Sorry for the delay but I've been out all day.
As I said, I already had all this stuff but the tin was bought from Wilkinsons a few years ago and was less than £2. If you're in England, you'll have heard of them. If not, they sell household and DIY stuff. You could just use stainless sheet if you can't get the tin but it worked out the perfect size for me and was already curved, so was easier to fit.
The picture #3 shows the remains of the tin after cutting, one is the top, which was just a push fit.
The main body of the tin was 3 1/4 inch diameter x about 4 inch high.
I simply cut acress the tin with a cutting disc to form 2 rings about 1 1/8 wide. It does not really matter about the size but I would say at least 1 inch is necessary.
The only reason I came up with that size is because I held a felt marker pen on a piece of wood, on the bench, and rotated the tin against it to get an even mark all the way round. You could make them wider if you wanted to.
I smoothed down the edges of the rings, then cut across them to form the open rings. It was very easy to cut accurately.
I then measured 7/8 inch from each cut end, drew a line across them with a square, put the end in a vice with the jaws level with the mark and bent them backwards to 90 degrees.
This left 2 tabs which I then found the centre of one and drilled a 6mm hole through it. I then clamped the two tabs together and drilled through the other tab to make sure they lined up when on the bike.
I had some 6mm stainless threaded bar (or studding)which I cut to two 2 3/4 inch lengths. I also had some 6mm id (8mm od) stainless tube from which I cut to two 1 3/4 inch lengths.
You could make these longer if you want.
I than simply screwed the stud into the indicator (turn signal) housing and tightened a 6 mm nut against it for extra security. (this is not strictly necessary but it just tightens things up a bit more).
I then passed the tube over the stud and put another nut on tight to keep it in place.
Then it was just a case of putting the ring around the fork shroud, passing the end of the stud through the hole and tightening another (nylock)nut on to the end.
I did make a boob on the wiring on the left hand bar though. After cutting and pulling the two wires from the right side with no problem, I tried it on the left but did not realise that the wires also go to the switch. I ended up having to split the sleeve open to repair them.
The only downside is that the indicators (being so big and heavy)do tend to bounce a bit when going over bumps. I don't know if this is that bad as there is some degree of shock absorbing created. The only solution would be to use heavier tubing. If I could get some to fit over the 8mm tube, I may try it.
Hope this helps.
