Author Topic: Math  (Read 18625 times)

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Offline GhostFist

  • Posts: 1556
Math
« on: January 09, 2011, 02:14 PM »
 Are you a numbers person or do you have your own "ultimate method" for determining common woodworking problems.
For instance, you're building a fence and need to determine spacing in between slats. There are three sections of fence, post to post distance between each section is as follows; 1st section 73", 2nd section 76 1/2", and the third is 82 1/8". the slats are 5 1/8" wide and you want roughly a 2" space in between.

What is YOUR method for solving this common problem? I've seen five carpenters each with their own method, none 100% clear on how to execute it argue amongst themselves to determine which method is best. This is a common mathematical problem and can be used for laying out wall paneling, to making head boards for beds, porch railings well anything that requires an equal division of solids versus voids.

Curious to see how many different solutions come up.

Festool USA does not pre-approve the contents of this website nor endorse the application or use of any Festool product in any way other than in the manner described in the Festool Instruction Manual. To reduce the risk of serious injury and/or damage to your Festool product, always read, understand and follow all warnings and instructions in your Festool product's Instruction Manual. Although Festool strives for accuracy in the website material, the website may contain inaccuracies. Festool makes no representations about the accuracy, reliability, completeness or timeliness of the material on this website or about the results to be obtained from using the website. Festool and its affiliates cannot be responsible for improper postings or your reliance on the website's material. Your use of any material contained on this website is entirely at your own risk. The content contained on this site is provided for informational purposes only and does not constitute professional advice.


Offline jonny round boy

  • Posts: 3227
Re: Math
« Reply #1 on: January 09, 2011, 02:24 PM »
There are three sections of fence, post to post distance between each section is as follows; 1st section 73", 2nd section 76 1/2", and the third is 82 1/8". the slats are 5 1/8" wide and you want roughly a 2" space in between.

Well using metric would be a good start... [poke]

 [tongue]
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Offline Deansocial

  • Posts: 2114
Re: Math
« Reply #2 on: January 09, 2011, 02:25 PM »
add the total minus 1 slat then divided by 1slat+ideal spacing take answer and round to nearest number.

take total-1slat again divided by last answer minus 1 slat=spacing

if i understand you correctly

Offline Deansocial

  • Posts: 2114
Re: Math
« Reply #3 on: January 09, 2011, 02:26 PM »
There are three sections of fence, post to post distance between each section is as follows; 1st section 73", 2nd section 76 1/2", and the third is 82 1/8". the slats are 5 1/8" wide and you want roughly a 2" space in between.

Well using metric would be a good start... [poke]

 [tongue]

thats why i didnt bother working it out, too much faff with gimperial

Offline Holzhacker

  • Posts: 893
    • www.aic-chicago.com
Re: Math
« Reply #4 on: January 09, 2011, 02:35 PM »
Not sure what you want to figure out here and make it over complicated. Since the difference between the sections is essentially one slat. Build one section, whichever one you choose, to the exact spacing dimensions. Fudge the 1/16" - 18" spacing difference on the last few slats on the other two sections. No one will see the difference. If for some reason it has to be really precise for a fence (picky client); split the spacing difference 1/2 between spacing and 1/2 between ripping a bit off of a few slats. It's a fence.
"The Code is not a ceiling to reach but a floor to work up from"

Offline Jesse Cloud

  • Posts: 1722
  • Festooling at the end of a dirt road in New Mexico
Re: Math
« Reply #5 on: January 09, 2011, 02:57 PM »
Not sure what you want to figure out here and make it over complicated. Since the difference between the sections is essentially one slat. Build one section, whichever one you choose, to the exact spacing dimensions. Fudge the 1/16" - 18" spacing difference on the last few slats on the other two sections. No one will see the difference. If for some reason it has to be really precise for a fence (picky client); split the spacing difference 1/2 between spacing and 1/2 between ripping a bit off of a few slats. It's a fence.
Well said Holzhacker!

Every now and then I find myself scribbling out calculations and then think, "What are the odds that all those are correct?"  Then I just measure part A with calipers (taking care never to look at the number), use that to mark the spacing on part B in a place that "looks good." 

