advice for a big try square

[AHill]

Look at Chappell framing squares. They are manufactured to good tolerances, won't rust, and they are Made in the USA. Shinwa is also good. Lee Valley sells Chappell squares. One advantage of a framing square vs. the Woodpecker square is all the cool data you have on a framing square. If you ever need to build stairs or do roofing or framing, it's invaluable.

[Ray Newman]

For those interested, Lee Valley has a framing square fence -- US $25.00 -- 

https://www.leevalley.com/en-us/shop/too...em=05N5401

Is Chappell still making squares? I periodically look on the sight sight about framing and other squares, but I do not see any squares listed or shown for sale.

[AHill]

For those interested, Lee Valley has a framing square fence -- US $25.00 -- 

https://www.leevalley.com/en-us/shop/too...em=05N5401

Is Chappell still making squares? I periodically look on the sight sight about framing and other squares, but I do not see any squares listed or shown for sale.

Link to Chappell Square:

https://www.leevalley.com/en-us/shop/too...em=60N4818

[Cooler]

You could start with a $5 framing square and turn it into a good tool for your purposes. Make sure the long leg of the square is straight and smooth then add a straight wood fence to the short side. Basically you are turning it into a large tri-square. you will have to cut a kerf in the wood fence as wide as the square is thick then figure a way to sturdily attach it. Use the make a line then flip and make another line method to align the fence. Maybe some epoxy in the kerf then a couple of brass rivets would work well for keeping the wood fence in place.
I found an article that basically does what I am trying to explain-     https://www.woodmagazine.com/woodworking...try-square

I would not cover the entire metal leg of the square as the article does. If you leave a little of the metal square edge sticking out on the inside it sits on the material. The square does not want to pivot down when not being held.

An easier method is to cut a long slot in the edge of 1½"  x 3/4" wood stock and then slip it over the short leg of the square.  A regular saw blade works fine.  I took two passes in opposite directions to the width I needed for my aluminum square.

If you hold the stock down to the table, the bottom of the slot will be parallel to both edges.  Then place it over the square's short leg and cross drill and install two screws. 

I used machine screws, but sheet metal screws would be fine.  I checked for squareness before drilling.  You can shim in the slot with paper strips if it is not square.  Regular printer paper is about 0.003" thick.  Mine did not require shimming. 

I did not calibrate the slot to the measuring scale, so that function was pretty much lost.

[BC in CT]

Drafting T-square would also work, very accurate and modestly priced.