Holding milling cutters in a drill chuck

It would be interesting to know the author's view on this.

N.

I use endmills in a small tailstock chuck on the lathe for drilling and sometimes for plunge cuts on the mill. I wouldn't use a drill chuck for sideways milling especially at smaller sizes, because that usually means faster speeds and if the cutter decides to snap it's likely to be thrown sideways by one of the jaws at quite a velocity.

IMHO, it's not something to encourage beginners to machining (like myself) to do.

I wonder how many articles in ME and MEW show endmills being used in a 3-jaw lathe chuck along with a verticle slide? or is that considered ok?

Ed.

I did try it with a cutter probably around 1/4" dia or maybe 3/8. Just worked loose.

No problem at all in a Peatol 3 jaw with machined soft jaws in it. 3/8 cutter 3/8 ms plate, slot in one go followed by a 1" x 1/8" woodruff cutter - and a number of other things. I've toyed with the idea of using a small grip true on my dore westbury and might yet if pushed by what I have around in ER. I have an ARC face mill arbour but am not keen on the design so if problems the 3 jaw might get fitted.

Think I saw ER coming loose ? Not an experience I have had.

John

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I've already contacted Ian

I can get away with up to 6mm cutter on my X2, my friend who has a Bridgeport uses nothing other than a drill chuck for milling with no noticeable adverse effect. Might it be a rigidity thing?

And Ian has just come back and asked if I could post his reply:

"This is a method that has worked well for me over many years. It gives convenience, speed of use, sufficient accuracy for most work & better access in restricted areas. If I'm taking heavy cuts or need maximum tool accuracy ( normally only when using a slot drill of the size of the slot I'm cutting ), I use an ER collect."

And not only does the method of holding work well for Ian, so does the threshing drum, this is it in action recently.

The one I tried was Chinese. Maybe he uses an older Jacob's from when men were men and drilled holes in etc etc.

For ex rugby players. Might remind some of them of drunken evenings.

Thought I had better add some of

John

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Edited By Ajohnw on 05/10/2016 13:28:20

I've only ever used a drill chuck, I had nothing else, only once and a small cutter, about 1/8". I must have drilled hundreds of holes with a hand drill and wiggled about a bit to enlarge the hole. Never had a bit come loose when using a key. Is this not similar to milling? Now I will use a EN collett when I need to.

I once tried using a 2" diameter slot drill in the Myford-Burnerd 4" Griptru chuck. I was only taking very light cuts, and it was the only way I had of holding it. Without putting a six foot length of gas pipe on the chuck key and making "Nninnnggg!" noises, there was no way I could stop the cutter "walking" out of the chuck. DO NOT TRY THIS AT HOME!

If you're using a 1/16" milling cutter with a 1/4" shank, it's unlikely that you'd have any problems at all holding it in a Jacobs chuck or similar for all milling purposes, if suitably tightened. The side loads would not be sufficient to cause problems other than the pinging noise you get occasionally when the cutter breaks...

Hence there is a limit somewhere between 1/16" and 2"...

Using cutters in Jacobs chucks (or even keyless) for plunge-cutting, as others have said, is not a problem and I do it all the time.

Interestingly. Does the same rule apply to a hex(or tri-flats) shank tool?

Don't see many of them though.

Michael W

Holding a milling cutter in a drill chuck is like lighting a barbeque with petrol, you may get away with it or you may not.

Tony

I always thought that the main reason for not holding a milling cutter in a drill chuck was that the drill chuck is usually attached to the spindle by means of one or two tapers and they are liable to work loose if subjected to side forces. A milling chuck is secured to with a draw bar.

Russell.

Most decent drill/mill machines come with drawbar type drill chuck.

As said keyed drill chucks have around same holding power of ER nothing to get hyped up ill founded about.

Isn't it the case that a sideways force is applied to any centre cutting slot drill because of unequal length lips ? if so this would apply regardless of holding device.

No doubt like many others I have used some of the smaller size milling cutters and slot drills held in a drill chuck, I stopped the practise after finding the slot became deeper and wider as the tool moved along it's intended path.

Emgee

They usually come on an arbour with a drawbar thread but that won't help much as the chuck is usually fitted to the arbour using a Jacobs taper fitting. A sideways force, particularly when combined with a vibration, can detach the chuck from the arbour. Don't ask how I know!

Russell.

Tried getting one apart with a wedge Russ. Takes a lot more effort than cutting force to part the JT6 been milling on current mill since 2004 where one day with me is around 6 months to mr average. Used to do on previous mill/drill 5 years without any clamping of the JT6 in the taper and know a fair few others that do likewise.

Don't get me wrong anything accurate will use collets but for general roughing and slightly oversize slots etc will retain and continue using the chuck.

Mine is clamped by three pull up screws any way and supplied cheap Chinese 5/8".

Milling on a drill with compound slide I always had cutters and drill drop out due to vibration of the machine, it had no drawbar.

Yes agreed. I've had my Jacobs chuck drop off the taper before now as well. As for draw bars on drilling machines, I've never seen one. Certainly my progress number one doesn't have a draw bar.

I think that any publication that shows this practice isn't doing its readers any favours.

The photos in question were on a small/medium round column mill not a drilling machine.

Its a pity some of those replying have not seen that article, some of the best work I have seen in ME for a while, pitty all the work is hidden insid ethe pink box.

If it was entered at MEX I would not hesitate to give it a gold medal, its got all the credentials from research, making own patterns, casting own parts many varied and intricate parts all manually machined and it's not just a glass case model it actually works. I think this is the type of work that should be featuredin the mag not just another loco or rear toolpost.

Also interesting that most of those who say they have used a drill chuck to hold milling cutters are those that seem to actually produce work and show it and those against we don't see much work from

Edited By JasonB on 05/10/2016 21:02:04

For what it is worth, I regularly use end mills and slot drills in a jacobs chuck in the lathe tailstock. In pre Mill days, all milling was done with a vertical slide with endmils and slotdrills held in the lathe 3-jaw, and job in the vertical slide.

Never ever had a mill slip or problems. I am talking up to 3/8" dia mills in quite a small antiquated basic lathe.

Pin drills in the pillar drill. They can be quite effective.

Cheers,

Julian