Fuel Cap Rehab

[CharlesHuddleston]

4 minutes ago, Yetti said:

Well done.   Since you are having so much fun why not upgrade to stainless?  (as they probably should have been in the first place)   Seems like if you could find the right size stainless bolt it would just be a cut the head off, cut down, rethread, drill some holes.  Stainless is a bit more of a challenge to turn.

Stainless was my first thought. That way, it would be one and done! I have been reading about turning it on the lathe, and will try to see if I can come up with a piece to try it on. I also considered just using a piece of aluminum bar, but wondered if it would be strong enough to last.

[Hank]

5 minutes ago, CharlesHuddleston said:

Stainless was my first thought. That way, it would be one and done! I have been reading about turning it on the lathe, and will try to see if I can come up with a piece to try it on. I also considered just using a piece of aluminum bar, but wondered if it would be strong enough to last.

Stainless comes in two flavors:  300-series is nonmagnetic; 400-series is magnetic and can be hardened. Both are somewhat more "sticky" than regular carbon steel and must be cut slower, with shallower cuts.

Good luck with the next one!

[carusoam]

Stainless work hardens while you are cutting it... you can probably read up a few hints on how to machine it Best... from tools, speeds and oils to use... or not use...

nice looking bits and pieces, Charles. Thanks for sharing the pics.

we have a couple of parts resources around here if you need a plan B...

Best regards,

-a-

[Yetti]

5 hours ago, CharlesHuddleston said:

. I also considered just using a piece of aluminum bar, but wondered if it would be strong enough to last.

So if you think about it the other wear points.  The lever and the places the lever hit down in the cap are alum.  The issue is the metal split pin for the lever.  I am guessing that is what is used, have not looked.  I would think it would wear the big hole pretty fast.   Now if you want to play with a light knurl you might be able to replace the split pin with an alum pin with interference fits and all parts are alum wearing on alum.  Realizing that AR15s are alum slides running on alum slides. There is some elasticity that the steel has over alum, but a spring is involved so that should not matter.  Bolts stretch when you tighten them that is what keeps them tight. AR 15 lowers use 7075 alum

Not an gineer, just been fixing things all my life.

[N201MKTurbo]

Shaw had access to all the materials you are mentioning, but choose to use the materials they did for good reason, I’m sure. They perfected the design over decades. You guys think you can make it better with a few minuets thought. 

You don’t know exactly what grade of steel or aluminum was used, what heat treating and plating was used or why. 

If you are going to make an owner produced part, you should stick as closely to the original material as possible. I don’t think they choose the materials they did to save a few cents.

[RLCarter]

11 minutes ago, N201MKTurbo said:

If you are going to make an owner produced part, you should stick as closely to the original material as possible. I don’t think they choose the materials they did to save a few cents.

I agree, my philosophy is the only evidence of a fabricated part should be the logbook entry. Most of us spend a lot of time either cleaning or tweaking this or that on our planes, a little shot of Tri-Flo periodically on the shaft of the fuel cap keeps things nice a smooth, having the tension set correctly keeps the wear to a minimum 

 

 

[Bartman]

12 hours ago, RLCarter said:

I agree, my philosophy is the only evidence of a fabricated part should be the logbook entry. Most of us spend a lot of time either cleaning or tweaking this or that on our planes, a little shot of Tri-Flo periodically on the shaft of the fuel cap keeps things nice a smooth, having the tension set correctly keeps the wear to a minimum 

 

 

Good point. After install of my most recent o-rings the caps were too tight. At first I thought this was good and would prevent leaks when I was away from home on the ramp, but after a couple of fill ups I had the cap adjusted. No leaks and optimal effort not just to close, but to open too. 

[Bartman]

I gotta give props to Charles for taking the initiative and trying something new. Maybe he will be even more successful than the Klixon switch covers ?

Heres to you Charles !

[Yetti]

On 9/5/2018 at 7:24 AM, N201MKTurbo said:

Shaw had access to all the materials you are mentioning, but choose to use the materials they did for good reason, I’m sure. They perfected the design over decades. You guys think you can make it better with a few minuets thought. 

You don’t know exactly what grade of steel or aluminum was used, what heat treating and plating was used or why. 

If you are going to make an owner produced part, you should stick as closely to the original material as possible. I don’t think they choose the materials they did to save a few cents.

I agree with you.

I put this one in the "wings fall off" catagory so only A&P/ Engineers  should take on the task.