The Swanson Speed Square is one of the most recognizable layout tools on a construction site, yet the booklet that ships with it—the Swanson Rafter Book—rarely gets the attention it deserves. Many DIYers and even some experienced carpenters treat it as a throwaway insert, reaching for a smartphone app or a construction calculator instead. That is a mistake, because the rafter book transforms an already dependable rafter square into a complete roof and stair layout system.
This guide delivers an exhaustive analysis of the Swanson rafter book, how it interacts with the speed square’s built-in rafter tables, and which speed square models pair with which book version. From the classic SWANSON S0101 7 Inch Speed Square, Blue to the Swanson Speed Square Pro 7-inch and the SWANSON SW1201K Value Pack, the right combination of square and reference guide will save measurable time on the layout deck.
TL;DR: The Short Answer
For readers in a hurry: the Swanson Rafter Book—often called the “Little Blue Book” on 7-inch models and the “Big Blue Book” on 12-inch models—is the compact reference manual that ships with most Swanson speed squares. It converts the rafter scales etched into the square’s body into full-length tables for common, hip, valley, and jack rafters, along with stair stringer formulas and polygonal layout data.
The table below summarizes every speed square featured in this article, including budget alternatives for DIYers who want the geometry at a lower entry cost. All units are current Amazon listings with verified buyer ratings and live pricing.
| Product | Key Features | Price | Rating | Buy Link |
|---|---|---|---|---|
 Swanson Speed Square Pro 7-inch |
Black embossed scales, pro-specific user guide, Made in USA | $14.98 | 4.8/5 (1,300+) | Buy at Amazon |
 SWANSON SW1201K Value Pack |
7-inch plus Big 12-inch squares, ships with Big Blue Book | $16.50 | 4.8/5 (10,200+) | Buy at Amazon |
 SWANSON S0101 7 Inch Speed Square, Blue |
Classic 7-inch aluminum square, includes Little Blue Book | $9.98 | 4.8/5 (17,200+) | Buy at Amazon |
 7 Inch Aluminum Rafter Square |
Double-sided engraved scales, budget price point | $5.99 | 4.6/5 (245+) | Buy at Amazon |
 Aluminum Alloy Rafter Square 7 Inch |
Laser-etched scales, multi-angle protractor, red finish | $7.99 | 5.0/5 (1) | Buy at Amazon |
What Is the Swanson Rafter Book?
The Swanson Rafter Book is the compact, spiral-bound reference manual bundled with Swanson Tool Company’s speed squares. Generations of carpenters call it the “Blue Book” because of its signature blue cover, and it answers a question many DIYers never think to ask: what do the numbers etched into the side of the speed square actually mean? The book breaks down every table on the tool, translating the line items into practical layout instructions for framing a roof or a set of stairs.
There are essentially two versions of the book. The Little Blue Book ships with the 7-inch square and covers common rafters, hip and valley rafters, jack rafters, stair stringers, and angle conversions. The Big Blue Book accompanies the larger 12-inch square, and it is also bundled with the SWANSON SW1201K Value Pack, which includes both the 7-inch and Big 12-inch squares in a single kit. The newer Swanson Speed Square Pro 7-inch takes a different approach, replacing the classic Blue Book with a pro-specific user guide focused on advanced roof-cutting workflows.
Understanding the Core Mechanics: Speed Square and Rafter Book Compatibility
A speed square is a right-angled triangle with a flange along one leg and a pivot point embossed on the hypotenuse. That pivot allows the tool to rotate through its degree scale, creating an adjustable protractor for cutting roof slopes, rafter tails, and stair stringers. The body of the square also carries a set of rafter tables that list calculated values for common rafters, hip and valley rafters, and sheathing angles. The Swanson Rafter Book functions as the extended instruction manual for these tables, explaining how each number is derived and how to apply it to a real cut.
Consider a simple 6/12 roof pitch. The common rafter table on the square tells you that each horizontal foot of run requires roughly 13.42 inches of rafter length. The rafter book does not simply repeat that number; it shows the full sequence—multiply the run by 13.42, account for the ridge board thickness, subtract or add the overhang, then mark both the plumb cut and the seat cut using the square’s degree scale. This step-by-step conversion from raw data to real cuts is exactly why the book matters.
