Advice needed on toolbox build.

[Mick B]

I want to make a second tool box for the back of my Toyota ute that will be sturdy and water proof. I think I will be using 2mm sheet and rather than get someone else to cut and bend it up from one piece for me I will have to cut the sheet up myself. Hopefully I can find a cut-off disc to fit my power saw (7 1/4") and just use straight edges clamped on as a guide. I think using an angle grinder would be hard to keep a perfectly straight cut. Measurements for the box will be approx 900mm long X 250mm wide X 210mm high with a slight slope on the lid. I have just had a practise run mig welding an open corner joint (I think that's what it's called .......... kinda hold the 2 inside edges together and fillet weld the external corner) and after lowering the settings I seemed to come up with a decent result.
Any other ideas for the corners remembering that I cannot bend anything myself ?
Also, would the cutting by disc generate enough heat to warp the pieces ?

 

[Wendelspanswick]

When you say a power saw do you mean a handheld circular saw with an abrasive disk in?
If you do it won't work very well as the speed will be too slow and the disc will disappear pretty quick.
Abrasive cutting discs are designed to cut with the periphery of the disc, if you pierce with a disc so that the disc is cutting in the sheet the disc disintegrates pretty quickly.

You can use an angle grinder and run the disc along a straight edge with good results.

If you are careful you can use the disc to groove a full sheet enough to enable you to fold the sheet, adding a few tacks to the bends to strengthen once bent, the trick is to keep the disk moving along the full length of the cut. Multiple fast passes rather than one slow pass.

 

[Mick B]

Yes I do mean a handheld circular saw with an abrasive disk in it. We often cut corrugated roofing iron with one at work and adjust the depth so the disc is just deep enough to cut the material. I realise I would need to be more precise with this project though.

I wondered about running an angle grinder along a straight edge, but I won't be doing that with my good aluminium ones.

The thought had crossed my mind about partially cutting through and then hand bending from there ................ Good thinking 99 !! Thank you from my heart's bottom !

 

[gordon stephenson]

I don't have a problem using a 125mm thin cutting disc on the angle grinder, following a straight line. Also cutting half way through on the bend lines. then simply weld up the external corners and dress up. job done looking like its been done on a folder,

 

[Mick B]

I think I am starting to understand how to go about this little project now thanks to you two. But do I really have to draw a STRAIGHT line ?
How about I draw a crooked line and don't follow it ............... then the cut might end up straight !

 

[rikrobson]

Just get the cricket team to do it for you. They'll be needing new jobs soon

 

[gaz1]

ive just folded 3mm doing this with a line cut and also a vice as dont have a folding machine as of yet

 

[Kent]

Your distortion wise will be the continuous corner welding. Go downhill back stepping. The best option by far is order the stuff cut and bent were it can be
As always tack everything and check for fit before you go buzzing everything up fully, expect some movement and allow for it
If you can stitch instead of fully weld any place do so

 

[Mick B]

Just get the cricket team to do it for you. They'll be needing new jobs soon

Even though I don't follow that boring game, I was expecting something like this !!

 

[rikrobson]

Even though I don't follow that boring game, I was expecting something like this !!

that was far from boring this morning. to be honest I was shocked. i was busy at work and didn't get a chance to check the scores until we had started batting at 12:30

 

[Mick B]

Many thanks for the advice. I just line cut (about half way through) a piece of 2mm X 200mm X 100mm lengthways, bent it to 90 degrees, put 4 tacks on it and then welded vertical down. I could see where the weld had penetrated through so I reckon I'll have a go at this. I was surprised to see it had gone from perfectly square to slightly under 90 degrees with the welding. I would have thought it would have gone to slightly over 90 degrees as the weld cooled and contracted ?

Below is a pic with rough dimensions and how I think I should go about welding the corners. I would probably clamp the bottom of the box down nice and tight as well to help prevent any distortion. How does that sound ? I know most of you could do something like this with your eyes closed, but as a beginner I want to be sure I going about it in the right way. I know I could get someone else to cut and bend it all for me, but that would take the fun out of it.

 

[Kent]

No need to clamp the box down it won't help a jot on such thin material