Working with Carbon.

[cranky cyclist]

Hi @RojoRacing , I have a pair of shoes with carbon fiber heels. I want to modify the shoes so that the cleat is in the mid foot position. I have a pair of pedals that are not lipless. They are great for a mid foot position, however it is difficult to keep the position because obviously I am not clipped in. The mid foot position made me feel like I had more power than clipless pedals. I also noticed less knee pain and less quad pain. So I meed to know how to drill holes in carbon fiber. Is there any special drill bit that I might need? I am asking you because I know that you have done a lot of work on carbon fiber.

 

[bladderhead]

I made myself heel-clips out of toe-clips. This gives me a mid-foot placement with ordinary shoes.

 

[RojoRacing]

If were talking thin carbon like 3mm thick or less then these 1/8-1/2" range step drills work great. They are also great for drilling most type of plastic and fiberglass where you're worried about snagging the material and cracking the product.
https://www.amazon.com/Neiko-10193A...05071&sr=8-2&keywords=stepping+drill+bit&th=1

For the most part using regular center point style drill bits are fine if you use light pressure and don't mind cleaning up a tiny bur on the exit side with a little sand paper or just leaving it if it's hidden. Covering the carbon with clear packaging tape can also help keep the most outer layer of carbon from flaking but if you go slow I find it's not really needed. Last year I drilled about 20 holes in my carbon giro shoes in an attempt to increase air flow to the bottom of the foot. I used a regular 1/8" steel drill(not the step drill posted in the link above) bit with little to no burs to speak of.

 

[tiltmaniac]

If were talking thin carbon like 3mm thick or less then these 1/8-1/2" range step drills work great. They are also great for drilling most type of plastic and fiberglass where you're worried about snagging the material and cracking the product.
https://www.amazon.com/Neiko-10193A-Titanium-Drill-3-Piece/dp/B001CBNPBW/ref=sr_1_2?ie=UTF8&qid=1512605071&sr=8-2&keywords=stepping+drill+bit&th=1

For the most part using regular center point style drill bits are fine if you use light pressure and don't mind cleaning up a tiny bur on the exit side with a little sand paper or just leaving it if it's hidden. Covering the carbon with clear packaging tape can also help keep the most outer layer of carbon from flaking but if you go slow I find it's not really needed. Last year I drilled about 20 holes in my carbon giro shoes in an attempt to increase air flow to the bottom of the foot. I used a regular 1/8" steel drill(not the step drill posted in the link above) bit with little to no burs to speak of.

Taping on the back side (can help on the front too, but especially helps on the back) of the workpiece can prevent flaking as the bit presses through the last layers of the laminate.

 

[tiltmaniac]

Also, carbon fiber dust is nasty stuff. From what I understand, it acts similar to asbestos in what it does to the lungs.

Slow is good. I use a wet paper towel around the hole which helps a bit to capture some dust.