Using a pillar drill for milling?

Good evening, I'm pretty new to model engineering and still working at getting my Myford ML1 up and running to learn on. I also have a Startrite Mercury bench top pillar drill. Just wondering if its feasible to use this for light milling work with suitable milling vice? As far as I can see the only(?) issue might be cutters slipping in the Jacobs chuck, but would it be ok for as I say light work?

Thanks in hopeful advance....

Chris.

NO! The Jacobs chuck will probably come off its taper in short order.

[This posting has been removed]

Not a good idea I think...spindle bearings on a pillar drill are not meant to be side loaded.

Thank you John, Bill & ChrisB for your prompt replies. Obviously I hadn't thought about the chuck coming adrift!

In anticipation of getting the lathe working eventually I did buy a set of collets with 1MT holder for the lathe. Presumably this would then be preferable for any light milling, but the issue might still be the collet holder coming loose in the morse taper? Would it be a reasonable (if/or necessary?) to adapt it with a bolt through the head-stock bore, I think this would be a draw bar?

The thread on the spindle nose is 7/8" x 9 tpi so guess I'm unlikely to get a collet holder to fit direct onto that?

Chris.

It is possible remove a lot of metal by chain drilling. Using an endmill instead of a drill will allow a little overlap of the holes. If you can get rid of nearly all the excess metal by chain drilling you might be able to get away with very light milling passes to clean up. Note my emphasis.

I tried it on my startrite drill it didn't end well. Lesson learned

If you want to find out how good a drill will mill, try searching youtube for AvE - turning a drill press into a s__tty mill. He does exactly that.

I too tried milling with a drill before a got a milling machine. The problem I had was, as John Haine said, that intermittent loading on the cutter just 'vibrated' the chuck arbor out of the quill.

Your plan to make a drawbar for your collet holder for milling on the lathe is entirely sensible and in fact necessary. You don't say what collet system you've bought, but if ER or finger collets should find that there is a female thread in the back end for precisely this purpose. Likely M6 or 1/4" for MT1. All you need is a length of studding, a washer and a nut.

Robin.

Thank you John R 'chain drilling' will be something to bear in mind but the consensus seems don't try to mill with the pillar drill. Thank you also Steve & Rob for your replies.

Also thank you Robin. I just checked and it is an ER (?)set of collets and it does indeed I now see have a tapped hole in the arbor end, I hadn't noticed that before, though its barely been out of its box. So that should be simple enough to sort.

I did in fact get hold of a Myford vertical milling slide, its not the earliest single stud version but the later two stud version which I figured was a design improvement. I think it has a tee nut to secure it to the cross slide along with two alignment pins. Guess what, it dosent quite fit. Think I will have to file a small flat on the two pins, its only about 0.5mm out, rather that modify the cross slide tee nut groove.

I have not personally tried any of these approaches.

Have a look at Popular Mechanics July 1954 & Jan 1969; Popular Science Jan 1952; and, MEW Jan-Feb 1996.

Google for a link to the archives of (USA) Popular Mechanics & Popular Science magazines

A few other thoughts I have gleaned from the 'net (afraid that I lack any links)

Suitable, perhaps, for light surfacing of small aluminum or brass parts with a small end mill and maybe some slotting

Do NOT buy an Albrecht chuck, it will not be up to the task.

If the chuck is held in place by a morse taper anywhere you risk it coming loose under side load. The friction retention force only works if the load is axial. (Some of the above articles detail the construction of a chuck support to resist lateral forces.)

End mills are very hard. They are harder than the jaws on a drill chuck, so the jaws will not grip them the way they grip the soft drill shanks. This means the axial retention force for an end mill is poor, it will be drawn out by the helix angle on the end mill.

Drill chucks only support the tool at three points around its periphery. This allows the tool to move sideways to some degree - a lack of rigidity.

If doing this I would purchase the largest Jacobs ball bearing superchuck that would fit the machine. When installing it I would aggressively clean the taper socket and the arbor with clean solvent, and heat the socket and cool the taper before installing.

Thank you Dunc, I certainly did not realize that about hardness of cutters not holding well in a drill chuck.

I presume I would be safe enough held in a collet chuck, though I notice some milling cutters have a threaded end I think?

For my perceived limited milling though I will stick to trying it on my lathe, first I need to get that up and running.

Appreciate your input,

cheers Chris.

Two words.

Just don't.

Another few words to add to thaiguzzi: It ain’t worth it.

Thank you both, I won't!!

Cheers

Chris.

Is there any way to drill a 10mm hole for a drawbar in the drill spindle? MT2 milling collets use a 10mm thread, unless they are old when a 3/8" W is the nom. Even in a mill with a drawbar, drill chucks have their own short taper which makes them unsuitable for holding milling cutters. I have occasionally held milling cutters in a drill chuck to plunge cut like a twist drill, but never to cut sideways.

