Neil's Puzzle Building Blog
29Feb/161

Really Bent Board Burr

It's been a while since I've sat down and shown the process of making a puzzle, mainly because I've been busy in the shop working on making puzzles, and haven't had time to write, however the Really Bent Board Burr by Derek Bosch is one that is worth writing about.

The Final puzzle

The Final puzzle

I've never owned a copy of this puzzle, and it has always intrigued me. I've talked about making copies for long enough, and now I finally have, so here's a little bit of insight to the puzzle, and the process of creating it. The puzzle was originally produced by Tom Lensch back in 2007 and the craftsmanship as you'd expect was superb. Hopefully I'm able to do it justice, but I'll let you be the judge of that.

An alternate angle

An alternate angle

Before I get into the details of making this puzzle, here's a few interesting things about the puzzle. It's hard to tell from the assembled puzzle, but this is a 6 piece puzzle, with three different types of pieces used in the construction. Each piece forms a 'Z' shape with two 'C' pieces attached to a central 'O' piece. The puzzle itself has two different solutions using the same 6 pieces. An easy and a hard solution. The easy solution is a level 10.6.1.4 while the hard is a staggering 20.2.10. In all honesty calling the easy solution easy is a joke. This is a really tough puzzle both to assemble and dis-assemble, however the final shape is well worth the time to solve. (And no, I'm not smart enough to assemble it without help!)

All six pieces that make up the RBBB

All six pieces that make up the RBBB

The pieces form a set where three of the Z's have the C's attached with the opening facing in opposite directions, two with the opening in the same direction, and the final is a mirror image of the second piece type. Given the length of the C's and the minimal gluing surface to the central structure, the joints need to be reinforced to prevent them from breaking. Equally, the end of the C's need to be reinforced to prevent them breaking too. All told there's a lot of work to producing such a puzzle, however the end result is in my opinion worth the extra effort.

Starting with square sticks

Starting with square sticks

The start of any such puzzle is with the preparation of the stock. Square sticks need to be accurately milled from the boards giving straight, consistent sticks as a starting point. For this run of puzzles, I had a selection of Maple, Walnut and Lacewood to work with. Fortunately all the stock I had was 8/4, meaning that I could create sticks that were over 1/2" in diameter, resulting in a very pleasing and not small final puzzle. Overall, each puzzle requires 12 feet of wood to make, and 2 feet of dowel to pin the pieces ensuring they are strong enough. That's a lot of wood!

You can see my cheat sheet in the image above, where I mapped out the pieces and produced a cut list for the individual sticks needed to create the final puzzle. The colouring on the pieces on my cheat sheet is partly to make seeing each piece easier, but it also helps with the wood selected for each piece, resulting in a pretty interesting final puzzle piece.

The size of each of the pieces is determined from the width of the square stock. That sets the size of a single cube, and from there the units required are 1x1, 1x2, 1x5 and 1x7. I made a set of these pieces, which are easily created my combining the smaller units, all cut from the stock I'm using to ensure their size is accurate. You can see them in one of the photos below, sitting on my saw.

Stacks of pieces.  Each stack is one puzzle

Stacks of pieces. Each stack is one puzzle

The square sticks are cut to the correct lengths for each puzzle in batches, and then stacked to create the pieces for each puzzle. In total, I cut enough pieces for 10 copies of the puzzle to be made. As I've mentioned before, once the jigs are setup to make the cuts required, the effort to create 10 copies is not significantly more than to create one, so it just makes sense to make multiple copies. I'm sure there are people out there who will be interested in a copy.

Making the C's

Making the C's

C's and O's

C's and O's

From each pile of sticks, the individual components of each individual puzzle piece are created. Since each piece consists of two C's and an O, those can be created en-mass, and then assembled into the correct puzzle piece.

Dowels glued in place and slot cut for the spline

Dowels glued in place and slot cut for the spline

Splines glued in place

Splines glued in place

After the individual components are completed, they are glued together to form the final puzzle pieces, and then holes are drilled through the O's to allow dowels to be glued into place, forming a much stronger joint between the components and helping to ensure that significant force would be needed to break the pieces. At the same time, the pieces are run across the table saw to add a flat bottomed groove in the ends of the pieces to allow a spline to be added. That spline will reinforce the ends of the C's again helping to ensure that the pieces will not break when the solver is playing with the puzzle. These ends are very weak without some additional support since there is very little gluing surface, but lots of force available given the length of the pieces.

