Thread: Eclipse magnetic Chuck

Hi

(My apologies for the lengthy post - hopefully it may help someone)

Here are some photos and details of my small magnetic chuck repair. (I have not got the large chuck apart yet )

Small magnetic chuck repair April 2015 001.jpg

The initial disassembly shows the insides to be like this. What little oil remained from I don't know how many years ago, was very thick. There is substantial corrosion on the inside.

Small magnetic chuck repair April 2015 002.jpg

The small chuck is held together with eight screws and five dowel pins - as shown above.

Small magnetic chuck repair April 2015 003.jpg

The inside of the bottom plate.

Small magnetic chuck repair April 2015 004.jpg

I kept the dowel pin locations the same by using a piece of cardboard - this is probably not critical as the chuck will be refaced when placed on the surface grinder.

Small magnetic chuck repair April 2015 005.jpgSmall magnetic chuck repair April 2015 010.jpg

I used penetrating fluid to clean out the holes in the magnets.

Small magnetic chuck repair April 2015 012.jpg

I filled the holes with oil before reassembly.

Small magnetic chuck repair April 2015 014.jpg

Ready for reassembly.

Small magnetic chuck repair April 2015 011.jpg

Gasket sealer to seal between the alloy frame and the top and bottom plates and oil filled holes.

The blood you see in the images was caused by my effort to "slide" the plate away from the magnets. The force holding the plate was quite strong up to the point when my effort exceeded that force. When the plate did move it did so quite rapidly and my hand at the base of my thumb, "slammed" into the sharp edge of the alloy frame. Don't do that! . I won't describe the details, but suffice to say it was BLEEDING (A couple of band aids held the skin in place for a few days. So I now have a scar to show for my efforts.)

Both plates and magnet surfaces were cleaned up with the sharpening stone. As shown in the photos, there is substantial pitting of the plate surface. This pitting is on both plates and the rust so generated was part of the problem in stiffening the operation of the chuck. The lack of oil did not help.

When I performed these repairs, I made sure that one plate or the other remained in contact with the magnets. The plate acted as a keeper and helped retain the strength of the magnets. How much strength was lost (if any) I cannot tell. However the chuck does work well after reassembly.

I filled the chuck with hydraulic oil (I'd read that somewhere?)

Here is a link to magnetos and info on keepers http://goo.gl/Gi7JtT There are many references to magnets and keepers on the net.

This link http://www.mtfca.com/discus/messages...tml?1162213402 shows the principle of creating a magnet or inducing a magnetic field into iron or steel. I remember doing this when at age 12, I was learning about electricity and magnetism at technical college all those years ago.

I expect that just such a method would be used to re-magnetise a magnetic chuck. The service people would have their own specialised coils to do this task.

My phone calls and emails to Eclipse in the UK did not provide any real answers to chuck repairs. I get the feeling that they want to keep this info confidential and make it seem like "smoke and mirrors" or black art to do magnetic chuck repairs. I expressed my intention to keep confidential any proprietary information they provided to me, but nothing was forthcoming.

The Australian service place (advised by Eclipse) is...

Magfield Manufacturing PTY Ltd
5/4 Ovata Drive
3043 Tullamarine
Victoria
Australia
Tel 0061 (0) 3 9338 3655
Fax 0061 (0) 9338 7222
Contact Peter Tedesco

I contacted Peter. He confirmed that the retention of the top/bottom plate as a keeper did help prevent the loss of magnetism.

He advised me that their charge to remagnetise a chuck is $130. For me, in WA, I'd expect to pay that much again for freight (of a 36kg magnetic chuck) to-from Victoria. Of course I would also have to make a suitable and substantial packing crate in which to transport the chuck to Victoria. That is getting to be a high price for something that (I believe) could be done carefully by most (all?) people on this forum.

The email from Eclipse said in part...

"Unfortunately though it is not possible to carry out a "self repair" as dismantling the chuck without "demagnetisation" reduces the clamping force significantly, and is not recommended. After repair and assembly the chuck is "re-magnetised" to bring it back to full power."

While I cannot argue with their statement, my resulting repair was acceptable for me. There may have been a loss of magnetism, however in MY case it was not significant enough to notice. Please keep in mind that I have no "scientific" or other method of measuring the magnetic strength of the chuck before or after the repair. The quality of the result of MY repair is totally subjective.

Eclipse further stated that...

"These processes are now carried out if required by our factory in China. Sadly all the skill, equipment, and process documentation have been lost to us over time.
In essence your efforts may come to nought as the chucks will not function correctly"

This is disappointing of course, but the implied failure "chucks will not function correctly", I think is dependent on the talent and ability of the "self-repairer".

All things considered, if your chuck is not working very well, you have a resource in Victoria to remagnetise your chuck. AFAIK this remagnetisation will require disassembly. The $130 price I quoted above was purely for the remagnetisation as I advised Peter that I had disassembled and cleaned my chuck.

Anyway, "armed" with the knowledge above and my previous small magnetic chuck repair, I am game to attempt repairs on the large chuck. I have yet to get it apart. According to Peter Tedesco at Magfield Manufacturing, the screws and pins I have already removed are all that hold the unit together. My assumption then is that only the "sealer" and magnetism is holding it together, but it is VERY difficult to disassemble. (Now where did I put that sledgehammer )

BTW, the large magnetic chuck had four screws secreted away under some whitemetal in an attempt to hide them from potential "disassemblers" - I found them ALL

I'll continue this thread with my large chuck repairs, when I eventually get it apart

As expressed in a previous post, best wishes to others that venture down this path. You've got nothing to lose except perhaps a $130 service fee. Be aware of the potential pitfalls (a chuck that does not work!), but you can recover to a "full"(?) strength magnetic chuck via a Victorian service centre.