Magnetic Chuck - Testing and Troubleshooting Questions

[Ray C]

Dave,

I truly don't know if all mag chucks have oil in them. I've taken apart 7 units from about 4-5 different brands and all had oil. That's all I can say for sure...

Just yesterday, I noticed my 618 CERAMAX was stiff to operate. I flipped it over for about an hour or so (purely due to other things going on) and it worked fine afterward... It seems to help for the ones I have. I could indeed imagine newer ones having some sort of long-lasting synthetic coating or plastic that obviates oil. -Maybe, but that's just a guess on my part.

Ray

Ray--I enjoyed this forum and I have a question for you. are all walker 6x18 manual chucks filled with oil? I rebuilt mine and it had no oil in it at all. I had to design and make the shaft and cam pieces by myself because I didn't know any specs for them--well I finally got them made and used grease on all moving parts and put it back together. It works good finally but will not having oil in it bother it later? it was quite an ordeal of assembly/disassemblys untill I got the cam made to lift inner end of magnet and slide it just enough to line up without hitting end. I don't want to take it apart again unless it quits working. Dave

 

[Dave Smith]

Ray--mine is not a new one---pretty old that I couldn't find any specs on it--my problem the the previous owner took it apart and tried but couldn't get the cam to work. he then just put it back together with bad parts and ----so I had no correct cam shape to go from. You know how difficult it is to just take them apart and reassemble them--I think I made the cam and pin out of stronger material than when it was new--but I think it is asking a lot out of those small parts. I rebuilt mine about 8 years ago. well thanks for all your info Dave

 

[Ray C]

Dave,

Here's another guess on my part... Don't take this as advice but just a guess.

If the unit is more than 15 or 20 years old, I'd say it was meant to hold oil. If the PO took it apart, he may have drained the oil and not refilled it -not knowing any better otherwise.


Ray

Ray--mine is not a new one---pretty old that I couldn't find any specs on it--my problem the the previous owner took it apart and tried but couldn't get the cam to work. he then just put it back together with bad parts and ----so I had no correct cam shape to go from. You know how difficult it is to just take them apart and reassemble them--I think I made the cam and pin out of stronger material than when it was new--but I think it is asking a lot out of those small parts. I rebuilt mine about 8 years ago. well thanks for all your info Dave

 

[Dave Smith]

yes Ray that was probably what happened--I know if I have to work on it again that I will drill and tap a small hole in on one end to fill and top off with oil--I can think back how inconvient it would be to fill it with oil each time I dissembled it----it was difficult and wearing on me just to figure a new cam and linkage---at least I didn't give up on a hard challenge. I admire you for fixing as many as you have. thanks for all your info. Dave

 

[Ray C]

I think one of the reasons they're typically not topped-off with oil, is because it will eventually leak out of the operating lever thru-hole. I've not seen a unit with a bearing to support the shaft so, a good deal of pressure invariably ends-up on the seal.

Oh, no need for admiration -not in the least. I live to take things apart and have a pretty good track record of successful reassembly...

I'm really sorry yours is putting up so much struggle and in a way, I feel badly since it was my suggestion to take it apart. On the flip side though, it was previously not usable so at the least, it's a learning experience...

Ray

yes Ray that was probably what happened--I know if I have to work on it again that I will drill and tap a small hole in on one end to fill and top off with oil--I can think back how inconvient it would be to fill it with oil each time I dissembled it----it was difficult and wearing on me just to figure a new cam and linkage---at least I didn't give up on a hard challenge. I admire you for fixing as many as you have. thanks for all your info. Dave

 

[RWL]

The technical staff at Magnetool sent me instructions on how to disassemble the chuck. Different than I would have thought. I'll have to put two of the screws back in. Their instructions say to pry the chuck top off of the magnet box and grind the top and magnet box if either need it. That's a lot different than what you see on the net where the instructions are to never separate the magnets from the top. On reassembly they say to grease the top of the magnet box with Molykote Grease BR2-5 or equivalent and say not to use regular machine grease. The case was filled with oil, so here's another one with oil in it despite the advice to grease the top. I don't have time to work on it tonight, but hopefully tomorrow I can get it apart and show some pictures.

