Author Topic: 12-Piece Burr Puzzle  (Read 14760 times)

Online Kim

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Re: 12-Piece Burr Puzzle
« Reply #15 on: January 08, 2017, 06:31:50 PM »
I’m a bit behind in posting here. I completed the 6 piece Burr before Christmas, but haven’t had any time since to post or to do anything more out in the shop.  Lots of wonderful family events and doing things with my kids while they were home (Plus a few less fun things that just happen and had to be dealt with.)

In my browsing about these Burr puzzles, I came across this online version of a book on polyhedral dissection as it relates to puzzles. I found it quite fascinating.  Thought some of you might be interested too: http://www.johnrausch.com/PuzzlingWorld/default.htm

There are literally hundreds of variations of a 6 piece Burr puzzle.  This one is a common one (so I am led to believe) and uses 6 uniquely notched pieces.  I found the pieces documented here: http://www.craftsmanspace.com/free-projects/about-the-burr-puzzles.html

And the six pieces look like this.  Note the letter I wrote beside each piece.  This was to help me keep them straight when working.


Since I had leftover 5/8” square aluminum bar available from my 12 piece puzzle, I used that for the 6 piece too. For this puzzle, each piece needed to only be 3 units long (where a unit is the width of the piece), so I cut 6 pieces and milled them down to size.  My 5/8” stock was actually 5 thou over, so the length was 3 x 0.630 = 1.890”.

There was a bit of symmetry in these pieces, but nowhere near as much as in the 12 piece. So, I chose to go a different direction in making these parts.  I decided to just work from one side.  So I setup a table of coordinates for a ‘left side’ and ‘right side’ cut for each notch that was needed, as shown in the sketches below:




Then I dialed in the position of my stop, set zero on the DRO, and went to work on one of the pieces (Piece “B” I believe).
 
The minimum width notches required were 5/16”.  So I used a 3/16” end mill to do all the milling.  On this part, I’ve already milled the left and right edges very carefully, and am now just milling out the middle of the notch, which happens to be two units wide.


Here’s the first notch completed in piece B.


Then I rotated it 90 degrees, and milled out a 1/2 unit wide notch.


Here I am starting on piece C (I started labeling them.  I need all the help I can get!)


Here’s the process I followed for each notch.  First, I would dial in the DRO at ~30 thou less than the actual desired edge, and cut multiple passes to the desired depth (which was always 1/2 unit, plus 2 thou.)


Then, at full depth, I would mill to the actual desired position of the edge of the notch.  I always did it so that the final pass was a climbing mill pass of 1-2 thou to get a nice smooth finish.


Then I would do exactly the same to the other side.  If there was something extra in the middle (as with piece B) I’d go back and remove that last.


Then I rotated piece C, and did an offset notch on that face.  Unfortunately, I apparently failed to get a picture of that operation.

After piece C, comes, you guessed it, piece D. :)  I repeated the same process to cut the notch in this piece.  Note that the notches are in different locations for each piece.


Then I rotated it, and cut the next notch in a different side.


Now, Piece D is a special piece.  It actually contains a blind notch – by that I mean one that isn’t just a cut through.  In this portion, only 1/4 of the cross section of the piece is removed. To do this, I CAREFULLY milled a half notch from one direction:


Then flipped it back to the original position.  Here you can see the curve left by the 3/16” end mill.  Next step will be to do exactly the same pattern here, to take out that curve on the bottom.


Like this:


Unfortunately, that sill leaves a little nubbin down in the blind corner that is curved on two sides, so the notch doesn’t REALLY go all they way down to the corner.


To open up that last little bit of the notch I used a chisel and cut down from all three sides to remove that little piece.  This worked just fine for me, using the aluminum, but if you were using steel, you’d probably have to come up with a different method to clean up that corner.


Next, I did…. Piece A!  Did I trick you?  I actually started with this piece, but as I was working on this one, it became clear that I'd screwed up my calculations.  So I had to re-do them, and consequently, had to re-do Piece A. And here it is, with the first notch removed.


The second notch on piece A is on the same side, but is a 1/2 unit notch, as you can see.


And finally, Piece E.  It required a wide, 2 unit notch to be removed from one side:


And a single unit notch to be made in the center on another side.


And here is my original picture with all 6 completed pieces.


I actually had to go back and widen my notches a bit. I wanted to make this one a little tighter than my first puzzle, so I tried make each notch only 1.5-2 thousandths extra in width.  But that was just not enough freedom to make the whole thing fit together.  I ended up going back and taking a few more thou more off of each edge.  This freed it up enough that things worked very nicely. Maybe its a little too lose however, but it works, and I'm happy. :embarassed:

Here are the completed beauty shots:




If (when?) I do another one, I’m going to be more careful on my notch positioning and see if I can make the tighter tolerances work.  The gaps I have now had to be this wide to make it work, but now it’s just a little loser than I’d like.  I’m sure if I improve my accuracy all around I can improve on that.

But all in all, I’m pretty tickled with how they turned out.  And these puzzles were a very fun little diversion!

Thanks,
Kim
« Last Edit: July 23, 2017, 05:34:22 AM by Kim »

Offline Gas_mantle

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Re: 12-Piece Burr Puzzle
« Reply #16 on: January 08, 2017, 06:45:23 PM »
Looks great Kim.

