I had earlier posted about my SP14 clock build. I wanted to share more details, but gave it some time so I could report on how well it is working. Overall, building the clock was an significantly satisfying experience, and I'm quite happy with the result. Im also impressed with the quality and thoughtfulness of the design and assembly instructions. As a software professional, I can see that Steve has long experience in documenting engineering designs.
Here are my lessons learned:
Read the instructions before you print. Kind of obvious I know, but I missed a few details in my rush to get started, for instance for the current version be sure to use the Classic wall generator (not Arachne). I had watched a YouTube video by Steve that talks about his new gear design and his use of Arachne. But in the end he changed his mind back to Classic. The instructions are the most up-to-date reference.
Buy the parts kit. It is priced fairly and it makes your life a lot easier. Thanks Steve for these great kits.
Drill out the spacers, gears, and holes for the arbors in the frame to insure a loose low friction fit. BUT be VERY CAREFUL when drilling into the frame. In my first build attempt I went too far into the frame. It allowed the arbors to slide too far in and out of their holes. I tried to fix by gluing the arbors at an appropriate depth, but was not able to make that work, so I had to reprint the frame.
If using PLA Silk for your gears (which looks great), dial in your parameters to get a smooth appearance on the surface. I discovered that adjusting retraction parameters made a big difference and reducing the nozzle temp by 5 degrees helped also. Dry the heck out of your filament if you are able.
End shake matters: Even though I took great care in printing and assembling, my clock did not run at first. It was perplexing because I tried things like running it without the pallet and it worked beautifully. I realized that I had run that test without two screws in the front frame (at 3 and 9 o’clock) and this made a difference. In my case I have to squeeze the frame a bit to get those screws in, and it compresses the clearances on some of the gear stacks. One of the gear stacks no longer had any end shake. I fixed this by reprinting one of the spacers with 1.4mm sliced out, and that fixed it.
Lubrication: It is entirely possible that no lubrication is required. I’ve seen suggestions by Steve and others that lubricants can attract dust and lead to friction and gunk over a longer period. I was interested to get the benefits of Teflon, but without the negative aspects of a a carrier fluid. I purchased CRC Dry PTFE Lube (spray), then applied it as follows: a. Place the gear on the relevant arbor, which you hold with one hand; b. spin it as fast as possible, then c. with the other hand gently spray the gear teeth for 2 to 5 seconds. This gives you a thin, no gum Teflon layer on the gear surfaces. I also applied (a little bit) of lithium grease to other surfaces. I think the lithium is especially important for the clicks' interface to other parts in the rachet. Everything is great so far, but I guess we won't know for sure for several years.
Weight suspension cord: The parts kit provides a suitable woven fishing line for hanging the weight, but I wanted something a bit "fatter" for aesthetics. I purchased 300 pound test black line (1.2mm thick) which I used instead. Doesn't work any better, but I think it looks a bit more substantial.
Which version of the moon to choose? Steve provides 3 different versions of the moon that you can choose for the moon gear. My wife and I couldn't choose our favorite. I liked the Melies "Trip to the Moon" version, but she liked the 3D moon version. So I made a new moon gear with one of each using the 3D editor in the slicer.
Result: My clock has been running great for 6 or 7 weeks so far. I've got +-3 (6+) degree swing on the pendulum with 8.75 pounds total weight. I should probably remove some of the lead, but I haven't gotten to that yet. It keeps great time. I'm still dialing in the pendulum length, but currently seeing about +-20 seconds per day.
Best of luck to all on your build.
Tucker
