Roll Bar + Chassis Plate Help

[Tatey]

I'm at the stage of welding the roll bar to the roll bar mounting plates, i've fettled the roll bar down so it now sits level on the plates, however when placed on the chassis the roll bar does not sit in the middle of the 2 plates, it is sitting more on the outside of the plate, i've attached a drawing to show you what i mean:

http://i292.photobucket.com/albums/mm22/Simon_Tate/Haynes%20Roadster/Untitled.jpg

The roll bar sits approximately 17.5mm from the outer edge of each side of the chassis. How has everyone else tackled this problem? Have you just fettled down the roll bar until it sits in the middle of the plate? Or have you just left it like that?

Also with the triangular chassis plate for the roll bar box thing, one side is 121mm and the other is 125mm, which side goes against cp3 and cp4? Is it the shorter 121mm side and the 125mm side goes vertically down? Depending on which way it is positions the angle it points at will change.

Cheers

[flyerncle]

I tweaked the roll bar to shorten it slightly in a pipe bender and as I said I bored out the center of the plates to put the pipe into and welded both sides of the tube. They do come close to the edges but you should still be able to fix the nuts underneath.

[gingea1pom]

I kept cutting the roll bar down until the ends sat in the middle of the mounting plates.

Do make sure both legs are the same length though, I know it sounds obvious.

Cheers Ginge

[Tatey]

30 mins with the grinder and its nearly sorted, just got another 20 mins at they both should be in the middle of the plates, i've been doing alternate side each time to make sure i dont end up with a wonky roll bar :D.

[twinturbo]

Take some photos so I can see what yar on about..

If I have a similar issue, I think I will just cut a hole in the plate and weld top and bottom.

TT

[Tatey]

http://i292.photobucket.com/albums/mm22/Simon_Tate/IMG_0097.jpg

http://i292.photobucket.com/albums/mm22/Simon_Tate/IMG_0100.jpg

As you can see the roll bar isn't located exactly in the middle of the plates.

Oh and before anyone mentions, yes i know the left hand CP6 is upside down....

[Bonzo]

Hi Tatey

Must be having one of my stupid days today ..... Couldn't make head nor tail of your post when I read it earlier :o :o

Just read it for a second time & it was crystal clear, now I notice you have posted some pics :cool:

Yes I would sit the roll bar centraly on the mounting plates, looks much easier on the eye.

I have just been out to look at my chassis & had a gander at the triangular plates. Although I cant get there to measure it ..... I would say that the shorter side goes against the other CP plates.
I have a feeling when you offer them up, it'll become clear ... You should have a nice open corner to weld rather than a tricky butt weld ;)

[gingea1pom]

Looking good,

Now if I was building another one and got to the stage you are at now I would weld the cross bar on next as mine pulled in loads so the bolt holes don’t line up by 2mm either side. Then weld the roll bar to the plates.

Sounds confusing hope you know what I mean.

Cheers Ginge

[Tatey]

I think i know what you mean ginge. Maybe i should stop fettling it now and get hold of a crossbar and hopefully that will sort out all of my issues, taking the lazy option and all :D

What has everyone made the cross bar out of?

[Bonzo]

If memory serves me right ( Roll bar down the pit at the mo ) I used a length of the bush tube steel, the 33.7mm OD stuff.

It was there kicking about & looked plenty man enough for the job :) :)

[HandyAndy]

Looking nice there Tatey :cool:

with the triangualted plates you mention, i can,t remember which way they are placed but if you wait until you weld in parts D12 then offer up the CP7 plates (triangle plates ) it,ll be easy to see their orientation ;)

I,ve used scaffold tube for my cross brace in the roll bar, not that i,m advocating finding a building site tho :D

I also did the same as Flyerncle, where as my roll hoop was sunk into CP3 & CP4.

Your chassis is really taking shape, nice one mate:cool:

are you fitting an Ali rear tub?

cheers
andy

[Tatey]

Cheers Andy, by sunk into CP3 and CP4, im guessing you mean the roll bar mounting plates? And then bolting it onto CP3 and CP4? CP3 and CP4 are the large chassis plates with the 4 holes in them and the suspension mount welded onto the bottom.

Oh and yes I will be going for an ali tub, hence why i ordered 2 x CP11 + 2 x SS1 plates from you last week :p :D

[RAYLEE29]

Hi, looking real nice there Tatey.
As for the cross brace, id bolt the plates to the chassis and weld the bar insitu then weld the crossbrace while its all bolted up then hopefully it wont be able to pull as it cools. you could also put a temporary brace between the suspension towers while you weld it up.
its normally as the weld cools thing start to pull.
Ray:)

[Tatey]

Sounds like a really good plan Ray.

I just need to see if my mate can come up trumps with some scaffy bar now.

[HandyAndy]

Cheers Andy, by sunk into CP3 and CP4, im guessing you mean the roll bar mounting plates? And then bolting it onto CP3 and CP4? CP3 and CP4 are the large chassis plates with the 4 holes in them and the suspension mount welded onto the bottom.

Oh and yes I will be going for an ali tub, hence why i ordered 2 x CP11 + 2 x SS1 plates from you last week :p :D

yes, thats what i mean with regarding sinking the roll hoop,

:o doh.... oh yeah , ordered some plates, silly me :o

cheers
andy

[flyerncle]

There is tons of it near the garage Tatey !!!:rolleyes: And I have some too.

