Re: Adjustable A frames
Posted: Fri Dec 04, 2009 12:30 pmYes Paddy. Exactly. This method would get round all the issues with ass'y and welding in close quarters to components that look to not like too much heat. I would not take off the entire component by 'undoing' the brazing. Although I do see where you are coming from. I suspect this could be tricky and might end up with (another!) scrap A frame. I think cutting out 180 mm of tube and fitting the 'unit' then refitting the tube is a good solution. A 'slip' of pipe over the joins at the 180mm cuts to just set the mind at rest (The butt welds alone would probably suffice). This would allow fitting the unit properly and re-taping of the inserts etc to make sure alignment (using the lathe) is right, threads are correct and not heat effected.
It was interesting to learn that Gerry had one of his Kelv*** ones pick up and seize also. Hmmm!
Geoff has very kindly sent me 4 A frames to fiddle with. All have bent tubes and 1 has a twist. The ones with the bent tubes could benefit from and be repaired by the above method. With or without adding the adjusters. I am confident that using the correct weld type, these a frames could be repaired. The bends are in the correct (rearmost) tubes. Front tubes are also bent but only very slightly and could be straightened on the press.
Now... Consider this.. Lets assume that Lotus made these A frames quite accuratly. If we cut out say 200 mm of (Bent!) pipe and replaced with new pc of pipe at 202 mm long we would have built in 2 mm approx' of toe in. Enquiries have told me the figure should be around 2 mm each side ''or a bit more'' (said my question answering device!). So.. we would have approx 4 mm toe in added to rear axle. Non adjustable of course, but...Would it need to be for a st'd road car? And of course would be checked for alignment tolerance. I would bet they would not be far out. If indeed out at all.
I am close to trying this. Fitted with the poly bushes etc and nicely powder coated.
The A frames are easy to remove & replace, so a test would be not a problem. Do the mods, fit and check alignment. All ok? Remove, blast and powdercoat, refit and forget!
Just a thought...
What do you guys think? .. Gerry??
Here I go again !
Alex...
It was interesting to learn that Gerry had one of his Kelv*** ones pick up and seize also. Hmmm!
Geoff has very kindly sent me 4 A frames to fiddle with. All have bent tubes and 1 has a twist. The ones with the bent tubes could benefit from and be repaired by the above method. With or without adding the adjusters. I am confident that using the correct weld type, these a frames could be repaired. The bends are in the correct (rearmost) tubes. Front tubes are also bent but only very slightly and could be straightened on the press.
Now... Consider this.. Lets assume that Lotus made these A frames quite accuratly. If we cut out say 200 mm of (Bent!) pipe and replaced with new pc of pipe at 202 mm long we would have built in 2 mm approx' of toe in. Enquiries have told me the figure should be around 2 mm each side ''or a bit more'' (said my question answering device!). So.. we would have approx 4 mm toe in added to rear axle. Non adjustable of course, but...Would it need to be for a st'd road car? And of course would be checked for alignment tolerance. I would bet they would not be far out. If indeed out at all.
I am close to trying this. Fitted with the poly bushes etc and nicely powder coated.
The A frames are easy to remove & replace, so a test would be not a problem. Do the mods, fit and check alignment. All ok? Remove, blast and powdercoat, refit and forget!
Just a thought...
What do you guys think? .. Gerry??Here I go again !
Alex...
