T174M
Plastic
- Joined
- May 8, 2008
- Location
- Doylestown, PA
OK,
I'm still pretty new to this forum and machining, and have learned a tremendous amount from reading this forum. I'm now in my third semester and working on a few projects of my own/with a buddy now. I decided to make my own sprockets. the steps I have taken so far:
1.Sketch the design I want
2.Draw in mastercam
3.Produce the code for it
4.Draw/Design/Make the fixturing
5.Cut out of particle board to see how it turns out!
I ended up with three fixtures to complete the sprocket. The first fixture is for doing the bolt holes and the center pocket(for the hub). The second fixture(one in the picture below) I bolt the drilled square onto it and cut out the rest of the sprocket. The third fixture is a lathe peice that holds the sprocket so I can turn down the 1/4" stock to the proper thickness, and put a relief on the teeth.
Here is a picture of me cutting out the particle board sprocket..Not sure how long this would last on the bike haha.
In the picture above you can see me roughing out all the pockets. I come in with an 1/8" endmill to clean up all the pockets.
Here is the finished particle board sprocket.
And here is a crappy picture of the engraving I put in it. I have 6 "174's" engraved around it, since that is my racing number.
Now,
Most companies out there make their sprockets out of 7075. I'm having a hard time finding sheets of 7075 at a reasonable price...Wait, I don't really know what a reasonable price is..So, what is a decent price for this material?
Would I be better off machining them out of 6061 and hard annodizing them? They take a good amount of abuse and all the sand/dirt that finds its' way between the chain and sprocket act as an excellent abrasive.
An aftermarket rear sprocket from a company is generally between 50-60 bucks. Can they sell them for this price because of the quantity and price cuts(from buying in such large numbers)?
Any help is truly appreciated,
Tim
I'm still pretty new to this forum and machining, and have learned a tremendous amount from reading this forum. I'm now in my third semester and working on a few projects of my own/with a buddy now. I decided to make my own sprockets. the steps I have taken so far:
1.Sketch the design I want
2.Draw in mastercam
3.Produce the code for it
4.Draw/Design/Make the fixturing
5.Cut out of particle board to see how it turns out!
I ended up with three fixtures to complete the sprocket. The first fixture is for doing the bolt holes and the center pocket(for the hub). The second fixture(one in the picture below) I bolt the drilled square onto it and cut out the rest of the sprocket. The third fixture is a lathe peice that holds the sprocket so I can turn down the 1/4" stock to the proper thickness, and put a relief on the teeth.
Here is a picture of me cutting out the particle board sprocket..Not sure how long this would last on the bike haha.
In the picture above you can see me roughing out all the pockets. I come in with an 1/8" endmill to clean up all the pockets.
Here is the finished particle board sprocket.
And here is a crappy picture of the engraving I put in it. I have 6 "174's" engraved around it, since that is my racing number.
Now,
Most companies out there make their sprockets out of 7075. I'm having a hard time finding sheets of 7075 at a reasonable price...Wait, I don't really know what a reasonable price is..So, what is a decent price for this material?
Would I be better off machining them out of 6061 and hard annodizing them? They take a good amount of abuse and all the sand/dirt that finds its' way between the chain and sprocket act as an excellent abrasive.
An aftermarket rear sprocket from a company is generally between 50-60 bucks. Can they sell them for this price because of the quantity and price cuts(from buying in such large numbers)?
Any help is truly appreciated,
Tim