Hollow spindle? That's crazy talk.

Next thing you know you'll be asking for something crazier still, like a hollow axle,. :eek:

https://farm4.staticflickr.com/3015/...eccbe849_b.jpgStronglight hollow cottered axle by Stronglight, on Flickr

We used to gun drill and tap 4140 excavator boom pins for grease ways using HSS bits without issue when I worked in machine shops.

That's a beautiful axle

If this is our December topic, I can't wait until January and February

That's funny stuff. :lol:

Do you remember the auctions for that stuff?

Or better yet, the PICTURES for the auctions. :wtf::eek:

No, I mercifully missed that one.

The previous owner/builder/racer of the Colnago I restored....the RD shift lever is drilled out. He looked at his work and decided not to touch the left side. I admire those that can drill an already "light" part with precision like a true artisan. Someday I will need a set of Campy shifters. :)

Not me, thanks. I'm well known for what my wife calls, in her inimitable Chinese way, "painting legs on a snake."
In other words, not knowing when to stop. ;)

Not all aluminum alloys are heat treat-able. Not sure which one Campy used. It's an interesting idea. But having just read a little bit on the process, it seems very complicated. Need a highly controlled furnace, etc.

Knowing I am among metallurgy genius types....that was only offered tongue-in-cheek. Those cranks are drop dead gorgeous!!

So, I'm wondering why Shimano didn't use hollow axles. What group is this axle from?
I don't know sheit about Shimano.

I would be surprised if it was anything other than some sort of mild steel. The case hardening would give it some serious stiffness. Titanium is actually pretty easy to machine. Not much more difficult than aluminum, in my opinion. They need carbide because steel chemically reacts to titanium and just destroys the HSS tools.

We're not talking about ordinary drillium. No. This was a special class of "artistry."

I should leave it to [MENTION=168558]Drillium Dude[/MENTION] to explain the work of Elden-Sama.

Just a basic 1988 cromo offering.

Hardening and even alloying are not going to significantly increase stiffness of iron (steel).

Shimano used hollow spindles in their better cartridge bb's, but never produced one with the integral 10mm threaded stud protrusions.

A non-drilled spindle has likely not been fully tested in the drilled condition, so becomes an experiment/test of it's durability into un-charted waters if drilled and put into service.

Lack of consideration for design, testing and quality-control can result in this:

https://c2.staticflickr.com/6/5601/1...5a27a18d_c.jpg

I watched those same cranks break twice from front row seats. (In races - the guy immediately in front of me.) Both broke across the pedal threads. Adding stress concentrators in line with a radial line across the pedal threads just doesn't seem like a good idea based on what I have seen.

Ben

It isn't obvious or intuitive to guess by looking, but the smaller holes have a higher stress-concentration factor than the larger holes that might seem to be more dangerous because more metal is being removed.
The radius of the hole is the problem, because a smaller radius changes the local cross-section more abruptly, resulting in higher localized stress levels so more-rapid fatigue of the metal.

Any kind of metal removal from parts that are designed to be lightweight in the first place will likely result in somewhat premature failure, and only lab and/or field testing will prove otherwise.

As for drilling deep holes economically, the production environment using controlled force and rate of feed of a particular specification of drill bit into the particular grade of steel means that the best hole is cut and that the cutting tool lasts the longest. Doing it by hand involves more risk of breakage and of dulling the bit from heat and/or insufficient rate of feed.
In other words, what cost Sugino 5 cents to do on the production line might cost the home-tinkerer ten dollars to accomplish!

I once removed about a full pound from a front brake rotor of an S/G motorcycle dragster, drilling 96 holes at 3/8" diameter through perhaps 7mm thickness of stainless steel. Although I developed some efficiency along the way, I went through a half-dozen bits due to my poorly-controlled drilling.
That was in the days when I also saved huge weight by eliminating the inner tube from the front tubeless tire on a spoked, tube-type rim. Each of the spoke nipples was set in a puddle of self-leveling silicone sealer inside the rim, and the tire itself was seated with the same silicone sealer. It held close enough to 35psi just fine for the few hours it spent on the track at each outing, and as I recall the old inner tube weighed a lot. I got it down to 341 pounds on the official scales with aluminum wheelie bars in place and 40oz of fuel in the tank, good enough for high 9-second passes at around 132mph with this 137lb rider in place.

https://c2.staticflickr.com/4/3734/1...9fe22c4b_c.jpg

The only parts that I can recall breaking were a shift shaft selector spring, a connecting rod bearing cage (non-catastrophic failure btw), and a fiberglass front fender and gas tank that both broke when I slammed down from a biiiig wheelie at about 60mph before I had the wheelie bars.

Who'd a think grown men were so bored that nearly 900 views have been rendered in 2-3 days about drilling out a piece of metal rod?:rolleyes:

The crank and stem were both for show, not go. C'mon, I have some common sense ;)

DD

I dunno, DD. I'd ride that crank. Even without heat treating. Which I'm not sure would help strengthen them anyway.

I'd ride 'em. After all...you left most of the material. ;)

Honestly, the millings in the spider scare me the most. I truly wouldn't have ridden it :)

Heck, I still run one or two factory-milled Campy cranks, and I'm picky about hilly routes when I put them to the stress test of real-world riding. I'll put holes in things, but I won't necessarily ride them - or even suggest that to those that purchase them. I'm not an engineer, after all, and trial-by-error becomes less and less appealing the closer the other foot gets to the grave ;)

DD

Oh, gawd...I remember him. Haven't seen his "craftsmanship" on ebay in some time.
S'pose he got hit by a bus or something?

Yeah, there were a couple of bush-league mad-drillers around that time. I think they burned out for whatever reason. I know I did for a couple of years.

One of them was also a dealer in Nazi memorabilia, right? Strange, that one.

DD

Drilling a spindle is boring. Only a dull tool would try it. The hole concept is not very sharp. What's the point ?

Yeah, the Vietnamese cross dressing Nazi with anger issues and a power drill.