John P
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| posted on 15/5/07 at 09:30 AM |
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Tack Welding Chassis - Where and How?
I've marked out a sheet of flooring grade chipboard with the chassis dimensions and screwewd blocks to locate the box section prior to tack
welding.
Do I need to clamp the box section down and if so what's the best method?
Should I tack the top face and the exposed sides?
Once I've got the base frame tacked the book suggested removing it and tacking the underside. After this should I re-locate it onto the board
or could the rest of the construction be done without.
I'm a bit tight on space and having an 8ft x 4ft board flat on the garage floor will be a bit restricting.
Any advice would be appreciated.
John.
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bpgoa
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| posted on 15/5/07 at 10:50 AM |
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I built an 8 X 4 table out of MDF 1 inch thick supported on 9 legs...
i then leveled the table using those plastic shim things under the legs..
i painted the board with mdf primer and used 2 m rulers to draw the plan out.. checking square by measuring the diaginals. the plan was set square
to/ and at a known distance to two perpendicular edges so i measure off them.
i then screwed plastic corner blocks down at regular intervals ensuring allignment with my plan.
Next, using an auger bit i drilled 1 inch holes close to each of the corners. these holes were used to pass clamps through to hold down the lower
frame. screwfix sell plastic cam clamps (red and black- ) in pairs for about £3.50 i bought six of them and clamped down everything before tack
welding.. When drilling the holes ensure that the clamps will not obscure the joint..
when the entire lower frame was tack welded, i turned it over and re clamped it to the work surface before tacking the underside.
(i don't know if this was a good idea but its what i done)
When tacking the underside i drilled a small (4mm) hole in the joint and welded into the hole. when tacked, i ground the tack flush so that when i
turned the frame back over it would sit flush on the table.
i cleaned the table then turned the bottom frame back over.
th bottom frame was clamped back down, and proceeded to build the jig for the nose...
by using set squares at the edge of the table i was able to measure off and ensure that the top section was alligned correctly....
then added the uprights ..
then the top sections ... always measuring off the known good edges.... and because the table was level, i could use spirit levels on the top section
to ensure the frme is square...
where the metal buts up to one another... it is ok if there is a small 1mm ish gap... but do not flex the rails for the fit as when it is released
from the jig it will twist...
when tacking don't put down loads of weld... you want to be able to weld through them later...
good luck... hope this helps...
On and On the River flows... We the Undertow
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Avoneer
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| posted on 15/5/07 at 11:09 AM |
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I used blocks of wood on each side of the chassis and block across the two blocks.
Some pics on my web site:
www.bitsablade.co.uk
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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andyharding
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| posted on 15/5/07 at 02:26 PM |
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lol - seems a bit ott.
I just placed my tubes on my table and tacked away with no blocks or clamps. The finished chassis is within 5mm on the diagonals.
Are you a Mac user or a retard?
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big_wasa
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| posted on 15/5/07 at 04:38 PM |
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I vote to keep the board untill its all welded up. Just the blocks where fine for me.
I know what you mean by lack of space.
 
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