My chassis build
 

Well i thought i may as well post the progress of my build. So id call today day 1 of my build as yesterday i waited until 4ish for the steel to arrive so didnt do much. Ive So far cut all thebottom base lengths and tacked them together. some difficulty i did have was getting it all to fit to the specified dimensions, as wehn i screwed the wood blocks in to the build board, i had to really force the metal in place to get it to fit, but got there in the end. Also today is the sencond day ive had a working tig at home and am loving it, but in trying to save money im being really stingy about how much gass i can use and set the gas flow rate as low as possible every time. :rolleyes:

Pics of today:

looks like a nice big work area :D

your not hanging arround on the chassis either.

Lol, yeah, i knew it would be a tight fit, but i guess ill have to live with it. :D

The rage 3 compound mitre saw is literally saving me hours though as i had to cut br8 and br9 with a hacksaw as they have 70 somthing angle on it which the rage3 wont do and it took me ages and was painful so id rather stick to using the rage 3. It should make the building of the front bits ff1-ff4 a breeze and i hope to finsih that today as well. However one downside o the saw is the ammount of metal swarf and in my size build area i keep on having to vaccuum to stop stepping of leaning on it. I even have a pair of tweezers for removing metal splinters as my hands re full of em'.

Looking good mate! Realy good feeling isnt it?
Keep up the good work!

well done Geeman, looking good :cool:
the space will get tighter by the day ;) :D

enjoy your build.

andy

dont worry about the space im building in a smaller area. in fact i think i have the smallest build area on the whole froum lol

as for the swarf! wait until you have to grind the welds back! thats the horrible messy bit.

Im tight on space too! building in my garage which is in a modern house ie not big enough for a modern car! but im managing. As AshG said grinding for long periods in a confined space is messy:eek:

i rigged up an extraction system with a small centrifugal fan and some 4" flexible hose with a clamp to hold it near work piece which helped alot, especially when welding up chassis.

Ok well i tacked together the nose )ff1-ff4) yesterday afternoon, but it was arel pain to get the angles on ff2,3 right as i kept cutting them wrong as i got abit confused and ended up wasting some(about 80cm) metal. Well ill probably continue with the build later today and lets see where i get then.:D As far as i can see im progressing well.:D :)

Edit:
forgot to add pics

Here we go

well done Geeman, don,t worry..... i think the front frame has caused lots of builders a few head scratching moments, it certainly did for me :o :eek: .
its a great feeling as the chassis starts to gain in height.
well done mate:cool:

andy
( you,ll be dreaming/nightmare of FF1 to FF2 To aaarrrggghhh ) :D

yup, it really is a great feeling, i just heald the nose in place for a few minutes and just stared at it...:o :rolleyes: , but really the kind of 2d to 3d transition really makes you feel good.

(we really should abbreviate the phrase 'really makes you feel good' as the ammount of times we all say it is going to get out of hand:p :p )

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

we,re all going mad really :eek:

andy

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

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

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 :mad: :mad: uhh. Time to get the cutting discs out as my tig welds dont come off easily.:(

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 :cool:

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.:p :p

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

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 :cool:

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

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

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.

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.

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 :eek:

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.

Well every single piece of mine was cut to the exact size im mm+->0.5mm, and every angle was exact, as i measured every peice several times before putting them inplace. The errors have happened while welding casuing distortion and metal to twist. For example my chassis isnt completely flat on the board anymore, its risen about 2mm after welding in places, but the +-3mm i was talking about is what things like diagonal sizes between welding a square.

Also i bet some people out there who will read this thread and are making there chassis will go 'oh s###' as they realise theve been working to much larger tolerances than 0.5mm:p :p :p

on a more serious note, i also realise for many having things like magnetic clamps could have made your lives easier, but ive only got 5 g clamps and a set of welding clamps atm, and im struggeling with just those to hold things in place for welding:o

:D i didn,t actually make this mistake, it almost got me so thats why i said to be careful about U7 as it is easy to get wrong :p

may i make a suggestion said with all due respect....... slow down a bit.......
yes it is very tempting to get on with it & get it done, i for one have got mine rolling in a fairly short time, BUT if you have the 10mm out at the front now plus the odd 3mm +- here & there by the time you come to fitting your suspension brackets it,ll be a nightmare to get the whole thing to come together, please accept my apologies if this sounds like "sucking eggs" but deep down we all want you to achieve a good build.
i hope you are ok with my suggestion.
stop, take stock of where you are with the dimensions & correct them.:cool:
i,m sure each & everyone of us that has built the chassis have made mistakes but they must be put right at an early stage.
best regards
andy