Once the glue has dried, the dowels are trimmed with a special saw which does not mark the surface the blade rests against, and the ends of the c-pieces are rounded to both clean up the spline, and add a visual element to the puzzle pieces in the assembled state. The other advantage to doing this is that is hides any tearout that was created from cutting the groove in the ends of the pieces. Normally I will back-up the cut with another piece of wood against the back of the piece where the blade will exit. This prevents the wood fibers which are unsupported otherwise from being ripped away from the piece, however with this type of cut that is very difficult, and taping the joint is only partially successful. So from my perspective as a craftsman, this rounding is both useful and pleasing to the final puzzle piece.

Applying finish really brings out the beauty of the wood

Applying finish really brings out the beauty of the wood

At this point, the puzzle can be tested to ensure that all the pieces fit together. Unlike many other puzzles I've made there's no way to test the puzzle sooner. That means that I could have spent 10 hours making the pieces, and have nothing but scrap to show for it. Unfortunately, the pieces are so long that without all the dowels and splines, they are not strong enough to be put together into the final puzzle meaning that it's an all or nothing build. Fortunately with the experience I have gained over the last few years, the puzzles went together without issue. Only minor sanding was required in a couple of places on one of the puzzles to ensure a good fit.

With the pieces tested and fitting together, they can be final sanded up to 600 grit to ensure a smooth and tactile surface, then finish can be applied to bring out the beauty of the wood. My go-to finish for puzzles is still a thinned lacquer then the Beall Triple Buff system to really make the pieces shine.

Just a few finished puzzles

Just a few finished puzzles

That's about all there is to it. Each puzzle takes around 15 hours to make from start to finish, and I'm now very happy to have one of these excellent puzzles in my collection. They are a lot of work to make, and I'll be honest, as happy as I am to have one in my collection now, I'll not be making more of these any time soon! Hopefully the write-up was interesting, and hopefully I'll be back to writing more soon.



8Mar/133

Lean 2

During IPP 32 last year, Dave Rossetti presented another Stewart Coffin tray packing puzzle as his exchange puzzle. Numbered #255 in Stewart's numbering scheme, this was isn't made by Stewart himself, but by the woodworking master Tom Lensch. Given that I have a number of puzzles made by Tom, and I thought I was getting better at these packing puzzles, it seemed like a good idea to pick up a copy of this one.

Lean 2 with the four pieces

Lean 2 with the four pieces

As you can see this is another simple four piece packing puzzle. The additional challenge here is that the tray is two sided, meaning twice the puzzling fun ... or frustration. Tom has crafted this using four different woods for the pieces, Zebrawood, Marblewood, Canarywood and Bubinga (I'm guessing on the Bubinga) with a Walnut framed tray. Measuring in at 5.5" x 5" and nearly 1" thick, it's a good puzzle to work on, and not too big that it can't be slipped into a bag and taken with you.

Given that I picked this up in August, you may ask why it's taken so long to write about. Well as it happens, I solved the first side fairly quickly. It took me several hours over a month or so as I'd pick it up and fiddle, then put it back down. I was fairly happy with that and feeling quite confident so moved on to the second side, and promptly failed to make much progress.

Lean 2's second side with the four pieces

Lean 2's second side with the four pieces

I was a little disheartened when a good puzzling friend sent out an email asking for people to send him all the solutions they'd found for this puzzle. The suggestion was that there were a couple of false solutions that could be made. Well I got back to it and kept puzzling. After another couple of months, and several emails back and forth with my friend, I'd sent him 4 invalid solutions to the second side, but seemed to be no closer to the actual solution.

After another month of puzzling on this one I have to be honest and let you know I admitted defeat and asked for help. I dropped an email to fellow blogger Allard who had already solved and written about Lean 2 and asked for his help. I wasn't looking for the solution, I'm not that much of a defeatist, but he kindly took pity on me and sent me a location for one of the pieces. I should note that I'd been sending Allard my 'solutions' and none of those I'd found worked on his copy of the puzzle, so he knew that I had given this one a fair shot.

