Magnetic chuck for Delta Toolmaker

[Vandeweb]

I'm in the market for a new magnetic chuck to mount on my Delta Toolmaker grinder. What should I be looking for? There seems to be two types of permanent magnet chucks, fine pole and standard. At first glance the fine pole seems to be more versatile since it can be used for thinner materials. Since the Toolmaker grinder is rather lightweight, the reduced clamping force on larger items may not be a big deal.

The appropriate Shars chuck seems to be just under $300, while I may be able to get something off eBay for $200, I wonder about quality. Certainly, I'd rather not spend the big bucks at Suburban tool. Theirs start around $500 and go north quickly.

Other than variable clamping, is there advantages to the electromagnetic chucks? I see that those are much more expensive new, but can be found used on the big auction site.

Thanks,
Brian

 

[projectnut]

As mentioned the fine pole is better if you primarily are grinding small parts. There will be more lines of magnetism going through the part. The downside is that each line of magnetism will be less powerful than the line(s) generated by a standard pole chuck.

The lines of magnetism can be multiplied on a standard pole chuck by using "magnetic transfer parallels" like these:
https://www.ebay.com/itm/Precision-...027482?hash=item216c028dda:g:8awAAOSwZd9eXaz3

If the parts you intend to grind cover 2 or more sets of poles of a standard chuck the parallels won't improve the hold much. In that case "blocking would be a good alternative. The part to be ground can be framed by pieces of ferrous metal shorter than the part to be ground that will span the poles.

My Sanford MG (6" x 12") grinder uses the manual 5" x 10" standard pole chuck that came with it from the factory. I've been able to grind 1" ID shim washers down to .016" thickness.

There are a number of new 5" x 10" and 6" x 12" magnetic chucks available on eBay for far less than $500.00. Just be sure you purchase one that will mount to your grinder. Some grinders have a T slot while others have pads with a mounting bolt at fixed distances

 

[benmychree]

One advantage of electromagnetic chucks is the ability to neutralize the residual magnetism in the part being worked on by reversing the polarity of the DC current momentarily, or better yet by a Neutrofier (trade name) or a Chinese version which work quite well.