Holding milling cutters in a drill chuck

I have read in various places that a drill chuck is not a safe place for holding milling cutters. I can see why. But on page 506 of the current ME, illustration numbers 50, 51, 52 & 53, we see this described and shown.

If it is OK for Mr Ian Couchman, and for the Editor, why is it not OK for us?

Regards, Tim

There is always a risk to the work or tool should it start to pull out but I would not think it is such a personal safety issue. All thoses hotos look to be using very small dia cutters so loadings will be quite low.

If your chuck is a key type you probably can get away with i for small cutters. If it is the keyless type , no matter what size it is I would sat no.

I am lazy at times more to do with times money aspect raising and lowering head, changing out for a collet etc saving time. Been doing exactly that for last 18 years where I can get away with it and you will be surprised how much grab a keyed cheap chinese chuck has and would go so far to say equal to the best ER collets.
In past 18 years only ever had 3 cutters drop, mainly due to being blunt and working loose. ER have had 3 cutters work loose in 6 mins.

Accurate stuff I use collets and perhaps 30% more cut depth and feed.

Not worth it, just wouldn't do it.

And i'd try most things! 

Michael W

Edited By Michael Walters on 04/10/2016 20:03:14

Because it's a 1/16" cutter so the side forces (which are the source of any problems) will be minimal?

Neil

You need minimal radial runout to ensure even loading of the teeth, particularly for small cutters. Drill chucks are not usually specified for runout, as it hardly matters. Has anyone measured runout on theirs?

Once the runout reaches the same magnitude as the cutting depth, pretty much all of the cutting is done by one tooth.

http://www.hobby-machinist.com/threads/jacobs-chuck-runout-expectations.47363/

Edited By Muzzer on 04/10/2016 20:33:33

Maybe a case of theory over practice, I seemed to manage quite happily in my early days with a drill chuck on the Unimat 3 milling attachment and also the odd cutter in a 3 jaw when I made my first models, these two for example don't look too shabby and I don't recall having cutters move.

Still do it occasionally now as a drill chuck can get me into tighter spaces than my collet chucks can.

I would not say it is best practice but with care and knowing what could happen its OK for me.

Edited By JasonB on 04/10/2016 20:40:09

Jon,

You are not Raymond's sock puppet are you ?

Not having seen the article, I can't comment 'in context' but, in principle, I agree with Muzzer ... and would add that, with cutting being on one tooth, slots & grooves will be cut oversize.

In my opinion a 1/16" diameter cutter almost demands holding in a decent collet.

Tim's original point is well-made.

MichaelG.

I agree, not worth the risk.

Just telling the way it is John nothing more.

Ooh Matron!

That sounds uncomfortable :D

When you don't have a milling machine, but you do have a pillar drill, a lathe and a handful of milling cutters, sometimes you have to work around it. I have even used milling cutters in my floor standing morticer to mill a long slot in a piece of 4mm aluminium - everything survived intact, including me and the milling cutter. You just have to take things easy and, dare I say it, have a bit of a feel for it.

A bit unrelated, but very nice checkering on the stuart beam, how did you do that, if you mind me asking Jason?

Ok, i can look rather sanctimonious when i say "just no", i get what people are saying when looking back at their early experiences, and quite honestly ask "well there must have been a time when you didn't know any better" Indeed there was, but i was very lucky to have a mentor in the form of a book written by Joe martin, which quickly steered me away from such lazy practice.

I was quite sad, as i read the manual of my little sherline mill from cover to cover, and on the topic of milling cutters, these are small machines, so the milling cutters are small likewise, from the very beginning, Joe very sternly said that this was a totally wrong practice and would not pass muster...do not pass go, do not collect $200.

So there we are, that's my story of how i came to know.

Michael W

Floor tiles part way down this page

JS, No no no, this one has absolutely zero to do with me. So I am keeping well clear of this one.

cheers.

I find holding a slot drill, up to 3/8" diameter, in a Jacobs chuck and using it as a drill (flat bottomed holes) does not present problems. As soon as you put a side force on the cutter (either end mill or slot cutter) when held in a Jacobs chuck or three jaw chuck the cutter is liable to work loose, from experience.

I am still happy to mill in a lathe using a vertical slide with a cutter held in a three jaw chuck but I check that the cutter is held tight after every pass. When you think about it the cutter will rotate in the chuck as it becomes loose long before it does anything nasty.

I think if you do it, take care.

JA

Further comment - I would only use a Jacobs chuck for drilling operations.

JA