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Building a large vertical drill press

MPYOUNG33

Plastic
Joined
Sep 19, 2010
Location
Australia
I am the owner of a lumber company that specializes in supplying 2x6 studs with 1.5" holes drilled in them. The predrilled studs are used by my customers to run electrical wiring. Currently we use an old boring machine that is manually fed 3 boards at a time to make these holes. It takes 2 guys 30 minutes to drill and package a unit of 2x6s (189 boards). We drill about 90 units a week and this technique has become ineffficient.

I have been considering building a machine that will drill a unit of 2x6s in one pass. I have tested 3' self-feed auger bits with an electric hand drill that will drill through a row of 21 2x6s in one pass. The problem with this technique is that it is very hard to pull the auger back out. Since hand drilling is not an option I am considering building a machine to get the job done.

I would like to build a drill press prototype that will drill through 21 2x6s in one pass and eventually build a machine that will drill an entire unit of 2x6s (9 rows of 21 boards) that would require 9 drill heads. I have the basic concept in my head to do this but I'm hung up on the idea of how to feed the drill bit into the unit. A 3'X1.5" drill bit is very fragile so I have eliminated feeding hydraulically. I was thinking about a manual quill type feed or something similar.

Any thoughts on what kind of feed system to use? I am not an engineer and any input would be much appreciated. Thank you in advance.
 
Unit of drilled 2x6. pic showed up sideways for some reason.
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I wonder if you set it up assembly line style. Drilling one hole at a time could eliminate the difficulty of removing the auger, and let the feed system be simpler and smaller. I'm thinking a conveyor with a stop. limit switches activate pneumatics to feed the drill in and out, then let the board move along to be stacked. Loading the individual boards could be done by an operator. Automating that could get complicated.

Do you for-see any changes in the future to dimensions of the boards? I wouldn't want to make a custom machine if it would only work for certain jobs.
 
If you are confident the 3' long drills are the answer (that they won't wander too far despite random knots and wood density); perhaps a motor driven acme screw feed would be the most positive and adjustable feed in terms of .0XX" feed per drill revolution. The feed could be synched right to the lead of the auger center screw. The screws could be contrived with half nuts to release for quick retract; or merely rapid reverse. Chain sychronisation of screws. If you do go with 3' augers, it would probably be a good idea to have them feeding through bushings at the business end; to control whip, start on position, and track a little straighter.

smt
 
As you say, the auger is "self feeding" so all you need to do is to present the auger to the wood with enough force to start the screw, and then retract when finished. I'm thinking a pneumatic cylinder and control system could be simple and effective. Orient the cylinder to pull (less piston area) during drill and push (max piston area) during retract.

I would think that the unit of 2x6s would need to be clamped during drilling and that might be a bigger deal than the drilling head. Certainly, clamping the unit will facilitate safe drilling and easier retraction of the auger(s).

As already mentioned, it's not obvious to me that an efficient single (or a few) board process wouldn't be better than dealing with 21 boards or 9x21 boards in one hit. I defer to your experience but please consider it well. Consider a much simpler approach drilling single (or a few) boards at a time, run multiple lines to increase output. If one line develops a problem, the others are still working. If the 9x21 approach goes down, production stops.
 
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The long bit you tested -- was it a "ship auger" or something like a Milwaukee Hole-Hawg -- basically a roughing Forstner bit that's self-feeding. A ship auger has a fighting chance to stay straight for deep holes. The Hole-Hawg, not so much.

Turning the entire hole into chips seems like a waste of power, and possibly speed. Have you checked out the Lenox (?) hole saws? I think they're carbide-tipped, and just a few teeth. If they clear chips nicely, you might be able to run them pretty fast. Set up an auto-eject for the core and go to town.

With regard to throughput -- is there anywhere on the line the boards stop for a second or two? Like maybe trim to length? That may be the place to put the holecutter. Don't know sawmills very well -- you may have a setup where the material never stops until it gets to the forklift...

Chip
 
Here's the process:

First the boards are end trimmed. The video is a 2x10x14 being trimmed but it's the same process for a unit of 2x6.


After double end trimming to length the boards are bored 3 boards at a time.

 
I was thinking drill heads similar to these might work. Maybe mounting them directly to the saw could be an option. The holes are always centered 6.5" from the end of the board.

image.jpg
 
I would suggest doing it with motion control stuff .. like used on cnc retrofits.
Maybe a plc.
(No sw, liability, reliable, widely available, easily understood. Good for a simple process).

Benefits of using servo:
It will fault on any error or excess load.
This would maybe save the auger bit, and would certainly save any further damage from occurring in case of aufger breaking, nails, etc.

Relatively cheap, easy to do.

A big ballscrew is not expensive.
You can use a cheap rolled screw.

As you dont need great speed OR great accuracy, it just needs to be stout.

The programmed system can later be adjusted, very easily, for new augers, wood species, cutting speeds, process reliability etc.

It would be an easy box to build as a trial or proof of conecpt, for not much money.
Since speed is quite low, a cheap 400-750W servo would be plenty, with suitable gearing.

Std gearbox from surplus center, maybe.
I doubt any backlash or accuracy concerns apply.

Both PLCs and servos are reliable, proven and widely available.
Lots of people who know about them.
 
I would suggest doing it with motion control stuff .. like used on cnc retrofits.
Maybe a plc.
(No sw, liability, reliable, widely available, easily understood. Good for a simple process).

