Hi all. I am new to the site and to machining and am looking forward to hearing helpful advice from folks. I have a 1937 solid cast iron drill press that is in spectacular condition. I have completely disassembled it and want to convert it to a non-precision, light duty milling machine. I know this is not a particularly popular idea and has many faults, but I just want to do it. I have new tapered bearings on order to deal with lateral forces so I think that is covered. The frame is solid but I will brace it up a bit more and make it as solid as I can. My big question is what to do about the tool holder. It currently has probably the original 3 jaw Jacobsons chuck on it.The spindle is a solid rod with a taper so it won't accommodate a collet system as it is. Any suggestions about tool holders for this (other than "get a milling machine")? Thanks
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Newbie question (Hope this is the right forum) - converting drill press to mill
- Thread starter Lmheim
- Start date
Can't argue with "just want to do it" but nice 1937 drill presses are not in everyone's shop. Particularly with the attributes you mentioned. An import bench mill would look good next to it and be more useful? If you can't have 2, perhaps there is good value in the old press.
off the top of my head, none of the morse or Jacobs tapers are up to the task without a draw bar or pinning.
off the top of my head, none of the morse or Jacobs tapers are up to the task without a draw bar or pinning.
I also contemplated this for an 1980's Taiwanese drill press.
I stopped because the only tool holding I could sort out was using the Jacobs drill chuck to hold an end mill. I tried it on aluminum. Once.
The cutting forces involved are very high for a drill chuck that makes contact in only three small areas on the tool. End mills pull down as they pass through the stock. So there is a high likelihood the end mill will pull out of the chuck. That falls under the category of bad things.
Equally bad are the lateral forces that want to remove the chuck from the taper and there is no way to hold the chuck on the spindle. So the risk of having the chuck come off the taper is high.
I stopped because the only tool holding I could sort out was using the Jacobs drill chuck to hold an end mill. I tried it on aluminum. Once.
The cutting forces involved are very high for a drill chuck that makes contact in only three small areas on the tool. End mills pull down as they pass through the stock. So there is a high likelihood the end mill will pull out of the chuck. That falls under the category of bad things.
Equally bad are the lateral forces that want to remove the chuck from the taper and there is no way to hold the chuck on the spindle. So the risk of having the chuck come off the taper is high.
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The bearings might help with side loads, but you won't be able to hold the tool securely. End mills want to pull out of the chuck. That force will try to pull the spindle down, likely pulling whatever you have on the taper off. Once that happens, you have a tool and whatever held it flying around. That's assuming you have some way to lock the spindle so it doesn't get pulled down. You might be able to bore it out with a collet taper and hold down. You would probably need a lathe for that, but you might be able to rig a tool holder on the table and use the spindle to feed.
You might be able to tap the spindle taper to hold the drill chuck on with an internal screw. That doesn't solve the problem of holding an end mill in a drill chuck, but it would keep the chuck on. Drill chucks just don't have the grip required to hold an end mill though.
Perhaps build an end mill holder that will match the taper with a hold down screw and use a weldon shank end mill with a set screw to hold it in.
I looked into this when I was getting started. I don't have the same drill press, but what I found was that you will spend the same or less on a mini mill and not be likely to kill yourself. In the event it does work as you expect, you would be lucky to take cuts of 5 or 10 thou. That gets old real fast. Even a mini would do a lot better. You also haven't dealt with X/Y movement. If you intend to use a cheap X/Y vise, I wouldn't. The screws are not designed for the forces required and will shift around. I've seen some that I would bet would snap from the cutting forces.
Drill presses usually can't run slow enough for milling. You also need to deal with that.
This winds up being a lot like using a butter knife as a screwdriver. Sure, you can, sort of, for very limited applications. But an actual screwdriver works a LOT better.
You might be able to tap the spindle taper to hold the drill chuck on with an internal screw. That doesn't solve the problem of holding an end mill in a drill chuck, but it would keep the chuck on. Drill chucks just don't have the grip required to hold an end mill though.
