I just went to hobby lobby to look for a new ruler and happened to stubble upon some precut equilateral triangular beams. but the density and variations of density is absolutely crazyyyy
Interesting! I had never heard of pre-cut 60/60/60 sticks, but it's good to know Hobby Lobby at least has something. I would recommend making them yourself from sheet balsa because you'll have way more control of the density and most likely, it will also be much cheaper. Good luck!!
Very interesting approach. I opted to create an angled stripper where you feed the member through a hole with a blade angled down at 60 degrees to cut the excess wood off. Once you run the member through the stripper twice, you are left with an equilateral member.
@@balsaengineering6686 Sorry I don't think my reply thingy worked but I was more interested in how the 60 degree stripper would work, as in how to build one but I think I have an idea of how to build it
@@completeandabsolutenerd I definitely encourage you to try and make a stripping tool if you can. My solution here doesn't strip the wood, but sands it away
Hi, balsa engineering! I watched the all division c 2025 videos so far, and are you going to make a video that shows each mass of all balsa woods? Like density of 2 layers of crossmembers at the bottom, and weight for each legs. Thanks for your video!
Yep! I have 2 more videos coming in this series. On 9/17, I'll publish the one where I talk about the assembly challenges, and then the one you are specifically looking for will be published on 9/21 where I show my optimization path to achieve the benchmark tower. That one will show all my notebook pages which includes everything you need. Good luck this season!!
If you check out the drawing at 1:25, you'll see that the finished side length is actually the same length as the original source square, in this case 3/16".
Without the precision of a 3d printer, it would be very difficult to make a sanding jig that works well. I don't really have any good suggestions unfortunately. There are some people who have experimented with making a device to cut the triangular cross sections (instead of sanding), but that also involved a 3d printer and a more elaborate design with a blade.
Thank you for your videos, very helpful and encouraging for everyone! I wanted to ask - can we use CA glue instead of PL3 for gluing this jig? Why PL3?
I found that CA glue doesn't work very well for gluing PLA parts together unless you have much thicker gel based CA. I found PL3 works much better than even gel based CA, but just about any glue that glues plastic should work. If you use any glue that doesn't set quickly (like PL3), make sure you clamp the parts together for best results.
Question: what grit sandpaper did you use with the orbital? I know I have 3M laying everywhere but that's for sanding cars. I assume I need different stuff for wood
I just used what I had on hand. For the drywall mesh sander, it was probably around 160-200 grit. I think the rotary sander had 100 grit, and it would probably have been better to use a finer grain as to not sand down the jig as much. Basically, pretty much anything should work if you are careful.
Hi Balsa Engineering! I'm curious as to why the 3D print is that big on the x&y dimensions where the cutout is. Was there a certain reason for that? Would it be fine if I made a jig that was much smaller but had the same cutouts? Thanks.
Hi! The dimensions of the cutouts in the jig don't matter too much, they are only to help the cross-members not get glued to the jig. The critical dimensions for this jig are the outer dimensions because the legs actually go on the outside of jig. It needs to span the 29cm circle with only 3 legs, so that part is almost a minimum sized jig already, but feel free to re-design it in another way if you want. My jig and designs are only meant to be a starting point for you this season. Good luck!!
Thank you for your help! This step has been way harder than I had expected. The resulting legs have quite different densities and I am worried if the integrity of the wood was compromised by all the sanding! Did you use light balsa for this? I am finding that a lot of my sticks are too light and I need heavier ones.
Hi! Yeah, this step sands away more than half of the original stick. You can double check my math with the info in my notes, but I think my original source sticks were around 11 lbs/ft^3 for density which puts them in the typical "medium" range. Usually the medium range balsa is the easiest to get, so hopefully you can track down some heavier wood for this application. Good luck!
I never even bothered make a non-bonus design for Div C. I really don't think it's the right approach this year given the rules. I encourage you to try and make one if you want and experiment, but I think the bonus is the way to go.
