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1929 chassis straightening - Howard Wright - 30-04-2019
Hi All
I have just acquired a 1929 chassis in bits. It will be the basis of a reproduction "Cox" sports tourer. There is one around already (RX 2740) but I hope there will be room for another one! The chassis is all there but there are a couple of questions I have.
Firstly my 1930 RK has chassis cross members with open ends and support for the body at its extreme ends. The acquired chassis cross members are shorter and have webs that have been folded in. Both types appear to be "factory". Purves shows the open ends on a 1932 chassis and the folded web type on several diagrams prior to 1928. I can't find any reference to when the change actually happened. Did this change occur with the wider AD tourer in late 1929?
Secondly the offside chassis rail is bent (vertically but not laterally) and cracked across the rear engine mount hole. I've read Parazine's thread on restoring a top hat but his chassis was bent laterally and I think he has used new straight rails. My cross members seem pretty straight too. I'd rather keep the original rail so....
Options for repair... Cold bending back to straight then welding up the crack?... Heating to cherry red straightening then welding a strengthening plate under the top flange?
Advice very welcome
Cheers
Howard
RE: 1929 chassis straightening - Hedd_Jones - 30-04-2019
Howard my March 1930 AE has the open crossmembers.
RE: 1929 chassis straightening - Ian Williams - 30-04-2019
The Cox was a creation of the furtive mind of Barrie Argent, I remember him building it when I was a neighbour in the 80's. I think it is fair to say there is some debate as to whether this is the only one ever built or Barrie copied an existing period design, either way quite a pretty car on a vintage chassis. You are essentially correct the chassis crossmember's changed in 1928, and if you intend to build a Cox you will need the shorter crossmember. Rails can be straightened by careful use of a hydraulic press, and cracked areas repaired, however there is always a stress point where the repair has been carried out. To counter this my friend Joss devised a period looking top hat section which can be hot riveted inside the weakened area of a cracked chassis once the crack has been repaired. Of course you could simply weld a plate inside but many repairs I have seen like this look somewhat agricultural in execution.
RE: 1929 chassis straightening - Howard Wright - 01-05-2019
Hi Hedd and Ian
Thanks for the input. My chassis is February 1929 so I had assumed that the change would have occurred with the introduction of the new AD body mid year.
The 1927 Cox Sports Tourer is described in Bryan Purves Source book on page 128. I had assumed that this reference would have made it authentic to 1927. But you could be right and the car could well have been from Barry Argent's fertile imagination and reported as original! In any case its a pretty car, quite easy to build and relatively strong.
This suits me as I hope to do some vintage trials with it. So your comment on strengthening the chassis are very useful. A top hat section under the repair is a great idea and maintains the look of the vintage chassis.
Cheers
Howard
RE: 1929 chassis straightening - Parazine - 01-05-2019
I have also assumed that the change in chassis cross members coincided with the AE body introduction, or at least around that time. I had a mid 1928 Chummy years ago with closed cross members and my current RK (Oct 1929, chassis 99000 and something) has the later type, so the change occured somewher between.
Regarding the straigtening, I'd look at trying to use some kind of press or straigtening device, someone suggested a rail straightener on my thread. I had to use replacement rails because the originals hade been extensively broken and then "butchered" back together with lots of heat. Try and keep heat away except where absolutely necessary as the chassis were apparently heat treated in the factory.
RE: 1929 chassis straightening - Howard Wright - 01-05-2019
Thanks Parazine
That is good advice. I've cleaned up the crack area and it seems to be local to the rear engine mounting hole so I should be able to weld it easily and probably weld in some form of strengthening U section inside the top hat section.
Cheers
Howard
RE: 1929 chassis straightening - JonE - 01-05-2019
Perhaps we could start another thread on the Cox history.... I'd be interested to know what is in the Source book but this looks very plausible in its contacts and right in the hotbed of Gordon Englandville, Putney... https://www.watfordobserver.co.uk/news/569979.from-putney-to-coxs-corner-watford/
Sadly nothing on coachbuilder register but must be some other references to support the images which do exist.
RE: 1929 chassis straightening - Howard Wright - 01-05-2019
Thanks for this Jon
Yes it does look the kind of establishment that could have dabbled in cars. I'm not sure I can reproduce the source book here given copyright restrictions but I can say that the only images shown of the car are clearly of the current "replica"? by Barry Argent.
By the way I've checked the rear cross member for possible signs of a painted chassis number but there is nothing there.
I do have a heritage certificate though which shows it to have been a tourer (A8 car number) and .....wait for it...export!
Cheers
Howard
RE: 1929 chassis straightening - Greig Smith - 01-05-2019
Howard when I was starting off with my new single seater, I used a '28 chassis that had been hanging on the various workshop walls for 40+ years. It was bent like a banana and had multiple holes & cracks in it. As I wasn't going to use the original engine mounts, I fitted a length of 38x38x2mm square tubing into the chassis from underneath & welded it all together
I first cleaned up the inside of the chassis really well & the outside of the square tube, coated both in a thick layer of Wurth zinc rich weld-thru primer and while it was still wet I slid & hammered the tube into place. It goes from the nose piece to the brackets for the brake cross shaft. To secure it I clamped it with some large C clamps and blocks of wood. This effectively straightened the sagging banana curve
I welded it to the chassis at 1" intervals. As I wasn't using the original engine mounting holes I welded them to the tube and I had also cut the cracks well open with an angle grinder & I welded those closed & simultaneously to the tube as well.
Not the solution perhaps for the purist, however the bottom edge of the square tubing could always be sectioned off to form an inverted U inside the existing chassis rails. As I was building a race car I wanted the strength, hence the 2mm wall thickness.... but on reflection 1.6mm would have been just fine & less weight
Aye
Greig