Johansson 60 Radial Drill Press as a mill?

Hello all, I have a radial drill press I purchased online at auction. I bought it believing it would make a nice addition to a metal workshop as drill press. Upon picking up the drill, I realized what I bought is much heavier than I believed when I bid on it.

Model: 60
Manufacturer: Johansson
Specifications
Arm Length: 4'
Column Diameter: 6"
Spindle Speeds (8): 60- 900 RPM
Spindle Quill Travel: 6"
Spindle Nose: #4 MT
Spindle Quill Feeds: 0.010"- 0.080"
Table Size (T- Slotted): 40" x 20"
Table Vertical Travel: 16"
Arm Vertical Travel: 12"
Dimensions (L x W x H): 75" x 36" x 80"
Weight: 4,000 Lbs.



The main motor is 3 HP at 460V and 1.5 at 208V and is 3 phase. The drill has a solid T-slotted table bolted to a vertical slide. This is set up for drilling up to drill and tap 1 1/2" I believe. I believe the arm and quill are power feed. I can feed power to the drill at 208V 3 phase.

I have been very curious about cnc for quite a while. I understand there is currently no feedback to give indication as to the location of any of the axes. Would it be reasonable to keep the existing motors for the quill drive, quill feed and arm travel? What would be involved to create feedback to the controlling software?

I don't remember the specs exactly, but years ago, I purchased a 4-axis 1698 oz in stepper kit with power supplies, drivers, breakout board (parallel port), proximity switches, etc. to make a cnc router but never got around to it. I understand steppers aren't really the ideal motors to move this machine. As I have not used cnc, I am not familiar with requirements for milling with steppers. I am not looking for speed, just something I can learn with to determine what I need...if I even really need cnc anyway.

I also own a Smithy Granite 1324 with DRO which I can make parts to assemble a cnc machine. Again, not an ideal machine, but don't we do with what we have?

I am going to assume that replacing the T-slotted table with a cross slide table would be a great starting point instead of relying on the radial slide. Is it possible to leave it usable as is, yet add cnc control? I do not for see needing heavy cuts. The drill currently has 8 speeds ranging from 60 to 900 rpm. For milling, is these too slow to be useful?

I don't want to get started only to find I cannot complete the project. I have too much I could use the drill press for to have it remain unusable in any state.

Wow that thing is really huge!

For a CNC conversion however, it might not give you the results that you desire.
I see the following problems:

1. The spindle
   Milling will result in a much heavier radial load than boring. The spindle is probably not made for that, which means milling with it will result in more wear and it might also be less accurate, giving you a bad surface finish etc.
   As you pointed out, a max of 900rpm is not really much for milling. You might get away with it if you only use bigger mills, but it's not really ideal. Your spindle is not made for higher speeds, so just changing the motor or using a VFD to turn up the speed will probably do more harm than good.
   While boring pushes your tools (drills) upwards, milling will pull them downwards. This is the reason most mill tapers, like the SK40, are fixed with a screw on top. If your drill press only has a (worn out) morse taper, it might fall out while milling. You also can't use the drill chuck for milling, it will pull out your endmills.


2. The ways/leadscrews
   Most drill presses aren't highly accurate and so are their ways so you might want to check that.
   Quill and arm feeds are probably realized using simple gears/leadscrews with a lot of backlash which might also be too weak for milling. CNC machines use ballscrews to remove that problem.
   Adding a new Crossslide is possible, but at that size not really economically.

I don't think it would make sense for a CNC conversion. It is definetly possible but I guess you will be happier and spend less money if you convert a machine that was made for milling.

andypugh wrote:

It would be great fun to convert this to CNC using Polar Coordinates and kinematics.
{/quote}

Might be fun if I knew what that was. Looked it up and it surely looks interesting, but above my thinking ability...for now!

andypugh wrote:

Great fun, but probably futile.

It might be worth considering making a bolt-on XY CNC table using off-the-shelf linear guides and ballscrews. Something easily removed when you want to use the drill for what it is meant for.

Looks like I will just have a tapping drill press...for $40. I cannot complain, just thought I might use it for something else. I already have a drill press.

Thank you all for your kind evaluation. Unless I could spend a LOT of time and money modding this machine for proper tool holding, load bearings and accurate ways, I'll just have a large tapping drill press. I'm not complaining. I look forward to renovating this machine for my shop. Then look for a nice clean mill for CNC. I already have my eye on a machine or two.

I see what you are saying. Might be a project I would be interested in. Something like that is lower priority than my other current projects. Too many buildings to erect before I can think of that though.

Just thinking...The head can spin around, why can't I install/make a milling head on the back side of the "y" side of the drill press? This would give me the ability to have high/infinitely variable head speeds and still use the same machine, therefore, saving valuable floor space and having a multi-use machine.

What should I be looking for to make additions to this machine to make this a reality?

Spindle type for reasonably priced tooling?
Spindle speeds for various milling?
I have not done this before so I do not know what I do not know.

Does a particular type of equipment work better with cnc and linux?

Should I plan on additional axes?

BTW, I have acquired a real mill! 38,000 lb of iron. Needs a bit of cleaning when I have time. Maybe I can get it ready in a couple years for some heavy work.