Just a thought - how much current draw does the motor show when the grinding occurs?
Just a thought - how much current draw does the motor show when the grinding occurs?
WFrom the video, it definitely sounds like a belt/pulley meshing
Ncurr_x and curr_y?
Nthat is the idea, but I'm not sure where I would go from there. To a different tooth # motor pulley? I'm just following what @Subsonic (Protomaker) 's guide prescribes. afaik no one else following that guide has dealt with this before. The other gimbal creaking type issues I can find plenty of troubleshooting solutions for, but not this belt issue
WAs a last ditch effort I can supply you an original Rhino pulley
Ncould you just send me a spec page/size spec for it? just to double check
Ncurr_y goes up to about 17A at max deflection, + and - in either direction, no weird behaviour
Hthen you are certainly not overstressing the Rhino.
Nyes, on walmis' recommendation earlier I tried turning the motor+pulley by itself and everything was smooth
Nmight be gimbal related as well since I know this one is particularly bad and it's going to be rebuilt with some new parts next week. Might not be out of the question that vibrations are starting inside and traveling out to the belt via 74t pulley
HSorry, if this is a dumb question, or was answered earlier - are you 100% positive that you have the right belt and pulley specs? regarding tooth profile and so on?
Nit is most significant at the belt but that makes sense
Nyes, I've double checked with the guide, other people who built, and david's own rhino
N74t pulley, motor pulley and belt spec are correct, I now have 4 motor pulleys i've mix n matched at will
HHTD5 on both sides?
Nyes
Hok! sorry - better safe than sorry
WWe machine those pulleys in-house, it's based on the HTD5M spec
N15mm width, 12 tooth, 8mm bore? well, width depending on the belt of course
Wofficial Rhino belts are 10mm, 12T pulleys
Hthat's what I use.
HYeah, but it shouldn't make a difference.
H(the width I mean - as long both gears are the same size)
W
N@Hiob before you installed the gimbal in the enclosure, did the oval-shaped X and Y gimbal frames rotate freely and smoothly around the grip connector?
NI think mine was overtightened. My gimbal frames barely moved at all, took a lot of force to rotate them
Nie. the main nut, sitting all the way down in the core of the grip connector
HYes and no - there is a bit of a "round edge" when you try to deflect both axis at the same time. This is a geometrical thing due to how the gimbal works. Once you add an extension and grip this (very small) hump isn't there anymore (or can't be felt anymore). The inner oart of the stick connector needs o rotate slightly inside the outer part and also needs to move up and down (very very slightly) - that is what the flexible TPU part is for. A bit like a spinal disc. But without any weight and leverage, it can be felt.
HThat your gimbal was hard to rotate isn't right though
HIt should move easily.
HPerhaps the bearings weren't properly seated?
Nyes, it's that second type of rotation that I mean. Was it smooth? Or did it take a lot of force
I took a picture on day 1 and X/Y frames were slightly crooked, which had me a bit concerned not because it was crooked, but because it was very hard to rotate to get aligned again
I took a picture on day 1 and X/Y frames were slightly crooked, which had me a bit concerned not because it was crooked, but because it was very hard to rotate to get aligned again
Nit did not feel like there was a bearing in there at all. More like just a screw and nut.
H"A lot of force" - certainly not!
NWhich I now understand looking at the subsonic guide that there are back to back flanged bearings in there
NI suppose if it was assembled like that, then two weeks of use under high spring force might have broken something
Nsince yesterday i've loosened the nut a bit, but it seems to be too late
HI'm thinking more of the big bearings that hold the main gimbal frames.
Nthe big outer 6808s? hmmm they are still pretty smooth but i'll check next week
HIf those aren't perfectly seated - aka not perpendicular to the axis of rotation, it could make the whole assemble get stuck
HTo give you an idea - When I disassembled the gimbal to change the stick connector to my "stubby" version - after reassembling and only the 80mm grip connector as a "lever" - without belts attached, the gimbal moved freely and buttery smooth in every direction.
Nwith no belts attached, the gimbal has always been pretty smooth in linear x and y motion, no issues with the 6808 bearings there
Nbut with circular motion it has always had some issues with internal creaking that can be felt all the way up the grip
Nprobably at the beginning due to the grossly overtightened nut, maybe now due to internal damage
Noh well........the belts weren't expensive, at least 
HYou shouldn't overthighten the central bolt that connects the two core parts. I would even argue, that the bolt doesn't need to be fixated in the outer part at all - but I haven't tried that yet.
Ni'll certainly keep that in mind for the gimbal rebuild
Nwould honestly be helpful if there was a guide out there for how tight the main screws need to be
Nthe main bolt/nut of grip connector and core joint, the preload screws, etc.
HFor the free moving variant I have in mind, you would need a different outer core and bearings though. The "stock" gimbal works just fine. It is mainly the central bolt that connects the gimbal core that can't be overtightend.
Nhold on, are you using a 72T pulley? in combination with 12T motor pulley