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Thread: Welding table

  1. #1
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default Welding table

    Have finally found some time to put into a table.

    I saw a slat top welding table using RHS, 30 years ago, walking past an open doorway of Uni Adelaide Engineering Dept. workshop one afternoon, and thought to myself, 'self: I gotta build me one like that one day' (thinking of the clamping possibilities), and not having to move a steel plate which in my current situation of limited access down and around the narrow side of the house and up 6 or 7 steps, would be a serious issue.

    I got the trolley base complete with wheels for $30 at a factory auction about 3 years ago. It had a couple of triangle frames on top, and was used for moving chipboard/melamine sheets. It's open C , 4mm wall, plenty good enough for the purpose at hand, given the cost and it being an existing construction; otherwise RHS would be the go. Two of the ends were cut down lower than the other for reasons unknown. So I had welded the offcuts back on a few months ago.

    Today I levelled the floor with some offcuts, using a laser, 1 mm discrimination was no problem. Wanted to have a level starting point, to then reasonably establish equal heights on the 4 corners. Ended up with 0deg in all directions including diagonals, using the Stabila electronic spirit level, so good enough, particularly over only 1.2m length. 0deg is nice to see of course, but alway have to bear in mind the inherent precision/error, so always a good idea to swap the level around 180 deg to cross-check. 0.1 degree over 1.2m is 2.094mm, so '0 deg' is of course an 'estimate'.


    So I then used the laser to establish tops for the 4 corner posts, and angle grinder action to trim down. The laser worked really well, often it was easy to get the 1mm wide laser line breaking over the very top of the leg, and the square when checking the 'shadowed' side ( see pic).

    The important flatness will be the co-planarity of the top RHS rails - for which I have a 'cunning plan'. As there will be some inherent amount of not true flat in the heights of the 4 corner post tops, despite the measured degree of level, I plan to make a 3 layer sandwich, consisting of the 2 main side to side rails , the main surface members, then 2 more side to side rails on top of those, clamped up for tacking, it should be reasonably flat.

    Cut some 90x8mm flat bar to act as supports on top of the legs. These will completely cover/close the leg tops. I was thinking of bolting down the 2 main RHS to these plates, so that the whole top could be taken off , if I ever need to move it somewhere else/fit through a doorway/ or if I bowed it )... But unless I change the spacing, a top (front to back) RHS rail will cover the access hole I was planning to put in the side to side support rails. So welded it will be.

    I have some RHS is 75x50x3mm offcuts from my shed build ( as per pic) for the top rails, but I am thinking I may as well go 4mm as I have to get more anyway (14 top rails in all).
    Attached Images Attached Images

  2. #2
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default

    Marked out, punched, and drilled (3mm/8mm, then 11/32", chamfered, then tapped the mounting plates (120x90x8mm) that will be welded to the tops of the corner columns, for M10x1.25 SHCS. Also made corresponding plates ( 40x3mm flat bar) for inside the RHS, to act as washer plates. and drilled the main side to side support beams. There is now 2 bolts per plate, so as to bracket the section lying above the corner posts.

    Marked out, punched, and drilled the bottom of the beams, thinking I would then use a long series 4mm drill to get the same position on the top side, but drill press etc. not set up enough yet to get secure enough and true enough plumb, so marked out top as well and went through the sequence again. Doing the bottom 50mm face of the RHS, i.e the joined/welded face, from the outside, allows locating the hole accurately. Trying to cross drill from the opposite side will cause drill point wander on the weld seam inside the RHS. Needed to utilise a spare Dawn 6" to get support at the right height. My smaller Tough has an MT and the extra length reduces what can fit on the table, so had to swing the table out and use the foot plate...

    Anyways, now done. Ordered the RHS for the top, pick it up tomorrow. I had decided to get 5mm (plan C), but of course not a stocked item due low demand in this state, so back to plan B; 4mm. It'll do. Also thought to get galvanised, rather than painted, as the galv might reduce weld spatter adhesion maybe. 14 pieces of 75x50x4mm $305.13.
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  3. #3
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Good Job node105,

    I see your table differs from most of the yank welding tables in that it is not an Ultimate Welding Table. It is encouraging to see someone utilising available materials in a thoughtful way and not to dump a ton and a half of plate on the frame as a deck. Each welding table should be different andshould reflect the type of work that the individual regularly performs.

