An arch punch, empty brass, an old inner tube and fatbobs finally mounted.
I needed some rubber washers to mount the gas tank on the trike, but the hardware store didn’t have the right size. I decided to make some myself. First I found an old inner tube that I had stashed behind the workbench, just for this sort of thing. Then I got an arch punch that I had found at a yardsale. I quickly punched out the ODs.
The ID needs to fit a 5/26″ bolt, but I don’t have that size punch. However, when at a recycling center I noticed some empty cartridges in their scrap brass bin. I bought a selection at scap price (and got the bucket for free).
5/16″ is .3125″, so 8 mm at .315″ is a nice fit. This is the cartridge head of an 8mm mauser (or 8x57mm) that I found. If you want you can sharpen the end, this also allows you to vary the size slightly, you can sharpen the inside (with a small round file or chamfer tool) for more clearance or the outside for less. So what cartridges should you look for? Well, obviously 6mm, 7mm, 8mm, 9mm and 10 mm will work for the corresponding metric sizes. An inside sharpened 17 caliber should work for a #8 screw and outside sharpened it should work for #10. The new 204 ruger might work for 5mm or #12. 25 caliber (25-06, 257 roberts, etc) or 6.5 mm for 1/4″ bolt. 8mm for 5/16″. 375 caliber or 9.3 mm for 3/8″, 44 or 45 caliber for 7/16″. And of course, 50 caliber for 1/2″. Good luck finding a 600 Nitro Express for 5/8″. Also, some cheap military ammo uses steel cases, obviously these will be sturdier.
I didn’t bother to sharpen the end and it worked fine.
Here are the rubber washers in place on the top tank mount, trapped between stainless washers. I have previously shown the bottom mount.
And here are the fat bobs finally mounted. The dash and filler are just sitting on top, they’re next.
