Variant construction set

thingiverse

So, this is Variant construction set, which was originally designed about 40 year ago by one Czech company and it is still produced till nowadays: https://www.kaden.cz/variant-stavebnice (please support the producer by buying the original set if you can). It's a LONG time ago since I was playing with it, but I still clearly remember the hours and hours of joy and entertainment it brought, as well as the skills I acquired by building different constructions. Recently I got into possession of one of these original sets and gave it to my son (3yo). He also likes it a lot. And then I realized that with 3D printing I can create more and new parts, limited just by my imagination. So I recreated most of the original set in SCAD and added a lot of new parts. From the original set I only did not try to model the chain gears since the chain consists of quite small parts and would be difficult to print accurately enough. On the other hand, I added many different gears to the original ones (12T, 24T). For quick overview see: <b>Part list with print instructions.pdf</b> <i>(Also because Thingiverse was unable to generate thumbnails for all the parts)</i> For ideas from the original set see: <b>Variant - original manual.pdf</b> Regarding <b>printing material</b>, the original parts (especially the beams and flat parts) are quite flexible but strong, I would say they are from nylon. I recommend to print most of the parts from PETG (including screws), but PLA would also do. The only problems with PETG I have is warping (even with heated bed and enclosure), therefore I made a version of the most parts with localized brim in corners to improve adhesion. These parts are with "_F" in the name. But you can also use full brim in Cura. Only components I print from PLA were gears because I did not want to bother with brim on those. Also boxes did not need PETG flexibility and were easier to print with PLA. Regarding <b>layer height</b>, most of the components is really insensitive and I recommend 0.28mm. Only anything with thread I do with 0.2mm. Regarding <b>infill</b>, 20-30% for most of the components, 60-100% for screws and nuts. Regarding <b>threads accuracy</b>, I designed and tested everything to be mix-and-match compatible with the original parts. For that I chose <b>7.9 mm</b> for M8 screws and <b>8.8 mm</b> for M8 nuts. I also prepared 8.6 mm M8 nuts in case you find it better. Anyway, I recommend to print the screws and nuts one-by-one to reduce stringing. And I also use M8 tap to clean the nut threads after printing. It works great for me. If you find thread too tight/loose, you can also change a bit material "Flow" factor in Cura (too tight -> reduce by 5%, and vice versa). For the big (M14) threads for axle clamps, I use a tiny bit of grease to reduce the friction. Also with great success. BTW these <b>clamps are a bit fragile for handling</b>, but due to the backwards compatibility, I did not change the design. In the worst case I print a new part :-) Regarding <b>holes accuracy</b>, the original holes are 8.5 mm, while the screws and axles are 8 mm. I designed the holes <b>8.6 mm</b> because I ended up with about 8.2-8.4mm holes after printing and clean-up. Only the center hole in the gears and everything with threaded clamp is designed <b>8.4 mm</b> to have more tight fit. <b>Gears</b> Not all gears are compatible, the rule is that the sum of teeth of both gears must be multiple of 18. e.g. 12T + 24T (1:2 ratio) = 36T = 2*18. The multiple will also tell you how far apart the gears are placed. In the example 2 holes apart. I prepared these gears and combinations: 6T + 12T (1:2) 12T + 24T (1:2) - the original gears 9T + 27T (1:3) 6T + 30T (1:6) 6T + 48T (1:8) Worm gear + 24T (1:24) Worm gear + 6T (1:6) You can also make many more combinations using the attached SCAD file. Regarding other, <b>non-printable</b> parts: <b>8 mm wooded rods</b> (original lengths are 12 cm, but this is up to you). I buy beech wood rods 0.6 euro per meter from my local hardware store. Only remark: <b>check the diameter with precise caliper when you buying it</b>. I found that they can way piece by piece from 7.7 to 8.3 mm. For me 7.8-8.0 mm fits the best the holes of the threaded clamps. I would toss in a few <b> M8 washers</b> for when you want to reduce gears side friction. Also a few <b> 8 mm ID o-rings</b> are handy for adding friction to when needed. <b>Last thing:</b> I plan to extend the set of components in the future. In that way I'm also open to your suggestions. And I'm also looking forward to you creations :-)