Offline VictorL

  • Posts: 576
Re: Math
« Reply #6 on: January 09, 2011, 02:59 PM »

Well using metric would be a good start...

Yes, metric is much easier for math unless you sticked to 16" between studs :)


Offline mastercabman

  • Posts: 1854
  • NORFOLK,VA
Re: Math
« Reply #7 on: January 09, 2011, 03:01 PM »

Well using metric would be a good start...

Yes, metric is much easier for math unless you sticked to 16" between studs :)


Yes,but we are not talking about studs [laughing] [laughing] [laughing]s!!!!
I don't understand!?! I keep cutting it,and it's still too short!

Offline mastercabman

  • Posts: 1854
  • NORFOLK,VA
Re: Math
« Reply #8 on: January 09, 2011, 03:05 PM »
Really it's not hard.Add the width of the board + the space in between.
Divide the overall by that number and you get what you need.At that point you can make some tweaking about the spacing once you get the answers for each sections.
I don't understand!?! I keep cutting it,and it's still too short!

Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #9 on: January 09, 2011, 03:08 PM »
Ya I agree with everything I'm personally not trying to determine anything. I use that standard division method, total minus one slat and so on. I was just amazed to see a bunch of guys arguing about this on a site recently and was curious as to how many ways there are to screw up this common problem. I'm with you on metric as well, a lot of crapenters still swear by imperial here though. I'm not saying you lot would screw it up either just curious thats all as to different people's methods.

Offline norwegian wood

  • Posts: 130
Re: Math
« Reply #10 on: January 09, 2011, 03:24 PM »
i use the iphone baluster app. works awesome

Offline Wim

  • Posts: 286
Re: Math
« Reply #11 on: January 09, 2011, 06:45 PM »
I'm so spoiled by computers, I make this into a formulea and open it in a spreadsheet. With the what-if method I try a few possibilities until I find the right one. Works like charm, especially when you have three different distances between the posts.
I did the same for drawers. Input the thickness of the plywood, the width, depth and the height and presto, I have a dimensional list of all components.

Offline mishle

  • Posts: 122
Re: Math
« Reply #12 on: January 09, 2011, 09:50 PM »
I would use sketchup that way I can change the spacing by a 16th of an inch or what ever needed to give it the best look before I start. Yes I take my computer to job sites.

Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #13 on: January 09, 2011, 10:38 PM »
Hmm interesting, using computers. how well does everyone trust their eye? ever tried this????
http://woodgears.ca/eyeball/

Offline mishle

  • Posts: 122
Re: Math
« Reply #14 on: January 09, 2011, 10:52 PM »

Offline Wim

  • Posts: 286
Re: Math
« Reply #15 on: January 09, 2011, 11:06 PM »
One of the things they teach you in Holland in the technical field is: Gissen is missen, meten is weten. Or in a sort of translation: To guess is to miss, to measure is to know. So if I can measure, I will do it. If I have no way to measure, I will give it my best shot.

Offline kdzito

  • Posts: 322
Re: Math
« Reply #16 on: January 10, 2011, 12:51 AM »
Actually my first comment is why did you set the posts at unequal distances of each section?

1st - Regardless of my question above and assuming that you are putting the slats on furring and surface mounting the furring to the posts then I would start at the center (middle) of all 3 fence sections being combined and work outwards and at the ends you wind up with both slats being of equal width.   Thus you have a fence run of a symmetrical proportion.

2nd - Just take a spacer block 2" wide and hold in between each slat being fastened to the furring, thus no difficult math calculations except for the layout in the entire run of all 3 combined fence sections when fastening the first slat.

For layout a carpenter always works from either top down or center out and tries to use math as least as possible.  

« Last Edit: January 10, 2011, 01:02 AM by kdzito »
Building one day at a time.

Offline Ken Nagrod

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  • Posts: 3438
Re: Math
« Reply #17 on: January 10, 2011, 12:57 AM »
Actually my first comment is why did you set the posts at unequal distances of each section?

1st - Regardless of my question above and assuming that you are putting the slats on furring and surface mounting the furring to the posts then I would start at the center (middle) of all 3 fence sections being combined and work outwards and at the ends you wind up with both slats being of equal width.   Thus you have a fence run of a symmetrical proportion.

