How to drill holes, do I need to?

[hudja]

Hi!

Could you give me some suggestion about drilling the holes into my new carbon-fiberglass blades? I have two pairs of H.Dessault footpockets for different type of socks, thus gluing blades is not an option. I also do not want to use silicon.

Could I just use blades without additional gluing - screwing?

If not, which is the best way to drill the holes, starting from the small drill diameter and increasing it gradually?

How should I machine the edges of the holes, should I grind them a bit or paint with epoxy resin?

Thanks!

 

[Bill]

I would use the thinner sox, glue the blades in, sell the larger pockets and wear the second pair of sox over the pockets when needed, but that's just my opinion.

After 20-30 times in the water the foot pockets seem to mold to my feet and 2 mm sox or maybe it's vice-a-versa. Hate to change anything so comfortable.

 

[hudja]

I would use the thinner sox, glue the blades in, sell the larger pockets and wear the second pair of sox over the pockets when needed, but that's just my opinion.

After 20-30 times in the water the foot pockets seem to mold to my feet and 2 mm sox or maybe it's vice-a-versa. Hate to change anything so comfortable.

Sorry, this is not an option, if you are diving in water ranging from 4 to 21 degrees Celsium. I have 3mm, 5mm, 7mm and 9mm socks. 3 and 5 sits fine in 44-45 footpocket, 7 and 9 are absolutely painful in these, but good in 46-48. Any other ideas?

I forget to add that my blades are Leaderfins carbon produced under the different name for the local market. They have nice rubber bordering and sit in the pocket very tight.

 

[Gugi]

Hi Hudja,
Here bellow is something useful for you:
H Dessault footpockets - Freediving Spearfishing Forum
If you let pass the avatar of the post's author , you'll need the showed there instalation kit to avoid the contact between the carbon blade and the naked screws and further to reduce the risk of eventual blade's crack around the holes.
Drill the holes to the final diameter at once! Use a new, quality sharp drill for steel, it's good to be used and vertical drilling machine as well.

 

[hudja]

Well, I drilled holes finally. Started with dentist's bur, then increased drill diameter: 3mm-4.5mm-6mm. I used brand new drills and vertical drilling machine. I manually grinded the edges with 7.5mm drill and painted them with epoxy. I also grinded screw thread and put a piece of thermocontractable tubing to protect blade from the sharp edges of the screw. Finally, I added four rubber washers.

Unfotunately, holes in one of the blades are shifted from the center in about 1,5mm, because I aligned the blade in the pocket and marked the position of the hole, but not did not find it exactly using ruler. Actually, it is quite hard to measure the hole position as blade is hand-made, thus it is complicated to find the exact position of the blade's vert. and hor. axes and even if you will find them the blade could not align perfectly in the footpocket. Anyway, I tested both blades in the footpockets and everything seems ok.

 

[Gugi]

If I were you, I'd apply some kind of plate instead of rubber washers. It will spread the pressure of the screws onto wider area. Something like that:

 

[hudja]

If I were you, I'd apply some kind of plate instead of rubber washers. It will spread the pressure of the screws onto wider area. Something like that:

I am almost not tightening the screws. Moreover, rubber washers fix screws really well, they won't loosen by accident, but I will agree with you, if screws sitting loose or somebody wants to tight them well, the plate is the best solution.

 

[Old Man Dave]

You've done it now so my opinion is a bit late but for anyone else this is my two pence worth.

I assume you used a series of twist drill bits, probably made of high carbon steel. I would have used a stepped cone drill. This type of drill bit is much better for drilling all sorts of plastic and causes a lot less cracking than twist drill bits. Stepped cone drills by their nature drill the hole out in progressive steps and they also are better at self centring.

Supporting the material from underneath with sacrificial wood and using a pillar drilling machine are also essential.

Dave.