I have seen many threads in which people argue about the merits of Mill-Drills as Milling machines, but I don't want to talk about that.
I have a medium drill press, a 20 year old Enco machine, with chaning belt type speed control, RPM 240-3800 RPM, mounted on a bench. It is
2MT, but I only use the regular drill chuck, goes up to 5/8 inch. The table cranks up and down fairly easily, and when I need to I can adjust the angle of the table. I do not have an XY table. It is a bench top model.
I don't have space for a drill and a mill, so if I get a mill-drill I would sell the drill. I would probably go for a lower end mill-drill. I have no machining experience.
So what would I give up if I upgraded from my drill press to a mill-drill? Or would I just have a better drill press with some milling capability?
It depends a great deal on what you drill on your drill. A mill drill usually is a heavier duty drill and has capacity for better feed and precision but it's drawback over a floor drill is what can be drilled as far as size of material. You have much less height adjustment on a mill drill. Dick
Probably the biggest thing you'd give up is not being able to drill a hole without taking down a setup on the mill.
I have a small knee mill and a tiny bench drill press. I use the mill a lot for drilling just because I have more clamping options and stuff that requires lots of rigidity like countersinking works better. Likewise, on the mill I can do a setup to drill a couple of holes in 50 pieces of work very quickly.
The only downside of using the mill is that the quill is not quite as sensitive as a drill press and I tend to be much more careful about not dinging the table.
The single biggest thing you'd miss is the hole in the drill press table. There isn't one on a mill, so you have to always be using parallels or sheets of sacrificial material or some other way to keep from drilling into your table.
The second thing you'd give up is portability. Plan to move soon? Do you rearrange your shop a lot? Your drill press can probably be picked up easily, maybe with one hand, but the mill requires an engine hoist.
With respect, I think you need to think carefully about that, otherwise, there isn't much reason to make the move. The exception would be if you plan only to drill holes in parts that already have clean edges. In that case, an X-Y table might be all you need; I will leave that for others to comment.
There's always room for another machine :) Ok, maybe not.
The comment about needing an engine hoist to lift a mill-drill is well taken. Turin makes a no-frills hoist w/ folding legs that sells for $140 or so. You can spend a LOT more, but if you don't care about having power strokes in both directions on the lever, air assist, etc., you can save a lot of money.
I recently bought a mill-drill (essentially a Rong Fu 31) and am thrilled with it. Read the recent "care and feeding" thread on this group to get some good advice from the experts. One thing that I did not get up front, largely because I posted to this group only after having purchased the machine, was that a dovetailed column might be an option. Investigate which machines offer it, how much they cost and weigh, and ask people who own them whether or not they stack up against knee mills [*] for alignment.
You probably already know that mill-drills, at least those w/ circular columns, have a problem with alignment after moving the head. I ended up buying an ER collet set, and find that it puts the endmills and drill bits at about the same working height, and the ER collets indeed change in a lot less vertical space than R8 shanks, so my 5 inch spindle travel looks fairly generous at this point. With many types of work being held in a vice on parallels, it is not hard to find a height that works most of the time. Yes, the spindle is often extended a little more than one might like, but the machine appears to be built for it.
Also note that if you lock your dials to a reference, you can likely move the table far enough to get the work out of the way for changing from a collet chuck to a "normal" chuck for times that this is necessary. Thanks to the dials, you will be able to return to previously visited spots with very good precision. Things change if you find that you need to move the head. If you work on large parts, you might need to move to a hole for the change, or will be out of luck.
If you attempt to match R8 collet held endmills with chuck held bits, you will probably have trouble.
FWIW, I design and build prototype hardware. Precision usually coincides with small parts, and I keep my machines (and my ability to use them!) in mind as I work. If you do not have that freedom, then you might find a mill-drill to be a waste of space.
[*] there really is not substitute, but I do not want a 2500+ lb machine right now.
This may sound strange, but I have a Mill-Drill which is MT3. I also have a new 10 x 44 verticle with power feed and DRO in all directions as well as a medium size horizontal with an ISO 40 taper spindle. I use the mill-drill the most, the horizontal next and the verticle the least. I have complete tooling for all. I use the mill-drill for drilling mostly, but it works very well for simple vertical milling applications. It is the easiest of all to set up. It is much stiffer than a normal drill press and sits in the same space as a drill press. It might be Chinese, but I wouldn't be without one. Steve
I'd be inclined to keep both. If space is that much of a problem, sell your full-size DP and get a $100 bench-top drill press. That will do most of what you need. No place to set even that? Crank the MD table over and clamp the small DP to the end of the table.
I'd keep the drill press in a corner somewhere. You can set it up on the end of the mill-drill table whenever you need to drill in some awkward place where the mill-drill won't reach. Otherwise a mill-drill makes a very nice drill press. You lose the tilting table and the ability to drill into the end of a long part or to swing the table so the bit passes down beside it. I'm not sure if the head of a mill-drill is balanced well enough to safely rotate it very far from center.
Those bench-top drill presses can be clamped to large stationary objects to drill holes in them. I used one that way to put 1/2" holes in a steel beam to make a log splitter.
For a hobby shop or with limited space a mill-drill is preferable to all but the best drillpress. The round column mill-drill allows you to swing the head around to work on thick or long pieces. You can hang angle iron off the back of the table for fixturing if necessary.
My mill-drill is MT3 and it's great to be able to use MT drills or have multiple chucks set up for quick changes. I do a lot more drilling than milling but it's nice to be able to run an endmill occasionally.