Rectangular magnetic chuck shopping

[Ian X]

I am after a 450x150mm permanent magnet chuck. The ageing Eclipse 12x6" fitted to a J&S 540 is too short for several jobs I have to look forward to.
I have looked at the going rate for new Walker, Eclipse and MSR chucks and after getting up off the floor had one of those moments when one realises one can never be wealthy enough.
Even my kindly local machine tool dealer asks for arms, legs and shirt off back. I am a bit shy of paying between £100 and £200 on ebay for fear of buying something that has been used as a welding fixture or enthusiastically tampered with by previous owners.
The Czech chucks seem to be around £450 but finding a UK distributor not easy beyond toy sized ones for model engineering.
Anyone point a mug in the right direction?

 

[nickk]

try s/h machine tool dealers ,the ones near me usually have a few in stock,in manchester you must be spoilt for choice.

 

[rikrobson]

can you not use 2 smaler ones or pack up on the ends, where it overhangs

 

[Ian X]

try s/h machine tool dealers ,the ones near me usually have a few in stock,in manchester you must be spoilt for choice.

There are 4 decent tool dealers in greater manc but they still want £400 for 20 year old chucks. That they sell for less than half price of new will be due to them being robust but they are still prone to gumming up and that is a lucky bag as far as buying one goes.

can you not use 2 smaler ones or pack up on the ends, where it overhangs

I thought about using a jack and plate at the off feed end but the pieces are gauge steel less than 2mm thick and I want holding force over the full length.

 

[Phil@mpliron]

Hi Ian
Have you had a look on the MSC website we brought 1 that size as replacement on our elliot surface grinder, although it's not an eclipse it handles what our toolmakers throw at it just the same as the eclipse ones on our 540's

http://www.mscdirect.co.uk/IMG-00618E/SEARCH:CATEGORY/product.html

This is the one we purchased (hope the link works)

Phil

 

[Pete.]

14" x 6" £100 each 2 to choose from. Both Eclipse chucks.

http://www.usedengineeringequipment.co.uk/store/p2/No_1___Permanent_Magnetic_Chuck.html

 

[Ian X]

14" x 6" £100 each 2 to choose from. Both Eclipse chucks.

http://www.usedengineeringequipment.co.uk/store/p2/No_1___Permanent_Magnetic_Chuck.html[/QUOTE

Those rusty beasts I would avoid. Stripping one of these chucks is a ******** own of a job before cleaning out and seeing what's left of the keeper slide drive arrangement. I washed out a couple of pairs of Eclipse 934 blocks that had become hard to activate and they took days to clean out. My kitchen and oven stank of Rocol and Gunk for days, the wife was away and I got away with it. I considered taking the cores out to clean the vee block innards but a friend warned me off that idea. The vee blocks came up fine but the process of getting 30 year varnished oil from them was a dark art. The Eclipse chuck that currently lives on the grinder took a dip in every solvent cleaner I had in stock before the lever would slide over easily. I had owned that chuck for 30 years before I had use of it, a timely lesson for hoarders everywhere.

 

[scott0031]

Its worth having a chat to msc. They often have a range of interstate brass, close pole chucks in there monthly offer catalogues they were from memory about the 180- 200 quid mark for a 6 x 18. The Reason i recall it so well as like you i could do with a bigger chuck as I'm stuck with a 14 x 6 and have been meaning to get one when funds allow. Earlier in the year i refurbished a punch and die grinding machine for a fab shop i work with and I got one the interstate 6 inch Diam chuck as a replacement and for the money is was not bad at all, good strong magnet and i could see nothing wrong with it, the only slight criticism was the movement for the chuck on/ off wasn't as smooth as the many eclipses i have worked with.

Ok having a search about for an old catalogue seems they may have changed there range a bit in last months offers.

May offer flyer
Standard pole mag chuck 18 x 6
£158.50 + VAT
Order code. JEIMG-00618E

Cant beat that kind of value and with a guarantee.

Go give them a call they will sell you one from an old offer at that price.... If they kick up beat them up hard, works for me. Msc like to sell If you don't like it when it arrives tell them they will get it picked up and credit you no questions, they are very good like that.

Hope this is useful

 

[Ian X]

Hi Ian
Have you had a look on the MSC website we brought 1 that size as replacement on our elliot surface grinder, although it's not an eclipse it handles what our toolmakers throw at it just the same as the eclipse ones on our 540's

http://www.mscdirect.co.uk/IMG-00618E/SEARCH:CATEGORY/product.html

This is the one we purchased (hope the link works)

Phil

That's a find that my internet skills didn't turn up! You may have found me a chuck. Rotagrip may have a suitable Pilana offering but the crap image does not show the lip for clamping. I will bell them and ask how the thing is held down. Likely I will contain my sarcasm and ask them what the depth of the end clamping lip is.
Your link holds promise though.

 

[Ian X]

Its worth having a chat to msc. They often have a range of interstate brass, close pole chucks in there monthly offer catalogues they were from memory about the 180- 200 quid mark for a 6 x 18. The Reason i recall it so well as like you i could do with a bigger chuck as I'm stuck with a 14 x 6 and have been meaning tot get one when funds allow. Earlier in the year i refurbished a punch and die grinding machine for a fab shop i work with and I got one the interstate 6 inch Diam chuck as a replacement and for the money is was not bad at all, good strong magnet and i could see nothing wrong with it, the only slight criticism was the movement for the chuck on/ off wasn't as smooth as the many eclipses i have worked with.

Ok having a search about for an old catalogue seems they may have changed there range a bit in last months offers.

