In my quest to create a more dynamic quadruped, I’ve started accumulating a lot of parts from bulk buys that could be reasonably useful to other hobbyists and experimenters. To maybe make life easier for everyone, I’ve started up what may be the worlds ugliest online shop where you can buy some of these components. For now, I have some bearings and custom gears that are useful when building servos for dynamic robots.
Check it out! https://shop.mjbots.com
Unfortunately US shipping only for now, email me or DM on discord to arrange something internationally.
Some samples of what I have online now:
M0.5 100 Tooth Steel Ring Gear
55mm +0/-0.02 mm outer diameter and 5mm width, only $17 each.
M0.5 20 Tooth Sun Gear
5mm tooth width, 4mm ID bore, 8mm OD hub, only $6
6708-2RS ABEC-1 Bearing 40x50x6mm
50mm OD, 40mm ID, 6mm width, only $8
2 thoughts on “shop.mjbots.com”
Wowza. Where on earth did you get 55mm ring gears that cheap? KHK 0.5Mod 100T 70mm gears are $50+ each! Looks like the 6708s are from AliExpress (given the ABEC rating), ya? How are their tolerances overall, anywhere near ABEC-1?
I had the gear set custom manufactured. The tolerances in the listing were what I specified and I’ve spot checked with my micrometer and at least the OD/ID look fine. I don’t have a way to verify the tooth tolerances, although the factory assures me at least the sun and planet achieved ISO grade 8. (I’ll get the ring gear to that tolerance too when I do an even larger run). Yeah, the KHKs were pricey, not to mention I spent roughly 30-45 minutes per-gear post-machining on the set of KHKs I used in the quad A0.
As for the bearings, they are an ali special, but seem to live up to their spec. I don’t have a CMM, but every test with my digital micrometer has come back fine. I just sampled 3 random 6708’s now, each at 3 equally spaced positions around the OD:
1: 49.997 49.993 49.999
2: 49.992 49.992 49.994
3: 49.994 49.995 49.997
ABEC-1 says the OD is +0/-0.012 for a 50mm bearing, so that seems legit.
You’re of course welcome to grab a few and see for yourself!
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