Magnetic swarf

Many folk use magnetic bits such as magnetic DTI holders and the like on their machines. In time there must be a build up of magnetism in the machine which in turn attracts the ferrous swarf.

I've studiously avoided the use of magnetic equipment on my machines until recently when I started using a magnetic holder for a DTI.

So, how do people de-magnetise their machines, or do they not bother?

Dave
The Emerald Isle

Never had a problem.

Not a problem

Tony

Not aware of a problem after 17 or more years with lathe and Mill.

I use a stick magnet in a copper tube to pick up ferrous swarf to get rid of.

Howard

That sounds very much like a non-problem.

OK. Thanks for putting my mind at rest.

Dave
The Emerald Isle

Cast iron does not hold residual magnetism in the same way as steel does which may explain why it is not noted as a problem with DTI mounts on such surfaces.

Regards Brian

Irritatingly, I have had chuck jaws ( the hard type) become magnetic and then it's a pain clearing the fine swarf from the jaws when inserting the workpiece. Likewise tool steel lathe cutters, and some milling cutters and even the hard steel capscrews in the tool-holder. This only occurs in the hard steel bits on the lathe - I have never had issues with the lathe structure. I am not sure how, for example, the chuck jaws, become magnetic but they do so repeatedly. I demag all the bits with a homebrew demagnetiser, and all is well for a few weeks. There is that high-school science trick where you align a hard steel rod say North/South, hold it so and smack the one end with a hammer a dozen strokes - it becomes magnetic - maybe I should stop smacking the lathe so hard....

Joe

Are you sure that your lathe is pointing North/South then? Dave W

Yes, it is hung from a rope so it aligns magnetically.

I have never noticed any adverse affects, in fact using lots of magnets when machining cast iron helps to control the mess.