ECLIPSE MAGNETIC CHUCK

[noel shelleyParticipant @noelshelley55608]

Does anybody know anything about stripping a 12" by 6" eclipse mag chuck ? It is VERY tight to operate. It seems that there are 4 screws hidden under little plugs in the 4 corners of the base plus the obvious ones. Instructions on the base say send it back to the makers, but that will be very costly ! I feel all it needs is cleaning and oiling.

Many thanks Noel.

Edited By noel shelley on 11/09/2020 22:01:09

[noel shelleyParticipant @noelshelley55608]

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Noel, I think I've read or heard somewhere that if they are not stripped down correctly, they will loose their magnetism. Perhaps they need some sort of keeper to be used to remove the magnets, but I may be wrong, but I believe it is not wise to open them, unless you know how to proceed.

Regards Nick.

[peak4Participant @peak4]

There are various warnings about not stripping these, due to the possible loss of magnetism.
I recently refurbished an old Herbert Junior grinder, which came with a 10"x5" eclipse chuck and was also very stiff to operate; I really needed a spanner on the handle.
There is an oil re-fill plug on the bottom, with a copper sealing washer.
Mine was bone dry, so, as a temporary job, I re-filled it with a mix of some 360 weight gear oil thinned down a but with some 20 weight hydraulic oil.

I'm not sure where I found the link now, but apparently, the correct oil is straight 160 weight plain gear oil- N.B. not hypoid.
After working the chuck for a while, it's now eased off, though still a bit stiffer than my other similar one, which came out of the Myford factory on one of their open days. I assume this one had been correctly maintained.

Also, I've just picked up a spares/repairs 10" diameter one, which was totally seized solid, despite the vendor saying it was "a bit stiff"
This doesn't have a refill plug, but there is one small screw in the bottom, which I now know to be a retaining pin for the operating spindle.
I sprayed a large quantity of a rust release agent into it, specifically "Degrip All – Penetrating Rust Oil " (+ some 20 weight oil again, after I'd left it to soak for a day).
After leaving it for a while, I used a ½" socket T bar with an Allen driver to gradually work it loose; it was VERY stiff, to the point I was concerned about internal damage, but it did free up somewhat.
Eventually the whole drive spindle popped out, it's a splined shaft about 9" long, sealed with an O ring. This then gave me reasonable access to swill it out with paraffin.
I then re-filled it with some 160 weight oil. It moves easier with the thicker oil, than the thinner mix, so I guess it holds the inner moving bits slightly further apart.

I did find that both of these chucks were quite weak, but I'd read that they should be stored "On" with a keeper plate, and that the addition of a plate might gradually restore some/most of the holding power.
I'm pleased to say, it seems to be working, even after just a couple of days.
I've just cut up a bit of old washing machine panel and use that as a keeper, separated with a layer of VPI paper to save anything rusting.
There is a copy of the Eclipse manual on this site if you don't already have one.
https://www.model-engineer.co.uk/wp-content/uploads/sites/4/documents/eclipsemagneticchuckhandbook.pdf

There's also lots of useful stuff HERE. 
https://sites.google.com/site/lagadoacademy/machining—lathes-mills-etc/my-surface-grinder—2

Bill

Edited By peak4 on 11/09/2020 23:32:15

[David George 1Participant @davidgeorge1]

Hi Noel the chuck will loose it's magnetism if you strip it down. You should persevere with lubricating it There is a hole sometimes on the side sometimes on the bottom with a grub screw. just use a 30 grade slideway oil and work it in by operating it in various positions to get the oil to all parts. If you find that it dosn't get better Eclipse can strip refurbish and they re-magnetise it on assembly.

David

[PlasmaParticipant @plasma]

I had a similar sized chuck repaired by eclipse in sheffield.

It wasn't very expensive compared to buying a new chuck.

Came back with revitalised magnetic strength so well worth doing in my opinion.

[Chris Evans 6Participant @chrisevans6]

Depending where you are based Rotagrip in Birmingham used to offer the strip down service. Worth a call to see if still available ?

[Mark RandParticipant @markrand96270]

Certainly re-oil it or send it out for a rebuild as soon as possible. The 24"x8" that was with my grinder when I got it from work was quite stiff. I didn't think too much of it untill it became less stiff and stopped working, The stress from operating the cam to move tha magnet assembly against the dried and corroded top and bottom plates had caused the aluminium casting to fracture…

I now have a newer (second hand) fine poled chuck which, to be honest, is far better than the coarse poled Eclipse one was.

[peak4Participant @peak4]

Posted by Plasma on 12/09/2020 08:10:23:

I had a similar sized chuck repaired by eclipse in sheffield.

It wasn't very expensive compared to buying a new chuck.

Came back with revitalised magnetic strength so well worth doing in my opinion.

