Anyone here ever used a magnetic chuck?

[adyParticipant @ady]

I can see the advantages, setting stuff up being a doddle, and some of the disadvantages, the greatest being I wouldn’t fancy magnetising my lathe, lol.

 

Has anyone got any input on these gadgets?

 

I had a look on youtube and the uploads/adverts all have giant flat surface area workpieces which is a bit of a nobrainer.

 

A steel vice holding a workpiece, mounted on a flat magnetic plate for milling for example.

Edited By ady on 08/06/2011 09:55:19

[adyParticipant @ady]

[Keith LongParticipant @keithlong89920]

Hi Ady

I’m not sure that using a magnetic chuck for holding your vice on a flat magnetic plate would give you any advantage over having the same vice mounted on a flat plate with numerous slots/holes to facilitate easy bolting to the bed of your machine. You’d still have much the same easy set up and a better/ firmer hold for machining. As I understand it magnetic chuck really come into their own with such jobs as surface grinding, where the cutting forces are low, you want to be able to take the tooling right off the end of the workpiece without hitting clamps and you want a clamping system that doesn’t induce distortion. Also I’m not sure I’d like to take a roughing milling cut with the work just held magnetically and definitely not in a shaper!

I’ve thought for sometime however that there is a distinct lack of information and “how to build one” instructions around I don’t mean the simple 3 or 4 magnets mounted on a base type thing, but the fully switchable designs such as are used at the small end in clock gauge mounting bases for example. With the ready availability these days of cheap NdFeB magnets with their high holding powers, in many ways the difficult bit has been done. The switching should be just a matter of making a system of moving pole pieces to either put the magnetic flux through the workpiece for holding or shorting out for release. Anywhere that you want to machine thin ferrous workpieces should have an application, making spacer /shim washers for example, as an alternative to a glue chuck or double sided tape on a faceplate. Probably the answer there is a magnetic chuck won’t work on brass or ali, glue and tape is simple cheap and will!

Any thoughts anyone – or possibly design?

Keith

[Anthony KnightsParticipant @anthonyknights16741]

Before retirement I worked on Security Systems. Many access systems use rectangular shaped electro magnets (generally known as a “Maglock”) to hold doors shut. These are powered by 12 or 24 volt DC supplies and I have often considered whether one or two

of these would be suitable as a a magnetic chuck. Unfortunately, to date, I have not had time to experiment.

[Anthony KnightsParticipant @anthonyknights16741]

Tried to enclose a picture of a maglock but appears to be unsuccessful.

[Anthony KnightsParticipant @anthonyknights16741]

I have managed to put a picture in my album

[NobbyParticipant @nobby]

Hi Guys & Andy

Mag Chucks are used on surface grinders ie Jones & Shipman 540 s etc.

I used an angle plate with square sides . this was usefull when squaring up inserts

What you do is put the angle plate on the mag chuck lay the insert beside it . then wsitch it on .Clamp insert on the angle plate useing toolmakers clamps (not g clamps)

Switch of Mag chuck turn ass. round swith on again . you can now grind the end dead square.

you can also use mag blocks to hold jig plates etc.

There is another system of holding blocks that span the poles of the chuck. any idias

These were perminent mag chucks I have used electric ones

Regards Nobby You did say Magnetic chucks ?

[Anonymous]

Yes, but……………..

 

I use a permanent mag chuck on my surface grinder. There are circular mag chucks available for cylindrical grinders, but personally I wouldn’t want to use one on a lathe.

 

The holding forces of the mag chuck are not that high when compared to the forces generated by the cutting process. Secondly the holding forces are disproportionally affected by small air gaps, so unless the item to be machined is already pretty flat it’ll probably part company with the chuck before machining commences.

 

No doubt some-one does/has machined on the lathe with a mag chuck, but I wouldn’t want to.

 

Regards,

 

Andrew

[KWILParticipant @kwil]

Magnetic chucks (flat variety) will pull a thin section down if the original is slightly curved, so it will grind to be parallel but will still be curved.

[PatParticipant @pat]

I have used these on a surface grinder and they are very heavy. A version for a lathe would be a lot heavier than a four jaw and be a lot less secure.

 

Also the part to be held needs to be flat and have a reasonable surface finish to get the best hold. Needs steel or iron parts and the chips will also stick to the chuck making a big fur ball. Obvious but it won’t work with any thing non magnetic including most grades of stainless steel

 

Regards – Pat

[NobbyParticipant @nobby]

Hi

I”ve used them on a cylindrical . for grinding water cooled round inserts for plastic moulds

As as Andrew said the item must be flat so I ground the ends flat on a surface grinder.

