Overhead Drill Press Design Ideas Sought

[Farrell]

I completed my first incarnation of my overhead drill press. Why do I say first incarnation? Because, after giving it a test run yesterday poking a few holes in an old pinblock, whereas I feel it is quite adequate, it is clearly not as good as it could be with a few modifications. The main deficiency is wobble in the system, 98% of which originates at the swivel.

One thing I really like about my overhead track is that it allows the drill press to travel the full width of the piano (and then some), and when not drilling in a piano, the press can travel over to its original bench and become an overhead bench drill press - simply by just pushing it over there (or floor drill press by just moving it over an open area of floor)!

I'm hoping one (or more) of the creative jig-building minds out there might care to provide some input to improve this drilling system. 

If interested in details and a challenge, read on. If not delete now! 

The basic features are listed below (listed as built - ceiling to drill press):

1) 10 feet of travel in the X (bass-to-treble) direction (via four-wheeled cart on steel rails)
2) About six inches of drill press height adjustment (unbolt, adjust, bolt - work intensive)
3) 360 degrees rotation (via nylon ball bearing seat swivel - sporting goods type)
4) 1 foot of travel in the Y (front-to-rear) direction (via 200-lb. rated drawer slide)
5) 10 degrees of rear tilt and 25 degrees of forward tilt
6) About 8 inches of drill press height adjustment (unlock, move head up/own steel pipe, lock)

#1 works great. No changes needed here. It is a 16" by 48" cart of 2x6s with four patio door (sliding glass type) steel wheels with ball bearings and small height adjustment. 

#2 is hard to adjust. It is nice and rigid - four steel 1" by 1/8" angle irons bolted to wooden platforms - just tough to adjust - need complete redesign of this for improved up-and-down gross adjustment - BUT, like I say it is not a problem, because it is nice and rigid. It would sure be a great improvement if a better gross up-and-down adjustment could be built.

#3 is where most of my wobble comes from. This swivel is very rigid when you hold it in your hand and try to wiggle it, but when you load it with 100 lbs. and give the weight some leverage, it has a lot of motion (the bearing are in about a 4" diameter circle). I have thought about these television turntables, but I am not sure they are any better. I have also thought of mounting a large (maybe 16" by 16") 1/4" thick FLAT steel plate on one side of my swivel and put several Teflon slides (with up/down adjustment) on the opposing surface near the perimeter of the steel plate. I think it would work, and would rob the present system of the leverage thing. Any better ideas? The best would be to find a large (between 12" and 18" or so) steel ball bearing turntable that works in a tension application - rather than a compression application.

#4 is a heavy-duty drawer slide. This works OK. It has a little bumpy movement in and out when the various sections start to move, and of course, the farther out you get it, the more wobble it has. I think if I re-do the swivel, I will re-do this also. I will remove the drawer slide and make a short steel track and a smaller cart with four patio door wheels. This system rolls so very easy and is absolutely rigid.

#5 Simple tilt. Works great. Can't imagine an improvement - except to make the unit smaller.

#6 This is simply moving the drill head up and down the original steel post on its base (mounted up-side-down of course). A drill press that cranks the head up-and-down would be nice - I wonder how stable (wobble-wise) they are?

Hey, if anyone comes up with a killer idea - I will include your name in the credits and give you a cut of the millions I make on this machine (if any). Well, at least I will acknowledge your creativity and helpfulness and buy you a beer/soda at the next convention!

Pictures available on request.

Thanks for any input anyone may have.

Terry Farrell