pic: So, Andy Mark was sold out!

[Big Ideas]

For flat pieces it's possible to hold the stock with double sided tape (thin like carpet tape) on a sacrificial subplate like MDF, HDF, or MDF with melemene. Or drill a few tooling holes and screw the stock down the the subplate. This way you can make your final thru cut and not have to file all of those perfectly machined teeth.

[artdutra04]

Originally Posted by Big Ideas

For flat pieces it's possible to hold the stock with double sided tape (thin like carpet tape) on a sacrificial subplate like MDF, HDF, or MDF with melemene. Or drill a few tooling holes and screw the stock down the the subplate. This way you can make your final thru cut and not have to file all of those perfectly machined teeth.

Double-sided tape on MDF won't work if you intend to use coolant. I've also had issues with parts shifting slightly on non-coolant milling (engraving acrylic) when relying only on double-sided tape to hold the parts in place.

Using a fixture plate (as sandrag already mentioned) is the best method. Since all AM sprockets have the same "standard" Ø1.875" six hole pattern, just make a permanent fixture plate if you intend to mill a lot of sprockets.

Originally Posted by sanddrag

Just curious, what did you use in CAD for the tooth profile?

I've milled 25p sprockets from the CAD models available on McMaster and/or SDP-SI. I've been meaning to create an equation-driven SolidWorks model where you can just edit the number of teeth in the equation and hit Rebuild to make any size sprocket you want (I did that with gears a few years ago), but downloading existing part models is easier...

[Brandon Holley]

Originally Posted by artdutra04

I've milled 25p sprockets from the CAD models available on McMaster and/or SDP-SI. I've been meaning to create an equation-driven SolidWorks model where you can just edit the number of teeth in the equation and hit Rebuild to make any size sprocket you want (I did that with gears a few years ago), but downloading existing part models is easier...

Following the old saying of "Work smarter, not harder". Totally agree, CAD files are so easy to find on the net (Mcmaster + SDPSI) that it makes it completely painless.


Also ditto the fixture plate, it's how we make almost all of our flat plates on CNCs.

-Brando

[Big Kid]

I was trying to do this on our team's 3 Axis CNC Mill, and I only managed to get one done right. The other attempts all seemed to have distorted pitch diameters. Any suggestions on how come this kept happening and any tips on how to fix it?

I used CAD files from McMaster, and I had the stock mounted to a mounting plate we made for the sprockets.

[James Tonthat]

Just an FYI, one of the forum sponsors, Innovation First sells 35 plate sprockets.

http://www.vexrobotics.com/products/...sprockets.html