2nd - Just take a spacer block 2" wide and hold in between each slat every time you fasten it to the furring insert the block and thus no difficult math calculations except for the layout in the entire run of all 3 combined fence sections when fastening the first slat.

For layout a carpenter always works from either top down or center out and tries to use math as least as possible. 



What happened to bottoms up?  [smile]

Offline kdzito

  • Posts: 322
Re: Math
« Reply #18 on: January 10, 2011, 01:03 AM »
Actually my first comment is why did you set the posts at unequal distances of each section?

1st - Regardless of my question above and assuming that you are putting the slats on furring and surface mounting the furring to the posts then I would start at the center (middle) of all 3 fence sections being combined and work outwards and at the ends you wind up with both slats being of equal width.   Thus you have a fence run of a symmetrical proportion.

2nd - Just take a spacer block 2" wide and hold in between each slat every time you fasten it to the furring insert the block and thus no difficult math calculations except for the layout in the entire run of all 3 combined fence sections when fastening the first slat.

For layout a carpenter always works from either top down or center out and tries to use math as least as possible. 



What happened to bottoms up?  [smile]

That's at the end of the day, drinking!!!
Building one day at a time.

Offline atomicmike

  • Posts: 190
    • atomicmike
Re: Math
« Reply #19 on: January 10, 2011, 01:10 AM »
What happened to bottoms up?  [smile]

Why do you think the posts are spaced unevenly?  [big grin]

Offline Top Knot

  • Posts: 64
    • Top Knot
Re: Math
« Reply #20 on: January 10, 2011, 03:37 AM »
What happened to bottoms up?  [smile]

Why do you think the posts are spaced unevenly?  [big grin]

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29891-0
Graham Terrell
+27832412828

Offline harry_

  • Posts: 1174
Re: Math
« Reply #21 on: January 10, 2011, 08:44 AM »
What happened to bottoms up?  [smile]

Why do you think the posts are spaced unevenly?  [big grin]

I have 2 guesses....

Beer

Rocks

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Offline waho6o9

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Re: Math
« Reply #22 on: January 10, 2011, 10:35 AM »
Great thread.  I would start at one end, place a picket, use a 2" spacer and so on.  The last piece is cut to fit. The even spacing  makes for a symmetrical appearance and the scribed piece looks good.  [smile]

Offline mishle

  • Posts: 122
Re: Math
« Reply #23 on: January 10, 2011, 11:08 AM »
But with sketchep you might not have
to cut that last picket if you spaced it 1 15/16. ;)

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #24 on: January 10, 2011, 12:33 PM »
! [big grin]  !

http://woodgears.ca/eyeball/
Best two scores on this computer:
Score      Time      Name
8.26              77 s      JMBjoinery
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Offline Top Knot

  • Posts: 64
    • Top Knot
Re: Math
« Reply #25 on: January 10, 2011, 12:54 PM »
This is exactly the kind of conflict Ghostfist is after  [tongue] :

I would start at one end, place a picket, use a 2" spacer and so on.  The last piece is cut to fit. The even spacing  makes for a symmetrical appearance and the scribed piece looks good.  [smile]

In a light hearted way: Waho6o9 I could not DISAGREE with you more!!!
This sort of look, (to me at least) looks far too unbalanced!!!
Graham Terrell
+27832412828

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #26 on: January 10, 2011, 12:58 PM »
This is exactly the kind of conflict Ghostfist is after  [tongue] :

I would start at one end, place a picket, use a 2" spacer and so on.  The last piece is cut to fit. The even spacing  makes for a symmetrical appearance and the scribed piece looks good.  [smile]

In a light hearted way: Waho6o9 I could not DISAGREE with you more!!!
This sort of look, (to me at least) looks far too unbalanced!!!

+1  Disagree!  

You could scribe the first and last so its look symmetrical but no way would I just scribe the last one.  Thats a site type of job where its all about profit so you just need to bang it up and go! Not for me!


