As a member of the Karakuri Group, when I renewed my membership at the start of the year I decided to pick up a few of the DIY kits that they offer. After my experience with Bruce Vinney's designs I was interested to see what Karakuri Group had created, and also to better understand the mechanisms used, which is one of the goals Karakuri set when making the kits.
When I mentioned that I had the kits on one of the puzzle forums, there were requests to show how to build them, so much like I did with the previous kits I built, I decided to show the build process in full. Watch the video below to see the build, and watch the kit come to life. In the video I'll cover all the tools I use and this isn't time lapse so you can see everything in real time. I'll be doing videos for all the kits shown in the video, so check back for more soon.
As promised in the video, you'll find the instructions below, with my guide to building the box. Be aware that this is in no way a translation of the instructions!
General Kit Comments
The Karakuri group offer a reasonable number of DIY puzzle boxes which they refer to as "Work Kits". Each of the kits consist of a number of pre-cut plywood pieces, some decorative pieces (like the beautifully made acorn on the Acorn Box), and any hardware needed for the mechanism, if it's not just a straight forward sliding panel or suchlike. The kits are all perfectly cut, and of the kits I own there have been no issues with the fit or finish on any of the pieces.
Something which is worth noting about the kits is the price. They all come in at around the $25 USD mark, so in terms of affordability, these are really affordable boxes. The quality of the cuts on the pieces is excellent and the fit is as good as you will find with anything from the Karakuri group, so I'd say from that side of things, they're great value.
One thing to note is that the build instructions for the kits are in Japanese language only. Don't be put off by that however as with a little thought, and some careful study of the diagrams, you'll build the kits just fine. Failing that, have a look at my Build Instructions section below, where I have detailed the steps (in English) to build the kit.
Kakukaku Kit Review
The first of the kits I built was (as you already know from the title of this post) the Kakukaku Box. I picked this one for no other reason than liking the look of the box. Interestingly it was the last of the four that I picked, and really the only reason was that I had set a budget and this fit within that budget after having picked the three others I wanted.
As you can see from the picture above, the box itself is fairly simple. The ply is visible on the top of the box, but personally I don't think that's an issue. If you don't like having the ply exposed, you could glue some veneer onto the top panel just to make it neater. The laser cut tree certainly adds to the look of the box, and is also a clue as to the solution.
Building the kit was fairly simple. The diagrams on the build instructions are very clear, and there's nothing complicated to this kit, so I didn't have any issues building it. The video is real time, so it took about 15 minutes to put together, and would probably be quicker if you're not recording a video and talking through everything you're doing!
As far as the puzzle box itself is concerned, I'll be honest that I was a little disappointed with the box. I have two reasons for this, and at first they seem contradictory, but bear with me.
The locking mechanism is both too difficult to open, and too easy to open at the same time. If you attempt to open the box using the 'solution' provided, it can be very difficult to move the two parts of the box in the right way to get them to open. The fit is pretty good, and as such the movements need to be made very precisely to get the box open. Sadly, there is a much simpler way to open the box. If you hold the top of the box, and shake it, the bottom falls out on its own, making it far too easy!
As a kit I certainly enjoyed building it, and you will understand the mechanism once you've built the box, so it certainly meets the expectations that the Karakuri group set out to achieve. If you're thinking of buying one (or more) of these kits, I'd say that there are better boxes in terms of the end puzzle that you could get, but if you just want to add them all, then go get it!
In this section I will try to give my guide to building this kit. Please note that this is in no way a translation of the Karakuri Group's instructions, but my own instructions based on having built the kit. If you have issues following my instructions, feel free to get in touch and I'll help you if I can, and update things below to clear up any confusion.
The instructions below match to the numbers on the diagram above.
Before starting, you'll need a couple of tools.
- Wood Glue / Elmers hobby Glue
- Ruler (or some measuring device)
- Tape - I recommend blue painters tape
- Glue Brush (optional)
- Engineers Square (optional)
Step 1 - The Locking mechanism
First up, sort the parts from the kit into the same order as shown in the top diagram. If you feel like you need to then you can mark the piece numbers in pencil on the inside of each piece. The way the pieces are laid out in the diagram shows the inside, with the exception of piece 'B', which will be inside the box and unlikely to be seen so even if you don't remove the pencil mark, probably not an issue. In my opinion, the pieces are pretty clear so you should need to label them.