    Thank you instead, for an Outstanding Welding Table .

    Grahame

  4. #4
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default table top

    Thank you Grahame )


    I picked up the RHS for the top today and first pic shows it laid up, just to check the spacing... One small disappointment is the flatness of the 75x50x4mm RHS on the non-seamed 50mm (top) side. The second pic shows the gap from the bow. A feeler gauge gives the gap as on the order of 0.20 to 0.25mm. Now I know that is bugger all in the greater scheme of things, but the blue painted 75x50x3mm offcuts from my shed build, give 0.1mm, and you can't see any light gap.

    The third pic shows the 50mm non seamed face, and clearly the feed roller impression from forming at the mill. Manufacturing tolerance it may well be, but it would be better if the tolerance was as per the blue painted. It way well be differences between mills, or a result of the 4mm vs the 3mm wall. Who knows. I'll get over it but for now I'll call it mildly disappointing )

    I had intended to check the flatness across the length, before tacking, after tacking, and after welding, just to see how much bow I put in it as a result of each stage ( if any he says optimistically). Approximately anyway; only have a meter steel rule, which is NOT a straight edge I know. I went to borrow a straight edge today from a mate, and thought to check it on the granite kitchen tops, straight it wasn't.

    I helped a friend build a similar and smaller bench 10 years ago in Cataluyna (Spain to the geographically challenged), only 2.0mm wall thickness (severe budget restrictions), and light stretchers and stick welding as that was all we had, and all was going well, until not enough time between weldments, ended up with a 2mm bow end to end, which was a pity. But it was more than functional for the type of stuff he did.

    Also stopped off at the fastener supplier to get some M10x1.25mm x 20mm SHCS. Noooo, we don't stock that length, its a fine thread [yes I know it's a fine thread , but not an extra fine M10x1.0) ] , will 25mm length do? Exposed thread under welding spatter, of course it will. Groan. Adelaide.
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  5. #5
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

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    With your earlier comment about weld spatter on galvanized, it sticks like the proverbial to a blanket. I suggest that if you've already got it, give it a coat of silver paint to protect it, or if you like that shiny finish, mix some elcheapo dishwashing liquid with water, and spray it on the bench, to protect it. Use the spray bottles that other stuff comes in, saves buying one.
    Kryn
    To grow old is mandatory, growing up is optional.

  6. #6
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default

    Quote Originally Posted by KBs PensNmore View Post
    With your earlier comment about weld spatter on galvanized, it sticks like the proverbial to a blanket. I suggest that if you've already got it, give it a coat of silver paint to protect it, or if you like that shiny finish, mix some elcheapo dishwashing liquid with water, and spray it on the bench, to protect it. Use the spray bottles that other stuff comes in, saves buying one.
    Kryn
    bugger! shoulda stuck to painted! I can paint it black with VHT, or a coat of Aluminium rich galv, or Copper /Aluminium galv... Shiny finishes are for Aluminium of Alf cam covers, gearboxes, sumps ... )

  7. #7
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default Top fit up

    I thought this morning I should measure the flatness of the 50mm seam welded side, and what do you know, it is flatter than the opposite 50mm side. 0.1mm or better! So seam welded side up! There is an explanation for this. I spoke to an engineering mate today, who explained ( at least it used to be this way) that the flat bar, is rolled into a round tube, seam welded, then passed through former dies to create the rectangle. The weld excess is actually scraped off, so blade flat, rather than the roller pressure effect on the opposite side. Flatness of 0.5mm is probably reasonable. The longer sides will flatten back themselves.