Edited:  Check my score out -----^ its okay try and beat it in time and score no cheating!  Have a FOG competition! Im going to have another go in a min! I need to do better lol!
« Last Edit: January 10, 2011, 01:00 PM by jmbfestool »
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Offline Top Knot

  • Posts: 64
    • Top Knot
Re: Math
« Reply #27 on: January 10, 2011, 01:06 PM »
I suggest you start another thread for that comp
Graham Terrell
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Offline Mavrik

  • Posts: 240
Re: Math
« Reply #28 on: January 10, 2011, 02:08 PM »
Best on this computer score and time:             
4.19      179 s
TS55, MFT 1080, PS300, EHL 65, Domino, OF 1010, CTL 22, RO 125, BS75

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #29 on: January 10, 2011, 02:09 PM »
Best on this computer score and time:             
4.19      179 s

Dam you! Slower but better score!
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Offline Top Knot

  • Posts: 64
    • Top Knot
Re: Math
« Reply #30 on: January 10, 2011, 02:24 PM »
4.25 in 141 sec
Graham Terrell
+27832412828

Festool USA does not pre-approve the contents of this website nor endorse the application or use of any Festool product in any way other than in the manner described in the Festool Instruction Manual. To reduce the risk of serious injury and/or damage to your Festool product, always read, understand and follow all warnings and instructions in your Festool product's Instruction Manual. Although Festool strives for accuracy in the website material, the website may contain inaccuracies. Festool makes no representations about the accuracy, reliability, completeness or timeliness of the material on this website or about the results to be obtained from using the website. Festool and its affiliates cannot be responsible for improper postings or your reliance on the website's material. Your use of any material contained on this website is entirely at your own risk. The content contained on this site is provided for informational purposes only and does not constitute professional advice.


Offline Mavrik

  • Posts: 240
Re: Math
« Reply #31 on: January 10, 2011, 02:28 PM »
Best on this computer score and time:             
2.81      134 s      Mavrik

This is addictive.
I must stop ... I must stop ... I must stop ...
TS55, MFT 1080, PS300, EHL 65, Domino, OF 1010, CTL 22, RO 125, BS75

Online Michael Kellough

  • Posts: 3537
Re: Math
« Reply #32 on: January 10, 2011, 02:33 PM »
Agree, this aspect should be in a different thread but it does have some relevance
to scribing and judging appearance.

Your inaccuracy by category:
         
Parallelogram   1.0   ----   ----
Midpoint   0.0   ----   ----
Bisect angle   0.7   ----   ----
Triangle center   5.3   ----   ----
Circle center   4.1   ----   ----
Right angle   0.0   ----   ----
Convergence   5.1   ----   ----

Average error:   2.31   (lower is better)
Time taken:   66.4

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #33 on: January 10, 2011, 02:39 PM »
4.25 in 141 sec


You couldn't resist could ya! Haaahaa
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Offline Wood_Junkie

  • Posts: 1313
Re: Math
« Reply #34 on: January 10, 2011, 03:02 PM »
! [big grin]  !

http://woodgears.ca/eyeball/
Best two scores on this computer:
Score      Time      Name
8.26              77 s      JMBjoinery

Cool little excercise!
Overall score: 4.40
Total time: 113.97



Here’s my approach.  I am usually simultaneously trying to figure out the spacing as well as how many boards I need.
I prefer to plan ahead to the end result, and make a spacer block that is properly determined, rather than just assume 2” is going to result in a nice width for the final boards.  You might start center out and discover that the final boards wind up extremely narrow.  That’d look weird!

For below, I assumed your start and stop points will be a fence board (not a gap).
The SS is deducted on the left side of the equation, because the last board doesn’t get a follow-on spacer.
If you want gaps at the start/end, then ADD the SS to the left side, instead of subtracting it.

First, add up the total lineal distance you need to cover.  
Your specs:  73", 2nd section 76 1/2", and the third is 82 1/8"  =  231.625” lineal distance


Add up the total of your fence boards + spacings and begin to calculate.
Tweak as necessary to arrive at the above figure.

Formula:  ((WW + SS) x YY)  – SS  = LD
WW = width
SS = spacing
YY = number of boards
LD = Lineal Distance

Use the desired approximate gap to solve once for YY, to get an approximate number of boards.
Then substitute YY with the lower integer.
Then re-solve for SS

Example:
Solve for YY:
(5.125” + 2” spacing) x YY number of boards  - 2”  = 231.625
7.125 x YY = 233.625       YY = 32.79 boards
Round this down to 32 boards if you want the spacing over 2”.   (You could also round up if you don’t mind having less than 2”).