Take Piece 'A' and lay it as shown in the diagram. The sides with the notches cut out should be at the top and right of the piece as you look at it.
Take Piece 'B' and glue it into the centre of piece 'A'. The piece fits snugly between the wooden blocks that surround the piece, so no adjustment or fine placement is required. Make sure that the lip on piece 'B' is on the left and top as you look at the piece. This can be confirmed by the angled corners as seen in the diagram.
Leave the top for around 10 minutes for the glue to dry (note if the glue you are using takes longer to dry, then follow the manufacturers recommendations).
Step 2 - Top Decoration
Once the top of the box is dry from step 1, flip the piece over so that the cut away sections are now on the top and left of the piece as you look at it.
Using a ruler, mark the centre of the piece, making note of the cutout which will not be seen once the box is complete.
With the centre identified, glue the tree piece to the centre as seen in the diagram.
Step 3 - Inner Box
Take the parts labelled 'E' in the diagram. The flat square is the base of the inner box. There are two sides with notches cut in each end, and two with no notches cut.
Place the base in the centre and then around that the two pieces with notches in the ends above and below it, then the two without notches at either side as seen in the diagram on the right.
You will notice that there is a grove running through the with of all of these pieces. The base will go into one of these slots, and the other is part of the locking mechanism.
Put glue into the notches on either end of the top and bottom pieces and using a brush, spread the glue evenly into these notches. Bring all four sides together around the base as seen in the lower left diagram.
Once all four pieces have been brought snugly together, tape the corners and check that the corners are square using an engineers square. Note: This check is not really needed as the pieces are designed to give a good square corner.
Note: You can put tape on the corners before adding the glue. This can make the job of taping the corners easier rather than trying to get tape around the corners after they are in place.
Leave the inner box to dry.
Step 4 - Outer Box
Take the top which was completed in step 2, and place it as seen in the diagram, where the cut-out sections are at the top and right of the piece as you look at it.
Taking pieces Labelled C-1, C-2, D-1, D-2, place these around the top as seen in the diagram.
Pieces D-2 and C-2 have a piece of wood inside the groove which ensures the pieces are correctly located in relation to the locking mechanism, and the centre of the box.
Pieces C-1 and D-1 have no insert in the groove, and will slide freely along the length of the top.
Apply glue into the notches on either end of pieces D-1 and D-2 and using a brush, spread the glue evenly into these notches.
Bring all four pieces together around the top as seen in the diagram on the right, starting with pieces D-2 and C-2 which will ensure that the pieces are correctly centred.
Once all four pieces are in place, tape the corners together and allow the top to dry. You can check the top for squareness before it is dry however as with the inner box, the pieces are designed to give a good square corner even without this check.
Note: As before putting tape on the piece before gluing can make this easier
Step 5 - Opening and Closing the box
To Close the Box, place the outer box onto the Inner box and move the top Right and Up as per the green arrow in the diagram. The box is now locked.
Top Open the box, move the outer box Down and Left as per the blue arrow in the diagram, then lift the top of the bottom. The box is now open.
This is to be the first in a series of posts in the run up to Thanksgiving Day here in the US. So what better to be thankful about than new puzzles to play with?
You'll have to indulge me for a few minutes here, as this set of puzzles comes with a bit of a story. Don't worry, there's puzzles in here too! So back in June, my parents came to visit me here in California. It's the first time they've traveled since my dad went through all his Cancer operations, and it was the end of a long road for him. Both he and my mum were in need of the break, and having not seen them other than the quick trips back to Scotland for work, it was the perfect time to catch up. While they were here we had planned a bit of a road trip. None of us (either my parents or my new family) had been to the Grand Canyon or Death Valley, and since it was likely to be the last time my parents would be able to make such a long trip, we took the 2000 mile round trip in an RV.
