Never read posts by Jeff the Drillium Dude when you're halfway through of a case of beer, in your room with a gran sport derailler and a dremel on hand. I couldn't make it look as pretty.

Will the small holes take away lot of strength ?? Should be ok for regular riding?? No bunny hops!!

Don't forget your tubes :P

-Kurt

The area of concern would be where the cross sectional area has been reduced by a large amount such as tangent to the pedal eye or where there is a hidden flaw that the drill bore will expose as the full spec material is gone and the flawed material is left to carry the load.

yikes.

Remember this one??!
http://i2.photobucket.com/albums/y44...R/DSCN9880.jpg
:rolleyes::rolleyes:
It certainly speaks for itself.....

Chombi

^^ Some people should not be allowed near power tools.
:wtf:

I really do not like the look or idea of drilling holes in crank arms. Not to say you should not modify them though. These 49D's have way more material removed from them than you take off with a dozen small holes. And there's no stress risers or problem areas created by the work.

http://farm6.static.flickr.com/5020/...157ddc0e_b.jpg

The cranks don't look to bad, I'd use them. The brakes are crazy, crazzy, carazzzy.

^ Hey guys - give me a break - that was my first-ever attempt ;)

DD

I thought this was your first attempt:

http://i936.photobucket.com/albums/a...400a071807.jpg

Near the spindle, he should have ground down Stronglite and engraved Failure Plane. It's a pretty basic engineering calc. I would bet that the initial stress at the outer surface near the 3-hole pattern near the square taper is at least doubled when starting from a dead stop.

Is there a result of that scenario you'd like to share? C'mon, don't hold out - we all have to start somewhere :)

DD

Which has more of an effect? The weight savings from drillium or the turbulance of all the air swirling through the holes. Maybe they cancel each other out.

A smart rider might also try trepanning. Save weight, relieve cranial pressure, allow air flow through helmet.

Wait a sec'... this is drillium dos thread? Can someone give me the link to the drillium uno thread?

:thumb:

I think the cranks need more holes.

Can you guys spot where he missed drilling a hole??:rolleyes::D
Must have finally chickened out or a caring friend must have pushed him away from the drill press just before he got done??:p

Chombi

Being generous and assuming that 1 cu. in. of aluminum weighs 1.75 oz...

3/8" hole bored through ~ .625" crank arm = ~.022 cu. in.

.022 x 1.75 = .0385 oz. per 3/8" hole.
Therefore you would need just over (415) 3/8" holes to equal 1 lb. There are no holes in that crank 3/8" in diameter. They all appear to be 1/4" or smaller.

I estimate about 1 gram per hole on the chainrings. The crankarms are a bit trickier, it all depends on how thick the part being drilled is, and how big the diameter the hole is.
Heck!,...............best to just weigh another undrilled same make/model crank next to it and subtract the difference Isnt that a Stronglight 105?

Chombi

You will also notice that the non-drive side does not have countersunk holes, either.

The hole that wasn't there (kinda Zen riddle stuff???), no counter sinking - did he give up, get a clue or break the drill bit?

I think his Harbor Freight drill bit wore out before he could get to that last hole. :D

Yes, one hole that is present at the lower edge of the flute on the LH arm is missing above the drive side pedal eye.

-Kurt

Driveside crankarm, at the pedal end of the factory-milled flute.

DD

Edit: Kurt beat me to it :)