boxing my frame

so im ready to start boxing my frame, now my rails are 4mm thick (8g?) should i box it with same thickness plate or is it just overkill? i was thinking 3mm (11g) would do just fine, easier for me to get and lighter in the end. any opinions greatly appreciated - Ross

 

FWIW, I boxed my 30 frame with 3/16 steel. Yeah, probably overkill but wanted something solid to weld to for engine mounts, cross members, etc. Haven't regretted it.

 

in my eyes it is over kill but i also weld motor mounts and cross members in before boxing.

 

I'd be tempted to use the same (3mm) thickness, so that the boxed tubes would experience similar strain/stress on all sides. If you need to double up or reinforce mount areas, then it's not adding weight to the entire plate length.

 

Are you sure your frame rails are 4mm thick? Most I've ever seen are stamped out of 11 ga (~.120 to .125"). You might be measuring thick paint or rust or measuring where there's a fat burr on the edge. Maybe strip it clean in a few different places and measure with a micrometer in away from the edge, so you won't be measuring a thicker burr part at the edge.

I have used 3/16" plate for boxing before, but that was for a big block powered rod, and I wanted to make it extra stiff, but I think it was overkill. I think 1/8" or 11 gauge is probably fine for most cars.

 

What would that frame be? Sounds too thick for Ford passenger car, are we talking a truck frame maybe?

 

4mm sounds right to me. I measured mine at 4.5mm or 3/16". I used 5mm to box it becuase I couldn't get 4.5mm. I do think it was overkill but the extra weight in that small amount of steel is negligable. It is very nice and solid though.

Oh yeah, that is an A model frame.

Pete

 

sorry guys, its a 26 dodge frame, should have mentioned that. Its been sanblasted and is clean and ready to start welding

 

Ok. Don't know how you're going to approach the cross members, but if you're using RHS it will no doubt be 3mm wall. You could use 4mm RHS, but that's some heavy stuff and way overkill. So on balance for the boxing I think 3mm would be fine.

For what it's worth the Government build guidelines and ASRF TAC guidelines in most states will recommend boxing material to be the same gauge as the frame material.



p.s. the original wasn't metic so 4mm may seem like the closest measurement on your metric measuring device, but then again 3mm plate for boxing may be the 'closest' metric material match you can get too.

 

Man - I would use the 3mm plate and spot every 12'' until the plate is on the frame ,
and skip weld about 1'' at a time all over not to get it to hot.

 

thats what i was thinking, the dodge chassis is a fairly strong unit as it is, i dont want to add any unnecessary weight if i dont need to.