May offer flyer
Standard pole mag chuck 18 x 6
£158.50 + VAT
Order code. JEIMG-00618E

Cant beat that kind of value and with a guarantee.

Go give them a call they will sell you one from an old offer at that price.... If they kick up beat them up hard, works for me. Msc like to sell If you don't like it when it arrives tell them they will get it picked up and credit you no questions, they are very good like that.

Hope this is useful

It is useful. I have decided an arbitrary sum of £400 so those are cheap.

 

[scott0031]

They are made for surface grinders, you don't have to worry how they are held down, standard fitting. There will always be one different somewhere i guess but ive not seen it in 30 years. It's only the round ones that i have ever seen bolt via the back of the chuck.

 

[Mr shiney]

How secure are magnetic chucks? I am thinking of getting one for my mill for when I need to work on flat stuff.

 

[Pete.]

Ill-advised, and if you do take light cuts only as milling forces are much higher than grinding ones. You can block the part but using too much block can diminish the holding force of the part you're cutting. Another problem is of course you can not make any cut that projects through the part, and it will magnetise your tools, possibly even the spindle since there's a flux path through the cutter that doesn't occur in a grinding wheel.

 

[Mr shiney]

Ill-advised, and if you do take light cuts only as milling forces are much higher than grinding ones. You can block the part but using too much block can diminish the holding force of the part you're cutting. Another problem is of course you can not make any cut that projects through the part, and it will magnetise your tools, possibly even the spindle since there's a flux path through the cutter that doesn't occur in a grinding wheel.

Thanks.

 

[scott0031]

Pete, sorry i am going to disagree with you a tiny bit on this one. Mag chucks are used a lot in heavier industry and for milling if the application allows. Electro magnetic chucks are used for full blow heavy milling, plenty of vids on you tube.

I would have no hesitation using a mag chuck (and have done so) for milling or turning for the right application. Although you wont walk into many shops and see them being used this if often due to most guys out there these days are cnc bods and have lack of experience and knowledge of grinding and the use of mag chucks, therefore it not something they will entertain.

A big part of trying to use a mag chuck for milling is that old thing called common sense and knowledge/experience, the three most important things to any Engineer that you cant learn from a book. If you are trying to hold a 1nch square block over one pole then yea, expect it to smack you in the face and rightly so. saying that if you block the part in with surrounding blocks to prevent the part moving then yes you will be able to mill it. If you try to face the part with say 4 mm cut then yea you should expect it to smack you in the face again. If you are using a small cutter with low forces then it will be fine.

On the other side of the coin if you have a big block with a large surface area that will cover many of the poles then the clamping force is a lot and you will pretty much be able to machine at will. Of course again common sense must prevail and be the dictating factor of how you approach the job.

One thing to note, using mag chucks on hardened materials it does not grip nearly as well as soft materials. I'm unsure why exactly without going and investigating, but hardening does something to the magnetic properties of the material, It may be carbon content, unsure. This is something to be aware of when using a mag chuck. There are any magic tricks you can do with a mag chuck, that most wont know about unless they have been in tool making. If i showed you the mag chuck tricks you would probably go' errrrrr seriously'?

Another thing to note is different chucks manufactures can have vastly different holding powers and also the age/usage of the chuck can affect the efficiency. I have used brand new chucks out of the box and the holding power has been dire. These are all things to consider when using a chuck for milling and knowing your tools and the limitations. There are many variables using a mag chuck for milling and its about weighting up all those variables to make the right decision.

In 99.9999% of circumstances there is not a valid reason to use a mag chuck over a vice as it is no where as universal, But for the right job and application then its a god send.

 

[scott0031]

A small addition to the above i have never had machine spindle magnatise through using a mag chuck nor any cutter problems of any consequence. Also anyone using mag chucks should have a demag anyway (google eclipse demagnatiser)

 

[Pete.]

I won't disagree with what you said, the more surface area the better the clamping. The main thing with mag chucks is once it moves, it's usually off like a missile. We've all bumped parts in a milling vice getting too ambitious or climbing inappropriately, often wrecking part and cutter. Usually you get away with bits not flying but in a mag chuck it's more likely than not.

Use with care I think it what I should have said, and plan your cuts because it's not very forgiving.

 

[scott0031]

Yes I totally agree Pete, but by using blocking techniques you can secure parts pretty firmly. But as you say if you smack a cutter into anything or hit something with an irregular force then you are in for fun no matter what. The only parts have seen launched are hardened parts that simply do not grip very well or very small parts and its normally because they have not been blocked in properly or because they should have been in a vice or because the operator was being lazy. Of course the other classic is forgetting to turn on the chuck which accounts for a lot of the Toolroom' errors' i have seen, then again you can also grind with the chuck off in the right situation which is a common thing. (I don't advise anyone try it unless you know what you are doing) Using back and end stops and using the force applied in the correct direction is also very useful many forget about and pretty important if milling, the chuck only has to worry about holding the job down and not any side forces trying to flick the part off the chuck

 

[Shox Dr]

@scott0031 . Do you know of any good resources for learning how to use a surface grinder. I understand the basic pinciples, but that's about it. There's very little on youtube, and even less elsewhere.

 

[scott0031]

Hi Mr Shox, Sorry I don't know of any resources, in the same breath i don't really need to go looking for them. There is some on you tube but most of what i have seen is a bit errrrrrr well ERRRRRR normal YouTube stuff, people half guessing what they should do then expose those dangers to the world to kill them self with.

You would be welcome to give me a call if you have a list of specific questions, as you know i don't like typing particularly. It also depends how far you want to delve into it. Surface grinding can get a bit complicated when you get into form grinding using diaform panto graph wheel dressers and optidress units.