I found a strange forum on the Internet, with people building
their own cars! Some even making their own chassis, based on
the idea of the Caterham and many others, and helped by a book
published by Haynes. Build your own Sports car for as little
as £250. The book now seems to be out of print, but a new
one hit the shelves in February 2007 called: - Build your own
sports car on a budget.
Chris Gibbs is the moderator. He posts amendments to the
book, helps with ideas and drawings for variations from the book
covering gearboxes, engines etc. Other builders supply ideas
and answers to many questions, pictures, drawings and support. All
in all, a community to the same end.
Another forum is http://www.locostbuilders.co.uk/ This is a generic builder forum and can provide lots of information and chit chat.
23rd June 2007
Bought the board to build the chassis on 19 mm ply x 2440 mm x 1220 mm, also a load of scant to strengthen and keep it flat. A small tub of white paint to help with the marking out. Then a week working away from home before I could get back in the garage.
5th to 7th July 2007
Back in the garage, another quick coat of white paint on the board, worked out things like a cutting chart, ordered the steel from K Steels, expecting delivery on Friday. Started to mark out the chassis on the board and fit blocks to keep the bars in place.
Steel arrived Friday morning as expected. Raining, so continue with the board until finished.
I know that it is bad practice to cut all the steel up but I could not store it without, so, out came the band saw and over a hundred cuts and several hours later; I had a pile of smaller lumps of steel.
The bandsaw is one of the best things I could have in the garage for this build, it is certainly a lot easier then sawing by hand. It can make cuts up to 45 degree angles, with the milling machine being used for all angles above this using a large end mill.
With the board now on legs, starting to lay out the bottom of the chassis, cutting angles as I go, again with the bandsaw. Slot all the pieces in place, weld up the front frame as it would not hold it self and this is what you get: -
It needs tack welding together before I go any further.
14th & 15th July 2007
A bit more over the past week when time allows, tacking the frame together and then this weekend start to fit the uprights and top frame, tack welding it as I progress.
25th & 26th July 2007
Did not get chance over the weekend, so had a go during the evenings. What a disaster! I added four diagonal braces, two in the sides in the arm rest area and two in the top seat back area. When I checked them I found the seat back diagonals did not match and discovered the back was leaning over by a degree or two. Enough to make one corner to corner measure 125 cm and the other 126 cm.
So the tack welds were ground out, the back braced, pulled and hammered and then re-tacked. I also managed to set some paper's on fire, so need to take a bit more care with combustibles in the area.
28th July 2007
Cut and angled the pieces for the rear suspension area, jigged it up but have not attached to the chassis as I need some plates for suspension area.
I have ordered the plates from a supplier on the forum and they are being laser cut, bent and should be with me in about two weeks. Also on order are Maxi ball joints and Transit drag link ends, basically to make sure I can get the ball joints, I have been told by a motor factors they are now obsolete!
Spent enough money on it this month, £141.12 on Steel tube, £163.18 on the laser cut parts and £69.92 on the ball joints and drag link ends. £374.22. I think some of my "not used for a year or so things" need to go on that Internet bid thing!
11th & 12th August 2007
Back from holidays this weekend so another chance to work in the garage, attached more diagonals, started on the transmission tunnel, attached the rear sub-frame for the differential. The pile of tube bits slowly getting smaller as I put them into place.
As I am building the chassis as the book, I have starting to look for a Sierra as a donor, initial thoughts are: -
17th to 26th August 2007
Work on the Roadster has been a bit slow this week, forgot to go and buy more 19 mm RHS must get some when possible to complete the back section.
The laser cut parts arrived and happy with them, saved my a lot of time and effort trying to make the pieces the hard way by hand. Managed to bend the rear tubes RP1 & RP2 on an old pipe bender I have in the garage, new it was worth keeping!
I attached the rear top suspension points and then realised I had then at the wrong end so out came the grinder to take them back off and then another go, think I got it correct this time.
Hoping that, in a few weeks, all the sections will be fitted and then the chassis can be fully welded. I have to make up the jigs to attach the front and rear wishbone points and tack these in place, 4 tubes for the transmission tunnel and finish off the rear of the car, perhaps three to four weeks then!
1st to 3rd September 2007
Done a bit more, progress is slow, as I am not getting a lot of time in the garage. Have attached the round tube, finished off the transmission tunnel and done the steering supports. Wishbone brackets to tack on next, jigs first!
