Any tricks to getting threaded cogs off?

[ColsonTwinbar]

Just got some NOS New Departure skiptooth cogs, I'm trying to replace the larger girls cogs, and having some difficulty getting them off.
-Nolan

 

[ColsonTwinbar]

nevermind... would have been easier if the wheel was still together.

 

[cyclingday]

The skiptooth cog has a right hand thread and the lock ring that holds it in place has a left handed thread. Park tool makes the spanner wrench for removing the lock ring. They also make the chain whip used to grip the cog securely. But I doubt that a skip tooth version is available. You may be able to modify one using an old piece of a skip tooth chain. I don't know if this helps but All mechanics is tough without the proper tools.