Welding a "box" around square solid, and getting it out?

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I've started collecting and building the pieces to build myself a 2"x72" belt grinder.  I realize a lot of the plans out there are "no weld" for those wanting a belt grinder but lacking a decently large welder to build one with.So the other night I cut up the steel - my main frame being similar to this build thread I ran across a few days ago: http://weldingweb.com/vbb/showthread.php...y-belt-grinder with only 2 instead of 4, holes for 1.5" steel square solid for tool arm and rest arm.I stared by prepping the steel for weld, everything 12" long and sandblasted clean, 2 pieces of 1/2"x2.5" for top and bottom, 2 pieces of 1/2"x1.5" on either side.  I used the mill to bevel edges pre-weld, and 2 pieces of .010 brass shim stock the length of the welded piece on 2 sides of the tool arm to provide the gap for the tool arm to slide easily.  Clamped all together, tacked, welded in sections to try and keep distortion to a minimum.After it had all cooled down, the tool arm was still a major PIA to get out, took quite a bit of oil and beating to get it out.  Now that its out, with brass shims removed it slides in and out easily enough but I'd rather not repeat that mistake on the second box that will be welded to the first using 2 more pieces of 1/2x1.5 and another piece of 1/2x2.5".A few thoughts - Would I be better off with 2 pieces of .005 brass on all 4 sides of the 1.5" tooling arm?Would it be better to use a piece of 1.5" square tubing to space out the sides of the tool/rest box, knowing that it will deform easier if it needs to be beaten out?I'm concerned that if I weld the box up without something in the middle it may shift enough to prevent the arm from sliding thru fully, which would waste a pretty good chunk of money I spent on steel and set me back in my goal of getting this thing done soon.I notice that the guy who started the thread linked to above never posted a finished update, I wonder how he or anyone who builds these sort of assemblies spaces them out so as to make them easy to get apart and properly gapped to slide thru easily?
Reply:Yes you may have to construct your alignment jig to break down to get it out.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Originally Posted by shovelonYes you may have to construct your alignment jig to break down to get it out.
Reply:Originally Posted by DSWI could never get them to understand if they cut out a section in the center and added a back splice, things came apart easy. If they did that, they'd usually do something else stupid, like drive the screws in from the side that faced the concrete so you couldn't reach the screws once things were poured...
Reply:You dont need a box as jig for a box. You only need to meet certain metrics. You want to keep it square, so you only need to address the location of the corners. Think outside the boxConstant Current Weldor.
Reply:Make the inside with smaller tubingDrill and tap a hole on each face at each end.Use screws to set the size you wantTighten the screws in to remove
Reply:Don't full weld with the piece inside. Just get some goo tacks in several places. Remove inner piece then full weld.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:I use paper when shimming something that has to come apart, most of the advertisement tablets that are left here have about .004 thick sheets.