Defining a gear for replacement

20 year old piece of equipment,. manufacturer doesn't support it, basically a miniature spur gear that controls the focus adjustment on a vision system. The spur gear is damaged and I need to replace it. I can measure the rack : .032"distance tooth to tooth, tooth depth .024" and included angle of the tooth is 42 degrees. About all I can measure on the damaged pinion is .188" OD and 16 teeth. Can anyone help me define what I need to possibly find a replacement (pitch, pressure angle, anything else I would need) and recommenced a source where I can get it? Somebody like Berg or Boston gear? I can machine a bore or shank or whatever I need to adapt it, but need help defining the gear properly. Rack is OK, just need the gear.

96 DP, 20° pressure angle (assuming a measuring error of 2 degrees).
Check around at:
Precision 96 Pitch Spur Gears | SDP/SI

At a quick glance, I couldn't see where they define the pressure angles of what they make. Maybe you could buy a piece of matching rack gear and mount it in place of the original.

If your Rack actually measured .0327249-ish Tooth-To-Tooth Pitch, and were actually 20° Pressure Angle, then you would be able to verify that Z+2/O.D. = D.P.

In other words, Number of Teeth (16) + 2 / 0.1875" = 18/0.1875" = 96.
If your Rack were the proper mate, a 1" Diameter's circumference divided by 96 would agree.
1" * Pi = 3.14159265-ish / 96 ( teeth ) = .0327249-ish.

After that, you need only specify the Face Width and Bore details.

So, a 96 Diametral Pitch, 20° Pressure Angle Gear, having a Face Width of ... ???? and a Bore of ....? And then you set off to looking. In this case, it should be a very simple affair to find something suitable to drop in with little to no murderfications.

Good luck.