Woodworker's Journal summer-2009, страница 56

Woodworker

To make a 2" wide cove that is 3/8" deep, use a fence angle of 31.75:

Understanding Plywood Labels

Product Standard:

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Agency . Gradestamp

Exposure Durability Classification

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lf| weather g

Panel Grade

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BBS "■"'n.

EXPOSURE 1

SHEATHING SPAN*

Nominal Panel Thickness "»

Performance Rated Panel ~~ Standard

C - D

15/32 INCH

32/16 RATING-— ________

Span Rating

MANUFACTURER'S NAME

- MILL NO.

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Here's a key to "reading" plywood.

Here's a key to "reading" plywood.

Seems like they could [produce 3/4"] with the same tolerances they use to produce the 23/32" stuff. Of course, they would be giving us more material and the cost would probably go up proportionally.

Walt Schubert Hobart, Oklahoma

Back in the 1950s, '60s and '70s, you could get 3/4" plywood that was indeed 3/4" thick. Nowadays, there is no longer any respect for the width and length, let alone squareness.

Like a lot of other businesses today, the MBAs rule the roost. It costs too much to maintain the old standards. Turn out a cheaper product, and to hell with the customer. If the plywood producers of old could maintain the standards, with their technology, it would not be hard to do the same today!

D.G. Towers Ormond Beach, Florida

Fun with Formulas: Woodworking with Microsoft® Excel

There is more than one method to accomplish almost any woodworking task. When I began my cove cutting quest, my first thought was that all I would need was an easy way to calculate the fence angles which would accommodate my various cove requirements. After some head scratching and reviewing some — by now — very old math books, I came up with an equation.

I then turned to my trusty computer, equipped with a spreadsheet program, for help.

I entered the following formula into cell C2 of an Excel spreadsheet (see chart):

=ASIN(B2/(2*SQRT(25-((5-A2)A2))))*180/3.14159

When you enter the depth of the cove into cell A2 and the width into B2, the correct fence angle magically appears in cell C2.

While this fence angle is just the beginning of the process, it is a very good start!

Len Urban is a woodworker from Rancho Mirage, California.

If you receive a "MUM!" error in the fence angle cell... you've entered data that does not allow for a fence angle that will cut a cove. Adjust one or both ofyour dimensions.

r 15 253afl92595 13 262687210a 10 9123659270 9 5940763306

23 2517133839

1 20 128323283a

j 16 3437639600 ' 144775244146

I 31 ''599611836

I 27 3117529933 j 22 3126407964 1 '947123708,,

I 41 1433766223 34 9974345170 26 3319660940 24.6243391515 521427784759 43 4915560806 -347150332765

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summer 2009 61