Any experiene w/ this C-frame dimpler mod?

jcfields · #1 12-09-2008, 10:26 AM

A fellow builder suggested to me a modifcation to the C-frame dimpler mod that is supposed to essentially give it the functionality of the DRDT dimpler. Anyone out there tried this? If so, how well does it work? Is it worth my time to do it? Thanks.

Vlad · #2 12-09-2008, 10:34 AM

The frame will flex and will flex a lot, preventing consistent dimpling, especially on thicker skins. Check the archive there was Paul Merems engineering proof somewhere. I welded DRDT frame myself. First frame I discarded because it was flexing though I used the strongest (heaviest) pipes I could get. It didn't work. The second one I welded per his drawings and it standed all dimpling without a hitch. Do not modify that C-frame, get the right one.

jcfields · #3 12-09-2008, 10:48 AM

Thanks, Vlad. "Unfortunately", I had a chance to use danielhv's DRDT before I ever used my crappy C-frame. There's just no comparison. Now I want the DRDT; it's so much faster (and way less noiser for when the kids are sleeping). Guess I'll have to spring for one of those too. Wife's gonna love hearing that...

llavalle · #4 12-09-2008, 10:50 AM

I agree with Vlad. The DRDT-2 plans specify tubes of 3"x6", 3/16" thick. If you look at the drdt2 website, there is a finite element analysis of it's design. You'll see that using the specified material, you'll get as much as .030" of bending...

That's using 3x6x3/16!

A regular c-frame upper section is designed to guide the pin, not hold it!