Setup Stands Part 1 – The Frame Job

Many moons ago, a buddy posted a few pictures to Facebook of his car on some setup / alignment pads. My curiosity piqued, I reached out and got a bit more info from him, as something similar would be phenomenally useful. I’d looked at commercial options for these, but they are prohibitively expensive, and John’s homebuilt pads looked pretty close to what I wanted for a lot less money.

After a great deal of figuring and bouncing ideas off of engineer friends, it became clear that a set could be made that would also incorporate setup scales, for relatively little cash (and a great deal of time….so, so much time). Initial designs were drawn up and steel ordered.

What follows is going to be a boatload of photos of various stages of the build. It was a very very long process of evolutionary engineering and problem solving, but now that I know how to build them, additional sets will be made relatively (and it is very relative, because they’re a ton of work) easily.

First step: getting a bunch of steel home. I had various pieces cut more or less to length, as I didn’t know exactly how they would go together but had a general feel for at least what the long legs needed to be. The rest were cut to fit in the back of the truckster to get it home.

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Lots of measuring (way more than twice), cutting, coping and beveling later, and the first frame was roughed out.

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The scales will sit on the side with “floor” on all 4 edges, and the rolloff pads will go opposite them.

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Cutting 45 degree miter joints would have been far easier from a fab standpoint. However coping the joints has 2 very big advantages: it leaves nice, flat areas on each end of the “long” side of the frame for the legs to sit on, and with that, there is a lot less strain on the welds and puts everything in compression, with the welds mostly holding the pieces together, and not supporting the weight of the car.

It’s not that I don’t trust my welds, but with something that needs to hold the weight of a car from crushing me to death, I will take every bit of added strength I can get.

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A quick test fit was very encouraging. My measuring a dozen times lead to a fit that allows the scale pads to rock in and out easily, but not enough that they can move around too much.

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Mocking up the legs:

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Got the rest of the gussets and the horizontal supports done.

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A design requirement was to have feet at each corner that will allow the full set to be leveled. The first step of that are these that make the bottom of the legs, with the threaded nut inside the leg. So, weld the nut to the washer, then weld that assembly to the leg.

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The rest of the parts stackup.

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This once again goes into the strength of the thing. Once the jam nut is tightened up, all of the load is on the big washers at the bottom of the legs and the bolt, and virtually none of the operating load is on the tack welds securing the nut on the inside of the legs.

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With the basic design roughed out, we’ll work on the roll off pads in Part 2.

To be continued….

 

Part 2
Part 3

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Differential NVH Damper Delete

The NVH vibration damper on the input flange of one of my diffs has started shaking loose (a semi-common problem). Given that they’re not a critical piece, that they can be a critical failure. that they would be a royal pain to fix in the field (assuming I have access to air tools, which I typically don’t), and that I’m in the process of having them both in and out of the car before and after the hill climb, it’s time for them to go.

The piece in question is the big steel (? might be cast iron) cross sitting between the input flange and the differential housing. It’s mounted on a rubber donut bonded to the input flange.

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A few minutes on the press (for the good one, the other nearly came off by asking it nicely) and it came right off. A little time on the wire wheel to knock off the excess rubber off of the flange and it’s ready to go back in.

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I didn’t expect it would add up to much, but it did end up being a worthy gain (or loss, depending on how you look at it), taking 1.75 lbs of rotating mass off of the drive line. Like removing a small flywheel off the front of the differential. Success!

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Saws and Welders and Stands, oh my!

Workshop update! I’ve made a few tooling changes and upgrades 😀

The biggie is a welder upgrade. The old, tired Harbor Freight 180 amp welder has now been replaced with a Millermatic 211. It’s a massive, “the last MIG welder I’ll ever need” level upgrade, but with the projects going on in the shop (including a few that will be getting sold), it really was time to get something better and more consistent.

Miller had a rebate going on, so everything sort of lined up for it. I’m still getting used to what it likes & setting it up right, and unlearning a bunch of bad habits, but man this thing is nice. The old HF box didn’t much care how your technique was, it was going to weld the same way (mediocrely) regardless. On this one, small things make big differences and you can really tune everything in.

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Next, I really needed something that could fairly easily & effectively notch heavy angle iron to build some frames for a project or three that I’m working on. An angle grinder will do the job, but it’s slow, hot, messy and not nearly as accurate as I wanted for this. A vertical band saw is the correct answer, but is also way out of the budget. Some poking around lead me to SWAG Offroad, which sells laser-cut and pre-bent kits for converting a portable band saw into a benchtop upright bandsaw, and there are enough glowing reviews out there that it seemed worth it to try. Turns out, they were correct!

