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Drill press couple questions

Mach1

Plastic
Joined
Mar 15, 2005
Location
Stansbury Park, Utah
Whenever I install a drill bit into my sears crapsman 15" drill press, it takes me about thirty tries before the drill runs true and straight. The bits are straight but the chuck isn't consistant. What kind of chuck could I install that won't give me this problem?

Utilizing a small milling table, can I do light milling with this machine?
 
I think the standard chucks on most DPs of that cheaper type are crap. On my "flung dung" DP, I had that nonsense going on also when I got it (very used). I put an LFA chuck on it and have had no more trouble.

The milling thing comes up regularly. Short answer is "not if you expect to do even a crappy job.".

There are indeed DPs on which you could mill. That probably isn't one of them.

Bearings are not designed to hold up to that force.

The lack of a drawbar will encourage the chuck to drop the cutter onto the work when it vibrates out of the socket (if it has a morse taper socket).

I know I found that mine wouldn't consistently rout a straight line in WOOD with an end mill....let alone mill metal. Wanted to wander off due to the side forces and general looseness of a DP to side force.

Cheaper ones or cheaper built ones are worse that way.
 
i'd think you could do some very light milling
w/ smallish tools in soft metals without
destroying your d.p.....1/8 - 1/4 endmills with
very light cuts shouldn't kill the thing...
just be careful...
 
A nice keyless drill chuck will help the first problem you are describing.

As far as light duty milling, sure you can do a limited amount of it, if you are very careful. But as mentioned, the chuck may drop out because of vibration, the bearings are too light, the arbor is too light and may bend. In short, most consumer drill presses were never designed to do milling. There are some serious industrial type drill presses out there that might hold up, but they have big tables (24") and are heavily constructed. If you want to do some limited milling, get a mill drill (and wait for the howls of anguish), even those are a marginal machine.
 
As everybody has said, get a Jacob's or other decent chuck and your problems will cease.

I have tried the milling thing with a dp... don't do it. The only way it might work is with a draw bar, but as has been mentioned, the bearings are not up to the duty.

There's more, though. You may get a few days worth of successful milling out of the machine without the drawbar, but you will have a major problem on your hands very quickly. Most dp spindles are not hardened in the socket. You will wallow the taper due to side loading. Ask me how I know.
 
I didn't mean to imply that you would mess up the bearings trying to mill. You could, but I don't think you would persist in trying that long....!

The issue I found is that many don't have bearings which will hold the spindle rigidly against side deflection. That lets the end mill wander, taking deeper or shallower cuts, springing back in and causing a "crash", etc.

If you have a heavy DP, with a male taper chuck holder, and double bearings in the quill, it may work. A couple people have shown theirs on the HSM board. But they were heavy Swedish drill presses, IIRC.
 
The manufacturers of small X-Y tables are probably to blame for the seemingly irresistible urge to convert a $39.95 drill press into a milling machine. Those little tables are handy for lots of semi-precise positioning but they do not constitute a safe or efficient means of removing metal (except by drilling).

In addition to the objections stated in previous posts, here's a couple more: the fit of the spindle in the head casting is loose and usually cannot be adjusted (inexpensive drill presses) and there is no good way to adjust and lock the spindle in the Z axis.

Given these attributes and the not-too-precise bearings used in these machines, it's guaranteed that the thing will chatter, even if one is only trying to cut WOOD.

Chatter=vibration=OOPS, the chuck with a very sharp milling cutter just fell out of the spindle, spinning at 2000 RPM, glanced off the workpiece and perhaps landed on your sneaker-clad foot.

Don't do it - the machine wasn't designed for it, the little X-Y tables weren't designed for it and your body wasn't designed for the mishaps that will surely occur.
 
Have a look at your drill shanks.
they may have raised burrs on them from being spun in the chuck.
before you tighten the drill chuck keep spinning by hand the drill bit as you tighten......then it will centralise its self in the jaws.
rotate the drill by hand wheen the jaws have a loose grip on the drill shank .....if it has burrs you will feel the resistance.
all the best..mark
 
If the drill chuck is secured to the spindle
only by a morse taper, it *will* come undone
if a side load is applied. This has nothing
to do with vibration, but rather is an effect
of the way that self-holding tapers work.

They lock on very nicely for *axial* loads,
but radial loads will resolve into force
that unlock the taper rapidly. Without a
drawbar to counteract that effect, the chuck
*will* come out. This aside from the fact
that jacobs chucks will not grip an end mill
properly because the end mill shank is miles
harder than the jaws.

Jim
 
This has nothing
to do with vibration, but rather is an effect
of the way that self-holding tapers work.

They lock on very nicely for *axial* loads,
but radial loads will resolve into force
that unlock the taper rapidly
Not to be argumentative but vibration is the enemy of all friction-held devices, whether they be conventional fasteners or tapered devices. That's why split lock washers, star washers, nylon locking pellets, lock-wire and many similar vibration-resistant locking mechanisms were devised.

Additionally, a side (radial) load by itself on a morse taper will do very little to "unlock the taper rapidly". A simple trigonometry exercise will reveal that a one pound side load on a #2 morse taper (as an example) will produce less than an ounce of axial load in the direction of unlocking the taper.

However, attempting to mill with a tapered toolholder unsecured by a drawbar produces an effect similar to driving the taper with an impact wrench. This is the result of the vibration acting upon the helix of the end mill, producing both an axial load and a torque - the worst possible scenario since the tapered arbor is being twisted and pulled from its socket simultaeously.

edited to add:

(For accuracy's sake, "chatter" produces a complex periodic waveform that is comprised of both vibration AND repetitive shock impulses.)
 
