Need help with screw sizes

[A.J. Schreder]

I have a screw gauge on the way, but figured I'd ask just to be sure. Would like help on screw sizes for the following:

- fuel sender

- headlight covers and back window (prefer black coating if possible)

- seat brackets to floor

- track day splitter to front support (I had Fran leave my splitter off for delivery)

If these are already posted somewhere, sorry for the repeat.

A.J.

 

[Scott Rowland]

Headlight covers and windows could be attached with the good 3M outdoor double sided tape for a clean look and a good seal. But replacing would be tough.

I'd go 1/2" on the seat bolts x4 each seat. Button head with allen coming up from bottom and nylock nut on top. Splitter could easily be done with 1/4-3/8" bolts. They would be stronger than the material it is holding, especially if all was grade 8.

 

[Grant S]

After seeing how the cabins can pressure up at speed I would still use some sort of mechanical fastner on the windows for sure. the black nylon #8 counter sink screws are what some of us are using on the lexan. fuel sender could be different on yours then mine you will have to check that one by trying different screws in it till you find the right one.
Seats 3/8" grade 8 will work use large washers on bottom sides. Its the seat belts that keep you in the car so make sure they are fastened well and properly, if you mount the shoulder straps to low behind you they can break your collar bones in a crash. The cross bar on the roll cage in the SL-C should work for everyone as it is pretty much behind your head.

 

[A.J. Schreder]

Thanks for the info. Grant, do you have a part number? I assume from McMaster but even with this criteria there are still a bunch of options.

What length on the seat bolts? 1" and cut em down if necessary?

And as much as I would like to not have screws holding my windows on, the windows need to be removable. And I think the problem with the headlight buckets is sealing the back side of the light assembly so no moisture at all can enter. Probably a lot easier to seal the front side than the back. Due to the fact that sealed oem headlights occasionally get moisture in them, I don't think I have much of a shot at sealing the fiberglass sufficiently.

A.J.

 

[Scott Rowland]

When drilling lexan/acrylic I usually heat the bit/countersink up really hot with a heat gun first. Helps make nice clean clear holes since it melts it on its way in and out. Helps eliminate chipping too.

 

[Cam]

Ditto on the nylon flat head black machine screws for all Lexan. They have held in the F/G for 4 years. F/G threads are just fine after dozens of in and outs.
95133A394 mcmaster carr. you might want to get an assortmetn of 3/8, 1/2, etc depending on the location. Or buy 1", chop and re-die.
My sender came form digidash, UK, so metric, i think they were 4mm that is close to 8-32

 

[Howard Jones]

Those of you that used counter sunk screws in Lexan are lucky. Polycarbonate manufactures expressly say NOT to use countersunk screws. I used a button head with a nylon washer between the Lexan and the screw head.

Drill the hole about 1 or 2 drill sizes bigger to give the Lexan some room to move. I used #6 button heads

https://www.fastenal.com/products/details/73716?r=~|categoryl1:"600000 Fasteners"|~ ~|categoryl2:"600039 Sockets"|~ ~|categoryl3:"600043 Button Socket Cap Screws"|~ ~|sattr02:^"Button Socket Cap Screw"$|~ ~|sattr02:^"Button Socket Cap Screw - Fully Threaded"$|~ ~|sattr03:^"Stainless Steel"$|~ ~|sattr04:^"9pound6 - 32"$|~

https://www.fastenal.com/products/details/76058?r=~|categoryl1:"600000 Fasteners"|~ ~|categoryl2:"600089 Washers"|~ ~|categoryl3:"600097 Flat Washers"|~ ~|sattr02:^"Natural Nylon"$|~ ~|sattr03:^"General Purpose Flat Washer"$|~ ~|sattr04:^5pound6$|~

You can use #4 screws and washers if you want it to look more smoothish or whatever you would call that. I simply cut threads into the fiberglass so I wanted the larger diameter thread for more thread area.

See pages 19 and 20 for drilling and fastener info below:

http://www.google.com/url?sa=t&rct=...=4rLI5_yjCliKC24UHw3oOQ&bvm=bv.95277229,d.aWw