I opted for the optional foot pedal as well (so that the machine can have the trigger locked on, but you can easily control its stop and start and keep your hands free), which I highly recommend if you do pick one up.

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I put a good metal-cutting blade in it (though from what I’ve read, that’s not necessary but will last longer), and man, this thing gets the job done. It’s not crazy fast, but it’s accurate, makes clean  cuts and doesn’t get the steel scalding hot in the process.

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Finally, I got sick of picking up my miter saw and having to find a place in / around the shop to run it, and of not having a good way to support the stock on it. I pulled together a few scrap bits and bobs and threw together a rolling stand for it that can be moved out of the way / out of the shop for the messy work (since race tires and steel chips don’t really get along). I wanted something that would work as a base for the metal cutting saw, and also serve as storage for assorted grinding & cutting wheels, and my 14″ chop saw that, until now, lived on the floor in a corner.

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Grinding wheel, flap disk, cutoff & wire wheel storage, to get them out from the bottom drawer of my toolbox:

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And with it at that height, it’s not only at a super comfortable height for me, but I can put 1 or 2 of those roller stands nearby and quickly have long stock support. And, as with all of these things, it should make life a lot easier.

That is, generally speaking, the whole point of tools.

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Event Report: Chasing the Dragon XI

Short version: Rolled it off the trailer, slid around in the wet, when it dried off, set new Personal Bests and class records 3 different times, in the end by ~2.8 seconds from what it was prior, had a celebratory beer and rolled it back onto the trailer. Absolutely epic weekend.

The REALLY long version:

It was a decent thrash to get it ready prior to the event. After last year, I knew I wanted to make some changes to the car before running, as opposed to running the 100% autocross setup I typically have. Due to time constraints I didn’t want to go too drastic, but there were a few relatively quick things I could do to make the car far better on the hill. Additionally, a few safety and maintenance items needed to be taken care of before arriving on the hill.

Number 1 is simply pull the ballast. SPU doesn’t have minimum weights, so out came 100 lbs.

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Next was…this. Just, all of this. Oil change, seat back brace, covering a few holes for fire safety, and a rear end swap. Running the hill last year, the car was very over-geared. Lots of places could have used downshifts to 2nd but would have been at the very top of 2nd and I’d have to immediately shift back up. All of that lost time, so it was speed maintenance all the way. And that’s fine, it IS a Miata, but a shorter gear would make any extra speed scrubbed less punishing, and let the car pull harder up the hill.

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And finally, since the rear end swap requires the exhaust to be removed, I figured it might as well SOUND like a hill climb car. I have a turn-down exhaust that slips onto the mid-pipe and replaces the muffler, so it went on instead of the big Borla muffler. In so doing, I drop a few more pounds.

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With the prep done, it was time to load up and hit the road. The forecast for Friday wasn’t great, but the rain held until we got everything unloaded, but when it came, it REALLY came. Since a few of the gang I was sharing a cabin with arrived, we covered the cars and took shelter under the canopies.

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Saturday morning started off wet. Really really wet.

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My 2nd run was the hairiest I’ve ever made up the hill. The Pucker Factor gets pretty high when the road suddenly just….disappears.

 

After 3rd runs, it was very quickly drying out on the lower half of the course and it was time for Deech, who’d come to crew, to do some crew stuff 😀

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Around then Jen and the boys showed up.

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To wrap up Saturday, with the last 1/3 of the road finally mostly dry, I put in my first real time and shaved about 4 tenths of a second off of the SPU record. Day 1 in the books and I’m 0.9 seconds faster than my best last year. It was REALLY cool coming back down and being able to wave to the family (who were at the Spectator area on the hill for the run) after having set a track / hill record for the first time in my life.

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Sunday started mercifully drier. A bit of dew had fallen, but that would quickly burn off.

After my 2nd run, the car didn’t feel quite “right”. At the top, I noticed that the 3 bolts holding the steering-wheel spacer to the quick release were loose. Like, “hold the steering wheel and shake it and watch the QR wiggle” loose. Oddly, I’d checked the QR specifically to make sure it wasn’t loose in the lead up to this event, but between the delrin motor mounts and the rough road, they had managed to vibrate loose.