This is the exact stuff I used. You can probably find it at your local hardware store as well. www.amazon.com/Loctite-Premium-Polyurethane-Construction-Adhesive/dp/B08BJC5WDD
@@YanaPandit-b2f I'm not sure how to do it without a jig either. That's why I created a jig to do the job :) In theory you might be able to create some kind of cutting device that sliced at at 60 deg angle and run the stick through twice, but that would most likely involve a custom 3d print as well.
Hi again Balsa Engineering, I asked my teacher at school to 3d print your jig but he said it would take too long and the amount of plastic required is too long. Do you have any helpful tips on reducing the plastic and the print time? In addition, do I have to make two duplicates of the triangle legs? Is it fine if I print one? Thanks!
@@belayadane8388 I mean, I talk about it in this video at the 2:29 point. Do you have a different question about it? The legs we are working with are 52.5cm, I made my jig 3x18cm so I could sand it all at once. In theory you could just print a smaller one and move the leg. That could work if you can't print the entire thing
Hi Balsa Engineering, I was wondering how you imported your 3D jig files into a 3D slicer because when I tried to do it with Cura, it didn't work for some reason. Thanks!
There was nothing special that I did, just load the STL file into Cura. You might need to rotate it 90 degrees to be oriented correctly for the print, but that shouldn't prevent it from loading.
Hi Balsa Engineering, I was just told that I’ve been put on this event with a meet coming up really soon and your videos have been a lifesaver honestly. I have a quick question about the triangular legs though: I don’t think have the time/resources to print the sanding jig. Do you think that something simple like sanding the balsa essentially in half, making a 45 45 90 triangle, would make a really big difference in the stability of the tower? Thank you!
Thanks! Using 45/45/90 legs could potentially work, for at least 2 of the legs, but you won't be able to build an equilateral tower with just those legs. In a pinch, you could use any legs and just individually sand flat the surfaces needed to attach the cross members. That is certainly not ideal, but might be OK if done carefully. Good luck!!
I mentioned in the video 3/16" square legs as the source: ruclips.net/video/MTHygxUS3YU/видео.htmlsi=k2m2p4nMrgML72bl&t=115 The length just needs to be just a bit longer than the final length. I was using 52.5cm.
Hi Balsa Engineering! I just wanna know where do you get your balsa wood from? Like is there an online store that you could possibly send a link too? Also, what are all the measurements for the wood that will be used in the build? Thanks!
Hi! I like to buy my balsa sheets from Specialized Balsa because you can specify the density range when ordering. specializedbalsa.com/products/balsa_sheets.php The final video of this series, due to be published on 9/21, will show my notebook pages for all my builds including the benchmark one. From those notes you'll be able to see exactly what I used for everything. As I mentioned in this video, these legs were made from 3/16" square source sticks. Good luck this season!
I have access to an older version of SolidWorks so I have been using that. These jigs aren't that complex, so just about any CAD software you are familiar with would work fine.
![Как устроены швейные машинки? [Veritasium]](/img/1.gif)
I just went to hobby lobby to look for a new ruler and happened to stubble upon some precut equilateral triangular beams. but the density and variations of density is absolutely crazyyyy
Interesting! I had never heard of pre-cut 60/60/60 sticks, but it's good to know Hobby Lobby at least has something. I would recommend making them yourself from sheet balsa because you'll have way more control of the density and most likely, it will also be much cheaper. Good luck!!
Very interesting approach. I opted to create an angled stripper where you feed the member through a hole with a blade angled down at 60 degrees to cut the excess wood off. Once you run the member through the stripper twice, you are left with an equilateral member.
That's a very nice approach too. If that works well, it would definitely be less messy than sanding it!
