yeah cast is you melt the metal and shove it in a mould and wait for a it to cool or cool the mould real quickly (gives different properties either way)
and machined is like you get some metal and just saw/cut/mill the excess off and make the shape you want.
ah thats what machined it, thanks
So, are Moments cast or machined?
The moments are machined from solid stock. What they do is they take a giant piece of aluminum, and cut of pieces of it that are about the size of the crank. Then they place it in what is called a vertical machining center (just a fancy milling machine) which has a number of cutters that rotate like on a wood router. With these cutters, they shape the crank. When they’re done, they polish it and check it for tolerance. Machined parts can be extremely precise. A human hair is usually ~0.002" around, while it’s not uncommon for machined parts to made to a tolerance of 0.0005" or better.
Casting is no generally a very accurate fabrication process. Usually they cast a part and then machine many of the faces. Sometimes they machine every exposed face of the part to hide the fact that it was initially cast. When you cast a part you simply makea mould of the part and then pour molten metal into the mould, and hope it comes out right. The difference between casting and machining is that machining is entirely based on cutting metal, while casting is just pouring it.
Another way to make a crank is what is called “forging”. They take a pair of steel plates and machine a negative of the top and bottom of crank into each piece of steel. Then they harden these plates. Then a simple bar or plate of aluminum (or steel) is placed between these plates. One oplate is attached to either a very powerful (>100ton) hydraulic press, or it is attached to a very, very large weight which is literally dropped onto the bottom plate. The force o the impact squeezes the metal like clay into the shape of a crank. This is how most wrenches are made. A forged part will often be somewhat stronger than a machined part of the same dimensions, since the metal has had its “grain” aligned with the lines of stress to some degree. Forged parts are more accurate than cast parts but not as accurate as machined. They’re also extremely expensive to set up, but very cheap to make once you do set up. The KH cranks could be forged, if Kris wanted.
Thejdw, thanks for the video, but that’s actually a completely different forging technique than what i described. Instead of using hundreds of hammer strokes, the part is made with just one. If you’ve seen Eminem’s 8Mile, the part where he works in the factory and has that big thing that smashes metal, that’s forging.
That said, the video was of forging in the pure sense. Damned if I’d make a crank that way though. I’ve made three knives and some other blacksmithing projects, and they’re completely different from bike parts.
I’m pretty sure I already know the answer but I just want te be extra sure.
Is it alright to grind the nubs of of the KH hub that is on my nimbus hoppley. I’ve heard that you can, you cant, and that you can but need different bolts.
Help.
I hope you mean cranks? What kind of cranks are they? Post picutres with crank bolt in and out.
oh so the hammer thing is a mold, now it makes more sence
Whoopse my bad yes I do mean cranks.
I’ll upload pictures after lunch.
Edit: There the Qu-ax cranks for the 8 spline KH hub.
Is this what you need? I dont know if you can see it but there are some threads on the inside of the crank nub. Does this matter?
Yeah those should be able to be denubed. I dont see the point in extractor threads in cranks like those. Give it a shot.
Will do, and thanks for all the help and i’m really glad that you havent completely given up on unicycling.
We’ll see, i hurt my should just roll hopping yesterday.
