Magnetic Chucks

[D45]

Who has a magnetic chuck?

Useful tool or novelty?

How are you using it in your shop?

 

[LeeG]

I have a cheap one I picked up from Amazon. I use mine for holding small parts that I want to hit with a wire wheel or flap disc. I know they are commonly used on surface grinders, and they make round ones to use as a lathe chuck. They are mainly used on surface grinders.

 

[Dave455]

I’ve got one. An old Eclipse, similar to below.



Fantastic bit of kit, PROVIDED you use it within it’s capabilities.

They were originally designed for surface grinders, and they are great for that - flatter than a vice and no gaps to get dust in. Work well on drills too.

But if you think it would be a good thing to put on your mill and start taking some heavy cuts, forget it.

I mostly use mine on my Jig borer. I generally switch between small vice, big vice or magnetic chuck as needed. Magnetic chuck is fastest in use. If I need a reference parallel to the table movement I tend to glue one on, and knock it off when I’m done. Great for small batches.

 

[D45]

Learning about these.......

Some plug in and some have throw levers

Do they just turn on and off, magnetically?

 

[Dave455]

Learning about these.......

Some plug in and some have throw levers

Do they just turn on and off, magnetically?

Yes, they are permanent magnets, but when you move the lever it redirects the magnetic flux (internally) which has the effect of turning the magnetism off (externally).

In theory, the magnetic force can reduce over time, but I’ve had my chuck probably 25 years (and it was well used when I got it) with no issues. Drilling some small blocks recently, maybe 2 inch square, half inch thick, if I didn’t turn the switch to exactly the “off“ position, you couldn’t lift the workpiece.

I also have a magnetic V block which I use probably more than the chuck. When turned ”on” it holds the workpiece to the block, and also the block to the drill table. Nothing moves. Great for drilling round bar.

 

[Downwindtracker 2]

I have an Eclipse on my Delta Tool Maker. When I was in Grizzly they had a bunch of mag base accessories . They looked handy, but I don't have any of them, yet.

 

[darkzero]

I've got one but it's not the type I assume you are thinking about, ie rectangle shape mostly used with surface grinders.

I've got a round mag chuck to use on my lathe. Scored it on ebay, wasn't looking for one, just happened to come across it. I cleaned it up & made 2 backplates/adapters for it. Doesn't get used a whole lot but I'm happy to have it & comes in very handy when I need it.




The second backplate is to mount it on my rotary table but I haven't had to use it on my RT yet. With that same backplate I can mount it directly to my mill table.

 

[D45]

Thanks

I like some of the older , used vintage units on ebay and such

They can get pricey!!

 

[rlitman]

I have a 6x18 magnetic chuck on a workbench. It's great for all sorts of weird uses. It holds down a diamond sharpening stone perfectly, and I have three angle grinders hanging from it. Each has a super magnet tied to their cord strain relief, and with the chuck in 1/8" from the bench edge, the magnets grab to the side of the chuck and don't slide off

Years ago, I hand stamped a whole bunch of name tags. I put a few steel blocks down so one name tag would stay in an exact spot with a way to line up my alphanumeric stamps, I put a scrap of copper sheet flashing into the space, dropped in a name tag and hammered each punch, then repeated. I'd go through maybe 15 tags before needing to rotate the copper.

The only down-side to my magnetic chuck was when it fell on my foot and broke my big toe the day I bought it.

On a similar note, I have a 12/24V 1200lb magnetic door lock that I use with a 12V cordless battery to clamp my featherboard to my cast iron tablesaw top. Magnetic locks have useful similarities to magnetic chucks, and their own pros and cons. A door lock will have less residual magnetism when off, but while a magnetic chuck has a good flat surface and will grip small objects, a magnetic lock isn't so flat and works best with objects at least its full size.

 

[D45]

Why do some of these have an electrical cord with a plug?

 

[Dave455]

Why do some of these have an electrical cord with a plug?

I’m guessing that’s a cheaper thing with an electro magnet. I’ve never seen one like that.

 

[csp]

Why do some of these have an electrical cord with a plug?

Because they are electromagnets.

 

[matt_i]

Keep in mind its grip is limited. Could never be used as a milling chuck unless taking paper thin cuts.

Even in surface grinding small pieces one often has to place a backup piece of flat stock to contact more "poles" and thus develop more grip.