Roughly what sort of figure are we talking please?

Bill

[David George 1Participant @davidgeorge1]

Bill sent a message as I am not sure if I can put up information about a company on here but as they are not far from Meadowhall shopping center it helped to deliver and collect the chucks with a visit for my wife to said shopping center.

David

[not done it yetParticipant @notdoneityet]

Posted by David George 1 on 13/09/2020 06:32:10:

Bill sent a message as I am not sure if I can put up information about a company on here but as they are not far from Meadowhall shopping center it helped to deliver and collect the chucks with a visit for my wife to said shopping center.

David

Why not just return the PM? Seems the obvious way to go?

[Pete RimmerParticipant @peterimmer30576]

Absolutely don't dismantle an Eclipse chuck, it will lose it's magnetism. There is no need to do anything in particular to preserve the magnetism (such as using a keeper or storing it switched on or off) except to never dismantle it.

I have somewhere a more informative Eclipse manual that someone kindly sent me as a collection of photographed pages. I will see if I can clean them up and present them in a PDF. It includes lubrication info.

EDIT: Here you go. I cleaned it up on my mobile phone using Camscanner app and put it in my dropbox.

Eclipse Permanent Magnet Chuck Users Handbook

Pete.

Edited By Pete Rimmer on 13/09/2020 09:47:02

[Gary WoodingParticipant @garywooding25363]

I'm going to show my ignorance here, but I don't understand why it would it lose it's magnetism just by dismantling it. The old-fashioned horseshoe magnets I had at school all those years ago had keepers, but they certainly didn't lose their magnetism if you removed the keeper for a few hours. What am I missing?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Pete Rimmer on 13/09/2020 09:29:31:

Absolutely don't dismantle an Eclipse chuck, it will lose it's magnetism.

[…]

Here you go.

.

Thanks for that very useful document, Pete

MichaelG.

[peak4Participant @peak4]

Posted by not done it yet on 13/09/2020 07:32:28:

Posted by David George 1 on 13/09/2020 06:32:10:

Bill sent a message as I am not sure if I can put up information about a company on here but as they are not far from Meadowhall shopping center it helped to deliver and collect the chucks with a visit for my wife to said shopping center.

David

Why not just return the PM? Seems the obvious way to go?

Thanks folks. There may be a misunderstanding, perhaps due to the difficulty of including punctuation on mobile devices.
David sent me a message, to which I've now replied; many thanks for the content.
As in; Bill, I've sent you a message………………
Rather than me sending a message to David. 

Personally I can't see a problem with listing legitimate company details on a forum such as this; I suspect the subject of moderation had made folks a bit too wary.

Interestingly from Pete's manual, there doesn't seem to be a mention of how to store the chuck when not in use, other than not leaving them on without a workpiece.
Two of my Eclipse chucks were very weak when they arrived to me, though they were "off" when I received them.
It looks like neither had been used for many years.
Adding a steel keeper plate, (a bit of old washing machine cabinet), seems to be restoring lost magnetic holding strength gradually. Not really sure just how strong the grip should be, but it's a lot better now than they were on arrival.

Bill

Edited By peak4 on 13/09/2020 11:37:26

Edited By peak4 on 13/09/2020 11:38:27

[OldironParticipant @oldiron]

Posted by Gary Wooding on 13/09/2020 10:31:03:

I'm going to show my ignorance here, but I don't understand why it would it lose it's magnetism just by dismantling it. The old-fashioned horseshoe magnets I had at school all those years ago had keepers, but they certainly didn't lose their magnetism if you removed the keeper for a few hours. What am I missing?

Nor me Gary. Seems to be plenty of YT videos showing the process for different makes. What makes the Eclipse so different from all the others ?

regards

[Pete RimmerParticipant @peterimmer30576]

Posted by Oldiron on 13/09/2020 11:37:34:

Posted by Gary Wooding on 13/09/2020 10:31:03:

I'm going to show my ignorance here, but I don't understand why it would it lose it's magnetism just by dismantling it. The old-fashioned horseshoe magnets I had at school all those years ago had keepers, but they certainly didn't lose their magnetism if you removed the keeper for a few hours. What am I missing?

Nor me Gary. Seems to be plenty of YT videos showing the process for different makes. What makes the Eclipse so different from all the others ?

regards

The difference is that those youtubers sole interest is in showing off their 'skills' whereas Eclipse produced their handbook as technical information about their products for their end-users. They don't state that the magnetism will be lost, but reduced. How is youtube-guy going to quantify that reduction, and why would they, if they could? It would be just inviting adverse comments about 'ruining' the chuck.

I guess if your chuck is so seized up that it's completely unusable then you have nothing to lose by making it work again, to whatever extent. Reduced workholding is better than no workholding at all and you can always add blocking or moderate your cuts. Just don't go stripping it down unnecessarily on the strength of youtube recommendations.

