July 14th, 2013

Lets see, where was I up to? It’s been a while. So long people were contacting me to see what was happening. I’ve been bashing here and there on the body so that’s making slow progress. I also had a go at rebuilding the rear axle again. I went to visit the Austin spares and came away with two old halfshafts and some other parts (brake pedal, and a spare wheel and a nice small gear knob). One half shaft is cracked unfortunately but the other was serviceable. I lapped it onto one of my hubs. I managed to put the differential halves on the lathe using the faceplate to mount them to. I carefully bored out the bushes to suit the later half shafts which are very slightly larger than the earlier sort. I had earlier had them hand reamed out but they were a little off centre so a light touch on the lathe sorted that out.

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Half shafts and boring out the differential bushes.

The new half shaft work but I still couldn’t get the meshing right. There were several reasons for this. First I was using the wrong blue! There are two sorts, engineers blue and marking blue. Marking blue, like I had, dries immediately. It’s used for marking out panels. You paint it on, it dries then you can scratch it off with a scriber to mark things out. Engineers blue is blue dye in grease so it doesn’t dry. This is that you need to check the meshing as it transfers form one face to another.


Different blues. You need the stuff in the tube!

I know this is probably obvious to most people but I just asked that the engineering shop for engineers blue and they gave me the marking out stuff in the bottle. I never knew there was a difference not having come across it before. You don’t know what you don’t know until after you know it!

The other issue was the crown wheel. The one I had was a 41 tooth one. The pinion is a 8 tooth but meshes with a 42 tooth crown wheel (it’s actually marked 8X42 on the end). The 41 tooth did turn but if felt ‘funny’. There is an 8 tooth pinion that will mesh with a 42 tooth crown wheel but not mine. Joss found in his parts a 42 tooth crown wheel so we tried that. That works much better but after messing about with that for ages I still can’t get the meshing right. Apparently this can be tricky on unmatched parts. I think the issue is the pinion isn’t far enough in the casing. To fix that I need to take apart the torque tube and shim the pinion spacer. The photos below show the meshing with no shims between the torque tube and casing. The second photos show with some shims added (which moves the whole torque tube, and therefore the pinion, out). At the factory things were set up so that the pinion was too far forward so it could be moved back by adding these torque tube shims. To move it close in I have to shim the pinion itself (so shimming the pinion spacer moves it in, shimming the torque tube housing moves it back out).

IMG_3979_1 No shims on torque tube.

IMG_3980_1 With shims between torque tube and axle casing.

It looks like the contact point needs to be further in which means shimming the pinion spacer so I will try that this week. You can see the spacer behind the bearing in the picture below. Mine was worn so I machined it then added in a hardened washer to take it back to the proper size. The only figure I have seen for the spacer length was on the A7 friends site where it said it should be 3/4 of an inch long. I measured another old one and it was about that.

IMG_3958_1 Pinion spacer.

I spent a day fiddling with that and got nowhere so instead I did more work hammering the body and also working on the remote gear shifter. I tried making a cranked linkage but it flexed far too much so instead I lowered the forward pivot point and used a straight bar linkage. I decided to make it completely solid rather that relying on threaded ends (which I am sure would come undone at some point) so I drilled out the threads and made the bar from a piece of solid shaft taken from an old printer (I always keep the steel shafts from dead printers – very handy steel!). I machined the ends of the bar on the lathe to be a nice fit into the clevis ends then silver soldered the ends on.

The gear knob on the end will be held on by a thread but I need to get an appropriate long bolt to make that from. The ball is just resting on the end for now hence looking wonky! I bored the end of the shaft out so I can silver solder the thread into it. It only just fit on my tiny lathe and I had to make use of the steady and grind up a special short drill bit to drill the end. The linkage runs parallel to the top of the transmission tunnel. Anything else looked a bit odd.

IMG_3987_1 Remote shifter.

Joss popped in and was disappointed I still didn’t have the rear wheels on and the skin sitting on the chassis. Looking about the garage it turned out I had enough clapped out bits to throw together an axle. Nothing you could run with but enough to get the wheels back on and the chassis rollable. The wheels do wobble since I only have an axle and no spare torque tube (the front of the casing is resting on a bar set across the springs to hold it in the right place for now) so I can’t do things up tight (everything is knackered anyway) but I was able to roll the car up the footpath from the big garage into the small one. I put the frame back on the chassis and temporarily set the skin in place. It’s not fully fitted yet. I need to trim the floor at the front to get it to sit correctly and of course the skin isn’t wrapped around the frame but you can get some idea of the overall look of the car now. It will get a new rear firewall once the skin is finished.

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IMG_3994_1 IMG_3997_1 IMG_3999_1

The body won’t look as deep once the bottom edge is wrapped around the frame of course. You can see the aluminium overhanging the frame around the cockpit opening too showing how much gets wrapped around. Still more hammering to be done but the skin is slowly getting smoother. It’s a slow process and quite hard work! it’s not the hammering arm that gets sore though. You only hammer gently. It’s the hand holding the dolly that you need to push had against all the time that gets really tired.

I have also been flattening my leather boot and bonnet straps. I wet them then left them hanging and also draped them over my recycling bin with lead weights on the ends to pull it down. They have flattened out nicely.

IMG_3962_1 Flattening straps.

So I STILL have a rear axle to mess with but at least the frame is on the chassis now and the skin on the frame. A little more fiddling and I can get it fitting properly.

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