Small Print Bed? No Problem!

January 24, 2025 by Bryan Cockfield 7 Comments

One of the major limitations of 3D printers is the size of the printable area. The robotic arm holding the printer head can only print where it can reach, after all. Some methods of reducing this constraint have been tried before, largely focusing on either larger printers or printer heads that are mobile in some way. Another approach to increasing the size of prints beyond the confined space typical of most consumer-grade 3D printers is to create some sort of joinery into the prints themselves so that larger things can be created. [Cal Bryant] is developing this jigsaw-based method which has allowed him to produce some truly massive prints.

Rather than making the joints by hand, [Cal]’s software will cut up a model into a certain number of parts when given the volume constraints of a specific 3D printer so it can not only easily print the parts, but also automatically add the jigsaw-like dovetail joints to each of the sections of the print. There were a few things that needed prototyping to get exactly right like the tolerance between each of the “teeth” of the joint, which [Cal] settled on 0.2 mm which allows for a strong glued joint, and there are were some software artifacts to take care of as well like overhanging sections of teeth around the edges of prints. But with those edge cases taken care of he has some working automation software that can print arbitrarily large objects.

[Cal] has used this to build a few speaker enclosures, replacing older MDF designs with 3D printed ones. He’s also built a full-size arcade cabinet which he points out was an excellent way to use up leftover filament. Another clever way we’ve seen of producing prints larger than the 3D printer is to remove the print bed entirely. This robotic 3D printer can move itself to a location and then print directly on its environment.

A pair of hands hold two dark brown boards perpendicular two each other on a light brown benchtop. There are two light brown oval dowels in the end of one board that then project toward holes in the opposite board. Circular holes in the oval dowels are visible perpendicular to the second board, and will match up with holes in the board once pressed in. A cylindrical dowel is laying next to the joint and will be placed into the circular holes once assembled.

Creating A Signature Wood Joint

December 1, 2024 by Navarre Bartz 25 Comments

We really love when makers make their construction techniques evident in an aesthetically-pleasing way, and [Laura Kampf] has created a clever joint that reveals how a piece is made.

[Kampf] is a big fan of using her domino joiner, which is similar to biscuits or dowel joinery, but she didn’t love how it hid the construction of the joint. She first figured out an “off label” use of the joiner by running it from the outside of the joint to show the exposed domino from one end.

Building on the concept to show an interesting contrast on both sides of the joint, she drilled a hole perpendicular the domino and placed a dowel through it, creating a locking joint. The choice looks great once a finish is applied to really accentuate the contrast, and another bonus is that if glue is only applied to the dowel and domino, it becomes trivial to separate the joint if needed by drilling out the dowel.

If you’d like to see some other interesting ways to join wood, how about this laser-cut wedge tenon, soda bottle heat shrink, or this collection of CNC joints.

Continue reading “Creating A Signature Wood Joint” →

This Laser-Cut One-Piece Wedge Tenon Locks Wood Joints Tight

December 4, 2023 by Dan Maloney 24 Comments

Woodworkers have always been very clever about making strong and attractive joints — think of the strength of a mortise and tenon, or the artistry of a well-made dovetail. These joints have been around for ages and can be executed with nothing more than chisels and a hand saw, plus a lot of practice, of course. But new tools bring new challenges and new opportunities in joinery, like this interesting “hammer joint” that can be made with a laser cutter.

This interesting joint comes to us from [Jiskar Schmitz], who designed it for quick, solid, joints without the need for glue or fasteners. It’s a variation on a wedged mortise and tenon joint, which strengthens the standard version of the joint by using a wedge to expand the tenon outward to make firm contact with the walls of the tenon.

The hammer joint takes advantage of the thin kerf of a laser cutter and its ability to make blind cuts to produce a tenon with a built-in wedge. The wedge is attached to a slot in the tenon by a couple of thin connectors and stands proud of the top of the tenon. The tenon is inserted into a through-hole mortise, and a firm hammer blow on the wedge breaks it free and drives it into the slot. This expands the tenon and locks it tightly into the mortise, creating a fairly bulletproof joint. The video below tells the tale.

While the hammer joint seems mainly aimed at birch plywood, [Jiskar] mentions testing it in other materials, such as bamboo, MDF, and even acrylic, although wood seems to be the best application. [Jiskar] also mentions a potential improvement: the addition of a ratchet and pawl shape between the wedge and the slot in the tenon, which might serve to lock the wedge down and prevent it from backing out.

Continue reading “This Laser-Cut One-Piece Wedge Tenon Locks Wood Joints Tight” →

Complex Wood Joints, Thanks To New Software’s Interactive Features

October 23, 2020 by Donald Papp 23 Comments

Artfully-crafted wooden joints that fit together like puzzle pieces and need neither glue nor nails is fascinating stuff, but to call the process of designing and manufacturing them by hand “time-consuming” would be an understatement. To change that, a research team from the University of Tokyo presented Tsugite, a software system for interactively designing and fabricating complex wooden joints. It’s named after the Japanese word for joinery, and aims to make the design and manufacture of glue and fastener-free joints much easier than it otherwise would be.

