Monday precision cuts

Cruel punishment

That is a terrible thing to do to us early on a Monday morning ;-) I can almost remember my name .............

Will have to noodle on that for awhile after I wake up. ;-)

Just to make clear...

the formed octagon is 12" across, NOT 12" on a side. That makes the sides much less than 12". Glue is permitted.

Re: Just to make clear...

12 inches point to point, or flat to flat?

Re: Monday precision cuts

15 plus ? according to how extreme you get with gluing the the little pieces back together.

Impossible To do

Last time I was at a BORG no such lumber existed. Everything I saw was mangled and twisted!!

Tom

Change of answer.

56 +

Note to self....Drink mo' coffee.....

After mo' coffee.

1"x6"x12' ripped into 5 equal pieces=5 1"x1"x144" strips--right?

Long side of each piece of octagon is appox. 4.25"--right?

Short side is appox. 3"--right?

Flipping 1"x1" strip 180 degs after each cut yields 48 pc's 3" long minus 48/8's or 6" off for cuts leave you 46 pieces per 12' 1"x1" strip--right?

46 pc's per strip times the # of strips (5)=230--right?

230 divided by 8 sides= 28.75 octagons--right?

I can tell now, it's going to be monday all day today.

flat to flat.

Hints

More than 15, much fewer than 56. Flat to flat distance is 12" to the outside of the octagon, which (big hint) makes the side dimension in the 4" to 6" range. You will need well over 100 cuts even if Tom can't locate the perfect board. Don't forget the kerf (1/8") and the possibility you can glue. Find the side length and you can get the cuts. Figure out what you have left and plunk it into your figurin' and poof you're there.

It is a regular octagon- all sides same

Re: Hints II

All strips are not equal, five are however

Your long side is incorrect and the short side doesn't figure into the problem

Number of crosscuts need a number

Total pieces you can get are over 150 but less than 200

Yeah and the mistake is.......

....the cut is 22 1/2 degrees not 45.

Just came from a soccer game, I'm tired. May work on it again in the morning.

Oh yeah, a little bragging. My sons team is undefeated again this season and have already won the league championship. Now we're in the playoff's and I don't foresee any reasons why we can't win everything.

Re: Yeah and the mistake is.......

I couldn't find some simple plane geometry formulas on the net that I needed to solve this. but.

Need to solve for a right triangle with angles of 22.5 degs., 67.5 degs. and 90 degs. when the length of one side adj. to the right angle is 6". .....then double that answer and that will give you the long length of "ONE" piece of the 8 piece octagon. ....and then it's on from there.

Whenever I run into a problem like this I want to kill whoever took my old yellow "CRC" tables books. It had everything a man could want in it.

Re: Monday's answer

I should have titled this the Highland Game, you�ll see why below.

You would be able to easily get 20 but 21 is the maximum I�ve found with minimum waste.

Each side of an octagon that is 12� face to face is 4.9704 on the outside edge and in that board you can get 31 crosscuts

To do it you would have to rip five strips at 1 inch and very carefully cut the pieces out of them with minimum waste.

Then with the remaining 1/2 inch strip you could glue this together to get one strip at 1 inch and you could get 15 more sides out of this one. Total is 170 pieces

This was all done allowing for a 1/8 " kerf.

If you did not glue the final 1/2 inch strip to make a 1 inch side you would only get 18 octagons.

31 pieces per strip and 15 out of the 1/2 inch gives 170 pieces divided by 8

equals 21.25 Again that�s using an 1/8 inch kerf.

There are some formulas to arrive at the length of a side but the easiest to remember is .4142 times the face to face width (12�)

It took some time to find because I haven�t a clue as to how to graphically illustrate how this is done, but the proof of this side length calculation is at http://home.bendbroadband.com/scottish heritage/ocagonnoel.html. That address doesn�t work on my computer (all I get is the home page of bendbroadband), but you can still get there using Google typing: scottish heritage octagon. Two titles will come up Scott Reekie and Noel Reekie. Choose Noel for the proof. Choose Scott for what I originally found. Hooray for Scotland.

Have fun

...uh.....

I don't think you have a 1/2" left over from ripping the boards but rather a 3/8" strip leftover.

Pfitzpluckted

I hate it when other people are right. I never thought to lay it out (or obviously) to add the kerf on that remainder piece. Basil gets kudos for sticking with it. Congrats to him. Razzzlefratz to me!!!!

So that's what happened to that darn Mars lander I never heard of again!

So the answer is 20 (I think). 31 x 5 = 155 pieces without a glue up. Divide that by 8 and you get 19 octagons without the glue up of the 3/8� piece. Take the 3/8" piece and glue and cut it and you can get 9 additional full pieces. 144�/3 = 48� On a four foot board divided by 4.97 you can get an additional 9 pieces. Total is now 164 pieces. Divide that by 8 and the new (I believe correct) answer is 20.5. 20 octagons not 21 as previously indicated. Apologies to all.