I've been having a problem getting the toothed belt installed properly in my nexdome. Interestingly the first belt shipped was 287 teeth and left a region larger than a tooth opened in the track with the gear track tight against the molding line of the dome (like the image in the instructions).
Now I have a belt with 288 teeth, which is what it is supposed to have. However I find I have overlap. I can have the belt hang off the bottom of the region for the tape, such that this is not sound for expectation of operation, and this belt is still too long and overlaps by about 1/4th a tooth.
I've asked Babek to provide panel sizes as review of all images of my dome does not reveal any user error. The dome does not seem to offer much of any play with what I've loosened so far and so I am not sure how I can expand the dome circumference further.
What would be a huge help is folks providing:
1) the length of their belt, perhaps the tooth count so we may know of yet another QC issue if present
2) the circumference of the molding line across the whole dome - preferably with millimeter precision, let's set our measuring tape above this line so we don't get involved with the gear train.
3) The easiest but probably most important: the length of each panel along the molding line (again, tape just above it)
I'm concerned one or more of the panels is "wrong" and unworkable. I bought my whole nexdome as one kit fwiw so while the dome if there's an issue present may have went unnoticed with a manual installation, the automated dome rotation is not in good or workable shape... I've made the same ask(s) to Babek so I can figure out what is wrong with this dome but it's been going slow.
Here's some measurements I took on mine with just a fiberglass measuring tape, I've got a track length of 132.5 inches due to it (sorry , tape was std, not metric). I stuck it ontop of the edge of the 3m extreme mounting tape.
I have checked this thread out: https://www.nexdome.com/forum/observatory-automation/toothed-belt-for-dome-rotation-3-8-too-short
So as of the pictures I listed in the first post, the bottom of the belt is 2-9/16 inches from the molding line, about half of the belt is hanging off the bottom edge of the track molding just as a rough idea of what's going on. I figured the work backwards trick to try and compress the belt a bit but the belt was pretty stiff w/ nylon threads and lifted off the tape when I tried it before (@ 3/8ths spacing from top, so bottom of belt -> 1.87 inches to bottom edge from molding line). Definitely will use again when things if things are close. But if I bring the tape back up where it's arguably more designed to install it and the belt is actually supported, I'm just not going to get that kind of compression out of the belt and it still seems too big for the 2-9/16 spacing from molding line.
Here was the belt 1/4 inch from the molding line: https://photos.app.goo.gl/1ShUqXtic1UY5NQH9 - a bit above 1/2 into the next gear tooth this is probably 2/3 inches.
1.87 inch from track bottom to molding line -> .66 overlap
2.56 inch -> .25 overlap
moving .7 inches down yielded .4 inches in circumference. To make it flush without compression of the belt or panels providing play they don't want to give, that means I'd have to push it down roughly another .7 inches . That's interesting because molding line to rim is 1.75 inches, and the bottom of the track would have to be ~3.25"... since the track is 1.5" height, that means we'd be at ~1.75 from the molding line or at the edge.
Ugh. Ok so I just went out to try again after retaking the above measurements. I had success putting the ends together first and pushing the ripple out from the end and back. I didn't have to do it to both track ends. So since this tape has had like 8 resticks (go 3m extreme tape), I went for flush with the molding line. Impossible, right? Wrong - the ripple with this one was strong and went from one end to the other then back... and then I was able to push it down, really made the belt feel like it snapped into shape or something, like almost no adhesive strength necessary at this point, so even with the reduced strength (now back down to a little under the gorilla 15 pound tape), I think it will hold. If not, now that I know it's possible I'll retape if it comes undone so I get a full strength stick.
So in this case, the instructions were still insufficient for the task and the solution is
a) have a tape that can deal with re-sticks, install it about centered.
b) put the gear track tape flush with the molding line, put as much as the tape as can be fitted onto this rough install
c) when down to the last 2 feet, install the tape end flush with the other end of the tape and work backwards, travel with the track lifting ripple and chase it to the other end (babek should film this...), you will probably reach the other end and may need to reflect back out - make sure the ripple is getting smaller. Focus on pushing it out now and you may find it will snap in when small enough.
It does take some fettling, mine barely fit until I did what RP suggested, it’s a slow deliberate process.
I’d also consider Loosening off some of the dome screws, it may be torqued too tight and bunched up a bit, need some play before installing and retightening. It certainly didn’t just ”IKEA together” for me.
I know I'm late to this thread, but I had the opposite issue when I first assembled my dome, I was one tooth short. My track was too high on the dome. I basically did what Roldophe did but then lost adhesion to the dome wall. I am now using the black 60 pound version of Gorilla tape. There are others out there, so the choice is yours.
This is how mine is set, flush to the top :
I had to go around a few times when installing the belt (288 teeth) to make it fit. So I started on one end, went around but on the last feet or 2 I put the end of it to connect to the other end before pushing it to stick.. and then worked my way back from there in the other direction.. it's a tight fit but after going around 2 or 3 times it's in place and not moving.
So on your first picture , unstick about a feet, put the left side against the other end and start moving around left, pushing it and making is as tight as you can.
If when you get back to the connection from bot side you still have some extra, repeat the same but going right this time.
To confirm the overall size I used my own firmware (based on the old 2.x firmware as I contributed to it and it's easy for me to make changes in it) to check by doing a calibration. The math says it should be 440640 micro steps, calibration return 440658 micro steps so the dimension is correct (18 micro steps is just mechanical error at this point as it's 0.004% off which is 0.014 degree ).
PS : Metric is standard (SI, International System of Units), imperial is not ;)