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Forum topic by woodklutz posted 08-05-2013 08:50 PM 726 views 0 times favorited 4 replies Add to Favorites Watch
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woodklutz

221 posts in 2236 days


08-05-2013 08:50 PM

I am trying to make a cutting board from 30degree cuts. Problem is this. Blanks measure 1 5/8 wide. I set my 30deg stop 1 5/8 from cut each successive cut follows with no deviation,1 side comes out 1/4 wider even though all is set true. What am I doing wrong? Sorry for the description being so fuzzy.
I am winding up with a rhomboid which I don’t want.

-- honing my craft one mistake at a time.


4 replies so far

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PurpLev

8523 posts in 3116 days


#1 posted 08-05-2013 08:57 PM

what is this “30 degree stop” that you are setting? are you setting up the blade at 30 degrees bevel? or are you setting a stop on your miter gauge which is set to 30 degrees from perpendicular to your blade?

a cut at 30 degrees (or a triangle with a 30 degree angle) will always have 2 legs which are of different lengths… if your cut was at 45 degrees, than you would get 2 legs of equal lengths.

maybe a picture would help others decipher what you refer to?

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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RogerM

764 posts in 1867 days


#2 posted 08-05-2013 10:09 PM

As already noted by PurpLev, the only triangle that will have equal legs is a one with two 45 degree angles and a 90 degree angle. Note that if you add up all angles in a triangle they will always equal 180 degrees. From this, a 30, 60, 90 degree triangle will have two legs and a hypotenuse (the longest side of a right triangle, opposite the right angle) that have the ratio of 1, 2 and the square root of 3 (1.732). That is, one leg will always be twice the length of the other and the hypotenuse will always be 1.732 times the shortest leg. Hope this helps.

-- Roger M, Aiken, SC

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PurpLev

8523 posts in 3116 days


#3 posted 08-05-2013 10:14 PM

...unless you are trying to use triangles which are 60 degrees angle on each corner – then you should have a triangle with all 3 legs being equal – but that is a 60 degree cut, and not 30.

edit: (sorry, been a looooong day).... or a triangle with 30/30/120 angles… in which case you’d have 2 equal legs…

so I go back to my initial question – what exactly are you setting up, and what are you trying to accomplish? a pic (or a link) is worth a 1000 words.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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woodklutz

221 posts in 2236 days


#4 posted 08-05-2013 11:33 PM

You guys are great, thanks for the wake up. Should have paid more attention in geometry.
THANK YOU ALL1111

-- honing my craft one mistake at a time.

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