Chiaphua gearing (Chippy and Bosch)

We are using the Chiaphua and Bosch also. Low gear on the Bosch and 20 to 60 from the Chippy. The center to center axel distance for the 9T pinion Chippy to the 44T cluster gear sent us searching in the Machinery Handbook, p. 649, 1964 Ed. The useful relationship is that the Diametrical pitch equals the Number of teeth divided by the Pitch Diameter -- this equals the number of gear teeth to each inch of pitch diameter. The center to center distance on the axels is the sum of the pitch diameters divided by two. This gives the correct backlash and insures long gear life and proper mesh. FIRST gave us Data in Update #1. From a diametrical pitch of 36 and 9 teeth, solve to get Pitch Diameter of pinion equal to 0.25 inches. On the cluster, Diametrical pitch of 36 and 44 teeth solves to Pitch Diameter of 1.2222 inches. Their sum divided by two is 0.7361 inches center to center distance for the Chiaphua pinion to 44T cluster.

[Joe Johnson]

The 9 tooth pinion is enlarged, according to the data on the print given.

Depending on the method used to enlarge the gear, you may have to add distance to the center distance.

For cases of somewhat unknown gears, I would believe an actual measurement before I would use the calculated theorectical.

36 D.P. is not all that large of a pitch for such a torquey motor pinion. I would be careful about adding too much backlash or you may end up losing gear engagement which will lead to higher stress on the teeth.

As if you didn't already have enough to worry about...

Joe J.

[Chris Masten]

I believe that I read elsewhere that the measured distance was 0.74". My measurement was 0.7428.

CM

we turned down the otherside of the cluster gear to 3/8 so that it would fit into the aluminum timing pulley...then we went to a size 60 tooth plastic timing pulley on a custom made shaft for the bosch where our final take off drive is on the same shaft of the bosch...we did alot of research, and last year we used tandem motors with the fisher price and the bosch....


we got it under control...i hope