While we were in Death Valley, we stopped at an old Ghost Town by the name of Calico. This is an old silver mining town which has been restored and has the tourist trap costumed inhabitants wandering around. One of the shops there was a modestly sized Puzzle shop; Calico Woodworks, selling 'old west' puzzles, including various disentanglement puzzles, tavern puzzles and wooden puzzles. I must have spent an hour in the shop (much to the dismay of the rest of the family who wanted to see the town) browsing, and talking with the owner, who had a fantastic knowledge of the puzzles she was selling.
As it happens, we struck up quite the little banter, and I have no doubt our discussions helped her sales for the day as the shop was packed when I left. Not long after I walked in, and I was animatedly pointing things out to Jen and my Mum, she hands me a puzzle which she calls the 'Manhood Puzzle". Clearly its something she hands to all the men as it comes with a story that if I can't solve it, she'll have to change my name to something girly. The puzzle she hands me is a nut and bolt puzzle, which as it happens I've seen before. I play along for a minute, and poke and prod at the split washer which is secured in the middle of the screw between the head and a nut which is soldered to the screw, before unscrewing the bottom section and removing the washer.
She then picks up a few other puzzles to show me, and entice me into buying. As she's off finding the puzzles, I spot a two piece pyramid puzzle sitting on the counter, and promptly solve it. (After all it was sitting there un-solved!) She comes back, spots it solved and asks if I did it. "Yes", I reply. She curses me, then proceeds to tell the story of having received it from Creative Crafthouse, spent days not being able to solve it (having received 1,000 of these), and calls them telling them their puzzle is broken. When they told her how to solve it, I believe a large chunk of pride and humble pie was swallowed!
She picks up a series of three puzzles, which for the Shippers Dilemma series. It turns out these are made by Creative Crafthouse and come both individually and as a nice set of three. As it happens, she didn't have the first in the set available, but I did end up buying the other two puzzles from here (amongst other things).
So now that I'm done with my story, back to the puzzles at hand! The two puzzles I ended up getting are Shippers Dilemma 'Y, the middle difficulty puzzle, and Shippers Dilemma 'Z' the very hard puzzle.
Both puzzles come in their own wooden boxes, which have been routed with a number of grooves to signify the difficulty of the puzzle. It's a nice touch and means you can easily tell which puzzle you're picking up without having to leave the lids off! Also, the 'lid' is really the base, and the puzzle can be built inside it then the rest of the box slipped on top to put it away (that is if you get it back into a cube)!
The first of the two puzzles is made entirely of 'y' shaped pieces, 25 to be exact, which have to be placed together to make a 5x5x5 cube. The puzzle was designed by David Klarner and published in the Journal of Recreational Mathematics in 1970, so its not a new puzzle. Originally thought to have just 236 solutions, Burr Tools shows there to be 1264 solutions possible. Never the less, this is still a challenging puzzle, and it's unlikely you're going to solve it in 5 minutes. I think I played around for about 30 minutes to get one solution, and was happy enough with that.
There are a number of other shapes that you can make from the pieces, including a 10x5x1 rectangle from 10 pieces, and a 15x4x2 using 24/25. So lots to keep you occupied with this particular puzzle. It does come supplied with a solution sheet showing 4 possible solutions, and the other shapes you can try, so if you're struggling with the 5x5x5 then one of the others may prove easier!
The pieces of the puzzle themselves are unfinished and fairly rough. While the fit is fairly precise between pieces, there's evidence of glue on some of the pieces, and not all the small cubes are glued perfectly straight onto the longer 'base' section. That said, this isn't an expensive puzzle, and given that it's well worth the money.
The second of the two Shippers Dilemma puzzles is 'Z'. You'll not be surprised when I tell you that this puzzle is made from 25 'Z' shaped pieces (or N in pentominoes sets) which need to be made into a 5x5x5 cube. Like it's little brother there are a number of other possible solution shapes using varying numbers of pieces which are listed with the puzzle, so again plenty to keep you occupied. This is listed as a very hard puzzle, and given that there's only 4 solutions, which are provided, I can see why. Around an hour found me a solution that let me put it back in its box, and I was pretty happy with that. Burr Tools confirms that there's only 4 solutions.