Hey, im curious as to how you went about doing this
@@completeandabsolutenerd If you have any specific questions, let me know and I'll try to answer them as best as I can
@@balsaengineering6686 Sorry I don't think my reply thingy worked but I was more interested in how the 60 degree stripper would work, as in how to build one but I think I have an idea of how to build it
@@completeandabsolutenerd I definitely encourage you to try and make a stripping tool if you can. My solution here doesn't strip the wood, but sands it away
Hi, balsa engineering! I watched the all division c 2025 videos so far, and are you going to make a video that shows each mass of all balsa woods? Like density of 2 layers of crossmembers at the bottom, and weight for each legs. Thanks for your video!
Yep! I have 2 more videos coming in this series. On 9/17, I'll publish the one where I talk about the assembly challenges, and then the one you are specifically looking for will be published on 9/21 where I show my optimization path to achieve the benchmark tower. That one will show all my notebook pages which includes everything you need. Good luck this season!!
What are the side lengths of the equilateral triangle legs after being sanded? Thank you!
If you check out the drawing at 1:25, you'll see that the finished side length is actually the same length as the original source square, in this case 3/16".
Is there a way you'd suggest to make a jig for sanding without a 3d printer?
Without the precision of a 3d printer, it would be very difficult to make a sanding jig that works well. I don't really have any good suggestions unfortunately. There are some people who have experimented with making a device to cut the triangular cross sections (instead of sanding), but that also involved a 3d printer and a more elaborate design with a blade.
Thank you for your videos, very helpful and encouraging for everyone! I wanted to ask - can we use CA glue instead of PL3 for gluing this jig? Why PL3?
I found that CA glue doesn't work very well for gluing PLA parts together unless you have much thicker gel based CA. I found PL3 works much better than even gel based CA, but just about any glue that glues plastic should work. If you use any glue that doesn't set quickly (like PL3), make sure you clamp the parts together for best results.
Question: what grit sandpaper did you use with the orbital? I know I have 3M laying everywhere but that's for sanding cars. I assume I need different stuff for wood
I just used what I had on hand, which was 100 I believe. Something a bit more fine would probably be better to use.
Hi Balsa Engineering. I was wondering which of type if sandpaper would you recommended me to use in order to sand my triangular legs.
I just used what I had on hand. For the drywall mesh sander, it was probably around 160-200 grit. I think the rotary sander had 100 grit, and it would probably have been better to use a finer grain as to not sand down the jig as much. Basically, pretty much anything should work if you are careful.
Hi Balsa Engineering! I'm curious as to why the 3D print is that big on the x&y dimensions where the cutout is. Was there a certain reason for that? Would it be fine if I made a jig that was much smaller but had the same cutouts? Thanks.
Hi! The dimensions of the cutouts in the jig don't matter too much, they are only to help the cross-members not get glued to the jig. The critical dimensions for this jig are the outer dimensions because the legs actually go on the outside of jig. It needs to span the 29cm circle with only 3 legs, so that part is almost a minimum sized jig already, but feel free to re-design it in another way if you want. My jig and designs are only meant to be a starting point for you this season. Good luck!!
Thank you for your help! This step has been way harder than I had expected. The resulting legs have quite different densities and I am worried if the integrity of the wood was compromised by all the sanding! Did you use light balsa for this? I am finding that a lot of my sticks are too light and I need heavier ones.
Hi! Yeah, this step sands away more than half of the original stick. You can double check my math with the info in my notes, but I think my original source sticks were around 11 lbs/ft^3 for density which puts them in the typical "medium" range. Usually the medium range balsa is the easiest to get, so hopefully you can track down some heavier wood for this application. Good luck!
hi there - Where could I find the non bonus version of the stl files? It appears the jig files are for bonus version. please share!
I never even bothered make a non-bonus design for Div C. I really don't think it's the right approach this year given the rules. I encourage you to try and make one if you want and experiment, but I think the bonus is the way to go.
@@balsaengineering6686 appreciate the response and makes sense. Thank you!
Hi what kind of pl3 construction adhesive did you use?
