Drilling machine as a milling one

Thanks all for these precious hints That's why when I was milling into plastic, I loose my chuck falling down I supposed the chuck was bad but after all your mails, I see what tangential forces can do with an 10mm end mill in PCV

Endless replies to this question, one that comes up all too often.

Milling machines require considerable rigidity to resist cutting forces. They also require serious bearings in the head, and a quill that is very well supported in the housing, and has provisions for being locked where desired. The part being machined would require a means of being propelled in a straight line, also at a right angle, and a flat plain. Hoping to achieve any of this from a drill press is stretching things quite a bit. even with an added table. There's almost no guarantee you'd get the table dialed in with the spindle, due to the table not being square with the column, and not adjustable in two planes. The topic of draw bars and chucks has been beat to death, time and again. Chucks do not grip end mills well, due in part to the shank of end mills being hardened, very unlike drill shanks. Drill chucks rarely run with the degree of desired concentricity as well. So far, nothing is right for a drill press to function as a mill.

Consider this: A light duty milling machine (Bridgeport, for example) weighs roughly 2,000 pounds. A drill press typically weighs under 100 pounds, but could go as high as 200, I'm sure. Where are you going to find the necessary mass and rigidity from your 200 pound drill press when a

2,000 pound Bridgeport is considered a light duty machine?

Drill presses are that. Drill presses. They are not milling machines, nor are they intended to function as one. The closest you'll come is a mill/drill, and they're a miserable compromise on a milling machine at best. I can't even begin to imagine how poorly a drill press would serve.

Harold

You just have to use a different approach, Dave. I used to build tools for a living and didn't ever use counterbores for SHCS's. Counterbores are truly a PITA, particularly if you get a chip between the pilot and the hole, or one floating under one of the cutting edges. I used them in production drilling long ago, so I have a fair understanding of their application, and the pitfalls of their use.

For SHCS's, using one of my Albrecht drill chucks, I start my c'bore with a twist drill, the same size as the desired c'bore. I drill deep enough to generate a full diameter, then switch to a flat bottomed drill. The cutting speed (of the drill, as opposed to a c'bore) makes up for the time lost changing the tool, and the pilot developed by the first drill prevents the flat bottom drill from wandering about. You end up with very nice counterbored holes, with no money invested in tooling that is often more trouble than it's worth. All of this, of course, works very best when you're using a drop spindle mill (like your BP), not a drill press. You have far better control over everything that way.

Give it a go! It served me very well for years.

Harold

NO!!!!!!!!!!!!!!!!!!!!!

Gads...somebody want to write a FAQ on this subject once and for all?

Gunner

If you are going to use that phrase then you should use the full phrase of "Fuck Off and Die and Rot In A Ditch and Get Eaten By Maggots and Pissed On and Shit On By a Dysenteric Elephant (but not necessarily in that order)."

Crash Street Kidd

I have a 700 lb Clausing milling machine that illustrates this point well. Although it's very nice for light precision prototype milling and drilling, a 1/2" 2-flute end mill cutting 3/8" deep in steel can set the whole machine vibrating. The force involved in pushing a milling cutter through metal is similar to the force needed to hammer a chisel through it.

jw

We'll put you down as a "Nay", then :)

The chuck doesn't even need to be loose in this case. An ordinary drill chuck will NOT grip the hardened shank of an end mill (drills have soft shanks). The chuck jaws must deform and indent the tool shank (not visibly) in order to grip to it, and a milling cutter is too hard to deform enough to provide a useful grip.

Thus a chuck should never be used to hold a milling cutter, even in a milling machine.

Collets are far better, but even they can slip if inadequately tightened or under heavy load. The best tool for the job is a milling cutter holder.

Dan Mitchell ============

Well, a mill/drill is not nearly as nice as a knee mill but they are very capable of milling with some limitations. I started with a jet mill drill (JMD18) that will take quite respectable cuts and in some ways has a better work envelope than the small knee mills (I now own both). The five inch quill travel is very useful for some operations and the large table accepts a 6 inch kurt vise or 8 inch rotary table that won't fit on the clausing or rockwell knee mills.

chuck

Except that Albrecht makes a special version, with either an R-8 shank or one of the NTMB tapers, which has diamond impregnated jaw faces, and which *can* grip a hardened shank end mill.

Agreed, DoN.

Agreed ... but I DID say an "ORDINARY" drill chuck! And, I doubt that a diamond impregnated Albrecht drill chuck is what someone who wants to use a drill press as a milling machine is likely to have, or want to buy ($$$)!

