Round Magnetic Chuck for Lathe

Ok, will do. I'll probably start another thread when I get working on it.
 
Coarse pole mag chucks are best for THICKER and larger parts. Fine pole mag chucks are best for THINNER and smaller parts. The heights of the magnetic fields above the chuck are proportional to their spacing. The holding power will be minimal for much lathe work, compared to a regular chuck, and light cuts will be be necessary. I think I would prefer the brass spacers over the white metal ones. The white metal ones are made out of something similar to Babbitt metal. Both are soft, as are the chucks themselves, which are made from mild steel for better magnetic properties and less residual magnetism. A fine India stone will be your friend with these mag chucks, get used to feeling for burs with one before mounting anything to the chuck. I would prefer to grind the chuck in while mounted and turning on the lathe, perhaps with a tool post grinder, but it would sure be messy! Still, all in all a very nice score, and a useful tool in the arsenal...
 
I was messing with the chuck last night and put a thin washer on the face. I cannot move it with my girlie-man hands when the magnet is engaged, although I can knock it out of position. I think it will hold well enough for my purposes. The last time I needed a thin washer, I was taking a 0.002" deep facing cut on a piece with only 0.003" sticking out of the chuck and maybe 0.007" being held by the jaws - too close for comfort. With all the tension I felt you would think I was trying to hold that part with sphincter power alone! It took a long time to get that washer aligned in the chuck as well so yeah, I think this new toy will come in handy.
 
Got the chuck today, man that was quick. My heart sank when I saw the box though. Completely smashed, I thought for sure the chuck would have been damaged. Luckily it wasn't & even the tiny chuck key didn't fall out, that's cause it was stuck to the face of the chuck. :)

It feels like it's got some sort of clear coat on the face but that will come off when I face it. Kind of cool, it has a 7mm square for the switch. Most of these either have a hex or D shaped key.

At first I thought it was defective. I put a razor blade on it, turned the key, I was able to slide it right off! Then I stuck my 6" hook scale on it, couldn't pull it off. Threw a M12 washer on it, same thing, couldn't move it. Then I put a 3" dia spacer that's about 1.5" thick, I tried my hardest to pull off by hand & I couldn't. So I'm happy!

It's 6.3". Time to order the back plate now. :)


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Looks good, Will. I bet a facing cut on that chuck will sure make it look purty.
 
Thanks Mike, I think so too. It's odd though, it really seems the mag surfaces of the chuck has a clear paint on it. I can scratch it & it turns white, just like clear coat. But the cast iron body doesn't seem to have it.

It was listed as NOS so I'm wondering if it some kind of protective coating on it. If it is, it's something I've never encountered before. Doesn't matter though, I just thought it was weird.

Another thing that is interesting is the switch is not an instant on off. The pinion turns more than I expected from end to end with no feeling of an indent or overcoming a cam or whatever. It's like it gradually applies the magnetism. When fully switched off, there is no residual magnetism like Stefan shows in his videos with his chuck. Not complaining though as I suppose I can adjust the strength of magnetism to hold different size parts for indicating & then fully switch on.

Does yours behave this way too? I'm just trying to learn more about how these things work.
 
Mine has a small amount of residual magnetic attraction when disengaged, then pours it on when fully engaged. You're right though; you can gradually increase the attraction with the key. Mine is a hex, by the way, and I'm wondering why the difference. Maybe you got the deluxe model?
 
mikey said:
Mine has a small amount of residual magnetic attraction when disengaged, then pours it on when fully engaged. You're right though; you can gradually increase the attraction with the key. Mine is a hex, by the way, and I'm wondering why the difference. Maybe you got the deluxe model?
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Thanks Mike. That is weird, I too wonder about the differences. I wish there was some sort of documentation on these. I even searched Yuasa's catalog, they show mag chucks in the table of contents but the pages they're on is not available for download.

Of the 2 models I posted on, they even have the same exact p/n which is more confusing. Mine says made in Japan & the other one says made in France.

Mine, deluxe model, I don't know about that. I got the cheaper one. Mine was listed at $190 + $15 shipping & the other one like yours is listed at $259 free shipping by the same seller. I know that doesn't mean anything but it seems the seller thought the other one is worth more.
 
Hey, you're right - mine is made in France! I searched but could not find who made it - LFA, you think?

I suspect performance will be very similar because the ability to hold the work depends more on the thickness of the work piece. For small or thin work, not much force is transferred so I doubt we'll see much difference. What I want is to be able to machine both faces of a thin part without distorting it and this tool has that potential - we'll see.
 
Yup, I believe both of our chucks will work fine for whatbwe want to do.

Funny, I was just searching on who possibly made these, well yours anyway. On pics of the 8" model made in France is the name Braillon on the name plate which is Brallion Magnetics located in France. They don't list models in the same size or appearance as the Yuasa models though. I'm thinking Yuasa had them specifically made for them or these are older discontinued models.

Braillon does say that one of their features is adjustable power from 0-100% so it looks like our chucks are working as they should be.

Well that explains yours, mine is still a mystery!
 
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