This puzzle is made from a darker wood, but again, I'm not sure what sort of wood has been used. It's of a similar quality and price to the previous puzzle, so all in all good value for money and a serious challenge regardless of how many times you solve it!
I may have to puck up the first in the series, as it has a beautiful symmetry to the way the pieces fit inside, which I really liked. That's one for another day though. Funny that I traveled all the way to Death Valley to pick up my first puzzles from Creative Crafthouse, but I've not been disappointed, and will likely buy more from them in the future.
Come back tomorrow to see the other puzzles I picked up while in Death Valley!
Flemin' is an interesting puzzle from Shiro Tajima from the Karakuri Creation group. This fairly plain looking Cherry box with an inlay detail apparently conceals a hidden compartment in its centre, however it's not easy to find!
As I mentioned the goal of the puzzle is to open the shell and find the secret compartment. Opening the shell isn't too hard. The outer panels are attached to the inner cube using short dowels which run in grooves in the outside of the inner cube. The way the panels of the inner cube are glued together prevent the outer panels from being removed, and keep the solver going round in circles. Confused? The picture below should help.
Made from Cherry, Rengas and Mizuki, this take apart puzzle while fairly plain (compared to some boxes we've seen from Shiro Tajima) still has a striking appearance to its outer casing. Created back in June 2010, this box has been around for a while now, but the internal mechanism was slightly redesigned and entered in the IPP 31 design competition in Berlin.
I've spent quite a lot of time on this box, which was kindly loaned to me by Derek Bosch, and (like Derek) have singularly failed to find the internal compartment. I spoke with a couple of fellow puzzlers about this puzzle, and eventually, talking with Jim Strayer, he pointed me towards the correct technique to open the inner box. It was Jim who mentioned while I was talking to him that the mechanism had been redesigned, and that he can easily open his copy, but was only able to open the IPP copy once.
Our thoughts seem to come down to the mechanism on this copy being locked solid as a result of expansion of the wood. Sadly, it is a potential problem with wooden puzzles, and it seems that the mechanism on this box is rather sensitive to wood movement. Given that I have the puzzle on loan, I certainly didn't want to force anything and possibly break a puzzle (and my thumb being slightly out of action doesn't help). Jim did mention that to open the internal compartment the mechanism needs to move very precisely, and I was concerned about damaging what sounds like a delicate internal movement.
So for now, this one remains unsolved. I can say that having spent possibly an hour and a half working on this one (most of that before my accident), that nothing I had tried would have led me to opening it, so it is a challenging box even when you understand its mechanism.
Given the comments of other puzzlers who've struggled to open this one, and the possible problems with wood expansion, I'm not sure whether to recommend this box or not. I really like the concept behind the mechanism, and I'm sure if it works, it is both simple, unexpected and very clever. It is a challenging puzzle, so if you're looking for a puzzle box that is a little unusual, and will not work the way you expect then it's a great buy. On the other hand, if you get one where the mechanism is stuck, this will frustrate you no end.
Recently I wrote about my first attempt at building a puzzle in wood, from scratch. You can read about that here.
At the end of that post, I had a working puzzle, that I was very proud of, but it still wasn't finished. By that I mean that it was finished to the point it worked as a puzzle, but there was no finish on the wood. So I set about resolving that and with advice from a few fellow puzzle makers, here's the result of that process.
First up was to sand the outside of the puzzle, so it is ready for the eventual finish, and to break all the edges of the puzzle. Working my way through the grits, I sanded at 120, 150, 180 and 220 grit. Straight off the saw, the edges are all very sharp, and it's not the nicest thing to hold. By passing the edges over some 220 grit sand paper, it takes that sharp edge off, and makes the puzzle much more appealing in your hands.
Next thing to do was to apply a coat of lacquer to the puzzle pieces. This does a couple of things. It brings out the grain in the wood and gives some sort of protection to the wood from our greasy fingers. Going with some recommendations, I used 1 part satin lacquer, 2 parts lacquer thinner to apply a very thin coat. Leaving the pieces for 10 minutes after applying then rubbing off any excess with a soft clean rag.
The results are pretty obvious when you look at the two puzzles side by side. Given how much time I spent getting the tolerances right, you'll be pleased to know that the lacquer really doesn't add any thickness to the pieces given how thinly the lacquer mix is applied. It's pretty much flush with the surface, so no real issues that I can tell, and my puzzle making friends seem to concur.