Why the Book Is Not Just a Manual
The rafter book is often dismissed as a lightweight insert, but it is actually a carefully organized set of look-up tables built around the geometry of the speed square. Each page corresponds to a specific layout problem, such as finding the length of a common rafter, the angle of a hip roof jack, or the rise and run of a stair stringer. The book also includes corrections for ridge reduction and overhang, which are the exact details that lead to wasted lumber when they are overlooked.
Key Differences at a Glance: Little Blue Book vs Big Blue Book vs Pro Guide
Not all Swanson rafter books are identical, and choosing the right one depends on the size of your speed square and the complexity of your framing projects. The table below summarizes the three reference manuals and how they pair with the current Swanson lineup.
| Book Version | Ships With | Coverage | Best For |
|---|---|---|---|
| Little Blue Book | 7-inch Speed Square (S0101) | Common, hip, valley, jack rafters; stair stringers; basic angle conversions | DIYers, general carpenters, small roof repairs |
| Big Blue Book | Big 12-inch Square, SW1201K Value Pack | Expanded rafter tables, additional framing charts, larger scale data | Roofing professionals, heavy framing |
| Pro-Specific User Guide | Swanson Speed Square Pro 7-inch | Advanced rafter workflows, pro layout shortcuts | Trade professionals, experienced framers |
The Little Blue Book remains the most accessible entry point because it walks the reader through basic framing math without assuming prior knowledge. The Big Blue Book adds depth for larger roofs, while the Pro guide assumes the user already understands standard rafter layout and focuses on speed and precision.
How to Use the Rafter Book to Lay Out Common Rafters
Pairing the rafter book with a 7-inch speed square is straightforward once the underlying logic is clear. The following workflow mirrors the process used by professional framers and is drawn directly from the Blue Book’s common rafter tables.
- Step 1: Determine the roof pitch in inches of rise per foot of run. A 6/12 pitch, for example, means the roof rises 6 inches for every 12 inches of horizontal run.
- Step 2: Open the rafter book to the common rafter table and locate the row for your pitch. This row lists the rafter length per foot of run, which is the theoretical centerline length before adjustments.
- Step 3: Multiply the total run by the rafter length per foot to get the theoretical rafter length. For a 10-foot run at 6/12, multiply 10 by 13.42 inches to arrive at 134.2 inches.
- Step 4: Adjust for the ridge board. The book’s ridge reduction chart tells you to subtract half the ridge thickness from the theoretical length, ensuring the rafters seat properly against the ridge.
- Step 5: Mark the plumb cut using the speed square’s pivot point and degree scale. Rotate the square until the 6-inch pitch mark aligns with the board edge, then scribe the angle.
- Step 6: Mark the seat cut using the book’s birdsmouth diagram. The rafter book shows the correct depth of the birdsmouth relative to the rafter height, preventing the common mistake of cutting the seat notch too deep and weakening the rafter.
This sequence converts the abstract numbers on the square into a repeatable cutting routine. Once the first common rafter is correct, it becomes the pattern for the entire roof plane.
Hip, Valley, and Jack Rafters: The Rafter Book’s Hidden Power
Where the rafter book earns its keep is in hip, valley, and jack rafter layout. These members run diagonally to the common rafters, so their length per foot of run is different, and the angles at the top and bottom are compound cuts rather than simple plumb cuts. The speed square’s hip and valley table provides the length multiplier, but the rafter book supplies the complementary angles for cheek cuts and the shortening distances for jack rafters that seat against the hip.
Without the book, a DIYer cutting a hip roof is effectively guessing between a framing app and trial-and-error. With it, each rafter type becomes a predictable series of marks. The book explains, for instance, why a jack rafter must be shortened by a specific amount depending on its spacing from the hip, and it gives the exact angle for making the side cut with a circular saw. For irregular roofs where the hip does not bisect the corner angle, the book’s tables go beyond what the square’s fixed scales can express.
