Thursday 2 February 2017

Sheet Metal Work

The fuel filler support is just about done, so I thought I write down how I done it.

First I drew it on the computer to see what looked right, then I printed out two paper copies of the flat pattern, one to fold up & put in the car as a last check & one to make to.

The paper pattern fitted OK, it just needed a little more on the ends of the flanges, so having adjusted the "make to" copy with a crayon I selotaped it to the aluminium sheet & drew round the edge with a magic marker (disappointingly they're not actually magic - it's just a fat felt tip!).

To cut it out I used a jig saw with a very fine toothed blade, this can be a bit worrying - I still have no feeling in my left index fingertip after the jigsaw jumped & stabbed it a couple of times. Cleaning the cut edges with coarse & fine files stopped any further bloodshed & at this stage it looked like this:-

Even my brackets look vaguely aeroplane like.

Next job was to put in the lightening holes - GOT to have lightening holes! In this case I wanted to try to make flanged lightening holes because being aluminium sheet (not alloy) it's pretty soft & a flanged lightening hole gives a lot of stiffness.

So out with the hole saw & my bracket looked like this:-

 At this point I made a bit of a mistake because I got all enthusiastic & flanged the holes, which made bending the side walls down a bit of a git - but I digress.

At work I'd noticed that the really big sockets had a curved "neck" - just the right shape for pushing a lightening hole, I used the hole saw to put a hole the same size as my lightening holes in a lump of soft wood, then chiselled the edge away to make a sort of "bell-mouth", it wasn't pretty, but it was very soft pine from some cheap furniture, so it would deform nicely.

So I placed the sheet over it & clamped it down, placed the socket in the hole & whacked it several times with a mallet.

Here's the "female tool" if we're still allowed to say such things

Here's the male tool in place, about to get whacked with a mallet (note:- NOT a hammer - a mallet).


Here's a flanged lightening hole.

Good isn't it?

Flushed with child-like excitement I bashed all the others into the sheet & marvelled at how much lighter & stiffer it was (I didn't really)

Next job was chain drilling the hole for the filler - really not one of my favourite jobs, but not too bad in aluminium as it's soft enough to cut pretty easily.


Then I bent up the sides & tried it in the car. I think it'll be OK when it's riveted down. It needs a loose angle to attach it to the boot side wall, & a drain made up to stop it filling with water & I'll trim the bowl to height when the boot lid's fitted, but so far, quite pleased with it - 2 1/2 hours well spent 😊.

The only things left to do were clean up the filler hole, drill the holes it bolts to (which will also attach the bowl to the bracket) & see how it looked. Quite '50s techie I think - which is good 'cos that's how I wanted it to look.


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