6v starter repair

I had a 6v starter that needed brushes and armature turned. I replaced it with a 12v starter last year (2n 12v system) and just left it on the bench untill I felt motivated.Well today was the day, I turned the armature it was realy burnt but cleaned up good. 2 of the new brushes went in easy (screw on terminals)the other 2 are soldered in and to big for a small solder gun.I bought a butane micro torch from home depot $9.00 cheep and it worked great.starter bench tested good, the next problem I didn't mention in the beginning the p.o.must have replaced the drive years ago with the new style with the 6mm dowel I have heard complaints about on this sight well I can tell you that a 6mm dowel in a .250 hole does not work what a mess it made of the hole, his fix was to drill a new hole closer to the end of the shaft then weld it as well, he didn't want it to come off I guess and it didn't come easy a die grinder and some persuasion did it.I haven't put the drive back on yet, now depending on the dowel fit I may use a spot of weld myself the shaft is already messed up so it can't hurt it now.due to the fact new hole is about .250 forward the drive gear will not fully engage the ring gear and hasn't for years so if I am going to weld it anyway should put it where it belongs or not worry.

Do the basic math conversion 1/4" = .250" ; 6mm = .236" thus a 6mm pin would fall right thru a 1/4" hole.

You are right a 6mm pin would fall thru if it could but in the case of a startor drive it is captured by the washer and can,t fall out untill it wallows out the hole by beating back and forth as shown in the picture.The third picture shows the .250 hole the p.o. drilled .250 forward of the original hole.I read a post several months ago someone bought a new drive with a 6mm pin and wanted to know if he could use it I responded and said no because it would ruin the hole, well now I have pictures to show the damage.