15th September 2007
Just an update on recent progress, the chassis has not changed much from above. I have made the front wishbone mounting jigs and have tried fit the wishbone brackets. I seem to be 8 mm ( 4mm per side) out on the lower front frame mountings and this seems to be a mixture of mounting the uprights inward slightly from book and the brackets having at most a mm out on height. Nothing to major and will be sorted either with a packing piece to fasten the brackets onto, or I might just rebuild the front frame before the chassis is welded.
Pre-fabricated wishbones have been ordered from a supplier on the forum, and the parts should arrive in 3 weeks time. I also received a few missing pieces from the laser cut parts, this was down to the book not always listing the correct number wanted, so until you build it you never know!
Lastly for whenever I get the donor car I am having a straight cut reamer reground to a 1 in 8 taper required to modify the Sierra uprights to take the Maxi ball joints.
This should also allow me to make my own mushroom inserts for the tops of the Sierra to take the Transit drop link ends. Nothing like a bit of forward thinking.
So although not much is going to show over the next few weeks. Once the wishbones arrive these will be fitted to the jigs to make sure all is a good fit and the brackets will then be welded in place, then I also hope to have the chassis fully welded.
Simple cutting jig to help with cutting compound angles
On some of the steel tube sections you have to cut two angles at the same time, such as the 14° and 26° angles on FF2 and FF3. Well with a normal band saw or cut off saw, you can set one angle and have to find a way to set the other.
So perhaps this little idea will help. It requires a bit of maths and a few bits square tube, I used 19 mm. The maths bit is all about a right angled triangle.
Tan (ø) = o/a or opposite over adjacent sides. The opposite in this case is the 19 mm from the tube and Tan 14° = 0.2493, so the adjacent length works out to be 76.2 mm or close. a = o/Tan (ø)
So I made a jig with these two lengths as in this picture: -
The opposite length is the top piece of 19 mm tube and the adjacent length is 76.2 mm or closest I could make it.
So you rest a square tube on the edges and it will sit at an angle of 14 degrees. Put this in the bottom of the vice, rest the tube across the corners then clamp up. Set the cut off or bandsaw over at 26 degrees and the compound angle can be cut in one go. The jig shown has two angles on it, 14 on the left and 17 on the right. Hope it helps.
22nd September 2007
I have remade the front frame and aligned the two verticals U1 and U2 to meet against the brackets when using the front wishbone jigs. Therefore I should have less of a problem when they are attached. The old frame has been re-cycled, as in cut up so I may reuse the straight bits if needed. Time has also been spent rearranging the contents of the garage to allow me to walk around the chassis without having to climb over everything.
6th October 2007
Bit of a gap again before work continued on the chassis. I have reworked a Cosmo Welder, putting on a Euro torch and a separate power supply for the wire feed. Results with it are now quite good. It is a 130 amp device with bottle carrier and top lid containing the wire. Anyway have been doing some welding with it on the chassis, actually started last weekend but only a small amount. Managed to get a few hours in today before my welding mask started to fail! Tried replacement batteries but with no change so think before I dazzle myself altogether I need a new mask. One comment, there are lots of joints to weld up and lots of grinding to do as well in my case!
Views here with the chassis upside down and one on it's side. I am trying to do all the "from top" welds, then turn it over and do all the welds that are once again "from top", then turn on side etc. Hopefully this will make it easier for me to do. Must get them walls painted sometime.
As I mentioned above, I had cut all the steel tube in one go, well as the chassis progress continued I found the odd error in my cutting chart, things like missing the odd metre from a piece of bar. Small discrepancies in the book where the appendix is not listing quantities of tube, so I found these errors when trying to put it all together. Such as not cutting 4 off SB1 and 2 off SB2, 2 off is this and that. Cutting FF2 and FF3 too short at 320 mm instead of 359.5 mm. So all in all a few mistakes, so to help any others I am including a link to my cutting charts at the bottom of the page. As I find mistakes I will update this link. Saved as a normal text file it could be opened by any basic text package. Do not forget this is for an as book build.
Updated 25/08/07 Cutting length chart is here for 25 x 25 mm tube
Updated 25/08/07 Cutting length chart is here for 19 x 19 mm tube