[Gary WoodingParticipant @garywooding25363]

I read the statement in the documentation that says "Chuck cannot lose magnetism except by dismantling – Service by makers only", but I want to know why.

What magical internal parts preserve the magnetism that would dissipate if removed?

[not done it yetParticipant @notdoneityet]

Posted by Gary Wooding on 13/09/2020 12:30:42:

I read the statement in the documentation that says "Chuck cannot lose magnetism except by dismantling – Service by makers only", but I want to know why.

What magical internal parts preserve the magnetism that would dissipate if removed?

Hi Gary,

The ‘destructions‘ mention that the Eclipse chucks are magnetised after being assembled, rather than using pre-magnetised magnets. That is the reason quoted, re not dismantling – without the means of remagnetising after re-assembly.

[not done it yetParticipant @notdoneityet]

Posted by peak4 on 13/09/2020 11:36:11:

….

Adding a steel keeper plate, (a bit of old washing machine cabinet), seems to be restoring lost magnetic holding strength gradually. Not really sure just how strong the grip should be, but it's a lot better now than they were on arrival.

Bill

Well, I’ve tried that because I was surprised by that claim on the 11th.

I turned down a piece of steel bar (for about 15-20mm) until the end of the bar was just insufficient to lift my 10 x 5 Eclipse (~1/2mm on the diameter was the last cut). I then left it with a strip of mild(?) steel plate covering more than the chuck area and the magnet switched on.

I will attempt to compare the magnetic force per unit area or the lifting/holding power of the chuck at some point if there is a specification in the manual linked in other posts.

The chuck has stood around in my house for a good deal more than ten years, turned off most (probably all) of that time.

Checked this morning and no discernible difference, so far.

I have no reason to think it was weak or anything other than original.

Edited By not done it yet on 13/09/2020 13:15:47

[peak4Participant @peak4]

NDIY, yours may not have been weak, but mine certainly were for some reason.
After I'd freed up the 10" diameter one, I could slide a 6" diameter piece of cast iron around (the table off my Meddings high speed drill, so a reasonable finish).
After a couple of days with a keeper plate, it's now quite hard work to slide a 1-2-3 block or a 2" square block around on it; I can make it move, but not easily.
I can just lift the 10" diameter chuck up with the end of a rough sawn 50mm EN8 round bar. I certainly couldn't have done that originally.
Whether it/they will improve any more, only time will tell.

This one of the links from my previous link was what lead my to try it.
Do bear in mind the author is from South Africa, so probably isn't referring to Eclipse chucks, and certainly not when he discusses stripping them down.

Bill

[Gary WoodingParticipant @garywooding25363]

NDIY

So why, if they were magnetised after assembly, would disassembly demagnetise them?

It doesn't make sense to me.I'm not trying to be awkward, I really want to know.

Edited By Gary Wooding on 13/09/2020 16:08:31

[Pete RimmerParticipant @peterimmer30576]

Gary, just like some permanent magnet motors need re-magnetising after disassembly, the flux path needs keeping constantly for the magnets to not lose some effort. The design of the Eclipse chucks causes the on-off lever to divert the flux path rather than break the flux path completely.

It's all explained on page 12 of the manual I linked to, which has images showing how the control lever slides the magnets in and out of phase with the top plate to turn the chuck on and off.

Edited By Pete Rimmer on 13/09/2020 16:29:41

[Michael GilliganParticipant @michaelgilligan61133]

It doesn’t really answer the difficult questions, but we may as well add this to the references: **LINK**

https://toolsandthings.wordpress.com/portfolio/magnetic-chuck-rebuild-eclipse-brand/

The author seemed satisfied with the result.

MichaelG.

[not done it yetParticipant @notdoneityet]

Posted by not done it yet on 13/09/2020 13:14:53:

Well, I’ve tried that because I was surprised by that claim on the 11th.

I turned down a piece of steel bar (for about 15-20mm) until the end of the bar was just insufficient to lift my 10 x 5 Eclipse (~1/2mm on the diameter was the last cut). I then left it with a strip of mild(?) steel plate covering more than the chuck area and the magnet switched on.

I will attempt to compare the magnetic force per unit area or the lifting/holding power of the chuck at some point if there is a specification in the manual linked in other posts.

An update. I checked with the piece of steel, as previously. I detected no difference whatsoever. The test may not be entirely definitive as the bar cross section at the end was relatively small, compared to the whole table area, but switched on for well over a fortnight with a sheet of steel over the whole area showed no discernible increase of magnetic power.

The chuck, I decided/realised, had been switched off for virtually the whole period, previous to its recent move to my workshop, as the handle would have been projecting outside the end of the frame – and it was not stored in a sensible position to have the handle sticking out…

[Author]

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