Perhaps build an end mill holder that will match the taper with a hold down screw and use a weldon shank end mill with a set screw to hold it in.
I looked into this when I was getting started. I don't have the same drill press, but what I found was that you will spend the same or less on a mini mill and not be likely to kill yourself. In the event it does work as you expect, you would be lucky to take cuts of 5 or 10 thou. That gets old real fast. Even a mini would do a lot better. You also haven't dealt with X/Y movement. If you intend to use a cheap X/Y vise, I wouldn't. The screws are not designed for the forces required and will shift around. I've seen some that I would bet would snap from the cutting forces.
Drill presses usually can't run slow enough for milling. You also need to deal with that.
This winds up being a lot like using a butter knife as a screwdriver. Sure, you can, sort of, for very limited applications. But an actual screwdriver works a LOT better.
Howdy, Neighbor. Welcome to HM.
Not really much to add to the wise counsel already posted with regard to technical detail - all of it correct, I might add. But also consider the investment factor. By the time you make all the modifications necessary to turn a very nice drill price into moderately (at best) usable milling machine, along with the expenses associated with it, you could have saved that money, sold the drill press and bought a pretty decent milling machine. As a practical matter, milling machines can double as a drill press. Unfortunately, the converse is not true.
Regards,
Terry
Not really much to add to the wise counsel already posted with regard to technical detail - all of it correct, I might add. But also consider the investment factor. By the time you make all the modifications necessary to turn a very nice drill price into moderately (at best) usable milling machine, along with the expenses associated with it, you could have saved that money, sold the drill press and bought a pretty decent milling machine. As a practical matter, milling machines can double as a drill press. Unfortunately, the converse is not true.
Regards,
Terry
You can't tram a drill press like a mill. In other words, setting the bits square to both x and y axis. There is a utube showing this guy using router bits on a drill press. Yeah. he got it to work sort of. First, it's very dangerous. Second, you have spend all sorts of time making jigs to hold the work properly. Third, you can't get the proper speeds. Now, try this on metal where there are much greater forces involved. In the end, the guy came to the conclusion was get a mill.
I say go ahead and try it! No better way to find out for yourself what works (or doesn't) and why.
Get some cheap endmills, you don't want to ruin expensive ones
Have fun and be safe- wear eye protection and watch out for your fingers
-Mark
Get some cheap endmills, you don't want to ruin expensive ones
Have fun and be safe- wear eye protection and watch out for your fingers
-Mark
You must find a way to retain the endmill in the end of the spindle that does not rely on just the friction of a taper.
If you rely on friction, the endmill WILL fall out of the machine in the middle of a cut. Damaging your work and possibly yourself.
Machine the end of the spindle to make a weldon style endmill holder with set screw. It will work for one diameter endmill but at least you are safe.
The slop between the quill and the main casting is usually sloppy compared to a milling machine. This will limit the surface finish and quality of any machining you do. But its not a safety issue.
Not being able to tram the table square to the head will limit the accuracy and quality of the milling you can do. But it is not a safety issue.
If you rely on friction, the endmill WILL fall out of the machine in the middle of a cut. Damaging your work and possibly yourself.
Machine the end of the spindle to make a weldon style endmill holder with set screw. It will work for one diameter endmill but at least you are safe.
The slop between the quill and the main casting is usually sloppy compared to a milling machine. This will limit the surface finish and quality of any machining you do. But its not a safety issue.
Not being able to tram the table square to the head will limit the accuracy and quality of the milling you can do. But it is not a safety issue.
Dadgum it, seems like my idea is pretty much a bust. Thing is, I am extremely cost constrained so I can't go out and buy a mill - even a Chinesium, HF or craigslist special and I have a reasonably decent radial arm drill press already. However, the input I have received here and other places is overwhelmingly against doing this so I probably won't. Instead I'll just get a set of new regular bearings and put this thing back together for use as a second drill press. I guess it could be worse, huh? Thanks for all the comments and learnin' me somethin'.