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General Category => Brag Forum => Topic started by: EIEIO on August 17, 2014, 10:31:35 am

Title: Block Characters
Post by: EIEIO on August 17, 2014, 10:31:35 am
(https://lh4.googleusercontent.com/-UjOnHjSFYt0/U_C3wu6qtHI/AAAAAAAABm8/Rna5Hx40BGY/w1598-h700-no/BlockLetters.jpg)
A client wanted 7"x7" plaques that looked like wooden blocks. These are cut from a 1x8 (0.75 x 7.25) clear pine board. Border and lettering were done in Inkscape to get the proportions right. The outlines of the borders and the letters are cut with a #12 blade at 6 degrees. This gives a relief of about 3/16". Then sanded to break the sharp edges and glued back together.

For anyone that's interested, the blade angle can be estimated by:
inverse sin of angle = kerf/relief.
For #12, kerf = 0.020. For a 0.25" relief, angle = asin(.020/.250) = 4.6 degrees.
For my cut, relief = 0.020/sin(6) = 0.191" (about 3/16).
Title: Re: Block Characters
Post by: DWSudekum on August 17, 2014, 10:35:38 am
Thanks Ray.  That tip is a good one.  Thanks for sharing your signage with us.

DW
Title: Re: Block Characters
Post by: spirithorse on August 17, 2014, 11:39:24 pm
Very nice looking, Ray,
Thanks for sharing and God Bless! Spirithorse
Title: Re: Block Characters
Post by: Keefie on August 18, 2014, 01:33:14 am
great job there Ray, thanks for the little equasion, up till now I've always used the trial and error method on some scrap wood.
Title: Re: Block Characters
Post by: gordster on August 18, 2014, 06:42:24 am
Great idea and work..I do similar thing with address signs I have posted in gallery.letters, numbers and figures I cut around 4 degrees with table tilted to left and then cut counterclockwise. I stain the body and paint the letters. Then just spar varnish the body but not the letters as spar will turn them a little yellow..
Title: Re: Block Characters
Post by: frankorona on August 18, 2014, 07:38:24 am
Excellent work, looks great, thanks for sharing Ray.
Title: Re: Block Characters
Post by: pddesertrat on August 18, 2014, 09:31:56 am
Very nice looking!  I guess I don't understand the relief formula, will have to study that some more.
Title: Re: Block Characters
Post by: dunk on August 18, 2014, 10:44:10 am
Awesome.
Title: Re: Block Characters
Post by: EIEIO on August 18, 2014, 05:00:09 pm
Very nice looking!  I guess I don't understand the relief formula, will have to study that some more.
PD - if you scroll cut a shape (circle, square, letter, number, etc.) the kerf from the saw leaves a gap between the inside and outside pieces of wood. If the cut were vertical, the inside would fall straight through the outside. If you angle the cut then the inside piece can fall a little before it hits the outside piece. The amount it falls is what I called the relief. If you know the kerf (Mike's workshop lists blade thickness - about the same as the kerf in a straight cut) and the relief (how far you want the inside piece to drop) then you can calculate the angle to set the blade to for the cut. sin(angle) = kerf/relief, so angle = inverse sin(kerf/relief). You can get the inverse sin function on the Windows calculator  (Start/All Programs/Accessories/Calculator and set View to Scientific, then click on Degrees).

For a 6 degree angle, sin(6) = 0.105 = kerf/relief. From Mike's site, a #12 has a thickness of 0.020", So relief = 0.020/0.105 = 0.191".

If you know the relief you want to get and need to calculate the angle, then angle = inverse sin(kerf/relief). If you use a #12 (kerf=0.020") and want a relief of 1/8" (or 0.125") then the angle = inverse sin(0.020/0.125) = inverse sin(0.160) = 9.2 degrees.

The steeper the angle, the less the relief. The less angle, the greater the relief (until the inside part falls through the outside).
Title: Re: Block Characters
Post by: wildhorse on August 19, 2014, 01:43:59 pm
Great job on the cutting and thanks for the angle help. You actually can teach an old dog new tricks!!LOL
Title: Re: Block Characters
Post by: Marcellarius on August 21, 2014, 02:08:48 am
Great job Ray, and thanks for the extra explanation.
you teach well.
my 2 cents: for the inside of the 'A' = keep in mind to have your cutting way (counter/clockwise)  right ;)
Title: Re: Block Characters
Post by: wombatie on August 22, 2014, 02:21:41 am
Ray that is certainly a winner in more ways than one.  The main one being that that is my grandsons name as well  ;) :D  But apart from that they look great and thanks for the tips and info. on them.

Marg
Title: Re: Block Characters
Post by: Rover2 on August 23, 2014, 09:41:51 pm
Nice job Ray.
Al
Title: Re: Block Characters
Post by: smw on August 24, 2014, 02:47:24 pm
Nice work Ray