Magnetic chuck

[BrianS]

I need to machine some small thin pieces and I was thinking that a magnetic chuck would probably be the best solution to hold them. Problem is, I only have a small sherline mill. So does anyone know of one that is the right size for this mill? Or perhaps plans on making one? I'm not exactly sure how the permanent magnet ones "turn off". Thanks in advance

 

[Bernd]

Brian,

Need a bit more info. Are you turning the outside diameter, I assume. A facing cut, boring a hole?

Bernd

 

[BrianS]

No I'm thinning small stock and cutting bosses and steps in very small rectangular pieces in the mill.

 

[shred]

I use superglue or double-sided tape for those kinds of things on my Taig, though often because I'm cutting Al or brass or some such.

The permanent magnet chucks I've used turn off by moving the magnet parts away from the piece-parts. Usually with a lever on the side.

 

[Mainer]

A magnetic chuck probably won't do the job -- mag chucks are used for grinding, not milling, and aren't really intended to be able to resist milling forces.

Now, you might be able to do it, if you take LIGHT cuts and use work stops -- larger blocks positioned on the mag chuck against the sides of the workpiece to help hold it in place against the cutting forces.

 

[Bernd]

I guess I'd need a pic to see what your cutting to give a better idea of how to hold it. I would think superglue would let loose with the interrupted cuts of a mill. double sided tape may work. Perhaps some kind of jig would work?

Bernd

 

[shred]

I guess I'd need a pic to see what your cutting to give a better idea of how to hold it. I would think superglue would let loose with the interrupted cuts of a mill. double sided tape may work. Perhaps some kind of jig would work?

Bernd

I've used superglue to hold 1.5"x3"x0.25" Aluminum for CNC pocketing 1/8" deep and full-depth profiling with a 1/4" end mill, plus a lot more thin brass and Al sheet. The first couple parts I stood behind a thick plywood shield, but after a while it became obvious it wasn't going to let go unless it got way too hot. You'll want flood coolant or a cold air gun if you do a lot of superglue work (the same holds true for double-sided tape-- it gets hot, it lets go, but it's more of a nuisance with coolant)

You can also soft-solder small parts to thicker ones to hold them if they're solder-adherable, then melt them free. A guy I know that makes really nice model live steamers does that a lot for thin brass parts.

 

[Maryak]

Guys,

Another poor mans magnetic chuck is newspaper soaked in wood glue, (aquadere and the like), between the table and the workpiece

It's cheap and effective.

Best Regards
Bob

 

[BrianS]

Thanks for the answers. I have a couple of follow up questions. If you use the super sticky double faced tape and you have very thin parts that might bend easily how do you get it unstuck? Same with the crazy glue, how do you get it unstuck? Also how much do you use? Would you run a bead the entire length of the part or just a few drops?

Thanks guys. I always learn something when I vist here

 

[rleete]

Acetone disolves most double sided tape.

 

[mklotz]

Superglue breaks down when heated. Play a torch on your part for a minute or two and remove the part with pliers.

Acetone is a solvent for superglue. It works too slowly for me when removing the part so I use the torch but it's good for removing the superglue residue from the part. (Also works to unstick your fingers when you glue them together.) I buy acetone by the quart from Home Depot but, if you need only a small amount, it's the active ingredient in ladies' fingernail polish remover. Be reminded that acetone will attack many plastics.

 

[shred]

I use a heat gun (hair dryer on steroids) or sometimes an old wood chisel to pop parts loose (this will likely scratch and/or bend very thin parts). Acetone to then clean up the residue. Every so often run a fly-cutter across the sub-board to clean it up.

When I glue parts down, I usually use an old plastic cutting board or MDF as the sub-board. I sprinkle spots of glue over about 50% of the surface and press it together to cure, either by sticking the whole sandwich in a vice or setting a weight on top of it on the mill table.

 

[Dhow Nunda wallah]

The clutch coil from an auto air conditioner makes a great magnetic "grabber".
May be a little big for a Taig though.

 

[tel]

The clutch coil from an auto air conditioner makes a great magnetic "grabber".
May be a little big for a Taig though.

Can you expand on that Dhow?

 

[Loose nut]

Use Mitee-Grip from the company that makes the Mitee-Bite clamps. Its a precision paper that has a "wax based" compound that glues your part to a plate or table etc when you heat it. It's made for just the purpose you want and a role will last several lifetimes. I bought some a few years ago and it has worked very well for machining thin bits ferris or otherwise.