Author Topic: MAGNETIC CHUCKS  (Read 1489 times)

Offline Firebird

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MAGNETIC CHUCKS
« on: December 09, 2020, 09:52:40 PM »
Hi

I have been looking at magnetic chucks. This sort of thing



Anyone had any experience with them.

Cheers

Rich

Offline Mike R

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Re: MAGNETIC CHUCKS
« Reply #1 on: December 10, 2020, 02:20:07 AM »
I guess the question is what are you going to do with it?  I have a magnetic chuck on a surface grinder, and while it grabs securely enough for grinding (most of the time) I wouldn't trust it anywhere near a milling machine. Sorry no experience with that specific one - my chuck is probably 50 years old or more.

Offline john mills

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Re: MAGNETIC CHUCKS
« Reply #2 on: December 10, 2020, 10:16:56 AM »
I have note used that magnetic table  I have often used magnetic tables on grinding machines  for grinding..I also  used milling machines  manual and cnc.I used  an eclipse   it would have been about 24" by 8" on the milling machine  for milling  mainly first two sides parallel  and to thickness   an straight .mainly hot work die steels
often with a 4" facing cutter    the pieces 500mm long  often . the mill would run out of power with a 3mm deep
cut and 250 mm per min feed it would have been difficult in a vice.you have to make sure it is sitting flate no rocking  and no gaps fit shims in and gaps  you can have to do both sides several times to get sizes and straight
and to fine tolerances.i machined lots of material like this.over a long time.the other faces could then be machined square parallel in the in the vice. the facing cutter would not want to have much rake angle and the material up against the side an end fence.  the top and bottom of the chuck needs to be kept spotlessly clean and no scratches
or it is very hard to keep clean enough for precision work.
John
   
« Last Edit: December 13, 2020, 10:41:01 PM by john mills »

Offline Firebird

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Re: MAGNETIC CHUCKS
« Reply #3 on: December 13, 2020, 09:52:48 AM »
Hi

I haven't seen anybody using one for machining so I figured there must be a reason why.

Cheers

Rich

Offline john mills

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Re: MAGNETIC CHUCKS
« Reply #4 on: December 13, 2020, 10:55:31 PM »
the magnetic chuck can be very usefull holding material with out sqasing in a vice which will tend to put bending and twisting forces on the material tending to bend and twist.but it takes care .to get flat and parallel which other wis would be hard to hold .i mainly used facing cutters  the 4" one mostly not  end mills and i would not use some of the high rake cutters available these days.the material needs to be of size that the magnet will hold well not to high that might tend to want to roll.the material i machine were quite tough to machine but the chuck worked very well .Always feel by hand and make sure the chuck is holding.the chuck only needs to hold down the side and end fences stop from sliding.
  john   

Offline kvom

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Re: MAGNETIC CHUCKS
« Reply #5 on: December 14, 2020, 01:31:16 AM »
That's quite a small one.  The one on my grinder is 6x18.  I've thought about putting it on my mill for use with flat steel sheet, but in reality I think the method of using painters tape and epoxy glue will give a strong hold.

In any case, small pieces can be made more secure by wedging them between 123 blocks.


Offline pgp001

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Re: MAGNETIC CHUCKS
« Reply #6 on: December 14, 2020, 05:31:25 PM »
I have a circular magnetic chuck for the Myford lathe, it is very handy for facing washers to thickness etc so long as yo don't take heavy cuts.

Phil

Online Twizseven

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Re: MAGNETIC CHUCKS
« Reply #7 on: December 14, 2020, 07:08:29 PM »
Phil,

I'm glad you said that as I have just obtained one with a plain shank fitted to use in lathe chuck.  I may also use it without the shank on my Stent T&C.  Although it is hardly has any clearance I was thinking of either using it without the slotted table or raising the grinding head assembly another 1" or so just when grinding.

I also have a 6" x 12" mains powered magnetic chuck which I kept when sold the surface grinder (did not want to but only had 12" to work between it and the mill).

Colin