I just got a CF base from UDC. I need to drill the holes. What is the best way to drill them?
With a drill? 
are there premarked holes on the carbon fiber base for drilling? I plan on getting one soon since my seat flexs way to much
Link to john_childs’ instructions on how to drill out a carbon fiber (cf) base.
john_childs wrote a very good post about this, but it took me a while to find it originally:
http://www.unicyclist.com/forums/showpost.php?p=438013&postcount=3
That’s what I used to figure out how to best drill my CF base, and it came out quite well.
also, scroll all the way down the page.
Is there a way to put the nuts on the inside and have the bolts go from the bottom up into the seat?
Yeah. Scott Wallis has some flanged, threaded inserts (i.e. nuts without the hexagonal shape) that he epoxies into the seat base… kinda sorta like the one you see in the lower right of this image:
If you find one of these you just need to drill a hole large enough for the threaded collar to go through, then epoxy the flange to the top of the seat base (where the seat foam will sit). You’ll need to ensure your epoxy job is spot-on (the surfaces mate perfectly with each other, are prepped and cleaned, the epoxy does not have bubbles, etc.) otherwise you could torque them right off when tightening the screws. The larger the flange you can find, the better off you’ll be.
Not with carriage bolts.
You could loosely follow these directions from George Barnes, and just install all the nuts & bolts upside-down:
http://www.gb4mfg.com/gb4/air_seat.pdf
Keep in mind that if it isn’t securely fastened and something comes loose, you may have to remove the bumper, handle, seatcover and pad in order to re-tighten the base bolts / nuts.
I will definately look for those. Thanks.
I like the idea of a rubber bumper between the post and the base.
You can get rivnuts which are threaded tubes which are deformed to hold themselves in place with a rivnut gun, ive used them exstensively on fibreglass and they’re pretty good, tricky to get hold of tho.
Max Dingemans (from the TCUC) uses the T-nuts in the carbon fiber base. The T-nuts are designed to be pounded into wood (it’s the one in the above picture on the black square). For use on the CF base you cut off three of the prongs. Drill a round hole for the threaded part and cut a slot for the remaining prong. That remaining prong will keep it from spinning. Then file down the excess that is sticking up on the other side of the CF base.
The T-nut thing might be good if you’re using a foam seat. I don’t think it would be good for an air seat because the nut and bolt will stick up into the inside of the seat and that would be bad for the tube.
I haven’t tried the T-nut option. The advantage is that it would be lighter than the carriage bolt option (carriage bolts are heavy).
Alot of good stuff being said…
Heres one more thing to keep in mind: the little dots/indentations that are on the cf base when you get it that are kind of the suggested places to drill the holes can be wrong. Just ignore those are measure where to drill the holes. Take your time. Thats it. 