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Unread 19-01-2011, 04:15
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VEX Robotics Engineer
AKA: Arthur Dutra IV; NERD #18
FRC #0148 (Robowranglers)
Team Role: Engineer
 
Join Date: Mar 2005
Rookie Year: 2002
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Pressing Pinion onto Banebot RS775

On Subsystem 2 of our robot, we are interested in utilizing both the 2011 FP and one (or more) Banebot RS775 motor(s) in tandem. For this task, I'm looking at gearing these motors together; using the 2011 FP and Banebot motor spec sheets, matching the free speeds of these motors works out almost perfectly* using a 15t pinion on the FP and 24t pinion on the RS775, both driving the same 60t cluster gear.

I'm looking to do this using 32DP 20° gears. AndyMark sells a 15t FP pinion, and I'm currently looking at buying spur gear stock from SDP/SI for the 24t and 60t gears. So here's my questions:

1) What is the diameter of the Banebot RS775 shaft? Their website lists "0.2 in (5mm)". Can someone with a micrometer check the actual dimension of the 775 motor shaft and verify whether imperial or metric is actual dimension? (Unfortunately, I don't have access to a RS775 for a couple of days). This is important because...

2) We're looking to press the machined 24t pinion onto the Banebot RS775 shaft. While we've removed and pressed pre-made pinions onto FP motors before, this is the first time we're going to machine our own pinion out of gear stock. Are there any special considerations to take? Would a reamer sized for a 0.0002-0.0005" interference fit** with the Banebot shaft be sufficient for holding the pinion in place?

Thanks for your help.


* Within 7.5 rpm (fraction of 1%) of each other!

** If shaft OD is actually Ø5mm, I'm looking at buying McMaster #8803a378.
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Art Dutra IV
Robotics Engineer, VEX Robotics, Inc., a subsidiary of Innovation First International (IFI)
Robowranglers Team 148 | GUS Robotics Team 228 (Alumni) | Rho Beta Epsilon (Alumni) | @arthurdutra

世上无难事,只怕有心人.