 

[RWL]

I got the top off. For those with a Magnetool Magnetic Chuck, here is the procedure: . . 1. Remove all screws with the exception of the 2 screws on the opposite end of the ON-OFF knob and on each side . 2. Loosen the two remaining screws but leave enough thread in the top p l a t e so these two screws will act as a fulcrum. 3. With a screw driver, using the ON-OFF knob as fulcrum, pry the top p l a t e up. This leverage will "break" the top p l a t e from the magnet box. Pry only enough to insert small screw drivers , flat pieces, or wedges between the top p l a t e and magnet box. (On an 8 x 24 and 10 x 15), use two pieces per side or two pieces long enough to go more than half way across the chuck.
4. Remove the two remaining screws. Lift off the top p l a t e .
CAUTION: Keep the wedges in place u n t i l the top p l a t e is completely removed. Regrind magnet box and underside of top p l a t e if necessary. Photos below of magnets in off position, the top off, closeup of actuator screw, magnets in on position. That's epoxy between the magnets and a box holding them all together. My questions now are: What's an equivalent to Molykote BR-2?, and what gear oil is compatible with that grease? Man, the text editor for the forums is not particularly user friendly. I tried to format this into paragraphs and spaces in the appropriate places, but it won't let me.

 

[Ray C]

Congrats! -And that is very different from the insides of the ones I've seen.

 

[RWL]

I finished cleaning it up and reassembled it. The directions do not call for any oil, only Molykote grease or its equivalent. I used Mobilux EP since I had it around. I need to look it up to see if it's an equivalent, although since it's an extreme pressure grease I suspect it is. Here are the rest of the instructions from Magnetool. It has the instructions to adjust the off position. That was one of the things that had been giving me problems. I had difficulty lifting things off the chuck. I thought the screw had worn to the point where the magnets weren't being pulled back far enough. It turns out they were being allowed to move too far. Turning the adjustment screw in fixed that. , . . 5. To keep the end play in the operating screw to a minimum, use
the following procedure:
(a.) Replace magnet box with operating nut in casting.
(b.) Turn in operating screw.
(c.) Drop yoke in place.
(d.) Move operating screw back & forth. Take up excessive play
with shims.
Note: If casting does not have Bushing (1256-3) it must be d r i l l e d
and reamed to 7/8" d i a . so the bushing can be pressed i n .
6. Grease the top of the magnet box with Molykote grease #BR2-5 or
equivalent. Do not use regular machine grease. Put four screws in the
casting - two on each end. Hold the top p l a t e at an angle and place
the threaded holes of the top p l a t e on the two screws at one end of the
casting. Let the other end down on the other screws. The top p l a t e
will be drawn to the magnet box with a great deal of power and snap.
(Keep fingers out of way). Turn the four screws in loosely before
turning the chuck over.
7. Adjust the "OFF" position with the set screws located in the
end of the c a s t i n g .
(a.) Loosen set screw.
(b.) Turn handle to "ON".
(c.) With the s t e e l piece on the chuck, move the handle slowly
to "OFF" at the same time trying to move the s t e e l piece.
When the s t e e l piece comes off with ease, hold the handle
in that p o s i t i o n . Move the set screw in u n t i l it r e s t s
against a solid stop - which is the end of the magnet box.
This prevents the magnet box from moving too f a r . Replace
the locking set screw.

 

[RWL]

Further follow up on the chuck. I spoke with an engineer at Magnetool today. They do not use oil in their chucks, just grease. He said that Walker and the foreign manufacturers use oil in their chucks. They haven't used Molykote grease in decades and said that NAPA bearing grease is what they use. Their chucks contain ceramic magnets and don't suffer from removing them from the top plate. He said the magnets were actually in the epoxy between the steel bars of the magnet. The old Alnico magnets lost charge if removed from the top plate, ceramic ones don't. They rebuild all makes of magnetic chuck and have the capability to recharge old Alnico magnets.