After that it's time to apply a couple of coats of wax to the pieces. This helps to make sure that things slide nicely. I had a liquid wax recommended to me, as it's much easier to brush a liquid into a corner than it is to use a wax paste and a rag. If you're interested, I'm using Watco Satin Finishing Wax.
Finally I use some Renaissance Wax to buff and polish the outside faces. It's not cheap stuff, but it is effective. You really don't need much which is probably just as well. This really brings out the wood, and gives a good protective layer to the outside of the puzzle. If it's good enough for the British Museum, its got to be good enough for my puzzles!
If you're wondering, the first fully completed puzzle is now in the collection of a good friend. I'm waiting for him to open the puzzle to let me know what he thinks of it!
My first home built Puzzle
After the successes with creating both Square Sticks and Cubes, I had to go do something with them; and see if I could create a puzzle. I decided to make some of Stewart Coffin's designs, and having been in touch with him, he very graciously gave me permission to try to recreate any of his designs, and encouraged me to do so. With that endorsement, I was off and running. Well, almost!
I had to work out which puzzle I was going to create. There's so many to choose from that it's not an easy decision. In the end, I decided to create something that I didn't already own, so I'd be adding to my collection if it turned out to be any good. So I settled on a copy of STC #214, the Involute puzzle. The Involute is the third in a series of puzzles from Stewart Coffin, each an improvement over the predecessor.
The first was Convolution, a 4x4 interlocking cube which requires a rotation in the solution. Due to the rotation, some material needs to be removed from one of the cubes in the solution (if you have a tight fit) to allow the rotation to happen. You can read my review here. Stewart Coffin notes that given the rotation, and the nature of cubes (which don't like to be rotated when hard against one another), that this design could be improved. In his book "The Puzzling World of Polyhedral Dissections", he leaves it to the reader to see if they can find a solution to this problem.
At the same time, Stewart Coffin had already solved the problem, and created STC #198, Involution. Again a 4x4 cube with a rotation required in the solution, but this time because of the design of the dissection, no material needs to be removed from the pieces to allow the rotation. I'll not give away how this is done, as it would spoil the puzzle, but I will say it's a simple and clever solution! I was able to play with one of Scott Peterson's copies that he had made on my recent visit to see Scott, so I can say I've solved both the Convolution and Involution puzzles at this point.
The third in the series is STC #214, Involute. This is the final puzzle in the series, and is again an improvement over the Involution and Convolution. Again there is a rotation required in the puzzle, and again, no material needs to be removed for the rotation to take place. There's an extra trick in this puzzle, that I'll get to in a bit which makes it just that bit more devious.
All three puzzles in the series look identical from the outside, each having the same cross pattern on all six faces, so without knowing which puzzle you have in your hand, it could easily be any one of the three. Have I mentioned that this Coffin is a devious bloke?
Thanks to Allard and Kevin who both reviewed their copies of the Involute puzzle, I was able to model the pieces in burr tools, and from that create myself a parts list and a gluing diagram to be able to build the puzzle.
Given that it took several hours to create the diagrams, including the time to create the model in burr tools and so on, I'm not going to give you the whole thing. Not to mention it would spoil how to solve the puzzle (or would it - I'll come back to that thought). But the image above gives you an idea of what I created.
With the design in hand, I went off to the saw, and using the crosscut sled and my stops, I cut all the necessary cubes to make the puzzle. There's quite an array of pieces there when you see them all sitting together. Also in the picture is one jig I hadn't talked about previously. This is my cube gluing jig. It's not overly complicated, just three pieces of MDF cut and glued together to hold a 4x4 cube cut to my 3/4" stick size which has all edges at 90 degrees, and has been waxed to prevent any glue from sticking to it. I also have three 'end panels' which will distribute the clamping pressure evenly across all the blocks so as not to twist the blocks while the glue dries.
At this point I made something of a realisation. Sitting looking at this array of blocks, and my gluing diagram, gluing up one of these puzzles is hugely complicated. You're working in three dimensions gluing any number of pieces together, all of which needs to be accurate, and with no glue squeeze-out. If you thought Ikea furniture plans were Convoluted, then this is much more challenging!
