Proof of Concept Powered Drill Press Table

[rgsparber]

I'm looking for opinions on whether this is a risky way to implement a powered drill press table. Could this potentially damage my drill press?

If people have well reasoned arguments on why it could hurt my drill press, I will drop this line of development. But if the community feels it is safe, it could be a rather cool way to power my drill press table.

Thanks,

Rick

[Toolmaker51]

It clearly works, but kind of fiddly. Sufficient counterweight and sheave makes more sense to me. I'd extend a notched bar and quite heavy weight to accommodate varied setups. If it works on Tony Foale's Bridgeport pattern mill. . .

[rgsparber]

It clearly works, but kind of fiddly. Sufficient counterweight and sheave makes more sense to me. I'd extend a notched bar and quite heavy weight to accommodate varied setups. If it works on Tony Foale's Bridgeport pattern mill. . .

My counterweight set up works well and I may end up just making a few minor improvements to it. But it is always healthy to take a fresh look at stuff.

Thanks,

Rick

[Saltfever]

Not knowing the design of your drill press I can’t forecast the effect of your idea. However, I see some considerations. You are reversing the thrust of the Z axis. Are the spindle bearings suitable for this change? Normally, I grip the collar around the column to lift the table up. You have created a bending moment that is now putting stress on both the table collar and the column. How will this affect wear of these two parts?

[rgsparber]

Not knowing the design of your drill press I can’t forecast the effect of your idea. However, I see some considerations. You are reversing the thrust of the Z axis. Are the spindle bearings suitable for this change? Normally, I grip the collar around the column to lift the table up. You have created a bending moment that is now putting stress on both the table collar and the column. How will this affect wear of these two parts?

Very good points that I had not considered. It makes sense that the bearings were not designed for a downward force.

The center of gravity of the empty table should be close to that center hole so this would be the ideal lifting point with respect to bending forces. However, it is a terrible place to lift because it is right in the middle of the action when subsequently drilling. Place a heavy vise on the table puts even more weight near the center of gravity.

I've started to think about keeping the jack screw idea but not driven by the drill press. Although it adds complexity, a pinion gear that let me turn this screw from a drive shaft under the table would be cool. I could turn the drive shaft with my battery powered drill.

I like lifting the table near its center of gravity but the mechanism must be out of the way. It could swing out as needed under the table if not too much hassle. Maybe it could stay there. Clearly, thrust bearings would be good.

More comments from others plus think time will refine this.

Thanks!

Rick

[Toolmaker51]

Main problems with Vee-thread, combinations of diameter and pitch won't be very rapid lifting action, and Vee's have little tolerance for dirt and chips. I'm still a hold-out for ACME, which translate torque to movement quickly compared to a multi-start Vee.
Most round column drill presses use a rack and pinion. Bottom edge of rack is mitered, it rides in a chamfered ring encircling the column. Below that ring is another to take thrust. All it takes is a small handle, spins a worm/ pinion combination to climb or descend the rack. And when you let go it remains in that position, but table can still rotate about the column.

A couple Martin or Browning gears, matching rack, aluminum billet housing and a couple oil-lite bushings, and two stubs of thick wall pipe; if I insisted on mechanical positioning.
Aforementioned notched lever, stripper bolt, some chain and and a slug of rod stock for weight. Far simpler and equally effective.

How about a dedicated winding motor; provided 12v DC, attach a auto window or power seat motor. Substantial torque, controllable [single speed] RPM, hypoid-geared, reversible; need I continue?

[rgsparber]

Main problems with Vee-thread, combinations of diameter and pitch won't be very rapid lifting action, and Vee's have little tolerance for dirt and chips. I'm still a hold-out for ACME, which translate torque to movement quickly compared to a multi-start Vee.
Most round column drill presses use a rack and pinion. Bottom edge of rack is mitered, it rides in a chamfered ring encircling the column. Below that ring is another to take thrust. All it takes is a small handle, spins a worm/ pinion combination to climb or descend the rack. And when you let go it remains in that position, but table can still rotate about the column.

A couple Martin or Browning gears, matching rack, aluminum billet housing and a couple oil-lite bushings, and two stubs of thick wall pipe; if I insisted on mechanical positioning.
Aforementioned notched lever, stripper bolt, some chain and and a slug of rod stock for weight. Far simpler and equally effective.

How about a dedicated winding motor; provided 12v DC, attach a auto window or power seat motor. Substantial torque, controllable [single speed] RPM, hypoid-geared, reversible; need I continue?

I do have a length of ACME threaded rod. I played with it on the end of a small electric screwdriver and it does appear to work. It would work a lot better if my ACME nut was in a pinion gear so the screwdriver was horizontal.

My RF-30 mill/drill has the arrangement you describe and it works well enough. Once I changed to CNC, I have not needed to move the head much.

I forgot that I have a window motor from a car. That shows a lot of promise! It has a lot of torque so would add a mechanical fuse to the linkage to protect the drill press.

Thanks,

Rick

[Toolmaker51]

I do have a length of ACME threaded rod. I played with it on the end of a small electric screwdriver and it does appear to work. It would work a lot better if my ACME nut was in a pinion gear so the screwdriver was horizontal.

My RF-30 mill/drill has the arrangement you describe and it works well enough. Once I changed to CNC, I have not needed to move the head much.

I forgot that I have a window motor from a car. That shows a lot of promise! It has a lot of torque so would add a mechanical fuse to the linkage to protect the drill press.

Thanks,

Rick

re ACME nut; there have been occasions 'we' bored one gear and turned another to assemble a different drive. A matching pair of miters would be simplest of all.

I don't have a conventional round column drill. I use one at work once in a while, my go-to for chamfering/ de-burring, and table is never at convenient height. 50's era but very sound, and the column is clean.
Much harder to slide the table up holding the table than handling it adjacent to the clamp. Center of gravity might be middle of table; but real issue is close fit of clamp and column, ~.002 max. Holding table imparts angularity [likely in 2 planes] on the cylindrical fit; binding is unavoidable. I find swiveling it helps normalize the disparate axis but doesn't last very long.
I'd think propelling the table via a screw in the spindle would do same thing.

[Saltfever]

Agree about the CG but . . . There is friction between the collar and the column. That friction is multiplied by the moment. Again, don't know the quality of your drill press and the amount of friction. Love your creativity. :-)

[rgsparber]

Agree about the CG but . . . There is friction between the collar and the column. That friction is multiplied by the moment. Again, don't know the quality of your drill press and the amount of friction. Love your creativity. :-)

The collar to column interface is not an issue when the table is raised at its center of gravity. But when lifted at the column, friction can be a killer. As an experiment, I cleaned the column and applied some way oil. The table moves easier and quieter when lifted at the column yet the clamp still works fine. It is interesting how way oil can do that.

Thanks,

Rick