I'm not a big grinder hand but the "cuts" I take on a 6x12 surface grinder with permanent magnet chuck are usually sub .001" (for reference std copier/laser printer 8-1/2" x 11" paper is around .003" thick)

 

[2Manytools??]

D45, just got one off of eBay. It is a Fowler KNTW-510, made in Japan. My initial plan is to use it to hold parts for welding preparation, and possibly try it on the drill press, but am still considering that. It is 5x10, and very heavy!!! The holding strength is weak right now. I have taken it apart to clean it to see if that improves the performance. There is a little bit of rust inside, and there was a lot of grease. It has a screw port in the bottom labeled "oil". I am trying to find out if it is supposed to be oil filled or use grease. Does anyone have any information on that? I have not been able to find information on that particular model.

 

[dr_clyde]

Hard to use a surface grinder without one. My grinder has a 12” x 24” electromagnetic one. The less expensive ones use permanent magnets on a lever. Electromagnets can generate more magnetic field as well as de-magnetize.

I rarely need one outside of surface grinding, but I have found it handy in the past to hold flat or disc shapes to do some finish work to them.

They have a a fairly limited use window, but when you need one, they’re the tool to have.

 

[dr_clyde]

D45, just got one off of eBay. It is a Fowler KNTW-510, made in Japan. My initial plan is to use it to hold parts for welding preparation, and possibly try it on the drill press, but am still considering that. It is 5x10, and very heavy!!! The holding strength is weak right now. I have taken it apart to clean it to see if that improves the performance. There is a little bit of rust inside, and there was a lot of grease. It has a screw port in the bottom labeled "oil". I am trying to find out if it is supposed to be oil filled or use grease. Does anyone have any information on that? I have not been able to find information on that particular model.

If it says oil, it means oil. Probably just needs a light machine oil. Just because it has a zerk or threads doesn’t automatically mean grease. There are oil zerks too.

 

[2Manytools??]

Hard to use a surface grinder without one. My grinder has a 12” x 24” electromagnetic one. The less expensive ones use permanent magnets on a lever. Electromagnets can generate more magnetic field as well as de-magnetize.

I rarely need one outside of surface grinding, but I have found it handy in the past to hold flat or disc shapes to do some finish work to them.

They have a a fairly limited use window, but when you need one, they’re the tool to have.

dr_clyde, I'm new to using a magnetic chucks. I've noticed that some have grease others oil. Mine is a Fowler KNTW-510. It has a screw in the base labeled "oil", but it was full of grease. I'm only using it to hold pieces to work on, welding prep, etc. Right now the holding strength is pretty week, but hoping that cleaning up will help. Thank you for any information you can provide.

 

[Rabid Badger]

I've got one but it's not the type I assume you are thinking about, ie rectangle shape mostly used with surface grinders.

I've got a round mag chuck to use on my lathe. Scored it on ebay, wasn't looking for one, just happened to come across it. I cleaned it up & made 2 backplates/adapters for it. Doesn't get used a whole lot but I'm happy to have it & comes in very handy when I need it.

I didn't know it existed 5 minutes ago, but I need it.

 

[MongoTA]

I am trying to find out if it is supposed to be oil filled or use grease.

Oil.

 

[2Manytools??]

I didn't know it existed 5 minutes ago, but I need it.

I was unaware of their existence either (until I saw one made on Youtube), then started collecting the parts to do that, but during the researching found out about the manufactured ones...ebay...and presto, another tool found it's way to the house.

 

[2Manytools??]

Oil.

MongoTA,
Thank you for the information. It is 5"x8"x1.5", do I fill it full up? What kind of oil? Again, appreciate your time on this.

 

[MongoTA]

Last time I had to oil a mag chuck (a non-operable chuck that was thrown into an auction lot for free), after I rebuilt it, I added gear oil. Lucas 80-90w, since that's what I keep on my shelf.

A big mistake is that people see zerk-type fittings and think "grease". Well they can be oilers as well. Grease in a traditional mag chuck can harden over time and cause it to lock up.

Best, Mongo

 

[2Manytools??]

Mongo, Thank you again. It is manual/handle operated. No zerk-type fitting, but the plug on the base clearly says "oil". Will get some gear oil. Do I just fill it full? There shouldn't be much thermal affect, other than what is transferred from a hand grinder.

Thanks,

 

[2Manytools??]