So, I want to drill some small holes in my base bar and extensions to keep all wires internal. I’m not bothered about voiding warranties etc, just the correct advice please as to how to do the job properly.
Any tips gratefully received.
Many thanks.
I’ve just used regular drill bits. Start small and increase the size of the hole with larger bits.
The hardest part was finding a good way to clamp the part while working on it!!
Cheers Nordicskier, yeah I know what you mean about ‘gripping’ th carbon… tight enough to keep it still, but not so tight as to cause damage…
I think I have that bit sorted, a wooden vice as part of a work bench.
Useful knowing that standard drills should work.
Here’s a video from TriRig that overlaps your request to some degree:
http://www.youtube.com/watch?v=RORISzYGxso
It’s not about cockpits, but it does mention using masking tape, multiple drill bits, grommets, etc. Hope that is of some help.
Thanks Lamby, perfect!
Cheers Nordicskier, yeah I know what you mean about ‘gripping’ th carbon… tight enough to keep it still, but not so tight as to cause damage…
Try wrapping the area that will be clamped with electrical tape and an inner tube. This way you won’t have to clamp too tightly and the rubber will keep a good grip on the bars.
So, I want to drill some small holes in my base bar and extensions to keep all wires internal. I’m not bothered about voiding warranties etc, just the correct advice please as to how to do the job properly.
Any tips gratefully received.
Many thanks.
I can see drilling a hole in the extensions as they’re not subjected to that much stress. But the basebar? I’m guessing you want to drill near the stem, where the stresses are highest. Sounds like a bad idea to me, the consequences of a basebar failing could be pretty serious.
Cheers Nordicskier, yeah I know what you mean about ‘gripping’ th carbon… tight enough to keep it still, but not so tight as to cause damage…
I think I have that bit sorted, a wooden vice as part of a work bench.
Useful knowing that standard drills should work.
Realistically, if you need that much clamp-up you’re not doing it right. You should only aim to take a small amount of material at a time - run a high drill speed, start with a small bit, and go slowly through the laminate. I can’t stress the high drill speed enough. The high drill speed combined with the slow plunge speed will help to reduce delaminations within the laminate and keep the heat down.
Long as you’re drilling only carbon (or glass for whatever reason) a standard drill bit will work. If, for some reason, you want to drill boron - like in certain Trek frames - or kevlar, you’re going to have to run to the store to go shopping.
As far as the basis of this idea, are you sure aero trumps strength? Most likely it’ll be fine but when we’re facing a staggering knockdown in material strength for open hole compression, caution is a good course of action. Experimental data suggests when the hole diameter is 10% of the specimen width - say a 0.33" hole on a 3" base bar width - the notched laminate is ~55% as strong as the unnotched laminate. Here’s the problem, that data is for a quasi-isotropic lamiate made from AS4 unidirectional material - this would be less sensitive to notches than a presumably heavy intermediate modulus fiber laminate featured in a TT cockpit.
Thanks for the heads up. Food for thought…