kbrown

How about just laser printing the markings on a paper strip of correct width and length. Then laminate the print and superglue it onto the 3D printed ring? EDIT: Ah, @Alien 13 beat me to it

Managed to make a bit of progress with this. I redesigned the clamp so that it takes a NEMA11 stepper motor. I first tried with a smaller 6Ncm motor but that turned out to be too weak even with a bit of over current. I then decided to steal the focuser I've made for my other scope which has a 12Ncm NEMA11 stepper inside. That seems to be a perfect match. Just need to rewrite the software to be a proper rotator device instead of a focuser.

Not sure what belt this is but it looks coarser than GT2. I feel GT2 is too fine for putting pins in or at least it would be incredibly fiddly to achieve. At least with my eye sight and a bunch of frankfurters for fingers I've seen some jigs that allow drilling a 0.5mm PCB drill bit through the teeth but I don't think I'll go there... yet.

I just tried glueing only the diagonally cut edges without anything extra on the outside of the belt. Seems plenty strong and a lot more flexible than my previous attempt: Just need to print some kind of a jig to hold the ends aligned while gluing. I did this one just by hand as a test... Used this glue: https://www.everbuild.co.uk/products/adhesives/superglues-and-activators/industrial-superglue-hv/

Would love to see your other printed parts

Hi, Does anyone have a good method of making your own closed loop GT2 timing belts? After watching a few u-tube videos I decided to 3D print a little template that allows me to cut the belt diagonally so that the teeth match up: Then I joined it into a loop using a piece of fabric ribbon on the back side of the belt and super glue. It works okayish. The joint is pretty strong. The only problem is that the joint area is rather stiff. It's ok for larger pulleys but with smaller ones it's struggling to bend around it and causes some extra tension on the system. Wonder if contact glue would old up? Any other ideas?

I did consider that but there actually is quite a lot of resistance to rotate it. I might try smaller stepper later but since I already have a spare NEMA17 and a design I can quickly put together I think I'll give it a go and see what happens. Might be a bit bulky, I know... EDIT: Actually as a first test I'll just use the focuser I've already put together to get a feeling how it would work...

Here's my current idea: Basically a clamp that would go around the non-rotating part of the rotator section which would take a NEMA17 stepper motor with a GT2 pulley plus a another GT2 pulley that would be a tight fit on the rotating part of the rotator. This would basically allow me to use a repurposed version of the BullsEye Focuser I designed a while back. Think I'll print these out and see what happens...

Here we go. Just extract the contents of the zip file into your macro folder (in my case ~/.local/share/FreeCAD/Macro) and it should become available to FreeCAD under the menu Macro / Macros... When you launch it you should see an UI like this: Internally the macro creates a sketch for the thread profile and a helix path object. The profile is then swept along the helix to create the thread. It will also create a cylinder and do a boolean union (fusion) of the swept geometry and the cylinder. As a bit of a caveat it will do the same thing even if you choose "Internal" thread mode. The difference is how the tolerance value is handled. The resulting geometry is meant to be used as a cutter to another object (e.g. a nut or something). I should really have it to generate a proper internal thread instead of this intermediate thingy. Nonetheless, hope it's useful... thredster.zip

Yes it's Python. With the Python console open in FreeCAD you'll get an idea on what's going on under the hood when you use the program. I added a simple UI with PyQt to my macro as well. Anyway... I'll do some house cleaning on the macro and post here soon.

A long time ago I wrote a FreeCAD macro to create metric threads. It's nothing fancy but it's worked okay for me so far with all sorts of sizes. I'd have to do a bit of cleaning up work on the macro but happy to share if you like?

Why not, if you don't mind 😊

That's a great idea @Chriske. Might steal it for more permanent installations. I wanted to have my clip easily removable since I move my imaging train from scope to another often and they don't use the same wire harness I've made.

In my quest to tidy up and secure the cabling on my WO FLT91 I wanted to be able to attach wires and cables to cable tie anchors without using zip ties so I could undo them easily if necessary without tools. Here's what I came up with: http://knowhere.myqnapcloud.com/WordPress/2022/09/14/cable-tie-base-clip/

No it didn't as for imaging you don't typically use a diagonal at all. Regarding the focuser I did have some additional woes with it but I managed to get it to operate really well. Here's more info on that: http://knowhere.myqnapcloud.com/WordPress/2021/08/23/adjusting-william-optics-flt-91-focuser/

It's quite often the electrolytic capacitors that "wear out" first. Especially if they're frequently subjected to high temperatures. Not related but I recently had a PC power supply go bang with some smelly smoke. Turned out a lot of the electrolytic caps had just had enough. Didn't even bother fixing it any more as the shorts the caps caused probably caused a lot of other components to fail as well... You might want to look inside your PSU to see if you can spot any leaks or bulging of the el-caps. Maybe just replace them as a precaution, if you can access them easily (careful with the polarities!)...

2x2 mosaic of The Veil Nebula in SHO palette. Shot under Bortle 8 skies in London over several nights with my William Optics FLT91 + 0.8X flattener and Atik 383L+ with Baader NB filters.

Gotcha... Might work but it also could be a source of backlash that could translate to a couple of degrees of error in the rotation... Probably wouldn't matter that much... My existing electronic focuser is in the way anyway so I'd have to something about that too...

I'm not entirely sure if I understand you correctly. The trouble is that the rotating section moves (quite a bit) in and out with the focuser. I think I need to come up with a method to "clamp" the motor to the non-rotating part of the moving focuser somehow...

There is a manual field rotator on the focuser of my William Optics FLT91 (Unlocked with the rightmost thumbscrew in the image below).I'm wondering if anyone has attempted to motorise something like this for remote use? Might be able to wrap a timing belt around it but mounting a stepper motor in this section would be tricky as the rotator is on the moving part of the focuser. Any ideas?

I'm now leaning towards this solution. May I ask how big is the kit you're covering with this?

Speaking of coils... This might get convoluted quickly but if you used low voltage (i.e. safe) AC power instead of DC, you could then transfer it from coil to coil without having to have a physical connection. You'd then have to convert it to DC and regulate it to correct voltage etc. How this could be achieved in your application, I'm not sure. Maybe with some custom wound toroidal coils...

Tesla did some wireless power transmission tests, didn't he? Maybe a tesla coil?

Solar power? No hang on a minute... I'll get my coat

It was a long time ago but I'm pretty sure it was the front of the lens to the focuser. I didn't even think it could work the other way as well...