16v205 9 Posted July 21, 2008 (edited) Hi I need to weld some seat rails from inner sill to tranny tunnel but im struggling to find any written rules of what grade/size/type of material to use? Ive seen angle iron, square bar & round tube all welded in place in differing diameters. But I dont know whats right? Does anyone know what the blue book says about fitting them? Cheers Rich Edited July 21, 2008 by 16v205 Share this post Link to post Share on other sites
Mikey G 3 Posted July 21, 2008 (edited) Like you i have seen so many ways of doing it, i dont think there is a written rule on seat rails aslong as they are secure. A friend swears by using round tube, i prefer the look of square section myself. ETA: just had a look at a 2005 yearbook i have here and Q2.2 (f) "if the original seat attachments or supports are changed, the new parts must either be approved for that application by the seat manufacturer or must comply with the following specifications (see drawing number Q32)." The drawing is of a standard FIA side mount bolted directly to the floor, with a spreader plate on the underside of it. There are no drawings of seat rails. But it does go on to say... "Supports must be attached to the shell/chassis via at least 4 mounting points per seat using bolts with a minimum diameter of 8mm and counterplates, according to drawing no Q32. the minimum area of contact between support, shell/chassis and counterplate is 40sq/cm for each mounting point. . ." Edited July 21, 2008 by Mikey G Share this post Link to post Share on other sites
philfingers 5 Posted July 22, 2008 www.britishrally.com 's forum would be the best place to look, lots of Qs on here about this in the past, Phil Share this post Link to post Share on other sites
16v205 9 Posted July 23, 2008 Mikey thanks for typing that up. I think im going to use some angle iron and re-enforce the ends with a sheets of rectanguler plate where it joins the inner sills and tranny tunnel, then seam weld the lenght of it it to the floor. Cheers for your help guys. Rich Share this post Link to post Share on other sites
Baz 421 Posted July 23, 2008 Akin to what Mikey's said, the '08 blue book says basic stuff too. Must be attached via at least 4 points, with bolts at least 8mm with counterplates etc.. Your plan sounds good, alot of people don't bother butting up against a plate at each end to spread the load, but that's definitely wise. Share this post Link to post Share on other sites
James Stewart 1 Posted July 23, 2008 I would strongly suggest you use tube or box section rather than angle iron - they are much stronger. Ideally weld threaded inserts into the rails for the seats (or seat mounts) to bolt to as well. If not and you are going to bolt through the tube or box section, then go for tube as it will resist squashing over time. The rails can be butted up against the transmission tunnel/sills or you can cut holes so the rails extend into the tunnel/sills. Tube is easier to use if you want to do this because the holes are round! Make sure each mounting point is plated with 3mm steel around it to cover the 40 sq/cm area posted above. Personally I like tube of about 40 mm diameter and at least 3 mm wall thickness. James. Share this post Link to post Share on other sites
philfingers 5 Posted July 23, 2008 deifnately would go for tube too. The problem with angle iron is it needs to be reasonably thick to give the stiffness and this is then more difficult to get a good weld to the shell, as it (well the re-inforcing plate really) is thinner. As James says use tube inserts. My personal choice would be not to thread them and use nylocs incase the treads get damaged in some way. Either way threaded insetrts or not you still need to use nylocs to stop them coming loose. There are pics around of seats that have literally ripped out of the floor on impact, not pretty! Phil (Halesowen) Share this post Link to post Share on other sites
James Stewart 1 Posted July 23, 2008 (edited) As Phil points out, there is a risk of stripping the insert threads or for the mounting bolts to work loose. A threaded insert makes it easier to spanner check the bolt, but without a nyloc to rely on this must be done frequently and religiously! Any form of insert will prevent the tube/box section from squashing. It is in the same vain as the inserts in the subframe where the steering rack mounts - they don't look important but they are! James. Edited July 23, 2008 by James Stewart Share this post Link to post Share on other sites
16v205 9 Posted July 24, 2008 Cheers theres some good points there, I can see why not to use angle iron anymore I think due to time ill use 2"x1" box section and fit tubular inserts inside to stop compression. Cheers Rich Share this post Link to post Share on other sites
pdd144c 0 Posted July 25, 2008 Use some 50mm or 38mm CDS roll cage tubing. Share this post Link to post Share on other sites
