Tubing frustrations!

[Stew]

So lanyard tubing......

It occupies too much of my time.

I would hope that I drill an 8mm hole and with only a little bit of effort get an 8mm bit of tubing in place. If it's a tight squeeze, thin tubing collapses and deforms where solid bar can be encouraged through. I have got decent drill bits so my holes are the right size.
Material like brass is a bit more precise than some of the stainless I've got hold of.

How do folks deal with it or what am I doing wrong?

Giving the tubing a bit of a rub round with sandpaper can work but not always ok to get it even and without going too far to then get gaps and also parallel.
Sometimes I'll give the drilled hole a spin with some sandpaper to open it up a touch but even that is a bit hit and miss.

I would like some precision!!

I'm tempted to buy some drill bits 00.1mm bigger.

Or should I get the metal lathe up and running to thin sections of tubing down?

It really shouldn't be as hard as it can be!

 

[mike miller]

We use f drill for 1/4 inch which is .003 larger than tube.
Long time I would chuck a short section of tube in drill press. Spin it and smooth some off with a flat file to get it smaller and also had some better grabbing surface for the epoxy.

 

[Duncan Tipton]

I use a F drill for 1/4 as well. An F drill is .257 or .0035 per side larger than 1/4. .007 thou clearance makes pins and tubing fit easily, and leaves room for epoxy. Get a set of drill bits have letter drills, number drill, and fractions as well. With all those choices, it's pretty easy to find a bit that is a few thou bigger that your tube.

Do you have a lathe? I make all my tubes from solid stock with mine, just takes a minute and I get precision!

good luck, Duncan

 

[Doug Lester]

If you are using the same nominal size bit as the tubing or pin that you want to put in it will be undersized. It doesn't seem it should be that way but it is. For a pin or tubing with a 1/4" outside diameter I used to use a 6.4mm bit which is just a bit larger. What I do now is that I take a bur with my rotary tool and run it around the inside of the hole lightly until the pin just slips in. Remember to grind away a little and check a lot until you are happy with the fit. Actually it doesn't take all that much grinding.

Doug

 

[Fellhoelter]

Tubing is neither round, nor precise!

 

[HHH Knives]

Tubing is neither round, nor precise!

We need a like button. this is truth!!

Agreed oversize drill should solve your problem.

 

[EdCaffreyMS]

Amen to Brian's comment! I've heard too many stories from my buddy Steve on having to send back entire shipments of Ti tubing because it was so far out it couldn't be used for his puposes. Also, ya gotta remember that nothing of fractional size will fit in the same sized hole (1/4" tubing/pin will not fit into a 1/4" hole, because both are .250"....roughly) so holes always need to be SLIGHTLY larger.

 

[Fellhoelter]

Amen to Brian's comment! I've heard too many stories from my buddy Steve on having to send back entire shipments of Ti tubing because it was so far out it couldn't be used for his purposes. Also, ya gotta remember that nothing of fractional size will fit in the same sized hole (1/4" tubing/pin will not fit into a 1/4" hole, because both are .250"....roughly) so holes always need to be SLIGHTLY larger.

And I pay BIG bucks for that tubing Ed.
BIG bucks...
Buy a new truck, or a batch of tubing kind of money...

 

[brian7498]

Yep what they said! Brain Fellhoelter hit the nail on the head too, ive gotten pretty good results with swedgelock tubing, but even then... i usually just chase the hole with a ream.
Good luck buddy!