End mills in a drill chuck

[Chris TriceParticipant @christrice43267]

Posted by chris stephens on 07/12/2010 19:14:15:

This is the beauty of a home machinist, no H&S looking over my shoulder.

 

 Yet.

[chris stephensParticipant @chrisstephens63393]

Hi David, 

I take it that you are using a 6mm shank ball ended cutter, if so the inertia, even at highish speeds, would cause  little harm to anything except the job, if it came loose. 

 

I worry for the mental health of those who are too paranoid or lacking in experience, to “push the envelope”. As I said to Terry above, I try to use the right equipment, but come the apocalypse, when we will have to make do with what we have, it will be the lateral thinkers, and Ray Mears, who survive, and the ninnies who don’t.

There is more to it  than  “the right way or the wrong way” there is the ” that’ll do at a pinch way.”

 chriStephens

 

[chris stephensParticipant @chrisstephens63393]

Hi Chris,

How true.

There is one home machinist that I know who doesn’t even want his club to know what he has in his shed, in case the  “powers that be” start to snoop and then license, or not, workshops. His will not exist, officially that is. Still, with the cut backs in Government spending  there is little chance of them employing people for a new licensing dept., well not this week at least. Maybe in the new year, though.

chriStephens 

[chris stephensParticipant @chrisstephens63393]

Hi Chris , Missed one of your posts but I agree with 100%, and that is where experience is learnt, from your mistakes. The trick is to learn from others mistakes first, if you can.

As Trevor Howard said while playing Sir Keith Park in the film about the Battle of Britain, when talking about a missing pilot and his swanning around doing an instrument check and looking for the Hun “well we all do it but that doesn’t make it right”, ’nuff said.

christephens 

[Sub MandrelParticipant @submandrel]

Mea Maxima Culpa!

 

I have used an endmill in a drill chuck for a quicky.

 

Err in haste, repent at leisure.

 

Ever since one pulled a BIG 1/2″ capacity chuck off its taper, I won’t again, with one exception. That is a small chuck on an MT1 taper for use with my potts spindle, though as I bought a milling machine I still haven’t got round to using it.

 

Neil

[John HaineParticipant @johnhaine32865]

Is this one still going?

 

Anyway, I read somewhere that one of the big problems doing this is that if you’re taking a deep milling cut (as opposed to axial feeding e.g. to spotface), the varying sideways  loading tends to work the chuck off the Jacobs taper.  So OK for axial feeding and very light milling (like Lautard’s idea to mark out for cross drilling), but only a last resort for real milling.

 

I guess one solution is to use ER pattern collets so you can hold any size of cutter, but myself having used both ER and pozilock collet chucks I don’t think you can beat R8 straight in the mandrel – more rigid, more daylight.

[Chris TriceParticipant @christrice43267]

I tend to use my Auto-lok mostly but for important heavy stuff, I agree, can’t beat a well tightened R8.

[TerrydParticipant @terryd72465]

Hi Chris S,

I’m sure it was the farmer but I will always willing to listen to alternatives before rejecting them.  (just kidding – unlike some)

 

Re: making mistakes, another aphorism I’m afraid –  my trainer always told me “to learn from the mistakes of others.  One don’t live long enough to make them all ones self.”

 

I rather took that to heart and it is the wonder of the internet that we can do this.  He would have marvelled at the opportunity if he were alive now.

 

Re Boredom:  My garage workshop burnt down in July and due to inefficient Loss Adjusters, project managers, subcontractors, incompetent skip remover, late scaffolding and more cock ups bringing us into the devastating weather conditions of British November I am unable to take delivery of my hew replacement machinery so most of the time  am working here on my computer planning new projects and venting my spleen at incompetent fools and between times writing to a group of guys I feel that I am getting to know quite well and enjoy talking to on this forum.  I worked in the public sector as a teacher of practical subjects including design and metalwork, and IT but if I had been as efficient as these private sector buffoons none of my students would have managed a GCSE let alone the A levels they got followed by good apprenticeships.  With the sort of effort I have found in the private sector, I would still be marking the exams taken 8 months ago. Rant over – really.

 

Best regards

 

Terry

[Sam StonesParticipant @samstones42903]

I’ve come in on this thread rather late (or early if you live in Fiji, NZ or Australia), and have not taken the trouble to read all the postings.

 

But surely, isn’t there some particular skill needed in being able to hit the `STOP’ button, when the drill chuck drops onto the workpiece?

 

Or worse, when it lands onto the table?

 

Sam

[Gordon WParticipant @gordonw]

Got an ex libarary book for 50p. Milling in the lathe, by T Cain. On the front cover is a cylinder having ports milled out (?) Milling cutter held in 3 jaw. I think this T. Cain was quite well known at the time.

[Chris TriceParticipant @christrice43267]

I don’t think the issue is a lathe three jaw (if it runs concentric).. Drill chucks are the problem as they don’t tend to grip cutters so firmly.

[adyParticipant @ady]

I’ve used endmills up to 12mm in a 4 inch chuck.

Ordinary drill chucks lack both gripping strength and munching momentum .

 

Never had a problem, have cut good t-slots as well, but only in aluminium so far.

 

You only have to listen to the job and it tells you, no manual required.

 

Slow speed so no heat issues,  good stiffness and lots of torque.

