simple ideas for a dowel center drilling jig

[scorrpio]

Woodworking fails, plumbing to the rescue!!!

You need:

1. a Nipple. Get a 3/4" nipple, about 4" long. Steel is fine, but brass is better - smoother inside walls.

2. a Bell Reducer. I beieve you want a 3/4x1/4 one.

3. a Coupler. (A 1/4" nipple about 1" - 2" long will work, too) if you own any pneumatics, you should have a few of these rattling around.

Now, you assemble all this togeather. (pipe dope/teflon tape optional )
Dowel goes into the 3/4" nipple, drill bit goes into the 1/4" coupler. Drill as deep as you can, repeat from other end of the dowel.

[pierhogunn]

I really don't need dead-honest center, just the closer the better, I want as much material inbetween the screws that hold the dowel in place inside the Al tubing as possible, so that the points of the screws don't abrade the bungee cord so badly

[Ken Massingale]

Woodworking fails, plumbing to the rescue!!!

You need:

1. a Nipple. Get a 3/4" nipple, about 4" long. Steel is fine, but brass is better - smoother inside walls.

2. a Bell Reducer. I beieve you want a 3/4x1/4 one.

3. a Coupler. (A 1/4" nipple about 1" - 2" long will work, too) if you own any pneumatics, you should have a few of these rattling around.

Now, you assemble all this togeather. (pipe dope/teflon tape optional )
Dowel goes into the 3/4" nipple, drill bit goes into the 1/4" coupler. Drill as deep as you can, repeat from other end of the dowel.

Excellent idea, IF the dowels are 3/4". I find most dowels are less or more than the indicated size.
I'm still keeping this for future use, tho, scorrpio.

[scorrpio]

Dowel smaller than 3/4" - wrap some masking tape around it till it's snug.

Dowel larger than 3/4" - you'll need to move up to 1" nipple and then do the masking tape.

[pierhogunn]

friggin awesome, this will hold the drill bit, and I can build this mo-fo at home, w/out a trip to my inlaws to borrow the DP

cool

[pierhogunn]

is there a difference between a 1/4 inch nipple and that 1/4 inch pneumatic connector?

[scorrpio]

For your purpose - not really. You need 1/4" inner diameter and regular 1/4" NPT male thread. For me, the main difference would be that a 1/4" nipple, I'd have to buy.

[LarryG]

For this lash-up to work at all, you're going to have to use a pipe nipple. All the couplers I have, acquired from a variety of sources over the years, are 1/4" nominal size but the actual hole is smaller. It might be 3/16", but no larger, I don't think.

I'd also question whether a coupler would be long enough to effectively guide the bit for a 6" long hole. If the inside is stepped like the outside, there's not much meat there to hold the bit straight (even if the hole were large enough).

[pierhogunn]

I did assemble this jig, and there is way too much play in the pipe fittings, so I am going back to the 4x4 block on the Drill press.

Thanks for all of the great ideas though