Needed another three hands to put together, nice project! Thanks
A year later and your files are still in use! Thank you! I made 3 dodecahedra off your base design over the holiday break (2 lanterns, 1 solid backed).
Nice work!
Some tips from my polyhedron project in progress (pictures when done):
- Use Wikipedia (or remember Eulerâs formula) to help figure out the number of connectors you need. Two per edge, not (e.g.) six per triangular face, which will leave you with twice as many as you need.
- Make a few extra connectors in case some donât cut well, donât fit well, or break.
- Copy-paste in the GF UI instead of in your graphics app is good for maximizing use of scrap from other projects.
- Weeding and peeling lots of connectors is a great job for kids.
- Measure twice, cut once. I misremembered that the sides were supposed to be 2.5â, not 2â, and didnât check the connector fit until after Iâd cut all my pieces.
Still not quite done, but some pictures and important notes anyway.
First: The file at the top of the thread has the wrong connectors for the icosahedron. (The connector labeled icosahedron is a duplicate of the dodecahedron connector. The dihedral angle for that is close enough that you can assemble triangles into an octahedron⌠with some difficulty⌠so itâs easily mistaken for that, too. My kids and I sure did the first time we tried to assemble it.)
I made my own icosahedron connector (144°) and updated the original file:
Whichever connector youâre using, youâll be counting and printing and peeling a lot of them:
And then assembly is fun. (Weâre taking a break between steps because we didnât print as many connectors as we thought. Itâs not easy keeping track while youâre making and arranging copies in the GF UI to use up your scrap!)
The bigger kid is learning vector design software, so some of the faces have scored designs of his; both of them got to color the sides. Proofgrade draftboard soaks up magic marker pretty well, but it still needs a lot of drying time if you donât want it all over your hands.
This is awesome!
Iâve never made one of these before⌠How do you get the last piece on? lol
Push and pray!
It looks like! lol.
So helpful. Now I have a new way to sit in my room and ignore my familyâŚThanks!
Oh My Goodness - this rocks! Thank you so much!
@geek2nurse Thanks so much for this resource! Clearly they work as is since many people have posted successful projects. But for my own (GF newbie) understanding â when I pull this into my CAD program and measure, the offset from the face edges to the holes is 4.88mm, while the distance on the connectors from the internal angle to the tab is only 4.61. So it seems like maybe they wouldnât quite reach the holes. Is this difference to account for kerf, or something like that?
@geek2nurse will have the final word here, but in the meantime:
0.19mm is about 0.007 inches, which is a pretty good approximation of kerf in 1/8" materials on a basic Glowforge (especially when cutting slowly, like with proofgrade ply), so I think probably yes.
Faster cuts generally yield smaller kerfs. Basic machines are a bit slower than Pro models, and proofgrade ply is made of MDF core, which requires a fairly slow speed anyway (compared to BB or other easier-to-cut materials), all of which adds up to 0.007 (or a bit more even) being about right. The good news is that for projects like this even discrepancies of 0.005" (or maybe even more) is small enough that the end result wonât be noticeably affected. I think youâre good to go.
Because of that general âfaster = less kerfâ concept, things like cardboard and cardstock have tiny kerfs when focused properly. Itâs rarely enough of a difference with most projects that youâd ever notice, but when doing tight inlay, for example, veneers cut with far less kerf than 1/8" materials, so it can be quite noticeable.
^^^ What he said.
Thanks @evansd2 (and @geek2nurse !) for confirming my understanding (and quickly, too!) Iâve done 3Dmodeling/printing for many years but am brand new to laser cutting, so this whole kerf business is taking some getting used to!
I have a Pro, not Basic - will this have a pronounced effect on the kerfs I can expect? Also, is the kerf âcenteredâ on the cut lines? I realize this probably doesnât matter for this application but inlay IS on my radarâŚ
Kerf correction is a deep topic, Iâd suggest looking at a few posts on the forum, itâs been discussed in some serious depth.
I like the âstroke to pathâ method in Inkscape. These will get you headed in the right direction.
Perfect, thanks!
@evansd2âs approach to kerf helped eliminate a lot of my confusion; I was just 'way overthinking it. Iâve started defaulting to about a 0.5pt stroke when I design, because that is pretty close to the laserâs kerf, and helps me visualize how the kerf will affect my design.
In Affinity. It should be the same in other apps, but tbh Iâd use a true physical measurement if I were doing this. Points are supposed to be 1/72nd of an inch, but I wouldnât put it past an app to go off the reservation on that.
(btw, 1/2 of 1/72nd of an inch is 0.0064". I tend to use kerf values of closer to 0.006"-0.008" for a pro, so not that different)
Oh, you and your Affinity-hating. You can input line width in any dimensions you want; it just displays them as points after you do. And yes, it handles them accurately. 0.5 pt is about .007 in, which generally gives me a pretty decent fit on things.