Gear Ratios Options

[yeahmag]

I have Dr. Evils DVD (bought it forever ago and have yet to watch it) and am hoping to have some fun building up a shorter ratio gear box. I have a huge box of 914 gears and was wondering if I can use the "Ratio Calculator" in the 914/901 gear ratio workbook to pair them back up. For example:

KA 22 : 31 1.41

In this case would a KA be a 22 tooth gear and a 31 tooth gear?

I understand that they are typically matched sets and I may get noise or increased wear if they are paired wrong.

Thanks.

-Aaron

[toolguy]

OK try to get your head around this example

we'll use a J and K gear set for example
j is 21 :31
K is 21:30

IIRC, the 21 tooth gear from these 2 sets are NOT the same outer diameter even though they have the same number of teeth
It is the distance from the centers that
determine if they match. . and even gears of the correct diameter may not be a 'matched' pair. . meaning while they will fit on the gears shafts, the backlash may be too much or too little. . too much and they will whine and have slop. . to little and they will bind, run hot and probably not even fit. .

Likewise gearsets for N, O, and P all have a 23 tooth gear on one side
but a 23 tooth from O is not the same as a 23 for the P set
N= 23:29
O= 23:28
P= 23:27

what makes a gearset matched has to do with pressure angles and diametrical pitch, not necessarily the number of teeth. .Easiest explanation is it has to do with the location of the contact point of the 2 gears in relationship to the distance from each gear centers.