johnny.race Posted August 16, 2015 Share Posted August 16, 2015 I'm up to this - tapering the front of a new chassis build. I have cut a pie/wedge shape from out of the sides and intend to press the top down then weld. The problem I have is that as soon as you cut the pie shape into the sides - they (the sides of the RHS) kick inwards. If this only occurred at the big end of the pie cut then i could just pry them out and tac - but it occurs for quite a way in. See pic. The ruler part of the square is touching the top and bottom but not any part of the side wall in the center. It looks to be a real prick to get in there in order to wedgie both walls outwards. Anyone got any advice on how to go about it or what the DIY tool looks like to get it sorted? The RHS is 150 x 50 x 3mm. Ta. Quote Link to comment Share on other sites More sharing options...
downtrail Posted August 16, 2015 Share Posted August 16, 2015 Make a little jack. A bolt that just fits in the gap with a nut on it then undo the nut to jack them apart. 3 Quote Link to comment Share on other sites More sharing options...
johnny.race Posted August 16, 2015 Author Share Posted August 16, 2015 Yup, mate i hear you but the pie cut is 560mm in length. The inward lean of the sidewalls of the RHS commence around 450mm mark and get progressively worse as it heads out to the front/end. There is only 44mm max - room to work in at 450mm depth. I won't be able to swing a ring openender or anything in this space. I was thinking along the lines of something like a round piece of 8mm plate cut to the correct inside width of the RHS or similar ... welded to a slide hammer. tap it in there and slide wack it out as i tack it together as it spreads. Hmmmm. The rodders in here have done this sorta stuff before - I bet. Quote Link to comment Share on other sites More sharing options...
Ja1lb8 Posted August 16, 2015 Share Posted August 16, 2015 But late now but how bout just hammer a piece of wood in there thats a good fit before you cut the next one and pull it out once its tacked up. Hmm could risk getting it really stuck in there but could knock it out from the other end with a long bit of tube or something 1 Quote Link to comment Share on other sites More sharing options...
artyone Posted August 16, 2015 Share Posted August 16, 2015 I'd have something like a T with a really long vertical, or at long as you need to throw it down into the tube and use that 'handle' to lever open the sides and tack then move on to the next tack. But the end of the T would be the width you want it to be and then weld that slighly tipping one way onto a rod or whatever so lever and the width you want comes into play. 3 Quote Link to comment Share on other sites More sharing options...
sheepers Posted August 16, 2015 Share Posted August 16, 2015 drill and tap a thread in one side. wind threaded rod into hole and force two sides apart, weld top back on, profit. or, cut 3/4 of the way through the side at the bottom, bend out, re-weld everything. profit or cut the top off completely, bend sides out to correct place with a crescent or something, weld top back on, profit. 3 Quote Link to comment Share on other sites More sharing options...
johnny.race Posted August 16, 2015 Author Share Posted August 16, 2015 ... cut the top off completely, bend sides out to correct place with a crescent or something, weld top back on, profit. This. Fuk - sometimes the answer is staring you right in the face. Cheers. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted August 16, 2015 Share Posted August 16, 2015 Or.. Just jack the ends outwards until the bow is out further down the box. Tack into place, lessen the jacking until next spot is in the right place, tack, repeat. Quote Link to comment Share on other sites More sharing options...
artyone Posted August 22, 2015 Share Posted August 22, 2015 Most of my stuff like this is done intuitively but I've got this idea that unless you're putting the set right where the weld is then the length of steel being heated is going to take the path of least resistance so almost counter intuitvely you bend the sides inwards so when the heat goes on they flex out towards the point you want them to... steel's weird like that and goes where it thinks is best to be, which is usually not where we expect. 1 Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted August 23, 2015 Share Posted August 23, 2015 Get a bit of like 50x10 flat bar about 500 long. Tack one corner to the box wall while the other corner is above the top flange. Now pull the bar up and the tack to the wall will work as a hinge, the bar will hit the top flange and pull the wall out flush like a lever. When flush tack the top to the wall. Snap off bar and repeat a but further down. Mack sure this join is fully weld preped Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted August 23, 2015 Share Posted August 23, 2015 Or.. Just jack the ends outwards until the bow is out further down the box. Tack into place, lessen the jacking until next spot is in the right place, tack, repeat. Or that too Quote Link to comment Share on other sites More sharing options...
sentra Posted August 23, 2015 Share Posted August 23, 2015 i brought one of these recently, http://tradetools.co.nz/products/3475160 it has quickly become one of my most-used things for problems i never knew i had. so tiney. 1 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted August 23, 2015 Share Posted August 23, 2015 There are chassis straightening lots on TM for like 1$ reserve all the time They have that ram and a few others. Quote Link to comment Share on other sites More sharing options...
Roman Posted August 23, 2015 Share Posted August 23, 2015 I dont really live up to my namesake, sorry. 1 Quote Link to comment Share on other sites More sharing options...
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