Mod 1 5mm bore pinions
 

Does anyone know if the 5mm bore mod 1 pinions have enough material to increase the bore to 8mm ?

depends on the tooth count. I'd check http://www.sdp-si.com/ for 8mm pinions

Yes, but the web thickness where the setscrew threads are will also be 1.5 mm less... and you'd need a carbide bit if she's hardened or you'll just burn stuff up trying.

I asked Mike about this question before. He said he wouldn't recommend it. The "hub" is 10mm, so If you drilled it to 8mm, that would only leave 1mm. Not too strong and not enough for the grub screw.

Ok, so you need a Mod 1 pinion with a 8mm Bore with a set screw?

How many tooth?

Here's a 20 tooth.

http://cgi.ebay.com/Steel-Metric-Spu...3286.m20.l1116

SDP-SI does have them, but if you're planning on running a steel spur think twice about your decision, whether it be the motor or the spur gear.

So if you run a plastic spur, then by all means pick SDP-SI! I have an 18t steel one from them, and a 16t stainless steel gear. The quality is excellent.

Yeah, I've been looking at sdp-si.com.