Benefits of using servo:
It will fault on any error or excess load.
This would maybe save the auger bit, and would certainly save any further damage from occurring in case of aufger breaking, nails, etc.

Relatively cheap, easy to do.

A big ballscrew is not expensive.
You can use a cheap rolled screw.

As you dont need great speed OR great accuracy, it just needs to be stout.

The programmed system can later be adjusted, very easily, for new augers, wood species, cutting speeds, process reliability etc.

It would be an easy box to build as a trial or proof of conecpt, for not much money.
Since speed is quite low, a cheap 400-750W servo would be plenty, with suitable gearing.

Std gearbox from surplus center, maybe.
I doubt any backlash or accuracy concerns apply.

Both PLCs and servos are reliable, proven and widely available.
Lots of people who know about them.


I like this idea but unfortunately it's way beyond my capabilities. The benefits of the servo listed are definitely issues that I had concern with in a direct drive system. The Auger bits are costly and breaking bits would lead back to inefficiency. Does anybody have suggestions of who would be able to build such a machine? I'm located in western Pennsylvania.
 
The way I see it is a stout box frame that can clamp the entire unit square in both directions and eliminate any spaces between the studs. Geometry of the auger bit tip needs a bit of R&D to keep it from being deflected by knots. Auger also needs replaceable cutting edges. It would help if you could get an air blast through the bit to. Drill bushing to start the bit straight and that bushing should be a sleeve inside a ball bearing, rotate with the bit without burning up if side loads happen. Sleeve needs to be high enough for chips to evacuate, and extraction needs to be considered. Maybe just an air blast to shoot them into a bin.
Feed works could be ball screw or hydraulic, but ball screw better. The carriage that travels in the Y direction across the unit needs to be wide enough to accommodate 2 drill heads on a single Z carriage. Heads can be offset in Z so that the first head drills maybe only 8-12 inches deep when the second bit goes through. This allows for a much stiffer bit for the shallow hole to keep the hole straight. Having a short pre drilled hole may even eliminate the need for a drill bushing all together.
 
After watching the end trimming video, I'd be looking at mounting the spindle motors to the top of that ibeam and doing it all in one shot, drilling and trimming (if possible). Maybe some air through the auger to clear the chips, strip shims between boards for different widths?
 
I have been considering building a machine that will drill a unit of 2x6s in one pass. I have tested 3' self-feed auger bits with an electric hand drill that will drill through a row of 21 2x6s in one pass. The problem with this technique is that it is very hard to pull the auger back out. Since hand drilling is not an option I am considering building a machine to get the job done.

Two thoughts that seem really basic, and maybe completely stupid also, but I've never personally tried drilling through 32 inches of wood:

You can't just reverse the drill to remove the bit from the wood pile?

What happens if you continue to feed the auger through, removing it from the hand drill and either pressing it through from above or pulling it through from below? From the video of your space, it doesn't look like elevating the process four feet is an obstacle at all.
 
Two thoughts that seem really basic, and maybe completely stupid also, but I've never personally tried drilling through 32 inches of wood:

You can't just reverse the drill to remove the bit from the wood pile?

What happens if you continue to feed the auger through, removing it from the hand drill and either pressing it through from above or pulling it through from below? From the video of your space, it doesn't look like elevating the process four feet is an obstacle at all.

The drill bit gets hung up in reverse probably from the tension of the unit being banded together and chips that are jammed in the hole. Pulling the bit off the chuck leaves the same issue. I'm hoping that machine power will be able to back the bits out of the holes.
 
The auger shown is often called a ship auger. They're fairly stiff, and stay reasonably straight. Don't know about 3' hole, though... When I've used them manually, they generate fairly large chips, not sawdust. The chips clear OK, but I tended to "peck drill" anyway. Never used them at high RPMs -- only hand-drill speeds of 1200 or less.

A vacuum might be the best way to clear chips.

Overall, the problem with doing many at a time is that you can screw up many at a time. But if they never get unbundled except for drilling, then it's wasted time.

Maybe you need fancier material handling, rather than fancier drilling. If you could push a stack of 6 out of the group, all the way across, then attack them with a multi-head rig, then push 'em back in. Retract rig, push out another 6, drill, repeat. Re-band and ship.

The board mover would be a hydraulic ram, driving a plate across the non-drilled end of the boards. The fixture on the drilled end would have a "window" thru which the boards to be drilled protrude. After drilling, boards are pushed back into place, window and drills move up to the next batch. (Or pallet moves down, whichever is easier.)

Have you considered drilling the trees first? :)

Chip
 
Have you tried punching?

You might try to find someone with an ironworker or other type of single shot punch and a diemaker whose willing to experiment with die geometry (may have to be hollow with w plug ejector)to experiement to see if you can do it.

I'd guess that this may be possible and it would be done one at a time at the cut to length station at the same time as the cuts are happening.

As far as die geometry - you might start with those industrial paper punches that punch through inches of paper at a time.

Below is some minor thinking on the effort:

https://answers.yahoo.com/question/index?qid=20071227085349AAKwibZ
 
I would observe that maybe you should consider drilling horizontally, doing two or three at a time just after the trim operation. This is not only a drilling problem, it is also a material handling problem. With a powered conveyor, a couple of air clamps, and an operator station to supervise two stock drill motors, you could drill and then stack the members for shipment. I would stay away from wood augers over 10" in length. Regards, Clark
 








 
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