From 2ae732a13afc5b18b7c8f06da29071ae0c1ccada Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Sun, 10 Jan 2021 10:46:39 -0500 Subject: [PATCH] docs: Note the BMG extruder is actually 50:17 and not 3:1 Signed-off-by: Kevin O'Connor --- config/printer-tevo-flash-2018.cfg | 4 ++-- docs/Rotation_Distance.md | 11 +++++++++-- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/config/printer-tevo-flash-2018.cfg b/config/printer-tevo-flash-2018.cfg index 6017fcaf..e6bf3e86 100644 --- a/config/printer-tevo-flash-2018.cfg +++ b/config/printer-tevo-flash-2018.cfg @@ -53,8 +53,8 @@ step_pin: ar26 dir_pin: ar28 enable_pin: !ar24 microsteps: 16 -gear_ratio: 3:1 -rotation_distance: 23.050 +gear_ratio: 50:17 +rotation_distance: 22.598 nozzle_diameter: 0.400 filament_diameter: 1.750 heater_pin: ar10 diff --git a/docs/Rotation_Distance.md b/docs/Rotation_Distance.md index c143bbe8..b8134ce3 100644 --- a/docs/Rotation_Distance.md +++ b/docs/Rotation_Distance.md @@ -154,8 +154,15 @@ determine the gear_ratio by counting the teeth on the pulleys. For example, if a stepper with a 16 toothed pulley drives the next pulley with 80 teeth then one would use `gear_ratio: 80:16`. Indeed, one could open a common off the shelf "gear box" and count the teeth in it -to confirm its gear ratio. Note that the common "5.18:1 planetary -gearbox" is more accurately configured with `gear_ratio: 57:11`. +to confirm its gear ratio. + +Note that sometimes a gearbox will have a slightly different gear +ratio than what it is advertised as. The common BMG extruder motor +gears are an example of this - they are advertised as "3:1" but +actually use "50:17" gearing. (Using teeth numbers without a common +denominator may improve wear leveling as the teeth don't always mesh +the same way with each revolution.) The common "5.18:1 planetary +gearbox", is more accurately configured with `gear_ratio: 57:11`. If several gears are used on an axis then it is possible to provide a comma separated list to gear_ratio. For example, a "5:1" gear box