Next up I placed all the pieces into the gluing jig, to match my plans. This serves a couple of purposes. Initially, it shows me how good the fit is, and also verified that my plans were correct (at least in as much that I had the correct number of pieces). The other benefit to the dry fit is that it allows me to select which pieces I want to put where in the puzzle. Looking at the grain in the wood, I can select the 'nicest' grain to be on the outside of the puzzle, or look at creating grain patterns by selecting pieces carefully from the pile. Given that this was a first ever attempt, I wasn't too concerned with the grain pattern, but I didn't entirely ignore it either.
Since this was the first glueup I'd be doing, I decided to go with gluing up two layers at a time. This meant that I didn't have to work quite as quickly to get the clamps on the jig to ensure that tight fit I was going for. Fortunately, the way the pieces go together, there is a flat surface after every second layer, which was ideal as a stopping point. I also have a smaller glue bottle, where I've decanted some of the glue from my big bottle. This small bottle has a fine nose, and is much easier to work with that the full sized bottle. Given the small amount of glue I'd need for each piece, this is the only way to work.
With all the pieces separated into layers, I was as ready as I was ever going to be to start putting this together into a puzzle. Fingers crossed!
Working reasonably quickly, I glued up the first two layers, and thanks to tips from Scott Peterson, I managed to do so with little to no glue squeeze-out. That's pretty important since any glue squeeze-out will glue blocks together that shouldn't be, making the puzzle unsolvable. You'll notice the fairly large block of wood on the top of the gluing jig in the photo on the right. That's because I only have two layers build at this point, so the puzzle is half way inside the side plates. I needed to add some height to be able to clamp the puzzle effectively.
After the glue had set, I came back and added the remaining two layers, building on the two I already had. This time, you can see that the puzzle fills all the space, and there are no extra spacers required. I then had to wait a few hours for the glue to dry properly before I could take the clamps off, and see whether I had created a puzzle or a paperweight.
They may have a been a few of the longest hours I have experienced in a long time. My fiancée was about ready to kill me, as I wanted to go take the clamps off and see what I had, she kept telling me to leave it alone. I was like a kid on Christmas morning waiting to see what presents I had. I could barely sit still! When things had been left for long enough, I was finally allowed to go take the clamps off and see what I had.
I should note at this point, that I have never solved an Involute puzzle prior to making this one. Given that rotations are required in the solution, Burr Tools can show that there is a solution, but it can't animate the assembly for you (or in my case the dissassembly), so I have no idea how to take the puzzle apart. I'm now in new territory, and given that I don't know how to take things apart, or whether the pieces are glued together correctly, and not glued to one another I know this is going to be interesting!
Since I know where the key piece is, I can remove that fairly easily, but then spend the next ten minutes pushing and pulling on various pieces hoping that something else will move in the puzzle. I can see that there is movement in the pieces, so at least it's not all glued together, but I am having real problems in finding the second move. The pictures that follow were taken by my fiancée, so are unedited as I make progress. That grin on my face is real!
As I mentioned, I've never solved the Involute before, so I had no idea how the puzzle was supposed to come apart. The key piece in the puzzle is really well hidden, and without knowing where it was I would have struggled to start, especially not knowing if the puzzle was entirely glued together at this stage. The second move is also very clever. One thing that Stewart Coffin regularly has in his designs is pieces which are created so that the average person will hold the puzzle in such a way that you will be holding the piece you need to move, effectively pushing the puzzle closed and preventing it from being opened. The Involute is no different, and has this very same trick to allow move two. The look on my face when what looked like half of the puzzle slid to the side perfectly must have been quite the picture. I think for me not only was I solving a puzzle for the first time, which always brings a smile to my face, but also it was a puzzle I had built, and seeing it work the way it is supposed to is an ever bigger achievement.
