# Cross drilling tubes

Discussion in 'Workshop Tips and Secrets / Tools' started by paulgy80, May 5, 2008.

1. May 5, 2008

### paulgy80

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Dear All

What tips do you have for accurate tube cross drilling, loose tube then a Vee block on a drill press but what other methods and or jigs and fixtures have you come across to get the right end result.

Would love to have your input.

Kind regards

Paul

2. May 5, 2008

### Greg Mueller

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I saw a gizmo at a fair once. It hooked on the front of a hand drill. It had two pins that stuck out parallel to the drill, one to the right and one to the left of the drill. The idea was that you straddled the tube with the pins and then rotated the gizmo until the pins came to rest on the (opposite) sides of the tube. That put the drill right in the center of the tube. I thought it was pretty clever.

In the shop I measure the radius of the tube out from the fixed jaw of the vise and drill. It helps to have an edge finder

3. May 5, 2008

### steveair2

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Pual,

I can't seem to force my Harbor Frieight drill press to drill a straight hole.
I'm in the process of making a steel jig with bushings on both sides to guide the drill bit straight through my spar.
I'll post pictures as soon as I get them.

Steve

4. May 6, 2008

### Greg Mueller

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Are you drilling with a center drill first?

5. May 6, 2008

### paulgy80

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Hi Greg

I am cross drilling 1" aluminium tube with 3/16" and 1/4" holes, stuff on the drill press is not too bad but when it has to be drilled on the airframe it presents problems, the other problem is do you go straight through or do you drill either side???

Paul

6. May 6, 2008

### Midniteoyl

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Personally I'd go straight through to keep the alignment..

There are drill guides available for hand drills... http://www.grainger.com/Grainger/items/3ZH18 is one place.

As for the bench drill, using a V block is prolly the easiest. I like to drill a hole in the bottom of the V for aligning the bit. Just center the block with the bit in the hole and tighten the holding screws..

Last edited: May 6, 2008
7. May 6, 2008

### Greg Mueller

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Unless you have a fancy setup with stops and what not, I'd go straight thru

It would help to use "screw machine drills" they are short drills on the order of half the length of "jobber" drills. There's less length to "bend" on the short drills. You can get them with "split points" which helps to stop "walking".

Last edited: May 6, 2008
8. May 6, 2008

### bwainfan

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Lockwood Aviation sells a tube drilling jig that works quite well for 3/16 and 1/4 inch holes. Its a V-block wiht a built-in grill guide.

Barnaby

9. May 29, 2008

### Larry Lyons

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If you go to the EAA members site and look at their new shop tips videos you will see how to make a nice simple jig. Larry
PS: just saw another thread that has the link to the videos!

Last edited: May 29, 2008
10. May 30, 2008

### bundysax

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Center punch, center punch center punch !!!!

11. May 30, 2008

### bmcj

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I saw a big-a laser on the nose of an Air Force 747 that could probably punch a straight hole through your tube. Of course, you'll have to pick up what's left of your tube a couple of states away!

Bruce

12. Apr 7, 2009

### ekimneirbo

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If you can buy a small machinists V block with the U shaped clamp, they can be made to center your drilled hole thru tubing. The V is placed against the tube, and the clamp is tighted slightly to hold it secure. Two clamps are even better.
Prior to using the clamp, put it in your drill press and drill a small hole thru the center of the V. You may want to offset the hole slightly toward one end to allow room for the clamp to grip the slots on the sides of the block. That hole will be the guide for drill bit each time you need a hole. You use the same size drill you used to make the hole. Once you have this small pilot hole thru the tube,remove the V block and drill the finished hole. Don't make the guide hole too small.
The V blocks can be bought from Ebay but you may have to watch for an inexpensive set. $15/$25 should get you one or two of them. They are only about an
inch and a half long.

13. May 26, 2009

### lr27

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I found a combined hand drill/jig setup in a used tool store for doing this. At least I think that's where I found it. So such a combination was manufactured at least once. Have moved too many times since then, not sure current location!

14. Jun 9, 2009

### base363

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For anyone who built model Estes rockets as a kid, remember how you marked the tube in order to attach the fins?

You wrap a paper template around the tube, that has lines spaced to evenly space the fins.

This actually works pretty well for marking push pull tubes to.

I will then just drill from one side, as you can be assured that the other side will be 180 degrees out.

Colin
A/P IA
www.jumprunenterprises.com