YI4872 Internal Gear, 20 Degree Pressure Angle, 48 Pitch, 72 Teeth, Brass

This is the second "Boston Gear" ring gear I have bought recently. The gear geometry is the important thing of course and Boston gear makes beautifully engineered gears that always mesh nicely and run smoothly. I have no complaints at all about the design and function of the product itself. Sadly though both gears were poorly deburred. These are normally pretty expensive and should reasonably be expected to be finished nicely. I got this gear on sale (What! they have gear sales?? Yes.... apparently they do.) so that took the sting out of the half hour of deburr needed. To pay over 100 dollars (at full price) and then have to deburr it would have been a lot more irritating. This gear is going into one of Elmer's "geared steam engines" and for that, there really is no better choice as far as I know. If you are building one of these engines, build everything else before you buy the gear and that will spur you on to shell out the hefty retail price for one of these. (Spur... gear...: See what I did there?)

This is a very expensive gear; but, it would very, very difficult to make as accurate as this quality is.

Delivered quickly, perfect finish and fit, could not ask for more. I would recommend to anyone needing bronze gear sets.