explanation I've seen yet re the innards of a magnetic chuck.

The Don Bailey video is about the best one around for describing the construction. Assuming the Eclipse one is the same basic construction as the Suburban, the only thing I can imagine would cause the problem is that the cam isn't lifting the magnet assembly up high enough to touch the transfer plate.

So it might be a simple mechanical problem, rather than a problem with the magnets themselves? You can only hope...

A few measurements of the current holding force might be in order, A set of scales and a block of steel...

Ray

My mag chuck is still on the waiting “to be fixed” list so no current info regarding cost, but from memory I recall Alpha Magnetics were talking (3 or 4 years ago) about $30 per shot on their magnetizer. I remember thinking my 18” Eclipse would need perhaps $90; worth ignoring the dire predictions and taking a chance on losing magnetism.
The magnetizer jaws were about 200mm wide.
Needless to say – this is out of date info, check their current prices.
Neil

Bob, This chuck is said to be basically NOS, the bought it and it didn't fit his machine so he had to go buy something smaller. Still has the original box. Maybe the upside down trick will work as this could very well have been sitting undisturbed in the back of a cupboard and allowed to settle.


Ray. I believe the cam doesn't lift the magnets but moves them horizontally so the phase in or out with the top plate strips. That is my understanding anyway.

Just watched the video. Very informative. So the cam doesn't move the magnetic plate away from the base, it shifts it along to misalign the poles?

Simon

Originally Posted by DSEL74

Ray. I believe the cam doesn't lift the magnets but moves them horizontally so the phase in or out with the top plate strips. That is my understanding anyway.

Yes, correct, but what I think may be the problem with your chuck is that the magnets aren't close enough to the top transfer plate... that's the only thing I can think of that would be fixed by turning the chuck up side down.

Ray

Permanent magnets will lose their magnetism by themselves over time, but it is over centuries, not months or years.
They also lose "strength" with long exposure to strong alternating magnetic fields, or high heat, or continual hard physical raps or knocks where the magnet is subjected to high G forces, and especially when held at 90 deg to magnetic N-S.
If the field is contained, eg with magnetic shielding, the loss rate due to external factors is minimal.
(You can easily de-magnetise screwdrivers by sharply rapping the blade against a vice or workbench leg. Re-magnetise by stroking the blade with a magnet).

The chuck problem will probably be a mechanical shading problem.

I couldn't find an inch cube, so I used this piece of 10mm plate. DSC_0583.JPG I can not pull this off but I can slide it quite easily. (I did use it on the other side btw)

DSC_0579.JPG I thought the base screws were mean't to be lead filled, or is that just on older ones?? Maybe the base has been off?

DSC_0581.JPGDSC_0582.JPG

It is currently sitting upside down to test the theory mentioned above.

The lever is real stiff to move. I wonder if the lubricant has turned to crud??

Originally Posted by simonl

Ps. Take yours apart so I can learn! Go on, what could possibly go wrong?

Well if you can wait just a little bit longer, I am about to take my 450 x 200 eclipse mag chuck apart.

I have already repaired my smaller Eclipse magnetic chuck and it still works )

Do not take the above comment to mean that you can also do it without problems. Because it worked for me does not necessarily guarantee it will work for you.

If you do take the change then I hope you are successful.

One MAJOR point. When you take the unit apart ensure that ONE of the plate remains in contact with the magnets. This acts as a "keeper" when the other plate off (the top or bottom of the unit)

Google "magnetic keeper" for more info

I'll start another thread for other to review and make comments/suggestions or ask questions. I didn't take many photos of the first repair. I'll take a few more this time.

Feel free to continue on in this thread with your repair rather than start a new one if you wish to.

I did take the back of mine an have a tinker with it but not much improvement and I should probably disassemble further clean and re grease.

Magnets can loose their fields, I had a generator that wouldn't put out a charge to run anything, took it to a place, they plugged in a jumper lead type thingy, after 5 mins was good to go.
Kryn