SilhouEtsy: Homemade Tube Chassis RX-7 Racecar (and supporting stuff)

The Something Awful Forums > Discussion > Automotive Insanity > SilhouEtsy: Homemade Tube Chassis RX-7 Racecar (and supporting stuff)

casque: Mar 17, 2009

mekilljoydammit posted:

loving Mk15... but the latest changes do a lot for stiffness at a total penalty of like, 3 pounds. And no, it doesn't require any changes to the stuff I already have welded.

Going to work on front suspension parts next because it's a fun change of pace. Oh, and plasma cut stuff for rear end will be done Real Soon Now.

What sort of steel are you using for this chassis? I'm curious about the type, OD and wall thickness for something like this.

# ¿ Oct 7, 2021 18:12

Adbot: ADBOT LOVES YOU

# ¿ May 22, 2024 16:14

casque: Mar 17, 2009

mekilljoydammit posted:

So the safety structure is required to be minimum of 1.5x0.095" DOM mild steel. So it is. The rest is 1.5x0.065.

Thanks! Is there a reason cromoly, like 4130, isn't used?

Also, what filler are you using, something like ER70S-2?

# ¿ Oct 12, 2021 19:08

casque: Mar 17, 2009

mekilljoydammit posted:

Basically I'm stiffness limited not strength limited - 4130 normalized would get a touch more ultimate tensile strength (not a limiting factor) no extra stiffness, potential pitfalls with welding, and twice the cost.

Edit: that's true for the chassis though - suspension uprights will be 4130 and then heat treated.

And yeah, 70S2.

Thanks, this is a really cool project you've got going. What are the pitfalls of welding 4130?

# ¿ Oct 13, 2021 04:05

casque: Mar 17, 2009

Rubbing is racing.

# ¿ Dec 15, 2022 03:51

The Something Awful Forums > Discussion > Automotive Insanity > SilhouEtsy: Homemade Tube Chassis RX-7 Racecar (and supporting stuff)