Yuasa Round Magnetic Chuck for Lathe

[darkzero]

Some of this is from the other thread here. Mainly adding to my archive.

Got a 6.3" Yuasa round magnetic chuck a while back to use on the lathe. Mainly to work on thin parts & machine parts flat (parallel on both sides). Not meant to take heavy cuts (think surface grinder), just light skimming is what I'll be doing with it. I haven't got fully comfortable with how strong it will hold various sized parts yet but getting there. So far I'm happy to have this in my arsenal.





Used a South Bend branded 8" D1-4 back plate from Grizzly to mount it. Took quite a while to get it down to 6.3" but it was worth it.



Here's how it looked when I got it.



A bit of light sanding & scotchbrite cleaned it up very nice. I decided not to skim the face or grind it just yet.



Just with clean up it only had about .001" runout on the body & .0002" rounout on the face, +/- .0001" depending on where I measure it. Didn't see a need to face it at this time.



It came with the original key (square rather than hex like most others) but I wanted one with a bit longer handle. 7mm square keys are hard to find so I thought for sure I would have to make one. Found one from Myford, even coming from the UK it was a good price & good quality. Handle was way too long so I shortened it.



First thing I made. I needed a spacer for my slitting saw arbor. Wanted it as flat as possible so it wouldn't add any runout which was a success.

 

[darkzero]

I also made a backplate to mount on my rotary table. With the same backplate I can bolt it to the mill table. I may never use it on the mill but ya never know.




Making the backplate.



In the other thread I mentioned that this one did not come out that great & that I would get back to it later. Did that today. I got a bit over .001" difference over the 6.3" face.



What better way to try & fix it than with the mag chuck! Used a bull center to hold it up against the mag chuck, then bumped it true.



I use these copper slugs for knocking things around. They're perfect to use with the mag chuck. The pinion adds magnetism gradually. I turn the pinion about 1/2 to 3/4 of a full turn depending on the size, bump true, then fully turn.



Here's what I measured. About a thou of axial runout cause of the variation in thickness.



Ok, laugh, tease, make fun of me all you want but I was a bit scared. I didn't know what to expect spinning an 8" dia x 3/4" thick piece of cast iron even though it was only going to be a skim cut. I yanked on it pretty hard & couldn't budge it. Still, I used two MT extensions as a safety catch (don't mind the annular cutter arbor, tried that before adding the second extension & just left it in). Even it if it knocked loose I'm sure it wouldn't have completely seperated but better safe than sorry.



No dramas. Surface finish didn't come out as great as when I first made it but whatever, it's the bottom. Here's what it ended up at. That's consistent with the axial runout of just the chuck. Good enough for me!



Thanks for looking!

 

[mikey]

Awesome, Will! I would definitely be happy with 3 tenths over 8". As always, very nice photo-documentation and text - very clear. Its stuff like this that make other guys want to run out and buy tools ... you know that, right?

Have fun cleaning up all the cast iron. I still haven't gotten around to mounting my chuck; must be a subliminal wish to avoid clean up!

 

[darkzero]

Awesome, Will! I would definitely be happy with 3 tenths over 8". As always, very nice photo-documentation and text - very clear. Its stuff like this that make other guys want to run out and buy tools ... you know that, right?

Have fun cleaning up all the cast iron. I still haven't gotten around to mounting my chuck; must be a subliminal wish to avoid clean up!

Haha, thanks Mike! I have been one of those accused to be the cause of people spending their money when I first came here. One person even told me that his wife hates me. I hope he was just joking.

Yeah I'm pretty happy with the result. I was surprised actually, I measured like 5 times with 2 different mics. I'm not used to getting results that close in tenths. This thing is pretty cool, I know you will love yours too once you get it mounted!

Oh the CI, I already took care of. I did most of the work on the backplates on 2017. That's where I left off. Only had to drill the bolt circles to finish them off. I hope I never have to make that much of a CI mess again.

 

[mmcmdl]

Will , we used to use them on our universal grinders . Surprisingly , they hold pretty good . I've mounted them on lathes also and had great results with them . You'll get the occasional ooops and your part will move , but it usually does not end up in a scrapped part , rather just having to find it in your machine bed . Nice set-up there .

Double back tape was used on some jobs and it worked ok , but trying to remove the part afterwards was quite the chore . I did some thread grinding years back , and we would Loctite the mold cores to a plate and pic up the existing threads . Never had one break off ! A quick wrap with a brass hammer shocked the piece off .

 

[mmcmdl]

On a side note , you could do that on a SG ………………….














and I just happen to know where one is !

 

[mmcmdl]

Awesome, Will! I would definitely be happy with 3 tenths over 8". As always, very nice photo-documentation and text - very clear. Its stuff like this that make other guys want to run out and buy tools ... you know that, right?

Funny Mike , I don't need to read documentation OR look at cool pics , I seem to just buy tools for the heck of it ! I figure there are more worst ways to waste my money .

That is good looking set-up he has there , AND very useful.

 

[darkzero]

Will , we used to use them on our universal grinders . Surprisingly , they hold pretty good . I've mounted them on lathes also and had great results with them . You'll get the occasional ooops and your part will move , but it usually does not end up in a scrapped part , rather just having to find it in your machine bed . Nice set-up there .

Double back tape was used on some jobs and it worked ok , but trying to remove the part afterwards was quite the chore . I did some thread grinding years back , and we would Loctite the mold cores to a plate and pic up the existing threads . Never had one break off ! A quick wrap with a brass hammer shocked the piece off .

Thanks Dave. Is that what round mag chucks are mainly used on, universal grinders?

Yup, I quickly learned making that spacer. Had very little surface area so it kept knocking loose. That particular part never fell.off the chuck though, it would just slide.off to the side. Had to take very light cuts with a very sharp tool to get it done

On a side note , you could do that on a SG ………………….














and I just happen to know where one is !

Haha, as much as I would really really really really really love to have a SG I don't have the room for one.

 

[mikey]

Funny Mike , I don't need to read documentation OR look at cool pics , I seem to just buy tools for the heck of it ! I figure there are more worst ways to waste my money .

That is good looking set-up he has there , AND very useful.

Yeah, I seem to buy tools without Will's help, too, but he does make things worse. He made me want an Eagle Rock knurler so bad that I went and bought one. I'm glad I did but I will forever get to nag him about it!

 

[darkzero]

Yeah, I seem to buy tools without Will's help, too, but he does make things worse. He made me want an Eagle Rock knurler so bad that I went and bought one. I'm glad I did but I will forever get to nag him about it!

Just being here is a problem! We all do it to each other though. Why do you think I created the following thread?

What Did You Buy Today?

Don't remember if there is an existing thread like this. Many of you guys like to share your scores so let's try a new ongoing thread... If your here chances are you love tools & always love to get new ones. This thread is not necessarily for gloating (well maybe) but you can if you want but...

www.hobby-machinist.com

Haha, the knurler! Mike made me buy a TE-CO clamping set to replace the import set that came with my mill. Well maybe not made me but he made me want one bad as well.

It's still sitting in the box, I need to get it set up & mill the t-nuts. Thank you for the reminder!