Drilling deep 1/2" holes?

[lukaslouw]

CNC newbie here. I am finally taking the plunge to make a gantry style CNC router, and having only typical home owner's tools, it needs to be simple and easy. I've come up with a concept that should work well, but it hinges on one little obstacle that I need to overcome:

I'll need to drill/bore 1/2" diameter holes through 6" of material, being 4" Delrin and 2 1" thick aluminum bar, all clamped together. If I can pull this off, final alignment with assembly will be easier.

Unfortunately my Delta bench drill press only has about 2" worth of stroke, so that won't work.

I have visons of taking the head off the drill press, or use my plunge router motor, clamping it sideways in a jig, and making a rube goldberg guide to advance the material onto the drill bit.

Any suggestions will be much appreciated

Lukas

[ger21]

Clamp the aluminum together (or use double face tape) and drill those together. Then use one clamped to the Delrin to get that hole started. Remove the aluminum and drill as deep as you can. Then hand drill the remaning depth. Hopefully the first 2 inches is enough to guide it the rest of the way.

[Ken_Shea]

You could provide a fixture/stop on the drill press table to position each piece individually, drill, then mark them for orientation so they maintain the same relationship to each other as when drilled.

[miljnor]

just use the drill press with ger21 sugestion. BUT leave it in the drill press move the adjustable table up (I assume it has one) and use the previously drill 2" depth to line the next 2" drill and go for it. If your drill is long enough you should have to do this 2 times and your done. Of course this isn't the most accurate way to go but hey, you goto work with what you got .

[lukaslouw]

This is probably what I need, a drill press with rack and pinion table feed. Does anyone have any experience with Wilton brand power tools?

Thanks,
Lukas

http://www.amazon.com/exec/obidos/tg...&s=hi&n=552784

[miljnor]

my dad had one in his garage. It was a nicer one than the harbor freight version. Its probably on the high end of the import drill presses.

Depending on the needed accuracy of your hole you could probably just use the type of drill press without the rack and pinion (although the rack would make it alot easier). I've line holes up after moving the pusher type before. just depends on the kind of accuracy you want.

[lukaslouw]

Originally Posted by miljnor my dad had one in his garage. It was a nicer one than the harbor freight version. Its probably on the high end of the import drill presses. Depending on the needed accuracy of your hole you could probably just use the type of drill press without the rack and pinion (although the rack would make it alot easier). I've line holes up after moving the pusher type before. just depends on the kind of accuracy you want.

Yes, most drill presses don't have teh spindle stroke for deep holes and the question with these rack an pinion types is how much horizontal slop there is in the rack and pinion gear.....

Lukas

[JavaDog]

Originally Posted by lukaslouw Yes, most drill presses don't have teh spindle stroke for deep holes and the question with these rack an pinion types is how much horizontal slop there is in the rack and pinion gear..... Lukas

My Delta is almost identical to the one pictured (and only $10 more...) and you lock the table down once you put it where you want it. Once locked down, I haven't noticed any horiz/vert movement when pushing through alum.

[ger21]

If you're talking about the horizontal play while cranking up and down, I can move my 16" Delta at least an inch each way while not locked down. So you can assume it won't hold poition while raising or lowering. But if the work is clamped to the table, it should be fairly easy to line it up.

[rustyolddo]

One other point. You didn't say what the purpose of the holes were. If they are going to slide on rails, you my want to consider drilling under .5" dia and reaming the holes to size. If they are just for bolts, then you'll be fine.

[demanske]

I think if you use an extended length drill bit, you could try the following as an alternative method (and it should be dead safe to boot, you are scaring me with all the router talk!):
1. chuck it up as far as it will go
2. drill down 2"
3. without retracting- stop the drill press
4. lock your quill
5. loosen the chuck- watch out, as the drill will get hot.
6. unlock your quill
7. tighten chuck at the top of the quill stroke
8. drill down 2 more inches
9. repeat until you are through

I would clamp both bits of aluminum bar to the top, to become an ad hoc guide bushing for the rest of the operation.

You may need to hack the extended bit to an appropriate length, depending on your drill press.