With the hint in hand, I had the second side solved in about 2 minutes. Overall, this is a great puzzle, and kept me busy for many months. If you enjoy packing puzzles, then definitely pick this one up, it's well worth the money and will keep you busy for quite some time.



15May/120

The Distorted Cube – STC #61-A

What seems like a very long time ago now, way back in August in fact, Tom Lensch offered a number of puzzles through Puzzle Paradise. At that time I picked up a copy of the Two Boxes puzzle which I wrote about some time ago, and this Stewart Coffin Design. It's taken quite a while to get round to completing all the challenges set by Stewart for the Distorted Cube, but I've finally done them all, and it's about time I wrote about it!

The Distorted Cube, STC #61-A, showing the Box, Lid and Four Pieces

The Distorted Cube, STC #61-A, showing the Box, Lid and Four Pieces

As you can see, the puzzle consists of four puzzle pieces, made from 14 edge beveled cubic blocks, which have been joined together in different ways, as well as a rather unique rectangular covered box (But I'll come back to that!) The copy I have is made by Tom Lensch, and is from a run he did in August 2011. The box is Canarywood, and the pieces are made from a rather interesting Maple called Ambrosia. Ambrosia maple comes from regular soft maple and Hard Maple trees that have been infested by the ambrosia beetle. The small beetle bores a network of tunnels and short galleries called cradles. A fungus is responsible for the blue, gray and brown streaks and decorative patch work that accompany each tunnel and adjacent wood. The streaks and patch work add a unique look to this hardwood without affecting its structural integrity

Stewart Coffin first made this puzzle in 1988 in a very limited run of about 8 puzzles, and then again in December of 1996 making around 12 copies. He described it in Puzzle Craft in the 1992 edition, and in the 1996 run produced a puzzle sheet to go with the puzzle. You can see that sheet by following the link here.

The puzzle consists of a number of challenges, each of which uses the pieces in a slightly different orientation, which really explores the huge number of possibilities that these four shapes can be combined. One thing I found as I moved from one challenge to the next is that human nature starts to get in the way. As you find one solution, your brain becomes fixated on that orientation, and starts to rule out other possibilities, making finding the solution to the next challenge more difficult.

Challenge #1 Solved

Challenge #1 Solved

The First challenge is to pack the four pieces into the box so that the cover placed on top of them will be flush with the top of the box. A variation of this is to first lay the cover in the bottom of the box, in which case, the puzzle assembly will be flush with the top. Just so you can tell I wasn't cheating, I went with the latter option.

Challenge #2 Solved

Challenge #2 Solved

Challenge number 2 is to place the lid into the slot at the side of the box, converting it from a rectangular box, to a cubic box. Now place the four pieces into the cubic configuration. Again the top of the assembly will be flush with the top of the box. (No, you're not allowed to have extra pieces sticking out, despite how many combinations I found where this was the case).

Challenge #3 Solved

Challenge #3 Solved

For the third challenge, the cover for the box is put to the side, and the pieces have once again to be packed into the now much larger space so that they are still flush with the sides and top/bottom of the box. This really shows just how many ways there are to make use of the space (or possibly the holes in the cubes) to pack them more or less efficiently, depending on the space you have available.

I really love the versatility of this puzzle. What seems like a simple configuration of four pieces allows a lot of different configurations, and as I found many hours of happy puzzling.

But the challenges don't stop there! If you put the box to the side, there are yet another two challenges to try to solve. (And I'm pretty sure from my playing around with the pieces that there are more that Stewart just didn't list!)

Challenge #4 Solved

Challenge #4 Solved

Challenge number 4 has us making a square pyramidal pile using all four pieces.

Challenge #5 Solved

Challenge #5 Solved

The final challenge that Stewart set is to create a triangular pyramidal pile using only three of the pieces. Of course he's not telling you which three to use. That's up to the puzzler to figure out!

Overall, this a great puzzle and I'd highly recommend picking up a copy if you see one for sale. I spent many hours playing with this over several months, and still enjoy going back and re-solving the various challenges. I may even look further into the combination of the pieces to see if there are other combinations possible, as there are certainly some combinations of the pieces which were not used in any of the original five challenges.



23Dec/111

Two Boxes

This is a beautiful optical illusion from Tom Lensch. I really don't think I can write anything that will do it justice, so in a rather start departure from my usual reviews, I leave you with only this video.

Hope you enjoy!