Aluminum bolts.

[John Harmon]

I was unhappy with the cap screws I bought to hold the covers on my unused cylinders. They looked good enough, but were just too heavy. After all the steps I've taken taken to save weight, those cap screws didn't make any sense to me. After entertaining several ideas to eliminate those cap screws, I decided to make some aluminum bolts. I am happy with the results. The cap screw in the foreground of this picture weighs 22 grams, the bolts I made each weigh 8 grams. Using the aluminum bolts saves me 1/4 lb over using the cap screws.

[Steve]

Nice weight reduction - I'm going to look closely at the Carbon Cub engine installation when at Oshkosh - it is rumored that they are gluing .025 alum on assy. case openings...

I used Titanium studs on the bell housing casting used with the UltraVair conversion...

[John Harmon]

Thanks Steve, I considered epoxy to hold the covers on. My biggest concern was positive case pressure working them lose. I'm happy with my first attempt at making bolts.

[Tom H]

John, the picture, added to your explanation, suggests that you made the bolts from melting down beer cans.  Awesome!

[weasel]

Those homebrew bolts are definitely cool. I saw this http://www.mcmaster.com/#standard-cap-screws/=s7dmcy
The other day and was looking for places to use them.

[John Harmon]

Thanks for the link, I learned that I made screws not bolts.

[Steve]

Thanks for the link, I learned that I made screws not bolts.

John: I didn't find Metric Alum cap screws at that Link?  I think you may have a product line there... I did note that in available sizes the material was 2024 (T4), is that stuff easy to come by?
Steve

[John Harmon]

I ordered 0.625 hex stock from online metals. I used 6061 T6 since I was going for light. They are used in a low stress application so I wasn't too worried about super strength. I looked and they do also sell 2024 in hex. To make them, I cut the stock down to the major diameter and die cut the threads.

[Steve]

I ordered 0.625 hex stock from online metals. I used 6061 T6 since I was going for light. They are used in a low stress application so I wasn't too worried about super strength. I looked and they do also sell 2024 in hex. To make them, I cut the stock down to the major diameter and die cut the threads.

The 6061 is far better than 2024 for corrosion resistance - the 2024 might have a bad reaction in the mag case...