What ratio, sput/pinion, are you trying to achive. If you want to run a larger spur than 51 teeth you would need to run a larger pinion to get the same ratio. For example a 51/18 would have the same ratio as a 65/23, both about 2.83/1.
For the time being, just drill out some 32p pinions. It's not ideal, but will get you running 'til you have luck finding a Strobe. Don't you have a machinist at work willing? If not I have a drill press at my house we could hack into some cheapo pinions with
Sweet! Once again Pb4ugo to the rescue. I do have a machine shop here so I will have some work done. If not I will call you in a week. Its good news to hear I can use a 65\24 for the same ratio. Thats the way I will go until I can get a strobe purchased.