    Laid out the top sections, with welded seam up, and spaced with painted offcuts to see where things laid. As the base frame was already a made item, and not a metric construction, the corner posts centre lines did not fall to a multiple of 50mm, so some contemplation and juggling. One idea was to shim each gap with some tin (1 mm) or so, and with stack up, that would have taken up the extra gap (30mm or so). But decided to stick with alternate 50mm and just have one gap slightly bigger.


    top - 1.jpg

    Then it was marking up to ensure one rail at each end, fell coaxially over the predrilled support plate centreline, to give equal offset to the mount bolt access holes.
    top - 2.jpg

    Clamped one rail on its side, and used a spacer, to give a positive positioning stop to the rail ( green lip) over the leg centreline.

    top - 3.jpg


    Initially clamping test ( clamps are Bessey SGM f clamps , and GH lever clamps)

    top - 4.jpg

    Like all the steel ( c.2500Kg) in my shed build, Made in Oz

    top - 5.jpg

  8. #8
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default

    cleaned the ends with acetone, and marked the seam welded side to be the top surface, and the bottoms with approximate position of the bearer, so as to grind off the zinc coating prior to welding. Used a Norton ceramic pad, which turned out to be crap. Too soft, and completely worn out after 14 rails ; no sharp edges just smooth steel, rubbish pad.

    top - 1.jpgtop - 2.jpgtop - 3.jpg


    Now for the upside down lay up, so as to tack the underside of the rails to the top of the side to side bearers. First layer in the sandwich is two 100x50 beams. Cut some spreaders to reduce the degrees of freedom.

    top - 4.jpg

    Used the laser to initially square things up, against the scribed centrelines in both directions. Laid down some rails, and the main bearers, and checked the diagonals of course

    top - 5.jpg top - 6.jpg

    Measuring the length of the stackup of widths did not give a multiple of 50mm, grunge!. So cleaned up the accumulations from the sides of the spacer tubes. Should have also done the tops and bottoms, as will come home to roost later.

    top - 7.jpg

    Clamping lengthways stops with scrap 40mm back and front (AL angle) allowed setting the width between the main side to side members accurately, while still allowing finessing the diagonals on clamping... Its all about reducing the degrees of freedom, while still allowing adjustment in some dimensions. The bit of red tongue from Structaflor provided a support for the framing rule, to lift it up against the flat edge of the RHS, rather than under the curved edge where you can't see the contact/gap.

    top - 8.jpg


    After the usual fettling and finessing, the main front and back rails were parallel to 0.5mm, the parallelogram diagonals were better than 0.5mm. Front overhang 50mm, rear overhang 40mm. Tacked a top rail at a time and gave some cool down time, plus wet towels draped over to draw some heat.

    top - 9.jpg top - 10.jpg


    Some of the spacers were a bit difficult to ease out, requiring a little bit of tapping curiously . I just managed to lever up the welded assembly and remove the bottom layer of the clamping sandwich, and juggle it up on its side.

    top - 11.jpg


    In order to flip it over, and lift it into place (sans mounting plates). Happy camper. A welding table at last, hubba hubba.

    top - 12.jpg top - 13.jpg



    Initial steel rule across the surface and feeler gauges gives about 0.4mm out of flat in a couple of rails, i.e even though the rail surfaces are flat ( 0.1mm or so) there is slight variation in the height of the rail surfaces. Grrrr. I did notice when removing the spacers, to relocate at the right end (had to do 2 sequences) that some of the actual rails yet to be welded were a tad loose, while some were immovable. So I think the spacer heights were the culprit, most likely a few bits of grunge I didn't notice. Moral: use the SAME material batch for spacers as the material being welded up. For all intents and purposes, it is more than usably flat. If OCD takes over in the ensuing weeks, I might unpick a couple of rails and re-tack.

    It is solid, even without being bolted down to the base. It moves easily on the casters. Weight of the top : 75x50x4 x860mm x14 @ 6.92 Kg/m = 83.3 Kg, plus cross members 75x50x3 x1400mm x 2 @ 5.42 Kg/m = 15.7 Kg; total weight of top 99Kg.


    Additional improvements will be sliding extension supports to extend width and depth, spatter trays below the top deck, and possibly a round hole sliding clamp element mounting gizmo or two.

    Table top is 1400 x 860mm

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