This is the exact stuff I used. You can probably find it at your local hardware store as well. www.amazon.com/Loctite-Premium-Polyurethane-Construction-Adhesive/dp/B08BJC5WDD
Are the jig measurements in inches or mm?
They are in mm. You will need to scale them to something like shown at 2:58 to get a full-sized jig for a complete leg
Hey Balsa Engineering
So, I can't figure out how to convert my square balsa wood to Equilateral Triangle balsa wood
without a JIG
@@YanaPandit-b2f I'm not sure how to do it without a jig either. That's why I created a jig to do the job :) In theory you might be able to create some kind of cutting device that sliced at at 60 deg angle and run the stick through twice, but that would most likely involve a custom 3d print as well.
Hi again Balsa Engineering, I asked my teacher at school to 3d print your jig but he said it would take too long and the amount of plastic required is too long. Do you have any helpful tips on reducing the plastic and the print time? In addition, do I have to make two duplicates of the triangle legs? Is it fine if I print one? Thanks!
Also, could you give me your dimensions for the 3d jig? Thanks!
@@belayadane8388 I mean, I talk about it in this video at the 2:29 point. Do you have a different question about it? The legs we are working with are 52.5cm, I made my jig 3x18cm so I could sand it all at once. In theory you could just print a smaller one and move the leg. That could work if you can't print the entire thing
@@balsaengineering6686 Okay thanks!
Hi Balsa Engineering, I was wondering how you imported your 3D jig files into a 3D slicer because when I tried to do it with Cura, it didn't work for some reason. Thanks!
There was nothing special that I did, just load the STL file into Cura. You might need to rotate it 90 degrees to be oriented correctly for the print, but that shouldn't prevent it from loading.
@@balsaengineering6686 Okay thanks!
Hi Balsa Engineering, I was just told that I’ve been put on this event with a meet coming up really soon and your videos have been a lifesaver honestly. I have a quick question about the triangular legs though: I don’t think have the time/resources to print the sanding jig. Do you think that something simple like sanding the balsa essentially in half, making a 45 45 90 triangle, would make a really big difference in the stability of the tower? Thank you!
Thanks! Using 45/45/90 legs could potentially work, for at least 2 of the legs, but you won't be able to build an equilateral tower with just those legs. In a pinch, you could use any legs and just individually sand flat the surfaces needed to attach the cross members. That is certainly not ideal, but might be OK if done carefully. Good luck!!
What are the dimensions of the balsa sticks you used, including the length?
I mentioned in the video 3/16" square legs as the source: ruclips.net/video/MTHygxUS3YU/видео.htmlsi=k2m2p4nMrgML72bl&t=115 The length just needs to be just a bit longer than the final length. I was using 52.5cm.
Hi Balsa Engineering! I just wanna know where do you get your balsa wood from? Like is there an online store that you could possibly send a link too? Also, what are all the measurements for the wood that will be used in the build? Thanks!
Hi! I like to buy my balsa sheets from Specialized Balsa because you can specify the density range when ordering. specializedbalsa.com/products/balsa_sheets.php The final video of this series, due to be published on 9/21, will show my notebook pages for all my builds including the benchmark one. From those notes you'll be able to see exactly what I used for everything. As I mentioned in this video, these legs were made from 3/16" square source sticks. Good luck this season!
@@balsaengineering6686thank you!
The stl file wont open. could you please send a new one?
u gotta hit copy link address and then past it into ur browser, its flagged a suspicious download so that's why it wont open
@@hipeoples9607 Yep, thanks for clarifying. I'm not sure I can do anything about the browser flagging it.
What software do you use to design your jigs?
I have access to an older version of SolidWorks so I have been using that. These jigs aren't that complex, so just about any CAD software you are familiar with would work fine.
What size legs is the jig used for?
I mentioned in the video that I started with 3/16" square sticks: ruclips.net/video/MTHygxUS3YU/видео.htmlsi=k2m2p4nMrgML72bl&t=115