Ok, after reading all your advice, and to be honest all of you are really telling me the wright thing to do, its just im kind of in the 'denile' stage of thing(:p ), i went out to recheck everything, check measurements, angles... Here are my problems(ps having a book to hand may be handy, unless you know the diagrams off by heart). atm, the main thing is that u1, u2 dont fit in properly. I tried to figure out why, starting by measuring all the lengths. The only length that i cut that was out were ff2, and ff3, and the longer part for ff2 and ff3)the 290mm bit is about 292mm, but i think this is because the bend in the tube isnt perfect. Ok well what i said originally about ti being 9mm off if wrong, as i realised when i was measuring it i had taken all the clamps of the board as i needed them to hold tr1 and tr2 in place for welding. The meant that the whole thing has been raised by about 5mm and was supported by friction on the wood blocks that were used as guides along the drawings. This means that the front is actually 359mm not 355mm. the gap between u1 and tr1 is around the 4mm. So im nopt sure as to how to lower the frond without redoing the nose. I could also try cutting the bottom of ff2 and ff3 with a cutting disc and then weld that back to ff1 to fix it.

Also i was saying earlier that fitting tr1 and tr2 was very ight and required force as u3,u6,u7 and u8 may not have been welded completely square to the base. So i had to just bend it abit, but i was aware this would happen while welding, so i had only lightly tack welded u3 and u6-8 to the base.

Also the 3mm tolerance i was talking about only really applied to the diaganal between rectangle br7-10 which was just over 805mm rather than 808mm. Apart from this everything else is perfect:p

without actually seeing your chassis i think the main cause of the problem is more likely to be as you have said, caused by movement in the chassis from fully welding some of the pieces........ can i ask if you have fully welded BR1 BR2 to BR3 & BR4 ? as if you have then maybe this is why the chassis has been raised at the front ?

if so you might be able to cut the above out & re do them which hopefully will bring things in line for the front frame.

andy

ok.. umm imm trying what your saying, but first, can someone try and explain to me what figure 4.10 is saying on page 39. It doesnt make any sense to me:confused: it may not actually be the dimension problem, it might just be that i cant fit u1 and u as im not sure how they attath to tr1 and tr2 respectively.

if you place U1 as said in the text in the book square to BR7 then slide the piece U1 along & under TR1 then the top front corner of U1 should be aligned with the outside edge of TR1, suggest you clamp it in place then do the same in opposite hand with U2 & TR2, clamp that as well then look at the diagram at bottom of page 38 you will see that you need to achieve 361mm between the bases of U1 & U2, that is what is most critical for these uprights ( as long as they have been cut to the correct length & angled correctly) as they give the mounting angles for the upper rear front suspension brackets.

one question..... do you have the "first edition" book or the revised edtion thats states it was re printed in 2008?
as this may be relevant.

andy

I have the reprinted one from 2008 that has the corrections. Umm let me try what you said, ill be back in 5 min;)

ok, well i still dont get the diagram on page 39, but i think i shouldnt get so worried as it actually fits, there is only about a 1.5mm gap which can be fixed by lowering the nose very slightly, but im wondering if thats even nessacasy. look at attached pics.
ALso is there a way to attatch pics without uploading them to imageshack or equivilant??

looking good, did you get 361mm between the bases of U1 & U2 ? ( a little tip..... draw a center line down the length of your build table & scribe the center line on BR7, 10, 11 & 12 ) this will come in handy also later in the build.

how high is the very top of TR1 & TR2 & what is the distance between them( at outer edges) where they meet the front frame? sorry if this means going into your garage again, just trying to work out your dimensions to be able to help if i can.

andy

Well can you see the blue line second pic in the abouve post on br7, ive done 2 of those 361mm apart so yes. The distances from tr1 and tr2 is exactly as per the book(627mm) and there seems to be nothing wrong with that.
The problem is however that on the side of tr1 it is about 357mm and the side of tr2 it is about 359mm high which means the top bars are 2 amd 4mm to high. Now this is simply(or not so simply) because of ff2 and ff3 being too long, which can be solved by cutting along the blue line drwan on them(see pic) with a cutting dic, and then welding back onto ff1. That should hopefully solve the problem.
I thought id include pics of the build so far aswell, and im surprised that ive done soo much and its only day 2. Alsotheres a pic of where u7 use to be:o







Handyandy, i really dont mind going in the garage, if anything, it better than being in the house, and cooler than the house at this time of the year, but more importantly, theres a welder there.

