hi everyone , I am just starting to box my frame for my 30 tudor , here is my question and it is a very simple one , would 1/8 inch steel be heavy enough for frame boxing ,I am planning to use a small block chevy , what do you guys think ?
I say yes but then you will get the argument that 3/16 is best as it is closer to the original frame thickness..
I think your right , because I noticed there are a lot of 1/8 inch frame box stuff on ebay so they must think it works ok
1/8" is fine and set them in a bit because if you grind the welds to make pretty you lose strength. Some people use thicker material for boxing because it give a little extra thickness to drill and tap various mounting screws for things like brake line clips. Think about where you may plan to attach things and weld in captured nuts to the inside of the plates before welding.
I used 3/16 on mine for two reasons. I overbuild everything, and the extra wall thickness is easier to drill and tap threads into for non structural things like brake lines, wires, etc. More important than the boxing is the crossmembers though. Even boxed, an A frame will twist like a pretzel unless you put proper X or K crossmembers in to eliminate that twist. Don
I think where the confusion in the measurements comes from, is because when Ford built the Model A frame they did not use dimensional steel such as 1/8" or 3/16". The frame rails were stamped from sheet steel, formed in to a channel and then riveted together. I just put a mic on one of mine and it ranged between .152 to.160 which is 9 gauge, U.S. standard. I have seen both 1/8" and 3/16" frame boxing kits available, I know Chassis Engineering uses 3/16" on their kits. Both sizes will work for you.
when I was cleaning up the frame I noticed on the drivers side of it between the front crossmember and the middle crossmember it has a slight dip about 1/4 inch measuring at the top of the frme where the first body mount bolt goes , I can't see where it sprung or buckled , so how close are they , should I attempt to straighten it a little or jusy leave it
3mm plate is close enough to 1/8" and used all the time down here in conjunction with a stout 'K' member. The legs are run forward from each rear side rail to centre member forming a 'K' and a mandatory requirement down here. When fully welded the frame with 'K' member is stronger than just a frame with boxed outer rails and a single centre member for transmission like this frame. This frame will torsionally twist. These frames won't twist due to 'K' member and legs. http://www.dagelsstreetrods.com/super_x_crossmember.htm
The dip is very near where the original rear motor mounts are and where such frames typically sag. the Model A restoration books have articles on how to correct the sag. It might be wise to do that before you go further. A sag in the frame will affect hood and body fits. "How to Restore Your Model A, Volume 2" is the first book I looked at with a specific piece on straightening the frame. Brattons.com sells the book, as do many Model A parts suppliers. I just hopped to their web site and they seem to have TOC's on a number of the books they sell.
boy thanks Russ B that explains it right there , now to correct it , I was thinking some good heavy irons and a hydraulic jack and a piece of heavy angle iron so I don't bend it wear the jack goes
It might have been close to 3/16 but after 80 plus years of rust and gunk I bet its a bit thinner, 1/8 would be just fine.
Last one I built used a Dagel's un boxed frame and x member. His frame rails are thicker than stock. I was quite satisfied with it. My sort of stock frame had questionable suspension mounts made of flat bar, cracked front cross member, notches cut out for exhaust clearance and twisted unboxed frame rails from the torque of a 383 Chrysler. I was able to salvage the rear cross member out of it. I also had to relocate the brake pedal mount to the stock location on the Dagel's frame due to it being set up more for a SBC than a Flathead.