Solve again, this time for the spacing SS:
(5.125 + SS) x 32 – SS  = 231.625
(5.125 x 32) + SSx32 – SS  = 231.625
164 + 32SS – SS = 231.625
Move this parts across the equals sign:
  32SS - SS = 231.625 – 164
31SS = 67.625
SS = 2.1814”       The value is between 2-1/8” and 2-3/16”

In this case, it is pretty close to your 2” desired gap.
But, say you had gone with exactly 2”, you would be off by a total of 5.625” at the end, and would have a final board that is ½” wide, or you trim the start and end boards by about half their width…  Not great results IMO.

So, make some spacers 2-3/16” in width and your last board’s width will be only a very minor adjustment.


FYI, if you want to start and end with spacing gaps:  then 2-1/16”

« Last Edit: January 10, 2011, 03:04 PM by Wood_Junkie »

Offline jonny round boy

  • Posts: 3227
Re: Math
« Reply #35 on: January 10, 2011, 03:24 PM »
I love that little game!

First time I tried it, got 4.24, in 126 seconds. Didn't realise the first time it was against the clock!

Just had a second attempt, got the following:

Your inaccuracy by category:
   
Parallelogram 10.0 4.5 8.0
Midpoint 7.8 7.1 2.8
Bisect angle 3.4 0.1 2.7
Triangle center 2.2 0.8 3.5
Circle center 3.2 3.2 5.0
Right angle 0.4 1.6 5.5
Convergence 8.2 3.2 3.2


Average error:   4.11   (lower is better)
Time taken:   98.5

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Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #36 on: January 10, 2011, 03:38 PM »
i use the iphone baluster app. works awesome

What's the app called?  Thank you



I need get a better score take my time abit every body is getting 4 lol I did itmto fast


Jmb
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Offline Ken Nagrod

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  • Posts: 3438
Re: Math
« Reply #37 on: January 10, 2011, 03:48 PM »
Here’s my approach.  I am usually simultaneously trying to figure out the spacing as well as how many boards I need.
I prefer to plan ahead to the end result, and make a spacer block that is properly determined, rather than just assume 2” is going to result in a nice width for the final boards.  You might start center out and discover that the final boards wind up extremely narrow.  That’d look weird!

For below, I assumed your start and stop points will be a fence board (not a gap).
The SS is deducted on the left side of the equation, because the last board doesn’t get a follow-on spacer.
If you want gaps at the start/end, then ADD the SS to the left side, instead of subtracting it.

First, add up the total lineal distance you need to cover. 
Your specs:  73", 2nd section 76 1/2", and the third is 82 1/8"  =  231.625” lineal distance


Add up the total of your fence boards + spacings and begin to calculate.
Tweak as necessary to arrive at the above figure.

Formula:  ((WW + SS) x YY)  – SS  = LD
WW = width
SS = spacing
YY = number of boards
LD = Lineal Distance

Use the desired approximate gap to solve once for YY, to get an approximate number of boards.
Then substitute YY with the lower integer.
Then re-solve for SS

Example:
Solve for YY:
(5.125” + 2” spacing) x YY number of boards  - 2”  = 231.625
7.125 x YY = 233.625       YY = 32.79 boards
Round this down to 32 boards if you want the spacing over 2”.   (You could also round up if you don’t mind having less than 2”).

Solve again, this time for the spacing SS:
(5.125 + SS) x 32 – SS  = 231.625
(5.125 x 32) + SSx32 – SS  = 231.625
164 + 32SS – SS = 231.625
Move this parts across the equals sign:
  32SS - SS = 231.625 – 164
31SS = 67.625
SS = 2.1814”       The value is between 2-1/8” and 2-3/16”

In this case, it is pretty close to your 2” desired gap.
But, say you had gone with exactly 2”, you would be off by a total of 5.625” at the end, and would have a final board that is ½” wide, or you trim the start and end boards by about half their width…  Not great results IMO.

So, make some spacers 2-3/16” in width and your last board’s width will be only a very minor adjustment.


