Diem Turner
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Let me begin by stating, unequivocally, that it is not my intent to on your myopic motor plate machining meanderings (you thought I was going to follow this with a BUT dot dot dot, didn't you? You know what that makes you? An absolutely correct observer of reality so at this point I extend my congratulations) BUT...I’m getting really, really frustrated with this crap. I have a TP 4070 with an 8mm shaft going into a build. Guess what? The motor plate bore is (again) too small to accept Saga 8mm Mod-1 pinions. Of which I have a very nice selection. The shoulder of the gear barely fits in the motor plate, and when you factor in the grub screws? Nope. They rub on the bore. And no, thanks for the suggestion, but the shaft on the TP isn’t long enough to flip the pinion. So now I’m going out to my shop in the unheated barn nestled in the quite picturesque yet frozen, arctic tundra to fire up my drill press and machine the bore out of YET ANOTHER ”big motor” motor mount. I’m getting sick of this. The “big motor” plates from all brands I’ve used to date (PPS, the Arrma “option” big motor plate for stock mounts, and now the Iron Man “big can” mount) do indeed accommodate the bolt spacing of the bigger motors but apparently in no way account for the fact that the bigger motors might actually have a bigger shaft. I’ve successfully deleted so many expletives in this post…
WTF.
I don't understand what the problem is here. I mean, from a linguistic and contextual point of view, I understand the issue you're describing. As someone mentioned, spools can help circumvent this particular problem as some are designed so that you can position the spur gear anywhere on the shaft of the spool (so long as it remains between the motor mount and diff/spool support...going beyond those boundaries will present an all new slate of issues that I'll spare you all the indignity of watching me delve into at length, in verbose & autistic detail...) but even this is not necessary. This is a brief video of my 100% stock PPS grub lock motor mount where I have intentionally lowered (or slid sideways depending on your current orientation in relation to the axis of the motor as you read this) the pinion as far as it will go.
There's a cheap and easy solution to this problem (which I [sort of] never had because I got these before I ever got my PPS or Rotolock motor mounts because they're just better in every conceivable way...I say sort of because I did have this issue but it was with the stock Arrma motor plate that comes in the 6S BLX platform vehicles which wasn't intended for large motors so I found myself, much as you describe, widening the opening of the motor mount with a stepped drill to accomodate a protruding grub on a pinion gear).
Torx grubs are infinitely better than hex grubs. They're so worth the swap. Moreover, these are 5x5mm which makes them the perfect length for 8mm pinions as they barely protrude a half mm when snugged down. Should you be in a particularly tight squeeze, that half mm can easily be removed with a file or grinder leaving plenty o' meat to plunge your favorite Torx® bit into.
So in closing...save yourself the anguish, stop committing machinual assault on your motor plates and discover the joy and pleasure that affixing a Torx® grubbed pinion and/or spool/spur gear can bring to your life. I know what it has done for mine.
FG Grub screw with Torx M5x5mm - 15pcs. (part nr.: 6930/05) | 6,50 € |