Question about magnetic chuck

Well, as a newcomer to machining, I have no experience using magnetic chucks. I purchased one recently, with the idea of passing it on to a friend who has a surface grinder and has been searching for one. This chuck is about 5" wide by 12" long.

My question is this: Is there any safe application for using a magnetic chuck on a mill? I was not sure if the side forces during cutting operations would cause the material to be dislodged and thrown from the mill, or at least moved destroying accuracy.

If it is safe to use the mag chuck on a mill, I may decide to keep it and use it myself.

Thanks for any help or suggetions.

Tom

I advise against using a magnetic chuck on a mill. once you have gained much experience, you might find a safe way to hold a large steel or cast iron part while taking a tiny cut. But it is not a safe practice, in general.

Larry

Not sure about throwing, but your part will definatly skid along.

JL.................

Depending on the application Magnetic chucks can be very useful for workholding on mills.

For most applications a vise or clamps will probably be the best.

But for some applications a magnetic chuck make loading and unloading much easier. Most of the time this is for long think parts. We use magnetic chucks for several applications on mills in our shop.

We still use the backing plates to hold the part in place.

Many manufactures of magnets design them specifically for milling.

Alpha Workholding Solutions | A-Pod

Thanks guys! I think the best thing for me to do would be pass the mag chuck on to my friend to use with his grinder as I originally planned to do. I noticed it was fairly easy to skid a part sideways on the chuck while I was just trying scrap pieces to see how tight they gripped.

I appreciate the replies and value your advice. I would imagine there are different strengths or holding power of the mag chucks, depending on the construction or arrangements of the magnets. I see in photos some of the chucks have many more lines or divisions than the one I have. Does this in fact affect holding power?

A quick note about Alpha.

I met one of their salesmen about a year ago. One of the Nicest most helpful salesmen I have met.

Didnt end up buying their product though.

I used to do this same machining operation on these castings on a South Bend vertical mill with the same magnet. Arranged so the face mill was pushing toward the tilted face of the magnet, and with an end stop as well. It's a lot easier on the planer, though; force pretty much all in one direction, and no vibration.

I see in photos some of the chucks have many more lines or divisions than the one I have. Does this in fact affect holding power?

Click to expand...

Sort of. Mostly it means that small and thin pieces can be held easier and a little tighter, without having to consciously block them over specific poles. (they should still be blocked, but you can arrange them "where ever".)

It used to be said that a coarser pole chuck was better for larger work pieces. I have noticed that my fine pole chucks hold small parts "better" but never noticed they held large parts any worse than my coarser pole chucks.
As someone else noted, holding power has more to do with original design of the chuck. FWIW, I wouldn't waste money on the old fashioned chucks with widely separated areas surrounded by the different metal poles. (as opposed to more common "modern" chucks with the alternating bars. Unless you do really large work on really large chucks, and the chuck is cheap.

One of the chucks I like the best is on a 6 x 12 Robbins Excello compound sine, it has high/low bars. They do seem to be a good arrangement, but i don't know why.

smt

stephen thomas said:

I used to do this same machining operation on these castings on a South Bend vertical mill with the same magnet. Arranged so the face mill was pushing toward the tilted face of the magnet, and with an end stop as well. It's a lot easier on the planer, though; force pretty much all in one direction, and no vibration.

Sort of. Mostly it means that small and thin pieces can be held easier and a little tighter, without having to consciously block them over specific poles. (they should still be blocked, but you can arrange them "where ever".)

It used to be said that a coarser pole chuck was better for larger work pieces. I have noticed that my fine pole chucks hold small parts "better" but never noticed they held large parts any worse than my coarser pole chucks.
As someone else noted, holding power has more to do with original design of the chuck. FWIW, I wouldn't waste money on the old fashioned chucks with widely separated areas surrounded by the different metal poles. (as opposed to more common "modern" chucks with the alternating bars. Unless you do really large work on really large chucks, and the chuck is cheap.

One of the chucks I like the best is on a 6 x 12 Robbins Excello compound sine, it has high/low bars. They do seem to be a good arrangement, but i don't know why.

smt

Click to expand...

NICE SETUP. Simple but it gets the job done.

Mebfab said:

A quick note about Alpha.

I met one of their salesmen about a year ago. One of the Nicest most helpful salesmen I have met.

Didnt end up buying their product though.

Click to expand...

I have a bunch of the alpha lifting mags in my shop. 1200 lb and 2500 lb. I bought since they were very nice and MADE IN THE USA!!

Most other lifting mags come from Europe or China.

stephen thomas said:

I used to do this same machining operation on these castings on a South Bend vertical mill with the same magnet. Arranged so the face mill was pushing toward the tilted face of the magnet, and with an end stop as well. It's a lot easier on the planer, though; force pretty much all in one direction, and no vibration.


Sort of. Mostly it means that small and thin pieces can be held easier and a little tighter, without having to consciously block them over specific poles. (they should still be blocked, but you can arrange them "where ever".)

It used to be said that a coarser pole chuck was better for larger work pieces. I have noticed that my fine pole chucks hold small parts "better" but never noticed they held large parts any worse than my coarser pole chucks.
As someone else noted, holding power has more to do with original design of the chuck. FWIW, I wouldn't waste money on the old fashioned chucks with widely separated areas surrounded by the different metal poles. (as opposed to more common "modern" chucks with the alternating bars. Unless you do really large work on really large chucks, and the chuck is cheap.

One of the chucks I like the best is on a 6 x 12 Robbins Excello compound sine, it has high/low bars. They do seem to be a good arrangement, but i don't know why.

smt

Click to expand...

Thank you for the information. That makes sense that the finer pole chucks hold small parts better. I wasn't sure how that worked. The one I bought had coarser pole setup. I just went to my friends home workshop and passed it on to him. He was very pleased with it for his use on the surface grinder.