"If the drill chuck is secured to the spindle
only by a morse taper, it *will* come undone
if a side load is applied. "

Exactly. If that doesn't come loose, the Jacob's taper will. Once they come loose and spin a few times, the taper socket in the spindle (Morse) or the socket in the chuck (Jacob's) will start getting enlarged (wallowed) and it will fall out at the slightest bump.
 
I have a 25 year old Sears Craftsman drill press, with a #33 Jacobs Taper on the spindle. This particular design has a threaded retaining ring, to hold the chuck on the spindle. I have a shaper cutter holder that fits the taper, and the retaining ring. While the shaper cutter holder does not work as well as a regular wood shaper, it does work, I put tounges and and grooves on a lot of scrap lumber for shop shelves.

Never tried milling with it, as the downfeed is not very precise, and the spindle travel lock is not very substantial. The spindle is likely to move as you are trying to mill, spoiling your accuracy.

I have seen the same feature on drill presses described in older Delta catalogs.

I have swapped out the Jacobs chuck that came with the Craftsman drill press for an Albrecht. It made an improvement. When I got my used 17" Delta, the Albrecht chuck went on that, instead of the small Jacobs that came with it. It reduced drill runout, and made the drill press a bit more precise.

IMHO, I think a good chuck is worth the money, even on an inexpensive drill press.

Thermo1
 
>>with a #33 Jacobs Taper on the spindle. This particular design has a threaded retaining ring, to hold the chuck on the spindle

Rockwell /Delta 15 inch 6 plus 6 drill press uses the same design. I also remember seeing it on an old Atlas drill press a long while back. Ring holds the chuck on and facilitates removing it.
 
Sorry to have this discussion coming back to life again. Just finished restoring and old SB-9A Lathe. So I am getting all ready to turn drill and mill. Since the lathe is ready I can now focus on the drill/mill so I have been looking for some info across this forum. Thought I could do it the cheap way by either milling in he drill press or a drill/mill stand accepting a hand drill. From what I've read sofar it all seems to be a big NoNo flying chucks, mills etc. So may qustion is what would I use as a minimum to mill with safety an confidence. As it seems to me that also th cheaper Chinese Mill Drill combo's often do not have a 'drawbar'. Is a having a drawbar a true requirement even for relatively small hobby work (steam engines etc.) Like to have a Bridgeport or eq. but do nota have either the cash or the room to fit one. Sometimes on US Ebay you see smaller BP's coming by but here in Europe it's minly the full size machines that are probably too large to do hobby type work anyway.

Thanks,

Piet Butter
Heemskerk
Holland
 
relatively small hobby work
Exactly the type of work that needs a true milling spindle with the least possible "side-to-side slop"

You guys that want to make small stuff and do a nice job of it are not heading in the right direction by considering any milling in a drill press type machine. You probably have plenty of frustration already without adding to it. As well mentioned above, there is the safety factor too. Not only for you personally, but also for the item you are trying to make. Bummer if near the finish of some complex little gadget your "milling machine" decides to fall apart.

John
 
here in Europe it's minly the full size machines that are probably too large to do hobby type work anyway
An often used expression comes to mind: "Small work can be done on a large machine but the converse is not possible" or something like that.

Having said that, it IS sometimes awkward manipulating a large, heavy milling table with well-used, sloppy leadscrews to machine a small, precise part. But if the spindle in the large machine is in good condition , it's ALWAYS possible to find ways to accurately produce small parts.

One technique would be to lock the milling machine table and mount a small, tight X-Y table to the large milling machine for light milling, drilling and boring tasks ...

This might be a quick, inexpensive expediency for the home hobbyist to make use of a larger milling machine (available at a reasonable price) for small work. Naturally the machine, even with sloppy leadscrews, would be quite useful for heavier work too !
 
"Additionally, a side (radial) load by itself on a morse taper will do very little to "unlock the taper rapidly". A simple trigonometry exercise will reveal that a one pound side load on a #2 morse taper (as an example) will produce less than an ounce of axial load in the direction of unlocking the taper."

Have you ever side loaded a morse taper, without
a drawbar, sir?

Try it sometime and see what happens.

As far as that quote goes, the one I recall is
"you can do little stuff in a big vise, but
you can't do big stuff in a little vise."

That one's my favorite.

Jim
 
Jim asked
"Have you ever side loaded a morse taper, without
a drawbar, sir?

Try it sometime and see what happens."

Would you accept a B&S #9 instead of a Morse? I can't remember if I had any Morse taper cutters without threads for the drawbar on my first mill but on my Index I have some B&S taper shank cutters without drawbar threads and they work. I'm not doing production work here but these are old cutters and have survived the years. That said I no way would condone milling in the DP, I've had the chuck fall off just trying to use a hole saw. Learn't my lesson there.

As for the "simple trig saying....." I believe Randy is using the wrong set up of the problem. Randy is assuming the side force is directly perpendicular to the taper. Look at the problem as a lever that is torquing the chuck off and using to top of the taper as a fulcrum and the bottom of the cutter as the end of the lever. Now compute the force.
lg
no neat sig line
 
B&S and MT tapers both suffer from the same
trouble - they are self holding due to the
realatively small included angle.

When side loaded the forces resolve such that
the friction which self-locks the taper goes
away.

A simple geometric sketch of the angles won't
reveal the problem. Trying it with a MT shank
chuck will however in short order.

Jim
 
The January 1969 issue of Popular Mechanics has an article about milling with a home shop-type drill press, using a ball bearing support to take the side thrust along with special homemade vertical toolholders that use 3/16" square lathe tool bits. These holders fit into the regular drill chuck and work on the principle of a flycutter, which they say is the only practical method for doing drill press milling. The ball bearings on the side support run in contact with the side of the chuck and are supposed to prevent bending of the drill press spindle. They don't say if the chuck should be held onto the spindle with a bolt or not.
Mike
 








 
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