FYI, if you want to start and end with spacing gaps:  then 2-1/16”



 [dead horse] [dead horse] [dead horse]

Please give us your address.  We are sending a team of FOG member carpenters over immediately to build the fence for you.  While you're waiting for us, please gather up a lot of cardboard since we are first going to sit down with a bunch of scissors when we arrive, make a test cut of the whole fence in cardboard then set up a dozen MFT's and start the production process.  Some members will be designated to do the scribing of the cardboard onto wood with crayons at the scribing station.  Another group will do the cutting at the cutting station.  We'll set up a routing station just for fun.  Last station will be the painters.  To keep costs down, you'll be doing the installation.

Please respond in a timely fashion as we are on standby for just such carpentry emergencies.

Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #38 on: January 10, 2011, 10:25 PM »
Nice, you guys are getting into the geometry game. Really good exercise. the purpose of this thread was to see how many different ways there are to approach this problem, and it looks like we're starting to to a variety of answers. No one's wrong it's just what works for you, and more importantly your clients.

on a side note regarding the geometry test, you guys should take a look at the fella's site who put that up, real interesting character.

http://woodgears.ca/

Offline jonny round boy

  • Posts: 3227
Re: Math
« Reply #39 on: January 11, 2011, 03:43 AM »
Wow, just had a look at the rest of the site. There's some really cool stuff on there, including a page dedicated to the original question of this thread.


Had a third attempt at the eyeball test too:

Your inaccuracy by category:
   
Parallelogram 4.1 5.7 11.4
Midpoint 1.0 3.6 0.0
Bisect angle 2.3 0.6 1.7
Triangle center 4.3 0.8 2.4
Circle center 2.8 5.0 2.8
Right angle 2.4 2.0 2.8
Convergence 1.0 2.0 1.0


Average error:   2.84   (lower is better)
Time taken:   93.9
Festoolian since February 2006

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Wish list (in no particular order!): Anything not listed above....

Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #40 on: January 11, 2011, 07:12 AM »
Ya I noticed that too, he's got his own solution, which I rather like .

Offline Wood_Junkie

  • Posts: 1313
Re: Math
« Reply #41 on: January 11, 2011, 12:34 PM »
[dead horse] [dead horse] [dead horse]
Please respond in a timely fashion as we are on standby for just such carpentry emergencies.

OK ok.. I'll take my tedious mental excercises processes and go back to my day job.   [scratch chin]
I think I over-exposed my math dork bits.   [embarassed]

Looking back I can see my post was perhaps too deep, and I apologize if it came across as condescending to anyone. 
But rather than just post a cryptic answer, hopefully some n00b doing a google search on how to do just this task might be successful for having a detailed walk through and seeing the process for deriving the two answers.

Anyway, I know Ken is giving me a ribbing.  [wink]

Offline mishle

  • Posts: 122
Re: Math
« Reply #42 on: January 11, 2011, 12:43 PM »
Wow, just had a look at the rest of the site. There's some really cool stuff on there, including a page dedicated to the original question of this thread.

This also really helped my with Sketchup to layout rails (etc). Thank you.

Offline Deansocial

  • Posts: 2114
Re: Math
« Reply #43 on: January 11, 2011, 01:47 PM »
   
 
Your inaccuracy by category:
Parallelogram   2.2   2.8   3.2
Midpoint   3.6   5.1   2.2
Bisect angle   1.0   5.7   0.5
Triangle center   11.6   12.5   19.3
Circle center   5.7   5.8   10.2
Right angle   2.8   1.8   3.3
Convergence   15.5   3.2   6.7
Average error:   5.94   (lower is better)
Time taken:   97.0

Offline Deansocial

  • Posts: 2114
Re: Math
« Reply #44 on: January 11, 2011, 01:54 PM »
   
 
Your inaccuracy by category:
Parallelogram   5.8   5.4   5.0
Midpoint   5.0   2.2   2.0
Bisect angle   3.6   1.1   0.9
Triangle center   3.9   1.7   1.7
Circle center   1.0   3.2   2.2
Right angle   3.9   3.8   1.7
Convergence   2.8   5.4   5.0
Average error:   3.20   (lower is better)
Time taken:   128.9

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #45 on: January 11, 2011, 02:14 PM »
   
 
Your inaccuracy by category:
Parallelogram   5.8   5.4   5.0
Midpoint   5.0   2.2   2.0
Bisect angle   3.6   1.1   0.9
Triangle center   3.9   1.7   1.7
Circle center   1.0   3.2   2.2
Right angle   3.9   3.8   1.7
Convergence   2.8   5.4   5.0
Average error:   3.20   (lower is better)
Time taken:   128.9

Cant help your self can u Dean!  Its trails bike and Doritos race all over again!   Oh I got further on trails last nite on transport I cant beat it its pretty hard!