I took the puzzle fully apart, and was left with the eight individual pieces sitting on my sofa, with a huge grin on my face. I then realised that I had absolutely no idea how to put the whole thing back together! In my excitement of taking the puzzle apart, I wasn't paying any attention to how the pieces were coming apart! I then spent the next 15 minutes with my gluing diagram trying to put the puzzle back together. Remember I mentioned that having the full diagram may not help that much! I did get there, and the smile on my face seeing the puzzle back together was truly from ear to ear.
The rotation in the puzzle works perfectly, and I haven't removed any material from the rotational piece to make that move easier. The fit of the pieces is superb. It's difficult to tell individual pieces apart as you can see from the closeup above. This makes finding how the pieces come apart even more difficult that if the pieces fitted loosely together as there is no movement between the pieces. In case you're wondering, that tiny gap that looks like there's a chunk taken out of one of the pieces isn't tear-out as a result of a poor cut, but was some natural holes in the walnut. It's also worth noting here that there is no sanding done on any of the pieces, these are all straight off the saw. Many people in the puzzle community have noted that sanding reduces the accuracy of the pieces, and that a good clean cut can have every bit as good a finish as a sanded piece, perhaps better, since sanding is effectively scratching the surface.
To prove that it wasn't just a fluke and this was a one-off, I went off and created a second copy of the Involute. So what you're seeing here isn't some clever photography, but the two copies side by side.
And just to show that it works, there's a partially assembled version next to the fully solved cube.
I was really happy with the results. Over the weekend I produced two copies of the involute puzzle, and both have a very snug fit, and I'd be happy to add these to my collection. In case you're wondering, they're made from walnut with redwood corners. And not to sound like an American advert trying to get you to place an order for something you didn't want ...
But that's not all!
There's another of Stewart Coffin's designs that I've wanted to play with for a while. That's his "Half Hour Puzzle", STC #29. So I drew up the diagram for that, and made one of those too! The brilliant thing about the half hour puzzle is that even though Stewart coffin designed it to only have the cube solution, there are hundreds of possible solution shapes that can be made with the pieces. I've created a burr tools file with many of the solution shapes, so if you're interested in a copy of the file, just let me know.
So there you have it. Three puzzles in one weekend, all which I am very proud of, and is the start of hopefully great things. As Allard has put it, "One day there'll be a couple of us around who can say that we had one of the very puzzles created by someone the whole puzzling community now knows as the Juggler-guy! " Maybe ... one day.
I recently wrote about the first of my puzzle making jigs to create square sticks as the first stage in creating the building blocks of many puzzles. With that jig successfully completed, and working pretty well, I had to move to the next stage and create some cubes. I said in the Square stick post that I'd tell you about it soon. Well, soon is now, and it's time to make a crosscut sled!
For this jig, I needed a larger platform than the square stick jig, and as such I was going to be using both miter slots on the table saw. I cut myself a slab of MDF and marked it up for adding runners. I don't have enough of the fancy metal miter bar that I used for the last jig, so I made my own. Starting with a strip of wood rough cut to the correct size for my miter slot, I sneaked up on the correct width by taking thousands of an inch off at a time until I had a snug fit. It didn't take as long as I thought it might, and I think I now have an even better runner than the metal versions I used on the first jig.
My intention was to drill and counter sink holes in the top of the sled and screw straight into the runners below. Sadly that didn't quite work out as planned as I didn't have screws which would fit. What I had was either too short or too long so I had to go to Plan B. I decided to screw through from the runner side into the base. As it turns out, it wasn't too much of a change and in the end achieved the same end result.
With the runners mounted, I flipped the jig over and tested the fit in the miter slots with the blade below the table. I had a couple of spots which were binding slightly, so I lightly sanded the offending areas until I had a tight but smooth fit with no wobble in the jig. For anyone wondering, the way I found out where the runners were binding was to run a sharpie along the length of the runner sides, then move the jig in the slots. When you take the jig back out, where the sharpie has been rubbed away is where you need to remove a small amount of material. Simple yet effective!
With the sled moving smoothly, I raised the blade up, and cut myself a slot part way through the sled. That slot will help aligning the crosscut fence as I need it to be perfectly square to the blade. Without having the blade through the sled that would be almost impossible.
Given the slot I've just created, I now have a potential weak point in the sled where it could flex, and degrade the cut. Despite how it may look in the photograph, I wasn't trying to create a wing to add down-force to the sled.
