Roll Bar bases very tight fit.

I match drilled the roll bar while it was mounted on the fuselage. The only way I could get the roll bar on to the bases was to knock them in with a hammer while the roll bar on the bench. I had to remove the clecos to get the bases out of the roll bar.

I'm afraid that after I prime the parts and rivet them together, the fit will be so tight that I may not be able to get them apart - which I will need to do after I match drill the roll bar to the bases.

Any body else have this problem? What was your solution?

Boelube

Rick,

The roll bar base is a tight fit to be sure ? I made sure the inside edges of the roll bar were very smooth. I also primed my parts as well and if memory serves me correctly, I used a very thin coating of liquid Boelube on the bases prior to inserting them into the roll bar.

I had the same misgivings, but in the end it all went together well. Yes, it is a really tight fit, but once you get the bases bolted down, the fully assembled roll bar can be lowered onto them a tiny bit at a time, alternating left right left right as you go. It takes a little patience but surprisingly little actual force. No hammer was required. It would be best to keep the primer build up to the absolute minimum, though.

I remember a very tight fit as well. If I recall correctly, I removed a few pop rivets to relieve some of the stress, then reinstalled them later.

Rick_A said:

I match drilled the roll bar while it was mounted on the fuselage...What was your solution?

Click to expand...

I match drilled and installed the plates to the roll bar off the fuselage. Then bolted the assembly to the fuselage.

Jeff

Sounds like Boelube and leaving out a few rivets will be my approach.

I primed the parts today, so I will rivet up the roll bar and match drill to the roll bar bases tomorrow - then hope I get everything apart for deburring.

Rick_A said:

I primed the parts today, so I will rivet up the roll bar and match drill to the roll bar bases tomorrow - then hope I get everything apart for deburring.

Click to expand...

Rick... My best recollection is that I installed the roll bar bases into the roll bar using only clecoes, matched drilled, deburred, reinstalled the roll bar bases and then riveted up the roll bar.

Hope that better explains what i did.

Jeff

I also forgot to mention in my previous post I did the same thing Jeff did as well in that I Clecoed the roll base on the roll bar assembly then mounted the assembly on the fuselage.

Here is a link to the Blog with a detailed description on what I did hope you find it useful.

http://www.dogaviation.com/2014/02/roll-bar-assembly-mounted.html

Happy building,

Boelube worked like a charm

Since I had read a few posts about the roll bar not fitting correctly when match drill and assembled on the bench, I decided to match drill and rivet with the roll bar mounted on the plane.

The "tight fit" problem occurred when the parts were cleco'd together and I tried to install the roll bar on the bases. Once I got the roll bar installed, I match drilled the assembly while it was mounted on the fuselage.

Prior to priming the interior of the roll bar, I put a slight chamfer on the ends of the roll bar straps - enough to make it easier to get the first 1/8" of the assembly started. Today, after clecoing everything back together and putting some Boelube on the bases, the roll bar went back on with out a problem.

In order to make sure I locked the alignment of the roll bar parts in place, I installed about 75% of the rivets with the roll bar on the fuselage. I then match drilling the bottom 12 holes on each side and removed the roll bar. I came off without to much effort, so I'm very pleased with the fit.

John, You and I must think alike. I just finished looking at your web page and I did it almost exactly the way you did it.

I am also painting as I go. I did the interior of the roll bar with Azko but tomorrow I'm painting the exterior of the roll bar parts with my interior Jetflex gray - pretty close to the same color you are using.

I think I'll be checking you build log in the future.