CHASSIS SIDE BRACES

This is how I made the modifications to my TC3. You will find many pictures of the different steps of the mod and the tools I used. This idea is not mine, I took the concept of the Irrgang Racing Service (IRS) side braces and made them a little differently adding some support in the middle of the braces.

Why do it?

Because the modifications for the battery placement and the one to install the NTC3 steering rack leaves the chassis a bit less rigid since so much material had to be removed. These braces give back a lot of rigidity to the chassis.

Safety!

PROTECT YOUR EYES, WEAR A DUST MASK and take your time.

MATERIALS NEEDED

The best material would be woven carbon fiber. Since I had a slab of thick G10 fiberglass lying around, I used that instead. You will need 30 minutes epoxy and four 4-40, 3/8 inch long screws. I also used some thin pieces of scrap wood to make templates.

THE TOOLS

This is most of the tools I used to do the braces (fig. 1 and 2). Some thing are not in the picture like sandpaper, epoxy, bench grinder and miscelanious stuff.

Figure 1	Figure 2

The first thing I did was to make templates out of thin pieces of scrap wood being careful to line up the holes for the screws perfectly so that the braces don't tweak the chassis. (fig.3) You can view a crude plan of the braces (fig. 4), the most important measurement is the distance between the holes at each extremities. If the holes from the braces don't line up perfectly with the holes in the chassis, you may seriously tweak it.

Figure 3	Figure 4

I used these templates to transfer the design on a slab of thick G10 fiberglass. I used a finishing nail to scoar the G10 instead of using a pencil (fig. 5). I used a punch and small hammer to mark the holes' locations (fig.6). The result is very clean and you won't loose your lines by rubbing your fingers on them while manipulating the G10 (fig. 7).

Figure 5	Figure 6	Figure 7

I secured the G10 in a vise and used a metal saw to roughly cut out the brace (fig.8). Then I removed most of the material on a bench grinder, being just shy of the scoar marks (fig. 9)

Figure 8	Figure 9

I sanded to the scoar marks using sanding drums in the pressdrill (fig. 10). Then I drilled the holes with a 1/8 inch drill bit (fig. 11). Finally I countersunk the screw holes on the top of the braces (fig. 12).

Figure 10	Figure 11	Figure 12

Once the braces are on the car, they had a lot of rigidity to the chassis but I felt that some support in the middle of the braces (fig.13) would stiffen up the chassis even more. I decided to make triangular pieces (fig. 14) that I would epoxy to the middle of the braces and screw to the chassis' sides with two 4-40 screws. I drilled two 3/32 inch holes in the triangular pieces that acted as pilot holes for the corresponding holes to be drilled in the chassis' sides. After the chassis was drilled, I enlarged the holes in the triangular pieces with a 7/64 inch drill bit.

Figure 13	Figure 14

I used a 4-40 taping screw to put threads in the chassis' 3/32 inch holes I had made (fig. 15). I scuffed the underside of the braces with rough sandpaper (fig. 16) where the triangular pieces will be epoxied. Then I cleaned the two mating surfaces thouroughly and mixed a small batch of 30 minutes epoxy.

Figure 15	Figure 16

I started the last step by unscrewing the screws of the motor clamp. I spread some epoxy on all mating surfaces, positionned the triangular pieces and screwed them in place with 4-40 screws, I suspended the car on a very flat surface and put spring clamps to hold the braces to the triangular pieces (fig. 17). I let the epoxy cure overnight. The chassis regained the rigidity it had before I made the battery placement and steering rack modifications. In my opinion, the braces don't look hack. Of course woven carbon fiber would have looked better (fig. 18). Maybe it will be my next project.

Figure 17	Figure 18