[Tatey]

Flyerncle saves the day again! :D

Just an update on the roll bar situation. I finished fettling down the ends so that it was entirely level and the outer edge of the each side of the roll bar was 26.5mm from each edge, which to my eyes looks bang on in the middle of the plates.

I've also cut out a 50mm hole in the middle of one of the plates for the roll bar to sit though, as suggested by Flyerncle and HandyAndy, to give the joint some extra strength. I'll be doing the other side tomorrow and then welding it up, to quite a while to do with my pillar drill, hacksaw and rounded file, if only i had a 50mm slightly oval hole saw :p.

Cheers for the help everyone.

[AshG]

aarrrgh its purposly like that because when you weld the cross bar it pulls the roll bar in!!!

you are meant to weld the cross bar on first then weld it to the plates.

sorry i should have mentioned it in a more recent thread as it got lost in the melt down

[Tatey]

I thought there might have been a reason for it being a bit too long :rolleyes: . Ah well, make sure you let me know for next time eh :p

The upside of it is that i got to find out how good the new ceramic flap discs are :D

[gingea1pom]

aarrrgh its purposly like that because when you weld the cross bar it pulls the roll bar in!!!

you are meant to weld the cross bar on first then weld it to the plates.

sorry i should have mentioned it in a more recent thread as it got lost in the melt down

It makes perfect sense now. Well I have learn't something and every day is a school day.

Cheers Ginge

[Tatey]

After a quick browse of google and talking to people on the MIG welding forum, i've decided to go for CDS tubing for the roll bar supports and cross member, due to the fact that scaffolding tube deforms in a much different way to CDS, scaffolding is much more brittle and hasnt been designed to take impact loading e.g. from rolling a car, it has been know to break instead of deform, meaning there's a high chance you could end up getting impaled by the thing which is supposed to save you.

So i'll be ringing up my local steel supplier and see what price they can give me. From looking on the net it will be around £30 for a 6m length of the stuff.

[GraemeWebb]

After a quick browse of google and talking to people on the MIG welding forum, i've decided to go for CDS tubing for the roll bar supports and cross member, due to the fact that scaffolding tube deforms in a much different way to CDS, scaffolding is much more brittle and hasnt been designed to take impact loading e.g. from rolling a car, it has been know to break instead of deform, meaning there's a high chance you could end up getting impaled by the thing which is supposed to save you.

So i'll be ringing up my local steel supplier and see what price they can give me. From looking on the net it will be around £30 for a 6m length of the stuff.

Where did you get the price for the tube?

[Tatey]

A thread from the MIG welding forum, although that was a few year ago so im guessing it's massively increased in price by now....:rolleyes:

[Tatey]

Looks like it is still around that price:

http://www.metals4u.co.uk/products.asp?Cat_ID=162&gclid=CNzckrjm8p8CFZdi4wodkVZ_Xw

Metals4u seem to be a really expensive place to buy steel from as well, as they charge £15 per 6m of 25x25 16swg, i can get it for £8 per 6m from my local steel supplier.

[Tatey]

Looks like I have a bit of an issue, my roll bar isn't tall enough :rolleyes: :eek:. I guess thats the problem with being 6'6" eh....:(

I sit about 880mm from my arse to the top of my head. From the top of the build table to the top of the roll bar is 950mm, but then you need to take into consideration that theres the bottom rail which on top of that, which is 25mm, the seat supports + runners + the seat on top of that, I'd also be wearing a helmet and if i were to roll the car then i would be hanging from the harness.

So the question is....how much will a full cage set me back? :eek:. I was planning on going for a full cage after i finished the roadster, but it turns out that the CDS tube i'd be buying to support the roll bar will cost me £60.

What's everyone's thoughts?

[flyerncle]

Spud is taller than you and he fits ok ( I think ) use 40x 3mm flat to the floor and bend 25 mm either side of the floor and weld to chassis rails for seat mountings,that way you only loose 3mm other than that I am at a loss to suggest anything else.

[Tatey]

Spud has an extra tall roll bar :p. I got a quote back from caged saying it would be £400 + vat for roll cage, which to me seems like a very reasonable price. Slimtater has suggested I get in contact with Martin at MK engineering as he made the roll cage for his car, I am just waiting for a reply from him now.

[flyerncle]

Solves that problem Mr Tate.:D

[Tatey]

Solves that problem, but I'm always going to be wanting a full cage, so why postpone the inevitable :D. It will only be an extra £350ish once I have sold my current roll bar as I wont be needing to spend the extra £60 on CDS tube.

[flyerncle]

Read the IVA manual I think there is reference to cages,it may pay you to get it tested prior to fitting the cage and send someone shorter than you with it :p .

[Tatey]

The IVA manual just seems to state it needs to have strong joints where it joins the chassis and corners of the cage, as well as drill and welded seatbelt anchoring points. And be designed to spread the loads throughout the chassis.

So doesn't look too hard to get sorted since i'd be paying a company to do it for me.

[flyerncle]

Thats what I read and thought do it later rather than have something else for them to look at and give greif over and fit it later.