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Technical => Roo Man's Room => Topic started by: beargeorge on May 19, 2016, 12:10:57 PM

Title: Altered chassis question
Post by: beargeorge on May 19, 2016, 12:10:57 PM
I am building an altered useing both  the Mark Wiliams blueprint and the SFI chassis specs10.2  for6.00 =7.49seconds e.t..My question is the rear uprights that connects the bottom rail to the shoulder hoop the one that connects the rearend to the chassis.SFI calls for inch and a quarterx0..58 M.W.AA calls for inch and 3 eights x 095,which one do you guys prefer.
Title: Re: Altered chassis question
Post by: Paul New on May 19, 2016, 12:37:13 PM
10.1E calls out 1.375 x .083 wall.
Title: Re: Altered chassis question
Post by: rooman on May 19, 2016, 01:49:23 PM
I use the 1.375 x .083 as a minimum.  The altered frame that I currently have on the jig has 1.5 x .095 pressed into an oval configuration the same as Force uses on his funny cars. In fact I had Norm at JFR oval the tubing for me.

Roo
Title: Re: Altered chassis question
Post by: beargeorge on May 19, 2016, 03:03:16 PM
Thank You, ROO
Title: Re: Altered chassis question
Post by: beargeorge on May 19, 2016, 03:07:22 PM
Thank You Paul
Title: Re: Altered chassis question
Post by: Van on May 19, 2016, 11:34:57 PM
The Altered chassis I built last year got 1 1/2 X 120 wall, because it was in stock & 095 wasn't. I had used the same material on my FED when I built it.   058 never
Title: Re: Altered chassis question
Post by: beargeorge on May 20, 2016, 09:51:18 AM
All set, i was able to get the 1.375x095 cm from Shapiro Steel,i still dont understand SFI calling for 1.250xo58.Thanks everyone for your help.
Title: Re: Altered chassis question
Post by: janjon on May 23, 2016, 07:18:49 PM
Roo, I'm curious how it was ovalized. I recently had to duplicate a semi-streamline shape in some aluminium tubing for pylons for a FM antenna array for MD-500 helicopters; I made a die in an wire EDM that formed a tube into the desired shape with the help of a hydraulic press, is that how  JFR does it? Any pics available?
Title: Re: Altered chassis question
Post by: Paul New on May 23, 2016, 08:13:33 PM
I have made round moly tubing oval in my press. I use spacers to prevent the tubing from collapsing in the center whenever I do this I do a couple of samples to figure out the correct thickness to press the moly to
Title: Re: Altered chassis question
Post by: rooman on May 24, 2016, 04:58:57 AM
JFR have a flat die set up for their Trumpf CNC press brake and simply squeeze it in that. I presume that they have programmed the press stroke to end up with the desired result which is a tube with a 1.5" minor axis to match the frame rail diameter. The flat surface on the sides is only about 5/8" wide.

Roo 
Title: Re: Altered chassis question
Post by: dreracecar on May 24, 2016, 08:18:23 AM
Don Long started doing that many years ago for wing struts on alc. dragsters.  Since the tubing was thinner than RE uprites, took a lot of testing on the material. Alloy comp.  was a player (it needed % copper) and he dial indicated (because the tubing is not perfect) to index it in the press. I still have some of the rejected pieces(fractures) that I use to make decor tables and such