Dan Mitchell ============

[ ... ]

That you did. I just felt that I should mention that there

*are* exceptions to just about every rule, and I happened to know of this exception -- not that I have ever had my hands (or even my eyes) on one.

Not to mention that his drill press is highly unlikely to have either an R8 spindle or a NTMB taper one. If it did have either of those, it would already be a milling machine. :-) (And these Albrecht drill chucks have permanent shanks, not something attached by a Jacobs taper, so the opportunity for unintended separation is pretty much gone, as either of those options needs a proper drawbar to hold the shank into the machine anyway.

Note that there is still an opportunity for unintended release. Albrecht keyless chucks are self tightening under normal operation, but with an interrupted cut, and with a spindle which has lots of spring between the drive pulley and the chuck, it could wind up under load until the chip breaks free, at which point the chuck would rotate until it reached either another forming chip, or the end of the spring travel in the spindle. If the latter, suddenly the chuck outer body is running faster than the inner body, an action which tends to loosen the grip of the chuck. (I remember some years ago we spent quite a while here trying to figure out why an Albrecht chuck in a mill was releasing whatever it was holding.) The Albrecht catalog shows that they also have a version of the chuck which is designed to prevent this problem, as well.

Enjoy, DoN.

I find it hard to believe that albrecht recommends using this expensive precision item for holding milling cutters. I suspect it is intended to hold carbide drills.

You guys get off on some pretty wild tangents. Or are you actually recommending to get a albrecht drill chuck with diamond impregnated jaws, put in in a drill press with a 1/2 endmill and do some milling with it?

Personally I would throw anybody out of my shop that attempted to hold an endmill in a drill chuck of any kind.

chuck

LOL. And yet one invariably finds this *exact* question (can I put an end mill in my drill press jacobs chuck and do milling) on this and other fora all the time!

The discussion invariably devolves down to two sides, those who suggest it possibly could be done, and those who say it's a really bad idea.

Using harold V's maxim, which is you adhere to the standard correct approach for any shop task, one would have to say 'don't do it.' Why waste time and risk damaging shop equipment?

Doing this (end mill in jacobs chuck) shows the person is lacking some vital information about how end mills, chucks, spindle bearings, drawbars, and machinery in general works. As you say, anyone who goes ahead and does in in *spite* of instructions to not do so, deserves a free ticket out the door.

Jim

And yet, Jim, there have been a rare few times when I couldn't get that itsy, short little 1/8" bit down into the work, because my spindle nose was too big, and a baby 1/4" jacobs chuck saved the day (with extremely light cuts, "climbing", only).

LLoyd

Really? Climbing? Sounds like a recipe for disaster, although in the course of conducting business in my many years, I can't think of too many of the

*rules* I haven't violated, generally in favor of getting the job out the door on time. You place your bet and take your chances. Some days it's chicken, other days it's feathers.

The bottom line here is that some folks see a drill press and think mill------cheap mill. Often they think they're clever and have come up with something no one else has-----likely because they're far more *clever* than are others. Once a person has made up his mind that his hare-brained idea is good, it takes a heap of dissuading to swing them a different direction. I'm fast getting to the point where I think it's smarter to let them screw up and learn the hard way. Still, it's hard to stand by and watch otherwise smart people make such stupid mistakes.

The typical drill press, particularly today, where virtually everything is made in China, and not necessarily of great quality, even for a drill press. Armed with that idea, said drill press lacks *everything* necessary to be even a low quality mill. The only thing it has in common with a vertical mill is a spindle that rotates.

Harold

My wife's favorite line: "Experience keeps a hard school, but fools will learn in no other."

Unfortunately it's often directed at me!!

Jim

For those situations I use a jacobs double angle collet chuck. The DA300 series has a 1/2 inch shank that fits into an R8 collet and the nut on the end is not much bigger. The collets go up to 1/4. The collets will hold better than a drill chuck and will also be much more concentric. I think the runout on a drill chuck would make the 1/8 slot a bit wide.

It would, and does, but I wouldn't try to mill a to-spec slot with that loose an arrangement. Just doing a little side-milling touch-up of a narrow slot wider than 1/8". Climbing and really light cuts keep the bit from hogging, and give a _reasonable_ finish -- though not great. Not recommended.

The extension collet is the better solution -- but, HEY! I didn't have one, and so seldom need it, it just never got ordered.

LLoyd

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