JMB
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Offline Deansocial

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Re: Math
« Reply #46 on: January 11, 2011, 04:43 PM »
whata that jmb? 345m on skijump

Offline jmbfestool

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Re: Math
« Reply #47 on: January 12, 2011, 02:23 PM »
whata that jmb? 345m on skijump


Shut up! lol
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Offline Top Knot

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    • Top Knot
Re: Math
« Reply #48 on: January 12, 2011, 03:45 PM »
I noticed something I find really funny with all the scores that are coming in.
Everyone (for the most part) sucks at the parallelogram...
Graham Terrell
+27832412828

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #49 on: January 12, 2011, 04:23 PM »
I noticed something I find really funny with all the scores that are coming in.
Everyone (for the most part) sucks at the parallelogram...


I think that can be due to the screen resolution! As the guy who created the website says that if your resolutions is set different to what the monitor is the aspect ratio would be different and so example if you have two lines which are actually square on the system he has created  they do not appear square on your screen because the ratio has either stretched or squashed the image which distorts it and so it will be a lot harder for people to guess the angles and stuff!  

JMB
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Offline Top Knot

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Re: Math
« Reply #50 on: January 15, 2011, 01:50 AM »
I think that can be due to the screen resolution!

I tend to disagree... if your assumption was correct the same would apply to all the right angles too. All the right angles I have tried have all been in a random orientation, meaning, if your screen resolution settings were out then the same effect would apply to both right angles and parallelograms.
I actually think is a carpenters in ability to see and to accept things out of square or unbalanced  [cool] [big grin]
Graham Terrell
+27832412828

Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #51 on: January 15, 2011, 09:02 AM »
Back to mathematics, I'm currently studying for a trade test in the film union here. It's essentially a competency test in mathematics and layout and is mostly based on geometry skills, stair and rafter layout and is a timed test. While I wouldn't say I'm a super whiz when it comes to this stuff I actually do enjoy all the theory and practice of it all. Was wondering what everyone's, if you got any, fav math tricks were on the jobsite/workplace or do you just hate using math and try to avoid it as much as possible. As we all know theory and practice are two different things.

Offline Deansocial

  • Posts: 2114
Re: Math
« Reply #52 on: January 15, 2011, 09:32 AM »
I think that can be due to the screen resolution!

I tend to disagree... if your assumption was correct the same would apply to all the right angles too. All the right angles I have tried have all been in a random orientation, meaning, if your screen resolution settings were out then the same effect would apply to both right angles and parallelograms.
I actually think is a carpenters in ability to see and to accept things out of square or unbalanced  [cool] [big grin]

it tells you what to set it to on the site, its a 4;3 ratio apossed to the 16;9 we mostly have

Offline jonny round boy

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Re: Math
« Reply #53 on: January 15, 2011, 11:41 AM »
I think that can be due to the screen resolution!

I tend to disagree... if your assumption was correct the same would apply to all the right angles too. All the right angles I have tried have all been in a random orientation, meaning, if your screen resolution settings were out then the same effect would apply to both right angles and parallelograms.
I actually think is a carpenters in ability to see and to accept things out of square or unbalanced  [cool] [big grin]

it tells you what to set it to on the site, its a 4;3 ratio apossed to the 16;9 we mostly have

The guidance on screen resolutions is to do with right angles only. A parallelogram is just 2 sets of parallel lines. All you are doing in that test is setting lines parallel to ones that are already there. For this test, it doesn't matter if the screen is set wrongly.
Festoolian since February 2006

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Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #54 on: January 28, 2011, 07:51 AM »
Ok here's a new math problem for people. A cone with a base diameter of 2 1/2" has its top sliced off at a 45 degree incline 3/4" from the base. determine the elliptical shape of the hole and develop the surface shape for material to be wrapped around this structure.

