How to make an angle?

[Zhent]

Hi everyone,

In between working on my first workbench, I am trying to make a sawbench along the lines of Chris Shwarz. I am doing my best to follow the design shown here: Lost Arts Press Sawbench

The PDF drawings do a pretty good job of explaining all the dimensions I need for the bench, however I am stuck on making the 10* angle for the legs. Without something to replicate, how do I approach the correct angle? I'm not worried about getting 10 vs 11, however I could certainly see it lose stability if I eyeballed it around 10 and ended up closer to 15 or 20?

Thanks!

[Rob Young]

Hi everyone,

In between working on my first workbench, I am trying to make a sawbench along the lines of Chris Shwarz. I am doing my best to follow the design shown here: Lost Arts Press Sawbench

The PDF drawings do a pretty good job of explaining all the dimensions I need for the bench, however I am stuck on making the 10* angle for the legs. Without something to replicate, how do I approach the correct angle? I'm not worried about getting 10 vs 11, however I could certainly see it lose stability if I eyeballed it around 10 and ended up closer to 15 or 20?

Thanks!

Use a speed square.  Draw a line from the edge of some wood and then set a bevel gauge.

Use a protractor.  Draw a line from the edge of some wood and then set a bevel gauge.

Use a framing square and rise:run table.  Draw a line from the edge of some wood and then set a bevel gauge.

Get a free CAD program for your PC.  Make a 10* angle, print it and set a bevel gauge to that angle.

Borrow a miter gauge from a table saw or band saw.  Use it to draw a line from the edge of some wood and then set a bevel gauge.

Copy the angle from a tilted blade on a table saw.

Guess at what 10* looks like.  Draw a line from the edge of some wood and then set a bevel gauge.

[Rob Young]

PDF of a 10* angle attached.

1" scale lines provided for confirming it is printing 1:1

[Steve N]

Rob's idea for the PDF image, and cut and trace certainly will work, but I find one of these an absolute must have in the shop if you ever do anything with an angle. Jump in at your level of comfortable expenditure, all of them work well


I haven't read the book, and can only guess the 10* is what Schwarz suggested as an angle on a DT locking joint. 10*, 11, 14, 16 just don'r get too steep and you will be good to go. As long as it won't just pull out is what you are looking for, so you could make an arbitrary 12.6* and use that on a wedge of scrap wood, and trace it onto your part, and you will have done well. I prefer 14*, others prefer other angles.

[Zhent]

Thanks! A speed square looks incredibly useful, I'm definitely going to pick one of those up.

[joe1086]

If you don't have a bevel gauge (or T-bevel) you might want to get one of those too. Even Lowes or HD should have them for $5-10.

[Rob Young]

Rob's idea for the PDF image, and cut and trace certainly will work, but I find one of these an absolute must have in the shop if you ever do anything with an angle. Jump in at your level of comfortable expenditure, all of them work well


I haven't read the book, and can only guess the 10* is what Schwarz suggested as an angle on a DT locking joint. 10*, 11, 14, 16  just don'r get too steep and you will be good to go. As long as it won't just pull out is what you are looking for, so you could make an arbitrary 12.6* and use that on a wedge of scrap wood, and trace it onto your part, and you will have done well. I prefer 14*, others prefer other angles.

Its the splay angle of the legs, set into notches.  The notches are square to the top but the legs have an angled rabbet.

[Rob Young]

Zhent pid='7423210' dateline='1485533941']Thanks! A speed square looks incredibly useful, I'm definitely going to pick one of those up.

And get a bevel gauge (or 6) of some kind.  Small ones, 4" beam or less, as well as larger ones, 9" beam are very handy to have around.  All kinds of different locking mechanism.

Cheap plastic body ones work.  Expensive machinist quality ones work.  Home made ones work.  

You can also make quickie ones using index card stock folded to the angle.  The flap folded over acts as a fence and the card stock is thick enough to get a few angles penciled on before it becomes buggered up.  May not be as precise as a metal beam design, but works in a pinch.

[attachment=1111]
[attachment=1112]

[Cooler]

Using an on line triangle calculator I got these numbers.  It should be enough for your to  make a full size drawing to use as a guide.  You can check my calculations.  http://www.calculator.net/triangle-calculator.html

You will need to enter one side (19.25") and the three angles which are 10º; 90º and 80º.  The total of the three angles has to add up to 180º.  We know the 10 degree angle, and we are constructing he 90º, so the final angle has to be 80º.  Once you have that you only need to enter the three angles and the one side dimension and the calculator will do the math.

[Rob Young]

For a right triangle

tan(phi) = opposite / adjacent

(use the degrees mode on the calculator, not radians to tap this out for yourself)

tan(10) = x / 10   <- picked 10" as the "long" side looking into the right angle.  An arbitrary choice.

x / 10 = 0.176 

x = 1.76"  call it 1.75" (hey, guessed pretty good with the 10") and be happy.  That makes the angle phi about 9.9*