Little something to add to this. Progress got held up as I managed to injure myself three days after my last post in this thread in November last year. I needed a small operation and I didn't touch a tool for a few months. I've been back at it for a bit now though.
After a lot of research, deliberation and measuring I have got my FU tubes tacked in. The tubes are notoriously troublesome to fit and they carry some of the front suspension brackets. I offered up my top wish bones (That I'd bought about fifteen years ago) and after a lot of head scratching I realised that they didn't have enough castor on them. They had been built to the book spec which is one of the many errors in the book. If the top ball joint isn't set far enough back I don't have enough castor and the car wont self centre very well or at all. I need about 22mm of offset and the wishbones I have give only half of that.
So I have made a wishbone jig. Tube will be ordered next week when I'm back at work as I'll be chained to the house then for the delivery. I understand that the tube needs to be bent to clear the coilovers due to being less central than before. I should really get some coilovers bought to ensure I have clearance.
I milled a 16mm slot to accept a steel bushing which is 16mm OD for most of its length, this locates the ball joint end of the wishbone. The bushing is welded in so it doesn't move. The slot was milled far too long as I hadn't measured exactly where I wanted it at the time. The steel bushing is threaded internally M10. The bush grows to 25mm diameter to ensure that it lines up the the threaded end of the wish bone, this also sat outside of the slot and gave me something to weld to. They should all be concentric anway but it is a good visual aid. The bush is not threaded at the 25mm part. I just made a 10mm hole in so I had a clearance in case the weld distorted the bush too much, I was concerned any threads might be distorted and bind. The M10 thread and nut hold the wishbone end in place. The threaded end of the wishbone is threaded m18 fine. I've made a 16.5mm OD aluminum spacer/rod to fit inside and the spacer is threaded interally m10 so it all lines up. I used aluminium as it wouldn't damage the steel threads.
This is the locating bush welded in. The bush has been turned to a particular height so the wishbones are the correct length.
Threaded wishbone end held in place with M10 thread. I need clearance to weld down both sides. so the bolt holding it in place is a good solution. You cant see it but there is an ally spacer rod 16.5mm OD threaded internally M10 undernead the two nuts.
This is the old wishbone overlaid. You can see the extra offset showing on the jig. The picture might also make my garbled nonsense a little more clear.
The other side of the wishbone is a much more simple affair. I have 29mm ally bushes drilled m12 inside the tubes that will house the poly bushes. The m12 thread makes everything line up and that the two tubes were spaced the correct distance apart using nuts on the long thread. Locating brackets all welded in. It's not really my idea. I got the measurements and most the basic jig design off the locost forum. The silly threaded arrangement for the pointy end is my own idea as the pictures that I had been looking at weren't very detailed so I had to come up with something myself. I haven't used the mig in a while and it shows.
After a lot of research, deliberation and measuring I have got my FU tubes tacked in. The tubes are notoriously troublesome to fit and they carry some of the front suspension brackets. I offered up my top wish bones (That I'd bought about fifteen years ago) and after a lot of head scratching I realised that they didn't have enough castor on them. They had been built to the book spec which is one of the many errors in the book. If the top ball joint isn't set far enough back I don't have enough castor and the car wont self centre very well or at all. I need about 22mm of offset and the wishbones I have give only half of that.
So I have made a wishbone jig. Tube will be ordered next week when I'm back at work as I'll be chained to the house then for the delivery. I understand that the tube needs to be bent to clear the coilovers due to being less central than before. I should really get some coilovers bought to ensure I have clearance.
I milled a 16mm slot to accept a steel bushing which is 16mm OD for most of its length, this locates the ball joint end of the wishbone. The bushing is welded in so it doesn't move. The slot was milled far too long as I hadn't measured exactly where I wanted it at the time. The steel bushing is threaded internally M10. The bush grows to 25mm diameter to ensure that it lines up the the threaded end of the wish bone, this also sat outside of the slot and gave me something to weld to. They should all be concentric anway but it is a good visual aid. The bush is not threaded at the 25mm part. I just made a 10mm hole in so I had a clearance in case the weld distorted the bush too much, I was concerned any threads might be distorted and bind. The M10 thread and nut hold the wishbone end in place. The threaded end of the wishbone is threaded m18 fine. I've made a 16.5mm OD aluminum spacer/rod to fit inside and the spacer is threaded interally m10 so it all lines up. I used aluminium as it wouldn't damage the steel threads.
This is the locating bush welded in. The bush has been turned to a particular height so the wishbones are the correct length.
Threaded wishbone end held in place with M10 thread. I need clearance to weld down both sides. so the bolt holding it in place is a good solution. You cant see it but there is an ally spacer rod 16.5mm OD threaded internally M10 undernead the two nuts.
This is the old wishbone overlaid. You can see the extra offset showing on the jig. The picture might also make my garbled nonsense a little more clear.
The other side of the wishbone is a much more simple affair. I have 29mm ally bushes drilled m12 inside the tubes that will house the poly bushes. The m12 thread makes everything line up and that the two tubes were spaced the correct distance apart using nuts on the long thread. Locating brackets all welded in. It's not really my idea. I got the measurements and most the basic jig design off the locost forum. The silly threaded arrangement for the pointy end is my own idea as the pictures that I had been looking at weren't very detailed so I had to come up with something myself. I haven't used the mig in a while and it shows.