An M.G. Locost Build
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November 16, 2012
Tabs Everywhere

Our roll bar is on order and we've got our POR-15 chassis paint ready to go, so we're down to the last of the welding. Once the frame is painted, we'll never be able to weld anything else to the car ever again, so we're trying to make sure we have everything we need on the chassis before we break out the brushes.

We think we have a pretty good idea of everything that's left to do, but unfortunately we seem to keep finding places on the frame to attach tabs. We've welded on 28 tabs in the last week alone, and we're not sure that's all of them. In fact, we're almost positive there's going to be more. You can't have too many tabs. We're going to be assembling the Locost for the final time over the next couple of months, and the last thing you want to do when you're building a car is run out of tabs.

  Smallest tabs ever, before and after cleaning up
click to enlarge

Our most recent tabs were for bolting on the transmission tunnel console panels. These turned out to be our most ambitious tabs to date, at least if you go by how long they took to make. We estimated we'd need ten of them, although we later reduced this number to eight when we realized we were going to need a flange at the back of the tunnel to support the aluminum bulkhead that we hope to fit there someday. The two rear console bolts would be attached to that flange.

We wanted to keep the console tabs simple. We thought we could just weld blind nuts directly to the frame rails, edge on, and use those to bolt on the console. But the little buggers refused to melt. Three times we tried tacking a blind nut to the top transmission tunnel rail, and all three times, as soon as we released the clamp, the nut fell off. Just fell off, like it didn't even get warm. This might've had something to do with not actually pointing the torch at the nut, but in our defense the nut was really tiny, and we didn't want to accidentally weld up the bolt hole.

Not the actual console covers  
click to enlarge

So we realized we were going to have to weld the nuts to tabs first, and then weld the tabs to the frame. Unfortunately our stock of 16 gauge sheet metal is currently in short supply, so we made the tabs instead out of 16 gauge square tubing. This worked better than expected, despite taking about 2 hours to make the prototype tab, because after that we worried a lot less about how the other seven would look. So the whole job was done in under eight hours, and the tabs still look semi-professional, although fortunately no one will ever see them.

We think we've identified just about all the remaining tabs we're going to need. These include the aforementioned rear bulkhead flange, six more brake line tabs in the engine bay, two more wiring tabs in the engine bay, one more brake and fuel line tab on the O3 tube in back, and a few tabs for grounding the harness in various places. Plus, we need to cap the open radiator support brackets, although those aren't technically tabs, although tab isn't really a technical term so I think we're okay there. We hope that's all the tabs, but if it turns out we need more after the frame is painted, we'll just have to bolt them on somehow, so long as there's a tab nearby to bolt them to.

  Transmission tunnel tabs don't photograph well
click to enlarge

Even after all the tabs are done, we're still going to need to do a lot more welding before we do any painting. Besides all the paneling, we need to weld on the curved rear fender supports, the fuel tank supports, and the roll bar. It turns out the curved rear fender supports will also need a couple of tabs for attaching the bodywork, and the roll bar will need a couple of tabs for the upper seat belt anchors. The fuel tank supports won't need any tabs, so far as we know, so I think we lucked out there.

We haven't figured out yet how we're going to mount the seats, or the seat belt inertia reels, if we decide to use seat belt inertia reels. We want to install regular 3-point seat belts in our Locost, because we don't really like racing harnesses. We've had those in street cars before, and they're a giant hassle. If a Locost is supposed to give you the same freedom of the road as a motorcycle, you want to be able to hop in and go. So the seat belt issue is settled, except of course for how to mount them.

We're less sure about the seats. We may need to weld on some tabs for these, or we could just bolt the seats to the floor, like it says to do in the Locost book. Whatever we do, we'll need an answer on this soon.

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