Making one would be a useful exercise in milling that I could do with  ;)


Offline b.lindsey

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Re: 12-Piece Burr Puzzle
« Reply #17 on: January 08, 2017, 07:04:35 PM »
That's great Kim. I have ordered and received lengths of 3/8" brass, copper, stainless and aluminum to try and make your original 12 piece one with. One of the online metal suppliers had a free shipping day so I got more than enough for the project for $18.00 and change. I will cut them to length at work this week with each piece being 1 7/8" long...smaller than yours but should  make a nice desk ornament :)

Bill

Online Kim

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Re: 12-Piece Burr Puzzle
« Reply #18 on: January 09, 2017, 02:21:46 AM »
Making one would be a useful exercise in milling that I could do with  ;)
Yes, it is a good exercise in turning those knobs! :)


I have ordered and received lengths of 3/8" brass, copper, stainless and aluminum to try and make your original 12 piece one with. One of the online metal suppliers had a free shipping day so I got more than enough for the project for $18.00 and change. I will cut them to length at work this week with each piece being 1 7/8" long...smaller than yours but should  make a nice desk ornament :)

Bill
Good luck Bill!  Make sure and let us know how it goes.  I think the 3/8" size will be very nice.  I'm thinking if I make another (I'm considering an 18-piece Burr someday) I might scale down to 3/8".  Not only is it less material to start with, but there's a lot less material to remove too!

Kim

Offline b.lindsey

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Re: 12-Piece Burr Puzzle
« Reply #19 on: January 09, 2017, 03:24:56 AM »
I think your joints look great Kim, a lot tighter that the wood examples I have seen. I am thinking too tight and the difficulty of taking apart and putting back together may increase substantially. I will see when I get a start on mine. Looking at some of your sources...there are literally hundreds of these things. Makes you wonder who figured them all out  :headscratch:

Bill

Offline Lew Hartswick

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Re: 12-Piece Burr Puzzle
« Reply #20 on: March 06, 2017, 07:28:48 PM »
OK guys, I'm hooked. BUT before I make all those pieces, I want to know HOW to put them together. So someone please post the instruction
for assembling .  I think the 12 piece with all alike parts is the thing to start with. If it goes well ( Think I'll do it in wood at home ) it may be just the thing to get the better students at school to do on the mill. I've been looking for a couple of puzzles or gadgets for them to work on.
   ...lew...

Online Kim

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Re: 12-Piece Burr Puzzle
« Reply #21 on: March 06, 2017, 08:31:39 PM »
Lew,
If you google "12 piece burr puzzle solutions" you'll come up with a lot of info.  But here's one:

http://otherpeoplestrash.com/gallery/toys-puzzles/puzzle-solutions/

I think I had a different link in my build thread that included the basic plans too...
Kim

Offline Lew Hartswick

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Re: 12-Piece Burr Puzzle
« Reply #22 on: March 07, 2017, 02:34:46 AM »
A few hours later the parts (wood ones) are cut but a bit tight here and there. I looked at the link above and the first two or three steps look ok  but then it seems to jump and a different view. So when I get the fitting better I may have to find a different assembly view.
In any event with the fixturing I have for my radial arm saw the cutting went pretty quick. :-)
 more tomorrow, it's almost bed time.
   ...lew...

Online Kim

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Re: 12-Piece Burr Puzzle
« Reply #23 on: March 07, 2017, 03:38:18 AM »
Yeah, I looked at those instructions a little more closely and they seemed to rotate the whole thing 180 degrees between step 2 and 3.  Go figure.

OK, found a better one for you: http://www.popularwoodworking.com/projects/wooden-burr-puzzles
Look about half to 2/3 of the way down the page and you'll find the 12 piece.  These instructions are better, and they show more clearly where you have to do 'slide' operations :)

Good luck Lew.  Can't wait to see pictures!
Kim

Offline Lew Hartswick

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Re: 12-Piece Burr Puzzle
« Reply #24 on: March 07, 2017, 09:07:15 PM »
Thanks Kim. I finished the wood ones and they are a little loose but after much head scratching over the assy. pix finally got it together .




In the meanwhile spent a couple hours down at school on the bandsaw and mill to make a few .375 x .375 pieces of aluminum with the
idea of making a more suitable one for display :-) had a chunk of 3/8 material that was about .380 thick so could clean up to .375, band sawed    some strips and milled away. :-)


I'll have to do some fixturing to do the notches, later this week or whenever.
   ...lew...

Offline zeeprogrammer

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Re: 12-Piece Burr Puzzle
« Reply #25 on: March 07, 2017, 10:51:24 PM »
Cool stuff.

I love this hobby. Get to make nifty things. Get to make!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Lew Hartswick

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Re: 12-Piece Burr Puzzle
« Reply #26 on: March 09, 2017, 09:36:14 PM »
First had to make a set of soft jaws for the Kurt .






Then took one piece and did some shallow milling in the test cuts of the soft jaws to see  if the dimensions worked out and determine the
DRO settings.



So far looks OK
I now have to wait till I have a single block of time to do all the parts at one set-up.
   ...lew...

Offline Lew Hartswick

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Re: 12-Piece Burr Puzzle
« Reply #27 on: March 11, 2017, 02:10:15 AM »
A few hours this morning and a bit of touchup with a Swiss file and - There you go !!
   ...lew...

Offline b.lindsey

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Re: 12-Piece Burr Puzzle
« Reply #28 on: March 11, 2017, 02:23:36 AM »
That looks great Lew, I need to get mine finished up...to many projects....too little time though it seems.

Bill

Online Kim

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Re: 12-Piece Burr Puzzle
« Reply #29 on: March 11, 2017, 05:44:44 AM »
Nicely done Lew, that looks great!  And apparently you figured out how to make it all go together! :)

You guys and your little 3/8" puzzles.  They look so cute!  I might have to do some that size  ;)
Kim

 

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