Once back at the bottom I disassembled the parts-stack and tightened those back down. This was, thankfully, the only real ‘issue’ I encountered all weekend, save for the weather on Saturday.

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Run 3 on Sunday right before the lunch break was, in my mind, going to be my last really hard run up the hill. I pushed and knocked off another 1.8 seconds, getting down to 126.7 and my name on the leaderboard.

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I say “was going to be,” but after putting in a pair of easy, consistent 130 second runs, Lars was egging me on to take another real crack at the road. At the start line, I was still of a mind to make it an easy run. That lasted right until the launch, which ended up being the best I’d made all weekend. Immediately, Lars was in the back of my mind going “C’mon, you’ve gotta go for it!” After the 1st couple of corners went well, it was hammer time.

 

It wasn’t a perfect run by any means, but it did shave another 0.6 seconds off of my time, my Personal Best, and the SPU class record. It was definitely beer o’clock.

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With that, we packed up the truck, loaded the trailer, then said goodbye to The Dragon for another year and set a course for home.

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Splitter Leading Edge Reinforcement

So far I’ve been loving the new splitter, however because of the nature of the DiBond, the leading edge is a bit soft and has taken a few licks. I borrowed an idea from a couple people in other classes, and put a reinforcement / trim strip along the leading edge of the splitter.

Lowes sells aluminum channel to “trim” 1/4″ ply (which happens to be the same size as the dibond my & their splitters are made of)
This will make the leading edge much less of a wear surface. Bending and pie-cutting this stuff in a way that doesn’t cause stress fractures, and slotting it to clear the mounts is a royal pain, but it will add a ton of longevity.

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I reinforced both the front and rear edges. The front is to protect the leading edge of the Dibond. The spar across the rear is to add a little more rigidity along the ‘long’ side of the splitter.

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The fact that it looks a little Mad Max-ish doesn’t hurt either 😀

Big-Boy Welding Table

I have a few projects coming up that really need a decently flat surface to build on. While it’s served me well, the flimsy $30 Harbor Freight welding table just wasn’t cutting it in the long run (it has since been donated to a friend’s son who’s going to school as a welder).

Enter WeldTables.com and their CertiFlat tables. After pricing material (since I don’t have that much scrap laying around), I realized I wouldn’t be able to build a table for the price of one of theirs. I went for the 2 x 4′. Big enough to do what I need, but small enough (and on wheels…) that I can stuff it in the corner of my workshop, or in the driveway, should I need the space.

It came in far quicker than their advertised 7-10 day lead time, and once it did I set about cleaning all the parts with Acetone in preparation for welding it together. It really is a man-sized erector set 😀

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We did hit a slight snag that, in retrospect is obvious from the photo above, but we didn’t catch it until we were doing the final assembly. It turns out that they sent leg stringers for a 2×3 foot table, so the short sides were fine, but the long sides were about a foot short:

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A quick call to  WeldTables.com and they shipped the correct parts out straight away. The mistake was annoying, but their Customer Service in correcting it was outstanding.

With the correct parts in hand, I completed assembly and welding. I then flipped it over, did a little grinding of the few spots where the weld went higher than the slots, cleaned up the surface with a polycarbide wheel and sprayed it down with some WD40 to prevent rust from building up.

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I also ordered a couple of their 6×6 FabSquares and broke the new table in by putting those together. These will be super useful in the future.

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What with the Atlantic separating us most of the year, I don’t get to do too many fun projects like this with my Dad. Because of that, so I put a little something together to document it.

Aero: Front Splitter V2.0

After last season, Splitter V1.0 was seriously trashed. Placed on a flat surface, there was almost 2″ of bend across its width, so at a minimum I had to replace what was there. At a maximum, it was time for a complete rethink.

It was definitely time for a complete rethink.

So, based on what I’d learned making and repairing the first one, I set about replacing every single component save the 2 quick release pins. I didn’t intend for it to be that thorough of a redesign, but during the offseason, if there’s opportunity for improvement “while I’m in there,” you might as well take advantage of that.


Part 1: The Rear Chassis
Mounts

These were the pieces I had far and away the most trouble with last season. They were not adjustable, so once I eyeballed the height the 1st time, that’s where they lived. Furthermore they were difficult from a maintenance perspective, a once you hit something hard enough to bend them, the only thing to do was attempt to beat them straight with a hammer, or completely re-build them. There had to be a better way.