[The Merry MillerParticipant @themerrymiller]

I always wrap a piece of newspaper around the shank of and endmill before I put it into the three jaw chuck.

Had no problems so far.

 

Len P.

[TerrydParticipant @terryd72465]

Hi Chris and Gordon W,

 

I would agree with your statement about the Lathe 3 jaw chuck if the chuck is new and cared for, but I was also warned that an old and worn 3 Jaw chuck could have have tapered jaws at the outer extreme through wear and misuse.  Surely in that case the relatively short shank of the milling cutter could be held in that worn portion of the jaws and the grip would be reduced.  Hence the cutter could easily work it’s way out with obvious consequences.

 

Tubal Cain of whose books I have several, obviously knew his chuck and was secure in the knowledge of it’s accuracy, but that may not be the case in the situation where a newcomer buys a second hand lathe of dubious origin.

 

Terry

[Chris TriceParticipant @christrice43267]

To be honest Terry, most books on the subject by several respected authors all say a lathe chuck is fine. Cocentricity is important if you don’t want the cutter to cut oversize so anyone lacking collets to fit their spindle can use the chuck providing they recognise that lathe chucks aren’t as a rule as concentric. It also means not all the teeth of a cutter will be cutting if it’s not seated accurately. Four jaws can obviously be set bang on. The main reason for a thumbs up with a lathe chuck is that it grips with far more power than a drill chuck. Most drill chucks will let go and score a drill bit just by grabbing as you break through a drilled item if you’re over zealous with the feed.

[TerrydParticipant @terryd72465]

Hi Chris,

 

I’m not questioning what you say, just quoting my
trainers and some warnings I have read, I think by G H Thomas and I
think my lecturer, Professor Heinz Wolff.  I have read many books on the
subject like yourself and would agree with your assertions.  However I
was not concerned with concentricity but with parallelism.  I was always
taught that wherever possible one should use the whole of the jaw to
support the workpiece especially in a 3 jaw chuck, rather than the
outer parts of the jaw away from the chuck body.  The reason being that
when the chuck is worn the uneven forces lead to a lack of parallelism and the possibility of the work ‘walking’ out of the chuck as there is always some play in any mechanism.  This might be the case with a milling cutter. 
That was a basic piece of information taught by my apprentice
instructor and in the toolroom.  It may have been incorrect, but it
feels right.  I’ve made a couple of diagrams to illustrate what I mean.  The angle in the second drawing is exaggerated but illustrates my meaning.  As i said with an old, second hand chuck this could be worse.  If you put a longish piece of stout bar (say 150mm x 20mm) and tighten it really tightly in the sort of position in the second picture you can feel the effect.  When it slips the beginner then tends to make it even tighter, thereby exacerbating the effect.

 

 

 

 

 

  Best regards

 

Terry

Edited By Terryd on 09/12/2010 17:13:59

[John OlsenParticipant @johnolsen79199]

I mustr admit that the idea of holding milling cutters in a either a lathe chuck  or worse a drill chuck does not fill me with enthusiasm. One of the problem I have had with parting has been when the job decides to start moving outwards in the chuck. If a piece of soft mild steel, maybe half an inch to an inch in diameter, can start to work sideways under the forces from a parting tool, what chance have we of holding a milling cutter securely?

 

I know that not everyone, especially when starting out, can afford the proper gear, but there are cheap alternatives. One that I have already mentioned elsewhere on this site is to make a holder for the cutter. This can be a taper shank to fit the spindle, tapped for a drawbar, and bore in situ for the size of cutter. A couple of grubscrews/setscrews at right angles will secure the cutter in place. (you can grind little flats where the screws will bear to be extra sure if you like.) This sort of things is actually sold commercially, but is not too hard to make, especially if you buy the taper shank. If you don’t have a taper in the headstock (the Unimat does not) another possible plan would be a similar holder, but with a parallel shank to hold in the  four jaw chuck. This would need setting up with a dial gauge before use, but the holder being soft and a larger diameter should be able to be held securely in the jaws. It can of course be long enough to extend to the back of the jaws.

 

regards

John

[Chris TriceParticipant @christrice43267]

As John points out, a purpose made holder beats a lathe chuck but a lathe chuck beats a drill chuck. Frankly any chuck with jaws that tilt or are belled is no good to man nor beast. The jaws want regrinding parallel while gripping a ring at their tip or the whole chuck replacing.

[NobbyParticipant @nobby]

Hi

These home made cutter holders is

an  an alterative to holding cutters in my drill chuck on my kerrys drill. the abour is scerwed to an insert in the drift slot

Regards Nobby

[Martin WParticipant @martinw]

I notice in the Feb 2011 edition, No 173, of MEW that there are two articles that appear to show drill chucks being used to hold milling cutters , see articles on edge Finding and Strip Cutting! 

 

If this is such a frowned upon practice then should these articles have had the chuck obscured so that new comers to the hobby aren’t tempted into what many regard as bad practices? I will leave it to the more knowledgeable contributors on this forum comment as to the wisdom of employing a drill chuck to hold milling cutters  and whether this practice should appear to be condoned by such an august publication as MEW.

 

 

 

Cheers

 

Martin

[David Clark 13Participant @davidclark13]

Hi There

Missed those.

Slapped wrists.

regards David

 

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