All,
I'm looking for a bipolar DC stepper with a high gear ratio box and a 7mm D-shaft on the output. Output torque requirements are around 25 N-cm. NEMA 17 format would be good. Output rotational rate would only be 2-3 RPM, hence the high gear ratio. StepperOnLine products would be great, but I've not found anything of theirs in a 7-mm shaft. Hanpose has some 7mm devices, but the highest gear ratio of theirs I can find not coming from China is 5.71:1 . Would rather have something up around 20:1 or higher.
I'm new to DC stepper motors, so I'm sure there are suppliers I'm not aware of. I've done a fair amount of searching, and haven't come across anything. Almost certainly these things exist.
Thank you,
FlyBoy55
Will the common 28BYJ-48 fit the bill? Maybe use a 'coupler' to go from 5mm slotted shaft to 7mm shaft.
Inexpensive and readily available on Amazon with and without ULN2003 driver board. I don't know what their N-cm rating is.
https://www.amazon.com/s?k=28byj-48&crid=2LJRSFDK38ZLB&sprefix=28byj-48%2Caps%2C74&ref=nb_sb_noss_1
Datasheet
- Pull in torque: 300 gf.cm
Hmm, so maybe a little low.
These geared motors will do 70 oz-in = 50 N-cm
Sorry. I'm needing a 7-mm D shaft. Thanks for the suggestion.
So get your file out and make it a "D" shaft on the exposed part.
Paul
The shaft on the suggested motor is 5 mm. As stated, I need a 7 mm shaft. Motors I've already found are much closer to what I need than the suggested motor. It's a situation which requires a 7 mm D shaft. That's what I have to couple into.
5 mm to 7 mm shaft coupler and a section of 7 mm D shaft.
My situation is not really conducive to the additional length required for such a coupler. Really, I'm an avid DIY'er with good electrical and mechanical skills. I've considered all such optional workarounds and have ruled them out. I'm looking for a DC stepper with a gearbox with a 7 mm D output shaft.
Hmm, it does seem that NEMA17 and 7mm shaft are exclusive.
Yep. I'm coming to the same conclusion. Looks like I'll have to drill out what I need to fit into to fit an 8 mm shaft, which isn't hard to find.
Remember that drills ALWAYS drill holes slightly larger than the drill diameter, so work into the size you need.
Paul
I drilled it last night. Slightly smaller drill, then a rat tail file to finish it off to fit nicely. Then I drilled and tapped a hole for a 4-40 set screw that worked well. I'm satisfied.
Nice.
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