Drilling carbon fibre

[Browser]

Hi all, I have fitted a carbon fibre tailbox to my recumbent bike and have positioned the drink bottles inside it connected to a hose and mouthpiece Camelbak-style. To give access for the hose I've bought an connector from Alibaba and need to drill a 15mm dia hole in the front face of the box to allow the drink tube through.
I use RPE when drilling CF as I'm aware of the respiratory hazard, my question is what to use to drill and neat, cleanly-edged hole? I've drilled odd bits before using either normal twist drills or stepped hole cutters but always smaller diameter and always on things where it didn't matter if the hole ended up with the odd loose fibre poking out.
(useful and sane) advice welcomed

 

[PhillipM]

Diamond coated hole saws for glass work well, if a little slow.

 

[Bullet2012]

normal drill bits work ok, use high speed and low pressure if possible clamp a piece of wood to the reverse side to help prevent bursting. also best to drill undersize and finish with sanding if thats feasable.

 

[Agroshield]

...finish with sanding if that's feasable.

The sanding could be a simple as a piece of abrasive paper glued to a round dowel and held in a cordless drill.

As well as the backup on the exit side, maybe also put a piece of tape on the face side to prevent chipping.

 

[Bullet2012]

put a piece of tape on the face side to prevent chipping.

good point

also if you do wish to use a hole saw, use an abrasive one as per @PhillipM suggestion as a toothed one will never leave a suitable finish as it will tear and rip the fibres.

 

[Kayos]

Never drilled it but found a diamond disc in a grinder worked best when I needed to chop a seat post down

Suitable precautions including local extraction, backed up with PPE, were taken

 

[chunkolini]

Browser
What recumbent bike have you got?
I've owned a few over the years.
Great tourers

 

[Browser]

Browser
What recumbent bike have you got?
I've owned a few over the years.
Great tourers

M5 Mid Racer, cro-mo frame, carbon forks, Schmidt SON dynamo, Supernova lights, Thor Seats carbon fibre seat and now a Thor Seats tailbox. What's yours?

 

[chunkolini]

Speedy!
I've got and Radius Dino.
Classic long wheelbase under seat steering.
The cycling equivalent of and old Daimler.

 

[Ian X]

I cut several holes in the underbody of a VX220 using a smallish router with a 13mm bit, they were decent, thick woven glass though rather than light carbon. Perhaps tape might mitigate surface breakout whatever method you decide on.

 

[Browser]

I was worried that if the drilling had loosened amy of the fibres they'd just tear loose when I removed the tape? Masking tape might work though as that's designed to come off easily.

 

[Keithmac]

I was worried that if the drilling had loosened amy of the fibres they'd just tear loose when I removed the tape? Masking tape might work though as that's designed to come off easily.

The Epoxy is impregnated into the fibers (if it's been made properly), not bad to work with.

Worst thing that could happen using a drill bit is if it grabs, could crack the panel.

A cone style stepped cutter could be an option?.

 

[RichardM]

Masking tape to define hole, drill smaller than the hole you want and finish to size with emery cloth wrapped around a round file

 

[Bullet2012]

Masking tape to define hole, drill smaller than the hole you want and finish to size with emery cloth wrapped around a round file

mice to see you read the whole thread prior to commenting

 

[RichardM]

mice to see you read the whole thread prior to commenting

Rats, must read all the thread first!