On small and slender parts add loads of coolent to keep them cool & to stop them lifting with the heat..Grinding washers etc you can put a back stop that is thinner than the finished size to stop them sliding.

Holding copper you can use engineering double sided tape on the chuck.

A good tip when grinding copper fill the wheel with talow.

For quick setting things true I use a back stop made from angle on the back of the chuck

when screwed on you can grid it dead true with m/c. Dont forget to take it off as your mate might run into it

Nobby

[BogstandardParticipant @bogstandard]

I use two mag chucks, one on my small surface grinder and the other on a high speed Meddings drill.

 

Because when the drill is in use and using small steel jigs for holding parts, it takes only seconds to accurately fix the jig in place, whereas normally it would require a lot of hold down clamps.

 

For turning, no, for flat holding with not much machining pressure, yes.

[BogstandardParticipant @bogstandard]

Forgot to add picture

 

Edited By Bogstandard on 10/06/2011 20:11:28

[NobbyParticipant @nobby]

Hi Bogstandard

Good picture I like the adjustable sliding jig . I have a similar one but higher for grinding ijector pins . You did”nt say what make of small surface grinder is it an Eagle.? how about a picture ?

My mate & I fitted a round mag chuck to a Black Decker drill stand for drilling holes in the long side frames of a long print bundling M/C about 14feet long and 1/2″ thick.

Regards Nobby

 

[John Stevenson 1Participant @johnstevenson1]

Also depends on what you are holding because the part is it flux return path.

Try holding some very thin parts and without large substantial packing they won’t hold.

 

John S.

[BogstandardParticipant @bogstandard]

Nobby,

 

That is a picture of the mag chuck fitted to my Meddings high speed drill, and the jig is being held perfectly in position by the mag chuck so that I can drill multiple parts.

 

Maybe I should have shown you this picture, which shows the round mag chuck in position instead of the normal detachable round table. This can be swapped over in a few seconds with the normal drill table, as I mounted it onto it’s own spigot backplate that drops into the drill’s own table support.

This setup is for drilling 0.006″ (0.15mm) holes in the end of brass gas jets (once they are mounted into a steel drilling jig, and the jig set up on the mag chuck).

 

 

My surface grinder is an old Herbert Junior that has a 7″ x 4″ mag chuck on it.

 

This is it in use, grinding the modified bases of a pair of hi level adjustable V-blocks.

 

[NobbyParticipant @nobby]

Hi Bogstandard

6 thou thats tiny. Is the jig drill bushed ? I made a driil jig with drill bush guides for 6 holes. The inspection came round to the toolroom & there were 7 hole in the component. .

What happened the girl/lady drill operater missed a bush and drilled through to the job.

Any way it got sorted

I like the Grinder . I fit a small grinding head on my Brummond shaper for light work

Regards Nobby

[NobbyParticipant @nobby]

Hi

Sorry Drummond hand shaper

[BogstandardParticipant @bogstandard]

No bushing Nobby, just using fairly high speed keeps things on track.

 

I can get just over 6,000 RPM out of the Meddings, which if care is taken with the down-force, it gets the job done with very little attrition rate of the carbide drills, and besides, I am only drilling brass.

 

In reality, the drill should be turning at somewhere over 80,000 RPM to make it stable enough to drill thru almost anything with no support.

I have designed and almost completed an air pedestal drill that gets towards that speed, but I abandoned it after I was given the Meddings, as that copes well enough with what I want to do at this time. Why make life difficult for the sake of it?

The mag chuck on it make things so much easier to set the jigs up. Just use the correct sized blank in both the chuck and jig, press things down onto the table then turn on the chuck, everything lines up spot on, with no fiddling at all with clamps etc.

 

With regards to the surface grinder. Over the years, I have either made or picked up cheaply all sorts of fixtures to fit onto the mag chuck, so not only does it surface grind, I can resharpen almost all my tooling as well. The only thing I can’t do at this time is grind side flutes on milling cutters or reamers, but I am not worried, I will pick something up one day at the right price to do that.

 

This is now getting a bit far off topic, but hopefully, it may help someone along their journey.

[adyParticipant @ady]

Hi

Sorry Drummond hand shaper

——————————————————-

 

and wot does that mean??

 

And do NOT apologise please.

 

Edited By ady on 12/06/2011 01:29:12

[adyParticipant @ady]

Got an Adept no 2 recently.

Very impressed so far

 

Cant believe how easy they are.

Edited By ady on 12/06/2011 01:48:06

[NobbyParticipant @nobby]

Hi Andy

On my last post to Bogstandard I spelt Drummond with a b

Nobby

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