Eclipse magnetic table

I have an eclipse magnetic table mounted on my Jones&Shipman surface grinder ,unfortunately It leaks oil at the on/off handle ,has anybody experienced the same problem ,there must be a seal on the shaft to prevent the leakage .If anybody has dismantled the table or can tell me where to obtain a new seal or is it a standard type oil seal any advice would be appreciated

David

Hi David there is no oil seal on these chucks, you should only lubricate ocasionaly and use a slideway type oil which is thick and sticky 60 grade. Under no circumstances strip them down as you will loose the magnetism and it have to be returned to Eclipse for repair and re-magnatising.

David

This has been a burning question in my head for a long time? How can the magnetism be lost?

The fact that there is still oil in it is a good sign. As said, you need a sticky oil. If you don't want to strip it down,try draining out the current oil and then squirt in some 60 grade with it lying on it's back. Work the lever to get the oil in under the magnets. When you are not using it, store it upside down. The bottom side of the magnet pack should still be in good nick, since there is always oil there.

I have an Eclipse with the same warning on " do not dismantle" Taken mine apart a few times, to see if I can replace the magnet pack with neodymium magnets for better holding, but it works out very expensive due to the size.

You only need a small amount of oil if you plan on storing it upside down. Only enough to lubricate the pack.
Can only imagine that they fill them to the brim to ensure that both sides of the pack are always lubricated.

Hope this helps.

A magnet is subjected to a demagnetising force from its own magnetism. Older types of permanent magnet steel did not have a remanence as good a some of the more modern materials, so would gradually demagnetise themselves. Old magnetos quite often need remagnetising to get the proper performance. Providing a magnetic circuit reduces the demagnetising force seen by the magnet, which is why keepers are often used. In a motor or a magnetic chuck, there is effectively a keeper circuit provided, so the magnets will last longer if they are kept assembled. I would not have thought that disassembly for a short time would matter too much. The modern materials do have better performance, both in the initial strength and in their ability to retain it.

John

Thanks John. I agree with that since mine has been apart a number of times and never gotten any weaker, although it is not as strong as would like it. It is pretty old, so I guess it has just got weaker over time.

I would also say that it would be good practice to leave it switched on with a plate on to preserve the magnetic strength.

I do find it strange that the manufacturer states that it will never lose magnetism?

My original 8"x24" Eclipse mag chuck on my J&S 1400 had ferrite magnets, which won't lose their strength, rather than Alnico ones, which do. In the end, the problem was moot, since it didn't have any provision for re-lubrication and by the time I disassembled it the aluminium casting that the shaft/cam ran in had cracked and it resisted my attempts and machining a replacement and getting the resulting surfaces to be oil-tight with the original casting (only had the 10" shaper and the ML7 at the time). If there is an oil nipple/filler, I'd use it. If there isn't, I'd be very tempted to carefully drill into the end of the aluminium casting and tap for an oil nipple, then pump ISO 68 or 220 way oil in until it comes out copiously, without trying too hard to replace any oil seals. In the meantime, keep an eye on the auction site of your choice for sensibly priced fine-pole chucks. They're far more useful than the original Eclipse chucks.