Three-way joint that requires no glue or fasteners.

~~It looks like the software is so far only a research project and not something that can be downloaded~~ The software is available on GitHub and the approach it takes is interesting. This downloadable PDF explains how the software deals with the problem of how to make such a task interactive and practical.

The clever bit is that the software not only provides design assistance for the joints themselves in a WYSIWYG (what you see is what you get) interface, but also generates real-time feedback based on using a three-axis CNC tool as the manufacturing method. This means that the system understands the constraints that come from the fabrication method, and incorporates that into design feedback.

The two main limitations of using a three-axis CNC are that the cutting tool can only approach the material from above, and that standard milling bits cannot create sharp inner corners; they will have a rounded fillet the same radius as the cutting bit. Design can be done manually, or by selecting joints from a pre-defined gallery. Once the design is complete, the system generates the toolpaths for manufacture.

Currently, Tsugite is limited to single joints meant for frame structures, but there’s no reason it couldn’t expand beyond that scope. A video to accompany the paper is embedded below, it’s short and concise and shows the software in action, so be sure to give it a look.

Continue reading “Complex Wood Joints, Thanks To New Software’s Interactive Features” →

Hackaday Podcast 075: 3D Printing Japanese Joinery, Android PHONK, One-Armed Time Bandit, And Whistling Bridges

July 10, 2020 by Mike Szczys No comments

Hackaday editors Mike Szczys and Elliot Williams scoop up a basket of great hacks from the past week. Be amazed by the use of traditional Japanese joinery in a 3D-printed design — you’re going to want to print one of these Shoji lamps. We behold the beautiful sound of a noise generator, and the freaky sound from the Golden Gate. There’s a hack for Android app development using Javascript on an IDE hosted from the phone as a webpage on your LAN. And you’ll like the KiCAD trick that makes enclosure design for existing boards a lot easier.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

Continue reading “Hackaday Podcast 075: 3D Printing Japanese Joinery, Android PHONK, One-Armed Time Bandit, And Whistling Bridges” →

This Mallet Has Backwards Dovetails… That’s Impossible!

February 22, 2020 by Mike Szczys 14 Comments

Dovetails are a wedge-shaped joint found in woodworking. The wedge makes for strong joinery because a force that tries to pull it apart also increases the friction on the joint. This mallet has dovetails on either side that keep the head from flying off, but there’s also a through tenon in the center. This is an impossible joint as there’s no way to slide the mallet head onto the handle. The two pieces of wood must have grown that way!

As with everything, there’s a trick here, let it scratch your brain for a while before reading on… if you can guess how it’s done it’ll be very satisfying when you confirm your theory. Both the trick of the impossible mallet and the superb hand joinery are shown off in this video from the [Third Coast Craftsman].

The trick comes in the form of internal voids hidden from view once the two pieces of the mallet have been assembled. The through tenon is exactly as you’d expect: a straight tenon slides into a straight mortise in the mallet. The dovetails to either side of the handle and the pockets they mate with in the mallet head are not at all what you’d expect. The edges of the dovetail have been chamfered at 45 degrees so you can’t pull them to the outside of the mallet as you slide them into place. The opposite is the actual trick. Each of the dovetails bends inward until a ramp at the very end of the mallet pocket pushes it back into place.

Underside of mallet head shows “ramp” detail

Tenons clamped during assembly

The impossible mallet isn’t a new concept and stands as a formidable challenge for any accomplished woodworker. The images above are of [Jim Guilford’s] impossible mallet. Here the trick is fully exposed, showing the dovetail tenons of the handle clamped together as it is driven into place. Two things are striking here; the joints cannot be tested and must be perfect before assembly, and there is a real chance the tenons will break or the mallet head will split apart from the force of assembly. This project will test your courage as much as it will your patience.

Continue reading “This Mallet Has Backwards Dovetails… That’s Impossible!” →

Cool Tools: The Pantorouter Turns Tracing On Its Side

October 1, 2018 by Kerry Scharfglass 6 Comments

Not too long ago we wrote about a small CNC tool for automating certain parts of the woodworking process. At the time it seemed unusual in its intentionally limited scope but a few commenters mentioned it reminded them of another device, [Matthias]’s Pantorouter. It didn’t take much investigation to see that the commenters were right! The MatchSticks device does feel a bit like a CNC version of the Pantorouter, and it seemed like it was more than worth of a post by itself. The Pantorouter is a fascinating example of another small manual-but-automated tool for optimized for accelerating and improving certain woodworking operations.

Continue reading “Cool Tools: The Pantorouter Turns Tracing On Its Side” →