Each of the three spacers on either side is screwed to the piece below with three screws, and gives enough clearance that with the blade raised to the point that the blade stiffeners are just below the base of the jig, it doesn't cut into the cross bar. The cross bar keeps either side of the sled stable and prevents any twisting or warping of the sled. Yet again simple but effective. (I'm liking the fact that I can keep things simple. Less chance of things going wrong!)
Given that it was getting on for around 5 hours that I'd been working on the saw and building the jigs by this point, I took a break, stretched out my legs and back and relaxed for ten minutes. While I was doing that, I spotted a dragonfly floating around the garden. Standing watching him for a few minutes, he landed on the radio antenna for our car. Given that I still had the camera in my pocket from taking pictures of what I was doing, I grabbed it, as he posed for me! Looking at the pictures later, there really came out well, so I thought I'd share...
Anyway, back to the jig ...
With the back reinforced, I had to add the fence to the sled. The important thing here is that it is at exactly 90 degrees to the saw blade. If it's off, then the cut will not be square, which isn't going to make for a good cube. Using the best square I have, I sat one edge against the blade, and the other against the fence board I'd cut. Keeping both edges in firm contact, I drilled one screw hole, counter sank and then screwed the fence to the sled at one corner. With one corner in place, I double and triple checked the fence was square, on both sides of the blade (using two squares). That may be a little overkill, since the blade shouldn't be different on either side, but I figured it couldn't hurt!
Everything checked, I pre-drilled and screwed the other side of the fence to the sled, and checked again for squareness. With everything looking good, it was time to add the stop. Now this was something that I'd been puzzling over for a good few days at this point, and hadn't really figured out how I was going to perfectly measure the offset so that I ended up with good low tolerance cubes. As is ever the case, the answer came to me when I least expected it, in the shower in the morning before heading to work.
The answer. Make sure that the stop is far enough from the blade to make the biggest cut you'll need, plus a bit. The reason ... Well if you properly size a piece you want to cut (and I'll get to that) then you can use that piece against the stop, then cut a 'spacer' by placing it against the fence, and the piece you want to cut, then cut that piece. You get a perfect spacer, and no complicated measuring required. (Other than the piece you want to end up with). Yes, I know that's all very confusing, but I'll annotate the pics below and it will make more sense!
Having screwed the stop in place I could remove the clamp. The stop is placed 6" from the blade. I'm unlikely to ever cut a stick that needs to be 6", unless perhaps I'm making 18 piece burrs, so this is lots of space to create whatever sized stick I need.
If you click on the image on the left, you'll see I've annotated it to make my previous explanation simpler to understand. The single cube in walnut was created by shaving a few thousands at a time from the edge of the block and measuring after each pass until it matched the dimension of the square stick. In some regards, that is probably the most time consuming part of the process, as if you take off too much, then it's a case of starting again.
With the first cube created by hand, it can be placed against the stop, then a long stick placed against it to create the spacer. In the diagram, you'll see I created mine from some of the redwood sticks I'd cut when I was testing the square stick jig.
Now it's a simple task of swapping the order of the pieces so that the spacer is against the stop, and batching out some cubes. I've used a clamp to keep the spacer in place, both against the fence, and hard up against the stop to make sure that it doesn't move between cuts. It's also important after each cut to clear out any dust that gets between the block and the fence as this will affect the accuracy of the cut. It is possible to adjust the spacer by adding feeler gauges between the stop and the spacer and before each run of cubes, I'll need to check the sizes to make sure everything is within an acceptable tolerance.
Running through a few cubes, each cube came out almost perfectly. The worst cube had a tolerance of 0.001" from the size of the square sticks. I can't really complain when the cuts are that close. It's going to be pretty good for any initial puzzles I make.
Now with a few cubes cut, I measured them, and selecting two that were exactly cubic, I placed them together and verified that the length was exactly double that of a single cube. Repeating the process I had used for the first cube, I cut a 'two cube spacer'. This spacer will let me make double sized cubes, perfect for making any of Stewart Coffin's Convolution/Involution/Involute puzzles.
Let the fun commence!