Might be worth checking tr1 for straightness by looking down the length as a slight bow may account for the slight discrepancy. Seeing your pics jogged my memory that a couple of pieces of mine seemed to be a little out even tho everything was cut pretty much bang on and this was down to some of my steel being slightly bowed :mad:

Is it the same situation on both sides?

Those tacks are a touch too big so will have twisted things a bit but im sure you will sort it :) just a tiny tack on opposite corners is enough at this stage, its supprising how strong it becomes once triangulated even with tiny tacks :cool:

Geeman,
yes you are doing well, but lets get this front end sorted.
it may not be as easy as you say to just cut the bottom of FF2 & FF3 as where the bend in these two pieces is positioned it is critical to where you place the front upper suspension brackets, do me a favour please & go & get the measurement from the build table to the point of the bend in the FF2 FF3 at the outer most position, as this will determine the position of the suspension brackets mounting( i know you haven,t even thought that far ahead but it needs to be correct from where you are up to at the moment) hope i,m not being a pain in the butt? :o ;)

andy

Yep, its the same situation on both sides of being too high, but you are correct, there is a bow in it, but thats becasue i did that to make it fit as the nose was too high to tr1 and tr2 are being strssed alot as the are being bent upwards atu3 and u6 so they reach the extra height of ff4, but they are bent ever so slightly, whcih will be fixed by lowering ff4

im not completely sure as to what you mean, but i think this is it. If you look on the top diagram on page 162(or the drawing for ff2 and ff3 in appendix 1 if you have the old book which may be different) the bit thats meant to be 69.5 is about 69.5mm, but the bit thats meant to be 290mm is about 294mm and 293mm which is what is making it higher i think. Hope that helps.

Also id much rather get this fixed now than have bigger problems later, so any help is much appreciated.;)

yes i think you are correct, the bit that should be 290mm , as long as you have the 69.5 to the bend & the chassis is 355mm from the build table to the top of the chassis then if so it should all be ok, :)

lets say you cut the two FF,s to the reqired 290mm will this then bring the top of your chassis down at the front to 355mm? if so then i think you,ve cracked it.:cool:

sorry if i was being long winded but i was trying to make sure the suspension bracket placings will still be correct for later in the build.

also in an earlier post you made you mention that the top of front frame was now not 75mm behind FF1, have you cut TR1 & TR2 to correct lengths? as thats the only reason i can see that you had to push the front frame forward a bit, ( this needs to be correct for suspension brackets, yes those pesky suspension brackets :D )

cheers
andy

That sounds like could be the problem with front frame.

As Andy said The position of the suspension brackets is critical but as long as you use the jigs and dimensions as described in the book they will end up in the correct place. Its still best to have everything as close as you can though, some people have said they needed 3mm packing behind the upper front brackets to make them fit so dont worry too much ;)

Well it is just under 75mm as forcing tr1 and tr2 to join ff4 caused it to push ff4 back abit, but this should be fixed by shortening ff2 and 3( i desperately hope) anyway, its about 3-4mm or less pushed behindso around 72mm.

(wow, ive never worked to these tolerences before as normally if i weld somthing slightly off, i just change my design and say it was intentional and that i welded everything right :p :p :p )

as Mark has said, yes some(if not most) people have needed to add 3mm spacers behind the front upper suspension brackets ( i did too ), i was just making sure that the actual bend in FF2 & 3 wasn,t where the suspension bracket back face would be welded to, hope that makes sense:confused: :confused: , basically to be able to have a flat surface for the suspension bracket.

Nice one Geeman, i think you,ve sorted the front frame out & also this may help the placement of U1 & U2. :cool:

all the best
andy

At least you know whats gone wrong and you know how to fix it! its when you dont that it goes pearshaped! ;)