What's your best method for putting small holes in a body tube?

[BRS Hobbies]

What's your best method for putting small holes in a payload bay for an altimeter?

 

[Eric]

Drill a slightly smaller hole. Soak the hole with CA glue. Then drilled the hole out to the size you want after ca dries. Leaves a nice clean edge. I do the same procedure with cardboard, phenolic and fiberglass.

 

[BABAR]

This works for cardboard if the reach is long enough from the tube edge.

 

[neil_w]

For very small holes in very small payload compartments (I have several like this) I've been using a pin, and then enlarge the hole with a series of larger nails as necessary.

 

[dr wogz]

Use a backer of some sort to prevent tear out / "push in" A curved block is ideal..

Use a 'Brad' (spur) drill bit. usually for wood, that have little spurs on the ends of the flutes; to cut the hole from the outside in, to minimize tear-out

 

[BEC]

I use the sharpened end of a 3/32 inch or 1/8 inch brass tube. I have epoxied a couple of three inch lengths into spent 13mm motors to serve as handles. This creates a small version of the old K&S hole cutters.

Sharpen before each use with an X-acto knife and if possible back the location up with a stage coupler inside for support.

 

[jqavins]

Drill a slightly smaller hole. Soak the hole with CA glue. Then drilled the hole out to the size you want after ca dries. Leaves a nice clean edge. I do the same procedure with cardboard, phenolic and fiberglass.

I'm surprised fiberglass needs the CA. And, for that matter, that is absorbs any.

For backup, if you happen to be drilling, punching, cutting, or poking through a BT-5, 20, or 50, or a 29 mm MMT size tube, then use a spent casing for internal support. It's good and sturdy, and also disposable.

 

[roc_boy]

I use the sharpened end of a 3/32 inch or 1/8 inch brass tube. I have epoxied a couple of three inch lengths into spent 13mm motors to serve as handles. This creates a small version of the old K&S hole cutters.

Sharpen before each use with an X-acto knife and if possible back the location up with a stage coupler inside for support.

Sharpened brass tubing is what I use for cardboard tubes too, but I use a flat file to carefully sharpen the edge of one end. Apply pressure and slightly rotate back & forth. To get the cleanest cut, I'll cut part way through, resharpen, then cut some more. Prob resharpen 3 or 4 times - the brass is thin and soft. You do have to back-up the back side of the tube with something to support the tube so you can apply enough pressure to cut. Quicker & easier ways, but this works great if you're picky [emoji6]

 

[BRS Hobbies]

What is the procedure for sharpening the end of the brass tube?

 

[roc_boy]

By hand, I just use a flat file, rotating the brass tube in one hand while filing.

The brass is soft and thin walled, so you just can't get too fancy with the cutting edge you're creating. Just sharpen the outside of the tube at one end, holding the file at probably 30-45 degree angle to the tube. A shallower angle is "sharper", but the brass is so thin & soft that the cutting edge just doesn't hold up long enough to work. You just want the end of tube sharp as you can get it to cut the cardboard tube.

I've seen K&S small stainless steel tubing at the local hobby shop. If you found the diameter you need, it would probably make a better cutting tool. A little more work to file, but you could probably get a sharper, more durable cutting edge on it.

 

[jqavins]

I suggest also filing the inside with a curved fine toothed needle file, or even with some fine emery paper wrapped onto a small rod. Keep it flat against the inside wall so you've still got a one-sided bevel, and only stroke inward. This is to remove inside burrs, including nearly microscopic burrs you don't see. That will probably make your edge considerably sharper.

Also, if you've got access to a drill press I'd suggest using it, no matter whether fir drilling for butting with a sharpened tube. I know that for drilling you'll get better results because of the steady position and steady pressure. I suspect you may get the same benefit with the sharpened tube, suspect strongly enough that I think it's worth a try.