NO SKETCHUP!!

Offline jonny round boy

  • Posts: 3227
Re: Math
« Reply #55 on: January 28, 2011, 07:57 AM »
Ok here's a new math problem for people. A cone with a base diameter of 2 1/2" has its top sliced off at a 45 degree incline 3/4" from the base. determine the elliptical shape of the hole and develop the surface shape for material to be wrapped around this structure.

NO SKETCHUP!!

What's the height of the cone?  [poke]
Festoolian since February 2006

TS55R EBQ saw - CTL26 - CTL Mini - OF1400EBQ router - KS120 Kapex SCMS - ETS150/3 sander - RO90 sander - DF500 Domino - PDC18/4 drill - PSC420 jigsaw - OFK500 trimmer

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Offline GhostFist

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Re: Math
« Reply #56 on: January 28, 2011, 08:20 AM »
Sorry, 3 inches

Offline jonny round boy

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Re: Math
« Reply #57 on: January 28, 2011, 08:30 AM »
NO SKETCHUP!!

darn......


How about AutoCAD? [big grin]
Festoolian since February 2006

TS55R EBQ saw - CTL26 - CTL Mini - OF1400EBQ router - KS120 Kapex SCMS - ETS150/3 sander - RO90 sander - DF500 Domino - PDC18/4 drill - PSC420 jigsaw - OFK500 trimmer

Wish list (in no particular order!): Anything not listed above....

Offline GhostFist

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Re: Math
« Reply #58 on: January 28, 2011, 08:36 AM »
NO! Compass straight edge and set squares only [big grin]

Offline jonny round boy

  • Posts: 3227
Re: Math
« Reply #59 on: January 28, 2011, 08:39 AM »
NO! Compass straight edge and set squares only [big grin]

Sorry, I don't live in the 18th century. [tongue]
Festoolian since February 2006

TS55R EBQ saw - CTL26 - CTL Mini - OF1400EBQ router - KS120 Kapex SCMS - ETS150/3 sander - RO90 sander - DF500 Domino - PDC18/4 drill - PSC420 jigsaw - OFK500 trimmer

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Offline Wim

  • Posts: 286
Re: Math
« Reply #60 on: January 28, 2011, 09:52 AM »
This I learned in the late 50s at my technical education in Holland. These are the basics of metal sheet lay-out. It can be done with a compass and a ruler. Maybe I can find something on the Internet.

I found something in Dutch, but the pictures are quite explanatory. The trick is to make the different views and find the points of intersection. In the end it is just connecting the dots.

http://www.zelfbouwbikes.nl/images/handige%20documentatie/uitslagen.pdf

Success.
« Last Edit: January 28, 2011, 10:02 AM by Wim »

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Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #61 on: January 28, 2011, 05:44 PM »
NO! Compass straight edge and set squares only [big grin]

Sorry, I don't live in the 18th century. [tongue]
[thumbs up]

Offline Wim

  • Posts: 286
Re: Math
« Reply #62 on: January 29, 2011, 02:06 PM »
Just be prepared for when the oil runs out. Then we will be back in the 18th century.  [eek]

Offline mastercabman

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Re: Math
« Reply #63 on: January 29, 2011, 04:47 PM »
Just be prepared for when the oil runs out. Then we will be back in the 18th century.  [eek]

NO I don't think so.We will have lithion battery powered car! [laughing]
I don't understand!?! I keep cutting it,and it's still too short!

Offline GhostFist

  • Posts: 1556
Re: Math
« Reply #64 on: January 29, 2011, 06:31 PM »
Just be prepared for when the oil runs out. Then we will be back in the 18th century.  [eek]

NO I don't think so.We will have lithion battery powered car! [laughing]
Just dont drive it in the winter

Offline jmbfestool

  • Posts: 6625
Re: Math
« Reply #65 on: January 29, 2011, 06:36 PM »
Just be prepared for when the oil runs out. Then we will be back in the 18th century.  [eek]

NO I don't think so.We will have lithion battery powered car! [laughing]
Just dont drive it in the winter


I'll make sure mine is well insulated so cold won't get to my batteries!

Jmb
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