Narrowing my OBP Pedal box – or “is my warranty OK?”

So, as expected, my lovely OBP Pedal Box doesn’t fit the admittedly narrow fury footwell. There’s nothing wrong with this per-se. It’s a lovely made piece of equipment and I knew when ordering that it wouldn’t fit. This previous post shows the modifications I’ve needed to make in the footwell to prepare the shape to accommodate the OBP box, but after careful consideration, I decided there wasn’t enough room to make it all fit with any degree of clearance so decided to slit it like a cheap whore and make it thinner.

So, what you can see here is the pedal box in the 360 degree vice, scored and cross-hatched ready for cutting. I’ve been sure to leave enough room for the brake and clutch cylinders to have plenty of clearance, and the slit also takes into account the cross-bracing gusset. The only place it should be narrowed is between brake and clutch, not between brake cylinders – the clevises need to be straight when they go onto the cylinders. Moreso, it wouldn’t really be feasible narrow it here, what with the pedal wanting to be in the way.

Also worth note is the fact that I bought a 360 degree vice for the clean half of my garage. This means I can mount and mark and weld things without having to take them over to the dirty grinding cutting side of the garage. What you may be able to see on the right there is the corner cut off and grinded ready for welding.

It’s not all that clear in this photo, but I’ve got the whole thing cut now (0.8mm slitting disk for maximum accuracy). The steel used the the pedal box is only 1.2 or 1.5mm thick (hard to tell with the powder coat) so the disk went through it like a e.coli in an OAP home. I was pleased with the results though – the fact that it’s difficult to see the gap in this photo is because I’ve got very clean mating edges – essential when tig welding something so thin. One cock-up and you blow straight through.

This is what the extracted section looks like. There are a couple of stitches on each edge of the gusset that need removing. Up close, you can see where the stitches have penetrated the back plate (a good thing) and this meant I had easy guidelines to mark and cut against. The gusset came out quite unscathed, but in hindsight I wish I hadn’t ground it quite so thin at the base to remove the stitching – it made it very thin to weld. I would have rather left a little metal around it and used that as filler. Live and learn.

Next is lots and lots of spots at about 1″ distance. They’re done at 40A and with very little filler. Bearing in mind I am seam-welding this, and the metal is so thin it would just warp away from me (in the vertical plane) if I attempted to weld in a seam. Patience now means a better result later. At this point I was also glad I have so many different welding clamps.


When it came to completing the seam welds I stitched an inch and let it cool completely first. I also drilled mounting holes in it and bolted it down to my big heavy 1cm thick welding plate. Even then I ended up with a very small amount of warping, but so little that it pulls flat when bolted down. I initially kicked off at 40A but found that to be too hot when putting the seam in and had to back off to 35A. That gave me a great weld, full penetration and very little filler needed on the 1mm dia rod.

Here’s the end result. I’ve ground the seams flat (little effort) because I want to get the ‘not been touched or modified’ look when I get it back from the powder-coaters. You can’t see the gusset in this shot. I did struggle a little with this blowing through (where i’d ground it a little thin). I compensated by going up to a thicker filler rod and chucking a lot of metal in (it ended up looking like tidy mig). Then I got my pointy ended tungsten carbide burr and dug around in there like a demented dentist until it was all nice and smooth again. As long as the powder coat goes on reasonably thick, no-one will be any the wiser. The strength is all there though.

Following is the final result. Note the greater amount of room on left now – plenty of space to rework the foot well. I feel fairly chuffed with this result.

Feed the attention-whore