Thanks Old Mart, that interesting. As others have said also, if the sideways movement is out due to the bearing not being designed for sideways load it seems best to stick to milling on the lathe...and maybe upgrade that in due course if/when the need arises.

Cheers

Chris.

Hi Chris,

I successfully adapted a Pollard bench drill for milling. Although it was a vast improvement on milling in the lathe I had at that time (Hobbymat MD65), it has never been capable of other than light milling. I got around the drill chuck problem by making a ER32 collet chuck to fit the Jacobs taper, retained by a c/s screw into the end of the spindle; the spindle drilled quite readily incidentally. Unfortunately this also increased the overhang from the bearing, which compromised rigidity. I managed to replace the existing ball races with tapered roller bearings for the reason stated by ChrisB. There are plenty of other hurdles to overcome, like fine feed, quill lock and, of course the x-y table. If you are really that interested, I wrote an article on the adaptation for MEW, around 2010/11. If I had known how much work was involved at the outset, for the limited performance, I wouldn't have wasted all that precious retirement time. Hindsight is a wonderful thing!

Enjoy the hobby, it is addictive.

Alan

As others say... DON'T. With ANY type of drilling-machine and drill-chuck.

Regarding chain-drilling prior to milling, I would strongly advise filing the worst of the resulting "teeth" down before milling. That's because the milling-cutters will catch on the sharp edges and could cut inaccurately or even shatter. They prefer a smooth, continuous cut you will certainly not achieve on a drilling-machine. And if they shatter I hope you are wearing eye-protection.

'

Dunc's paragraphs:

" Drill chucks only support the tool at three points around its periphery. This allows the tool to move sideways to some degree - a lack of rigidity. "

Really? Line not point contact actually, but I don't recognise that lack of rigidity in a good-quality drill-chuck in good condition; used for drilling not milling.

'.

" If doing this I would purchase the largest Jacobs ball bearing superchuck that would fit the machine. When installing it I would aggressively clean the taper socket and the arbor with clean solvent, and heat the socket and cool the taper before installing. "

Clean the tapers yes, when fitting any chuck on any machine, though I don't know what you mean by "aggressively". It doesn't need degreasing, just any swarf and other particles removing.

Otherwise.... "if doing this..." (Milling) I wouldn't be doing "this".

And shrink-fitting? Not on my machines, you would not!

It's not clear whether you mean the Jacobs taper in the chuck itself, or the spindle taper. If the latter you do not want to shrink-fit anything in there, and anyway, to what temperature would you risk heating such equipment evenly, without harming any part of it?

'

Chris -

The threaded ends you refer to are common on most milling-cutters, to fit special chucks such as the Clarkson Autolock. The cutter screws into a collet ground accurately to hold the cutter shank, while the centre-drilled hole in the end of the cutter engages a pip inside the collet-chuck body fractionally before the collet-holder reaches its thread-end, to give axial support. A special ring-spanner is made to fit the flats on the chuck body.

NB: the cutter shank diameter and collet diameter must match. A 1/4" dia shank won't fit a 6mmm collet for example. However, although vice-versa will, you can't expect the collet to grip, and even if forcing it does not break the collet, the cutter could slip or jam and snap.

The collet chuck in turn has a Morse or other standard taper shank to fit a correspondingly tapered lathe or milling-machine spindle, with a draw-bar to hold the chuck back in the spindle. Collet sets of various patterns are available for standard tapers such as those in Myford lathes, and you can use these for holding milling-cutters.

There are two forms of ER collet then, if yours have a draw-bar thread. The ones I know use a dedicated chuck that fits the spindle nose, and holds the collet by a particular assembly / disassembly technique. This allows holding work-pieces that project backwards into the lathe spindle.

Myfords used to sell a neat version of its own, but sadly now they are as common as poultry-dentures and at avian-dentistry prices. I don't know if anyone stocks a copy of them, and if so, what they are like.

Again, the cutter must be the right diameter for the cutter or work-piece.

If you are milling in the lathe you can hold the cutter in the chuck if you must, but not preferably. It will only be as accurate as the chuck, and insecure if the jaws are worn. And being hard it won't do even hardened jaws much good if it slips round. A collet is far better.

'

The vertical slide locating-pins. Yes, modify them, not the lathe itself! And yes, the stud holding the vertical slide to the cross-slide will need a T-nut, but a good fit and generous length.

Be Aware that the stud or bolt should NOT pass through the T-nut, as that can load the T-slot shoulders very unfairly, and even break them. That's certainly the advice I have always known, and my clamping-sets' T-nuts all have the lower ends of their threads peened over to prevent it.

Hi Alan, Thank you for that. so its interesting to know that it could be done but as you say life is too short, I will focus on getting the lathe up and running and how to use that, then tackle milling later on.

Cheers

Chris.