break line fittings / section 5.22

I am having trouble or doubts about the fittings I produced. Section 5.22 explains what to do and I also have the homebuilt help DVD#s for the RV-12.


- step 1 in section 5.22 asks for drilling the tube with #29 drill bit. This bit was not in the tool list so I did not order one. Now the nearest #29 drill bit is 5000miles away. In all videos, there is no drilling. What to do?

- The brass insert is very, very hard to get into the tube at the 45deg elbow version (sleave with nut).

- At the 90deg assemblies the brass insert moves with reasonable force into the tube when properly heated. Problem here is to keep the sleave at 1/8" when pushing.

- An other problem with the 90deg version is the sleave which in some cases can be moved by hand on the tube.


I fear my fittings will never be thigt. Any advise would be helpful.

Just did this

I just did this, and it doesnt appear in my blog yet. I did the first one without drilling and it was nearly impossible to insert the sleeve; i got it but it was hard.
The others were easier with the drill. The drill doesnt take out much because the tubing conforms around it. Also, I had to put the ball on first and then insert the sleeve. If I put the sleeve on first, I had to use the fitting to help slide the ball down to the proper position after boiling. Good luck.

#29 is .136 inches which converts to 3.45 mm. I?m almost positive that a standard 3.5 mm drill bit works in there. You can test and if find the fit is loose to seal then use a 3.4 mm instead. I?m sure 3.4 mm is easily available at a local industrial supply store.

Just me

Nedimbek said:

#29 is .136 inches which converts to 3.45 mm. I?m almost positive that a standard 3.5 mm drill bit works in there. You can test and if find the fit is loose to seal then use a 3.4 mm instead. I?m sure 3.4 mm is easily available at a local industrial supply store.

Click to expand...

I think the 3.5 mm will be fine, jmho. This isnt a precision joint, but needs to be good enough to cinch down when installed. I think the most important part is to get the 1/8 ? spacing of the ball so it seals properly, and the brass sleeve inside so it doesnt collapse the tube.