I have the Bishop/Tardel book and have read it. I've searched here on the hamb and it seems most folks respect what was written in the book. There are a few posts I've read though, where the opinion is, a fishplate or boxing is in order. In the next week or so, I was going to step the rear on my frame. I'm looking for opinions. I wasn't planning on boxing the rest of the frame. Banger motor doesn't seem to warrant it. Is boxing just the Z asking for trouble? Does it need it?
It really depends on your weld quality. A fishplate on the inside of the rail wouldnt be a bad idea. Rob
I'm a believer in fishplates for any kind of frame modification. I boxed, stepped and fishplated mine, even though it's running a mild flattie. Boxing might not be essential, but it sure makes for a solid feeling ride, and as a bonus, the doors dont fly open from flexing during hard cornering.
I got a chance to step my frame today. I've decided to add fish plates for added strength. Can someone explain to me how to go about "designing" them? Should I use separate pieces or one piece straight through? Same thickness material as the frame? How about width? I know it seems elementary but, I don't like to take anything for granted. Here's some cell phone pics of my frame. I forgot to take some of the filler pieces on the side. I got on a roll.
Looks good.... but that's the problem. IMO, the welds on places like that should not be ground off. No-ones going to see them, and the whole ***embly would be so much stronger. Ground off welds scare the heck outa me. If you look at the pic of my frame a couple of posts back you'll see no welds ground in critical strength areas.
Just got done boxing and stepping my frame for my 28. I agree with the no grinding. Can't see it from up top. Great looking job on the step up.
the pics above show a simple way of doing step up ,,could it be done that way with the body still on by removing the floor pan in a 28 rumble seat coupe ,,maybe the body mounts would be a problem?,,,
I left the welds on the tops and bottoms and of course I didn't grind them down on the inside. What would you suggest at this point? I was thinking a 1/8" thick fishplate to run the full length of the step. At that point, do you think I be better off boxing instead? The Tardel book goes into little detail but, is of the opinion boxing just the rear step is a bad idea, adding rigidity where flex should be. Any thoughts are much appreciated.
Since you have the frame out now, it would be the best time to do a full boxing and be done with it. Who knows you may have a change of direction with this project either now or in the distant future and one thing you wont need to worry about is boxing the frame and pulling all the body off etc etc. Frame boxing is good insurance for your body, it actually keeps adjustments correct and prevents/reduces the chance of tears in you panels appearing, especially if you have a good body to begin with or are planning to invest some time and/or money into body work repairs. Nice work on the frame step.
I hear what you're saying about boxing now and I'm going to consider it. The thing is though, I'm using an A motor and rear. Kind of a late 30's build. I really didn't want to box the frame because of the look. Do you think boxing the rear only is a mistake?
What you can do is make a reinforcement "Z" out of 1/4 plate to fit inside of your frame and weld that in solid all around . This will keep your unboxed look you want while making your frame strong at the step area. Good looking job so far.
I've been doing some reading, and there never seems to be a consensus on this type of thing. I'm definitely going to add fishplates. Still looking into the boxing of the rear only. Would like to avoid boxing the entire thing but, the added rigidity would be welcomed though. Back to the fishplates... I plan on cutting one piece, the shape of the step, the length of the entire "Z" plus 2" on each side. Two questions 1. Would this be the recommended method or is there a better way? 2. Should I drill a hole or two in the plate and plug weld them? Thanks for the ideas and help so far
Box whatever you can now, because it sure going to save you later. Also like said earlier it will give a better feel when you drive it. If you can box upto the center crossmember where all the brake stuff is that is got to be good.
I ended up ordering boxing plates. I'm not sure if I'll use them right up to the front crossmember but, we'll see. I won't get to work on them for a couple weeks but, I'll post the results once I'm done.
OK for your fish plates - Avoid straight welds across the frame ( these would be vertical with frame or perpendicular to the main rail) make sense ? Your design of the step has incorporated 2 triangular pieces welded on each side , each triangle has one of those welds that should be avoided. (4 total ) Definitely add the fish plates , p*** those areas with it , and round the corners. On your next one, slice the frame at a 45* angle, long to the rear on top of the rail , and place the rear section on top of the main section. Two caps to add on each side and you're done.
Check out how he did his, on the first page of his build. There is no doubt that he is a craftsman and I personally feel it is done right. Yours looks good too and I agree with you, no need to box an A with a banger. That frame seems to have done well for the last 80 years flexing right along. Now you decide. http://www.jalopyjournal.com/forum/showthread.php?t=556599&highlight=guernsey+boys
Try this http://www.jalopyjournal.com/forum/showthread.php?t=556599&highlight=guernsey+boys I fixed it back on my original posting. Thanks
This in no way is a dig against the OP, what you have done is strong and acopmplishes what you needed to do. For cosmetics you could weld a plate on the inside that curves and blends into the rail. No model A frame running an A engine needs to be boxed. Pic B..I think this approach makes for a more factory, smooth flowing look. Cut a piece of metal with nice smooth lines, shape and weld on strap above and below and smooth. I would make the top and bottom straps out of tubing cutting them after the nice radius, so the welds are on the flat. The pieces can be welded on the edge/corner and ground smooth radius too. Weld the top and bottom pieces past the side weld, this will give the junction much more strength as all the welds are not in a straight line. This process does not need fish plates if welded properly. Pic A..I see alot of this type Z/step up and or C notch, and it works fine. In this type modification with straight cuts/welds a fish plate is probably a good idea, however, I would grind all welds smooth on the outside and add fishplates on the inside of the rail for a better look. One could also slip in a little smaller chunk of C channel so all 3 sides are supported.
hey Walls, if you feel that you may want to box the frame up front but don't want the "boxed look" how about installing the boxing plates inboard the frame rails some maybe a full inch or so. I know this would not be as strong as the boxing out closer to the edge but it would be better than no box at all and at a quick glance the frame may not have that boxed look. I boxed my full frame but I'm not running a stock 4 banger, I'm rumming a 292 Y block.
Due to the taper at the rear of an A frame, won't stacking in this manner put the rear crossmember at the wrong angle?
It certainly would if one did not address the taper properly with the appropriate BFH. It needs to be adjusted less than 1/8 over about 3"
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