Can anyone tell me why a mortiser can't be used as a drill press?

[Keith Gentile]

Everyone seems to talk about using a drill press as a mortiser but no one ever mentions using a mortiser as a drill press. I've never used a mortiser before, although I get the general idea of how they work. But even so, I can't figure out what aspect of the mortising machine would eliminate dual use as a drill press. Is it just a matter of fitting a different chuck? Must be something I'm not considering that limits a mortiser by design from being used as a drill press.

[Ben Rivel]

Seems even if you could it would make a pretty limited drill press being that it doesnt go that high off the work table and is very limited in its speed options (if it has any at all), as well as probably needing a different kind of or better chuck. But yea, other than that I guess you could. Still wouldnt trade my Delta 18-900L for one!

[Ken Frohnert]

You also don't have that much swing with a mortiser.

[Keith Gentile]

While the stroke is about the same as a drill press, yes, I can see that the table not adjusting would make it limited. As for speeds I never really change the speed on my drill press, I just adjust the pressure I apply to the handle. But I could see how that would put people off.

It just seems like someone would be making a machine that has the heft to handle the torque needed for mortising with the other features a drill press has along with a swappable chuck. In other words if you want both tools in one, it doesn't seem that difficult to design it and wonder why nobody has. They share so many features that if you're going to build one, why not just do both? Especially if you're talking about a large, stand alone machine that already requires lots of castings.

[Keith Gentile]

Ah! The swing. That's a good point. I suppose I could see that a lot of torque applied to an even further cantilevered drive base would require special reinforcement that neither of the two would otherwise require.

[John Vernier]

I did use my mortiser as a drill press a couple of times when I had just set up shop and didn't have a DP. It's a Delta bench top machine and it has a normal chuck, either 3/8" or 1/2" capacity (I'm not sure, but it held the Forstner bits I needed it to). Ben is right that it doesn't have as much capacity as a proper drill press, and it runs at a slow speed. It also has a fairly shallow reach, as bad probably as the smallest commercial drill presses, 4 inches or so. Also, the collet holder which holds the body of the hollow chisel prevents the chuck from getting very close to the work, so it wouldn't be practical for smaller sized bits. I used it with Forstner bits and spade bits with some success.

I also found that, when I did some mortising work in Southern Yellow Pine, and my hollow chisel bit would clog constantly with burning resinous chips, it was much faster to chuck a Forstner bit into the mortising machine and do a little clean-up of the mortises by hand, than to keep stopping to clean the mortising bit.

All the same I soon bought myself an ancient Delta DP and I haven't looked back. It is less awkward to use and much more versatile. Using the mortiser as a drill press is a limited emergency hack but not the way I would choose to set up a shop.

[Mike Cutler]

Keith

A mortiser will drill holes, but it would limited in scope of application.
Bench top mortiser have a fixed speed, or at least mine does. You won't get to far up in bit size before the bit is spinning to fast. Forstner bits would be impractical beyond the smallest few sizes. However, it will drill holes, but it won't replace a drill press.

[Dan Hintz]

As for speeds I never really change the speed on my drill press, I just adjust the pressure I apply to the handle. But I could see how that would put people off.

And just to be clear, varying pressure is not the same thing as varying speeds. The drill bit itself should be doing the work, which means there should be no need for any amount of real pressure with any material. Bits are designed to remove a certain amount of material per rotation... too slow and you burn up the bit, too fast and you overload it causing rough cuts and frozen/stuck bits. This is particularly true with metal substrates.

[Brad Shipton]

I have a 1hp mortiser and I had a special chuck machined for it for use as a drill press. The speed of the mortiser is too fast for many applications, but I still use if for some tasks. I suppose you could put a variable speed drive on it, but by the time you are done with that you would have the cost of a drill press into it and you would not have the versatility.

[Bob Vaughan]

It just seems like someone would be making a machine that has the heft to handle the torque needed for mortising with the other features a drill press has along with a swappable chuck.

Back in the days of good machines, this was pretty common, but it was mostly drill presses with good mortising yokes. Once buyers got the point of buying cheap machines made from peanut butter metal, the practice stopped because of failures.
Another problem is where the gears are that the pinion operates. A rack of gears cut into a cylinder as most drill presses are, isn't strong enough to take a lot of mortising without failure. Ender into that problem the crappy metal used to make the Asian imports, and drill presses used as mortisers are destined to fail after extended use.

Look at the up and down operating systems on mortisers. While the smaller mortisers have a drill press type operating pinion, where and how the gear rack is made is significantly different from a drill press. On better small manual mortisers, the operating system is a linkage system operated by foot pressure. Down pressure required on a mortiser can be significantly more than on a drill press because you're actually driving down a four sided chisel that doesn't rotate like the center drill bit does.