Customer Reviews

Johnson Level & Tool RAS-1 7-Inch Aluminum Rafter Angle Square

5 star:		(11)
4 star:		(1)
3 star:		(0)
2 star:		(1)
1 star:		(1)

 

 

This is a solid and nicely weighted square. The markings are impressed into the metal and should always remain visible. This is a handy tool just for marking quick cross cuts. It also comes with an instruction manual explaining how to use the tool for measuring angles.

I got this as a combo with a tool tote. Never owned one and never would have thought of buying one. I was very impressed with the instruction manual that comes with this tool. It has very complete instructions on how to lay-out rafters, stairs or angled supports (like attaching solar panels to a roof). These are jobs that I previously would have laboured hours doing the layout or (more often) having someone else do them. Well worth the price! I can do stairs now!

The quality of this small rafter square is outstanding. No rough casting ridges, well designed, markings clear, beautiful finish, "beefer" metal than other squares I've seen. No issues! The accompanying book is useful for explaining the concepts for tool uses. If you're beyond a tool assortment of a 16 oz hammer, a couple of screwdrivers, a pair of pliers, and a 12 ft tape measure, you will find one of these a handy tool to have. Highly recommended.
Get this free with a Mcguire Nichols 22217 16" tool bag

i have owned one of these for years and it has never left my tool belt. it works great for all the specified uses but also makes a useful guide for your circular or jig saw when needed.

i would recomend one to anyone. i finally just ordered the 12" model. i hope it comes in handy just as much

If you plan on doing any serious carpentry, pass on this. The notches are aligned differently on both sides and measurements would only be approximate. At the current Amazon sale price (the second star), it would make a nice gift for your pre-teen child. Otherwise, don't bother.

I'm sure every framer already has one, too. I have at least 5 or 6 of these. I use the square as often in the garage working on projects as I do building walls, floors, general framing and construction. The angle square is a great all around, easy to use, quick tool that is always within my reach. The aluminum is lite weight, very durable and can easily survive falling from an 8th floor roof as proven my all three times I dropped it.

I'm writing a book on tools and I give the angle square kudos as one of the best tools ever invented (it was invented by Albert Swanson in 1925). Spend the money -- you won't be sorry. You can (or at least you could) download the manual from the Johnson website. Most of the manual is concerned with rafter construction, which won't be of use to most folks (you'll know when you need it).

The square is (probably) die cast from aluminum and is about 0.19 inches thick (i.e., slightly less than 5 mm). The short legs are 7.3" long and it is a 45-90-45 degree isosceles triangle. On one short leg, the material extends out of the plane of the square so that it can index on a straight edge and be used as a square. When you measure angles with the square, the angle you actually measure is the angle off the normal; this may confuse you a bit in the beginning, but you'll quickly get used to it. The edges of the square are milled to give you the accuracy you need. These things are made in high volumes at low cost.

Lemme give you some of the things I've learned from using my square over the last few decades. First, a weakness is that the graduations can be a bit hard to read. This is easy to fix, however: get some nail polish and fill the graduations. Then wipe off the excess with a rag with some acetone on it. I used black nail polish on one side and red on the other and it is eminently readable.

I've filed notches at 1.5", 3.5", and 5.5" on my scales with a triangular file. This lets me scribe those dimensions quickly parallel to the edge of a board. These are, respectively, the thickness of "2 by" material in the US, the width of a 2x4, and the width of a 2x6.

One thing I discovered is that you can hang the square from a nail using the internal triangular cutout and the hypotenuse will be nearly level. This appears to be a conscious design decision by Johnson; I don't know if the other squares on the market behave the same way. But it makes for a handy level when nothing else is available.

The other thing that took me a little while to realize is that you're carrying a table of tangents around with you when you have this square, although you'll have to do a bit of arithmetic. The common top cut scale is 12 times the tangent of the angle. To read off a tangent, use a straightedge to line up the angle on the angle scale and the pivot, then read off 12 times the tangent on the common top cut scale. Example: 12 times the tangent of 45 degrees is 12.

The hip-val top cut scale is the same as the common top cut scale except the value is multiplied by the square root of 2. This gives you a low-resolution nomograph to multiply and divide numbers by the square root of 2. This is a common task when you need the diagonal of a square, given the length of the side. To multiply a number by the square root of 2, put a straightedge against the pivot and the number on the common top cut scale. Read the number times the square root of 2 on the hip-val top cut scale. Example: 10 times the square root of 2 is 14.1.

By far the most common uses I make of this square are:

1. Mark cross cuts on 2 by material.
2. Measure angles.
3. Guide my circular saw when cutting off.

I occasionally use it as a square, too. :^)

If you're guiding a saw when cutting off, use a clamp to clamp the square to the board if you're not cutting off at 90 degrees; otherwise, it's too easy to have the square move on you.

I just cut off a bunch of boards in making a fence, so let me indicate how I used the square for this. I had to measure the required length of each board (the ground wasn't flat) to have the tops all parallel. I put the fence board to be cut on my sawhorse, then used the tape measure to mark the cut-off point. An old carpenter taught me to make my marks as a vee with the pencil; the apex of the vee marks the measurement. The reason for this is that the vee is easier to spot later than a short line. Put the saw on the board and align the point on the saw shoe where it will cut with the apex of the vee. Then bring the angle square up to the edge of the shoe and lock it in place with your hand. Then make the cut -- it's perfectly square. It goes so quickly that it takes much more time to explain than to do.

If you have to repeatedly mark a bunch of stock at the same angle, you can make a "poor man's stair gauge fixture" by using a 5/16" bolt through the slot. To be foolproof, it should have a cylinder (e.g., a stack of washers) to index from rather than the hex nut or head. However, if you're going to do such marking, I recommend instead that you make up a simple fixture from a chunk of scrap plywood. The same applies if you have to mark a bunch of bird mouth cuts or stair cuts.

This is one of the most used tools in my toolbox. If you don't have one get one you will be amazed at all the little places you can use it.

I dont do much roof framing, but for cutting studs square or on the 45, these are great for running your circular saw base against to make a straight cut. The aluminium version is very sturdy and doesn't rust!

youll love to have this tool in your workshop as there are many uses for it.