My chassis build

[HandyAndy]

have you sat in the drivers area with an imaginery steering wheel in your hands yet???? thats a really good feeling too

we,re all going mad really

andy

[geeman]

Well i wanted to sit in the 'drivers seat' but was afraid the plywood might break as its aqueaking alot already

Ive now tacked on the front nose and 2 of the uprights

[geeman]

Ok, well i have a small sproblem on my hands. I welded on tr2 and tr1 onto the uprights u3,6,7,8. This wass all a bit difficult and i had to force everything into position. Once i welded tr1,tr2 in i test fitted u1 and u2 and heres my problem. They both are too short to reach tr1 and tr2 at the 24 degree angle. I think this is because when i welded tr1 and tr2 on i had to force the front frame forward abit,so it may have twisted forward stightlyso ff4 is no longer 74mm behind ff1, more like 65ish. So i measured the height of my chasssis and its meant to be 355mm but at the very front its 364 but is on a constant gradient down to the required 355mm as go go down tr1 and tr2. Im thinking i should just extend and ajust angles on u1 and u2 as it isnt going to really be a problem i think as at most its 10mm out in places but mosly my dimensions mach the books+-3mm which is pretty good i think.


Oh sh... i just made handy andys mistake ive welded u7 wrongly........uhhhhh uhh. Time to get the cutting discs out as my tig welds dont come off easily.

[mark]

Good to see your build progressing nicely but its prob best to try and sort out your dimension probs now whilst at any early stage. 10mm doesent seem alot but could cause more problems later.

Not teaching granny how to suck eggs (shout at me if i am!) but only a couple of small tacks are required on the corners of the tubes until the chassis is complete and needs fully welding. So any tubes can be easily be removed/repositioned without any fuss if you find an error.

There was times when i tacked things in and then had to change later and its very frustrating but you will only make the chassis once so try and get it perfect 1st time a bit extra time farting about now will make sure you have a nice sqaure straight chassis to enjoy for years to come

[geeman]

The thing is to fix the 10mm thing i will have to grind off loads and weld tr1 and tr2 back and thy gave mee soo much hassle.

I know what you mean about tacking welds, its just when i start, i get thinking.. oooo ,tiig welder, cool and stufflike that and often get carried away and it ends up abit(alot) more than a tacked weld.

Well i took u7 out but have given up for today and will carry on tomorrow. Im too tired now

[mark]

I think it will be worth it tho, that 10mm might stop fabbys bodywork fitting as good as its meant to!

I know what you mean about getting carried away with welding when i was serving my time as a plater i loved tig welding such a nice clean weld

When i welded up my chassis i started tig but reverted to mig coz it was taking forever

[AshG]

you must tack it first then fully weld it in stages otherwise it will never be straight

+-3mm is way to much you need to be working to +-0.5mm

if your forcing things into place your doing it wrong. simple as that. every part should fit perfectly like a puzzle

[geeman]

awww. im not sure about fixing this, oh well, will sleep on it.

Also i would have bought a mig, as for a start its cheaper(considerably as the welders cheaper and you can buy argoshield instead of pure argon which is loads), but ive never mig welded before, only ever done tig, so i thought id just get a tig.

Also i think fabbys nosecone should still fit as its not like 10mm higher, the actual from bit is kind of twisted forward(hard to explain, meaning tho only mods needed will be the diagonal supports and u1, u2.

[mark]

If you have mastered tig welding you will pick up a mig welder and be producing good welds within half an hour it really is that easy.

If you get the chance to aquire one i would because they are very versatile and faster than other methods of welding.

[mark]

Originally Posted by AshG

you must tack it first then fully weld it in stages otherwise it will never be straight

+-3mm is way to much you need to be working to +-0.5mm

if your forcing things into place your doing it wrong. simple as that. every part should fit perfectly like a puzzle

This quote above is probably good advice for someone starting a chassis, depending on your backround tolerances are different to people, when i was plating +-2.5mm was acceptable on most jobs, but when i done a spell in a machine shop +-0.5mm was huge on some jobs

On a chassis everyone should be aiming for zero tolerance i know in the real world this is almost impossible especially when its welded but we should strive to be as exact as we can.