Thanks for braving the cold Jim! Haven't found one yet that exactly meets that spec. When it is delivered, I'll carefully try out the one I ordered. It is 32 pitch. May be able to shim the plate the positions the shaft to avoid any skipping.
No idea on ages or how long they were catalogued. Mine has the bigger wood knobs on everything. Also the shaft on mine goes all the way from side to side so that both knobs turn when it's rolling out or in. Mine is in the 125XXX number so likely newer than yours. Also the way the geared movements work is less machined and probably cheaper to produce. All this stuff changed during long runs.
Last edited by Jim Galli; 17-Mar-2020 at 09:49.
The tooth pitch is measured from the rack. The number of teeth on the gear [pinion] is the circumference of the outside diameter divided by the rack pitch and then reduced to the next, or next but one whole, number. Since the number of teeth and pitch are measured at the pitch diameter of the gear [pinion] which is smaller than its outside diameter.
Conversely, if you know, or can guesstimate, the pitch diameter of the gear/pinion then (pitch diameter x pi [3.1416])/ number of teeth gives the pitch
regards
Tony
Last edited by tonyowen; 18-Mar-2020 at 09:22. Reason: erroneous comma, extra paragraph
Tony, never would have figured that out on my own. Thanks, Scott
You're welcome
A point of clarification - to measure the pitch of the teeth on the rack - measure over a 'large number of teeth' then divide that value by one less than the number of teeth. The more teeth over which you measure will give a more precise value of pitch --- (distance measured over N teeth)/[N-1]
regards
Tony
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