Bench Top Drill Press Converted To Milling Machine, Mounted To Lathe

Milling machines are nice to have around for precisely drilling holes or removing unwanted material from a part. However, they can be expensive and may not get a lot of use, two reasons why a mill purchase may not make sense for a home shop. [David] didn’t need a mill, he wanted one and he didn’t want to spend a lot of money. He did have an old bench top drill press and a lathe in his shop and thought it would be a good idea to combine them them into a DIY Milling Machine.

The problem with just throwing a milling bit in a drill press and trying to mill metal is that the drill press spindle ball bearings are not made for radial loading. [David] knew this and replaced the stock ball bearings with angular roller bearings. These new bearings would require an axial preload applied to keep the spindle in place. This was done by machining threads into the spindle’s shaft and adding a nut to secure and preload the new angular roller bearings.

[David] did not have an XY Table to donate to the project so he decided to mount the drill press to his lathe and use the lathe axes to move the work piece around underneath the mill. Thick plate steel was welded together to form a hefty bracket that bolted to both the lathe bed and drill press column. And yes, the lathe is still functional and the changeover process is simple. To go from Mill to Lathe; the work piece is removed from the lathe’s cross slide and replaced with the lathe tool holder. That’s it!

Overall, [David] is happy with his conversion. He doesn’t expect his project to be as precise or rigid as a proper milling machine but says he has no problem cutting 1mm deep passes in steel when using a 6mm diameter mill bit.

21 thoughts on “Bench Top Drill Press Converted To Milling Machine, Mounted To Lathe

    1. Adding an “x” and “y” axis on the far side of the mill head (I don’t know the lingo) might be functional. I don’t know how intuitive it would be moving something around like that. Also, the working space might be pretty limited depending on how it was set up.

    2. I’m sure a vertical slide would be cheaper than a second drill press.
      As for work volume, the travel on the lathe cross slide would be greater than the drill press throat.
      I have heard that production model lathe/mill/drill units are notoriously hard to work with, as one tool will inevitable limit the use of the other.

      Top marks for the hack, though.

      1. Because when I see a person mounting a drill press over a lathe I would conclude that person will incur a lot of cost to his/her account in the future. And not only because of the combination of those two machines but because it shows an interest in ventures that I would calculate would likely at some point end up in an unpleasant manner.

        But of course it’s not guaranteed, but insurance is a number and odds game.

        1. When I see a guy in a suit loading a chop saw in to the trunk of a Lexus I think exactly the same thing. What data do you have to support that someone who mounts a drill press over a lathe is more likely to get hurt than some insurance exec who buys a tool he knows nothing about?

  1. David missed another very important feature of a mill: the drawbar. Without it the radial forces will loosen the chuck on its mounting taper and it will eventually home off, most likely while in use. No drawbar is the biggest safety reason why you don’t mill on a drill press.

  2. This is a capital idea! We all understand that most of the time the inventor wouldn’t be milling heavily or using the improvised tool beyond it’s capability. Still this is pretty smart concept (bearing replacement, etc). Yes, drawbar and yes there would be runout and it wouldn’t be super precise, but I have to applaud his ingenuity. I’d have never thought of doing something like this so hats off to the inventor. Go slow, measure lots and work within the capabilities of the design.

  3. I keep seeing people posting that it’s so dangerous to use a drill press as a mill, With just a little work they do just fine for someone who doesn’t want to spend thousands on a mill

    1. Unless you somehow rig the drill press to us a draw bar it is dangerous to mill with it. The radial forces will try to loosen the taper holding on the chuck, and if it comes loose while milling it can seriously hurt someone. Even a light milling operation can produce surprisingly high radial forces.

      A mill doesn’t cost thousands; you can buy a new mini mill for $500.

      1. I have occasionally used my drill press as a very light duty milling machine (on steel with very light cuts) I did not modify the bearings and simply snugged up the slides to eliminate slack. Yes, now and then the taper did come loose but it only drops a few thou and all drive is lost, it was a pain but in my experience never dangerous,

        1. Depending on the type of cut and fixturing of the work, there won’t be anything to prevent the chuck from falling completely off the taper, at which point it can easily be flung, with the sharp end mill still attached.

          You have simply been lucky up until now, and in fact prove my point that milling on a drill press can and will loosen the chuck from the taper.

    1. It looked like the spindle was just bored out to turn it into an end mil holder(which I think is a great idea) also gets rid of the knee-jerk comments above talking about the taper not holding the chuck. From what I can see there isn’t a chuck and the mill bit is bored into the taper of the spindle. If so I just wanted to confirm and also see how that is working-Thanks

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