This piece took a bit of evolutionary engineering, but I think the result will be up to the task. You can see V1.0 on the left, bent in a couple different directions, and very unwilling to be bent back straight (especially along the longer edge).

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Instead of having a single piece mount, I decided to make a very strong mount to the chassis, with weaker sacrificial hooks to take the brunt of any larger impacts. The hooks are very easy to remove & replace, and to manufacture. The hooks are simply a length of 3/8″ threaded rod, and a short bent piece of steel round bar.

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A quick bit of welding and I have (what I hope to be…) a season’s worth of replacement. Hopefully more.

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After a bit of time on the drill press and a coat of Machine Grey, and the chassis mounts are done.

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Part 2: The Rear Splitter Mounts

The Hooks on the splitter that held it onto the chassis mounts also took a beating last year. Also, their geometry meant that with a good bit of load on the front, the rear hooks would lift off of the mounts. Unlikely to happen under real world conditions, but also suboptimal.

Given that, I went with stronger material (1/4″ Aluminum, up from 1/8″), and a more angled hook design that keeps it located both horizontally and vertically.

After a bit of figuring, this was the design I came up with. The bottom 3 holes are 1/2″, and the top one 3/8″ to tightly hold onto the chassis mounts.

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After a bit of cleanup and fitment testing, these are complete:

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Part 3: The Front Chassis Mounts

The front chassis mount (under the front bumper) has always been a pain. It allowed for no deflection (which meant bent front splitter struts), and because they only had 1/4″ holes for the quick-release pins, they were very finicky to get everything lined up with.

Inspiration from this came from a relatively prestigious place: The Dodge Viper ACR. I noticed that it had a mount that’s basically only rigid when downward load is put on it (ie: aerodynamic load), but would allow for upward deflection (ie: for off course excursions) to prevent the struts from taking all of that strain.

Here’s what I came up with. The D-rings are completely rigid in tension (ie: aero load), but will allow for deflection (ie: bigger cone strikes or bottoming) to hopefully prevent bending the struts. As an additional bonus, the target I’ll need to hit in order to mount the quick release pins is orders of magnitude larger, which will make mounting the splitter at the track far easier.

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Part 4: The Front Splitter Mounts & Struts

The front splitter mounts did the job, but were a little small in surface area against the splitter. They were also short legs, meaning that the nuts for where it bolts to the splitter and where it bolts to the struts were practically on top of each other. I used the miter-saw I received as a Christmas gift to throw these together (shown with a spare set):

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I also found some turn-buckle rigging forks on Amazon that, with a little bit of drilling and welding, I was able to make into a pair of new front struts.

 

Part 5: The Splitter and Final Assembly

Finally, we get to the splitter itself. Using the laminated sheets of DiBond ended up being both a ton of work, and fairly ineffective. After the rigors of the season, the bottom sheet was fairly worn down (another casualty of non-adjustable rear mounts) and it never was as stiff as I would like.

After consulting with some buddies who know more about this stuff than I, I decided to go with 1/4″ Dibond. The single 1/4″ sheet is far sturdier than the laminated 1/8″ sheets.

The first step was to make cleaner (and thicker) buck for the splitter. The lines on the 1st one weren’t all that clean. This will make for fairly quick & easy replication with a router & a flush-trim router bit.

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I picked up a brand spankin’ new sheet of 1/4″ Dibond, and we managed to cut 3 splitter blanks out of it, then trimmed them down with the router. It’s a super dirty process, but it is super effective.

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Instead of using sections of the Home Depot Racing Supply paver edging for the air dam, I went ahead and used the whole one (so it would be more rigid), then we riveted the original air-dam to it to use for mock up, to then make a pattern (and buck) for a new design:

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Once all the mock-up was done, it was time to disassemble the whole thing and put the “real” parts on. All of the parts were mounted using elevator bolts.

I made a spacer to use with a nut and a washer stack to pull each elevator bolt into place:

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After a bit of sweat equity, this is what the bottom looks like. The nice thing is that they have very thick bases, which allows them to serve as something of a wear surface without sacrificing too much strucutral integrity, as opposed to using button head bolts, which have much less metal to wear down before they’re rendered useless.

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With the base complete, we used Clecos to temporarily rivet everything together…

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And then finally completed assembly and riveting, and got it mounted in place:

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It was a ton of work but now that I have a good, solid design, replicating it will be relatively straight forward. Hopefully I don’t find any crazy weaknesses with this design that’ll require another complete rethink.