Rim Sprocket

[Paul1963]

I’ve just been given a hitachi (Tanaka made) CS51EAP saw
It takes the same 20 inch bar as my Tanaka 4000B saw does

in going over my Tanaka I noticed that the seven teeth on the drum that drive the chain are a bit worn so I ordered a new drum and needle bearing and while waiting for these parts I took a good look at this Hitachi saw and the hitachi saw has a rim sprocket that goes over the seven teeth on its drum the drum itself is a different part number but I wonder if when Tanaka made the 4000B just to save money they didn’t put rim sprockets on those drums
has anyone added a rim sprocket to a drum to prevent wear on the teeth of the drum itself and maybe possibly improve performance?

 

[Steve]

Do you mean replace a spur drum with a rim drum? The answer is yes, if a comparable drum is available.

 

[Paul1963]

Do you mean replace a spur drum with a rim drum? The answer is yes, if a comparable drum is available.

I’ve recently learned that they are two diff types
I had it my head that the rim sprocket went over a spur sprocket but I’ve discovered that they’re two different style drums
So theres a perfect example of “learn as you go”
Thanks for getting back to me
Paul