Stair Stringers and the Rafter Book
The rafter book’s stair stringer section is one of its most-used features. The table lists rise and run combinations for all common stair pitches, and the speed square makes the layout process almost mechanical. Set the square along the edge of a 2×12, align the rise on one leg and the run on the other, and scribe the first notch. Slide and repeat, checking total rise and overall run against the book’s guidance before cutting.
The book also covers headroom clearance and stair width requirements, which are the details that separate a code-compliant staircase from a frustrating one. For homeowners building a deck stair or a basement stair, this section alone justifies keeping the book close at hand. The speed square marks the notches quickly, but the book tells you whether the stair will actually pass inspection.
Matching the Rafter Book to the Right Speed Square Model
Choosing a speed square is largely a decision about which book and which scale layout come in the box. For the vast majority of users, the SWANSON S0101 7 Inch Speed Square, Blue is the sweet spot: it is affordable, accurate to within a fraction of a degree, and arrives with the Little Blue Book. Its 17,000-plus reviews make it the most battle-tested entry in the category.
| Product | Included Book | Scale Style | Price | Best For | Buy Link |
|---|---|---|---|---|---|
| Swanson Speed Square Pro 7-inch |
Pro-specific user guide | Black embossed scales | $14.98 | Advanced layout, high visibility | Buy at Amazon |
| SWANSON SW1201K Value Pack |
Big Blue Book | Standard embossed scales, two squares | $16.50 | Roofers needing 7-inch and Big 12-inch | Buy at Amazon |
| SWANSON S0101 7 Inch Speed Square, Blue |
Little Blue Book | Standard embossed scales | $9.98 | General carpentry, DIY projects | Buy at Amazon |
For professionals who routinely lay out both small and large framing members, the SWANSON SW1201K Value Pack delivers more value than buying a 7-inch and a 12-inch separately. The Big 12-inch square is ideal for marking wide stock and transferring long reference lines, and the included Big Blue Book expands on the data found in the pocket version. The Swanson Speed Square Pro 7-inch targets those who want the black embossed scales for high visibility in low light, plus a user guide written for experienced framers rather than beginners.
The Budget Alternatives: Do They Include a Rafter Book?
Homeowners on a tight budget often look past the Swanson brand entirely. The 7 Inch Aluminum Rafter Square, Double-Sided Engraved Scales and the Aluminum Alloy Rafter Square 7 Inch with Laser-Etched Scale deliver comparable geometry at a fraction of the price. However, neither ships with a dedicated Swanson-style rafter book, so the buyer loses the instructional layer that explains the etched tables.
| Product | Engraving Type | Rafter Book Included | Price | Rating | Buy Link |
|---|---|---|---|---|---|
| 7 Inch Aluminum Rafter Square |
Double-sided engraved scales | No | $5.99 | 4.6/5 (245+) | Buy at Amazon |
| Aluminum Alloy Rafter Square 7 Inch |
Laser-etched scales | No | $7.99 | 5.0/5 (1) | Buy at Amazon |
If you can interpret rafter tables on your own, these budget squares work fine for marking angles and reference lines. But serious roof framing still justifies the Swanson bundle, because the rafter book supplies the correction factors and compound-angle guidance that a bare square cannot communicate.
Expert Tips for Getting the Most Out of the Rafter Book
The rafter book is a durable reference, but a few habits will keep it functional and speed up your layout work.
- Laminate the book or cover it with clear tape so sawdust and moisture do not destroy the pages on a jobsite.
- Mark your most-used pitches on the cover with a permanent marker for instant access without flipping pages.
- Use the book’s ridge reduction chart even on simple gable roofs. Forgetting half the ridge thickness is the single most common framing error among DIYers.
- Cross-check the first rafter with a construction calculator. The book’s tables are exact, but checking the first cut before reproducing a pattern prevents waste across a full roof order.
- Keep the pivot point on the speed square clean. A burr or build-up of resin in the pivot will shift every angular mark by a noticeable margin over long cuts.
- Scribe with a sharp pencil or a marking knife. The book assumes precision marks, so a dull pencil introduces enough error to make a tight roof sheathing joint frustrating.
Common Mistakes to Avoid
Even experienced carpenters make avoidable errors when pairing the rafter book with a speed square. Awareness of the most common failures helps you catch them before the saw blade runs.
- Using the rafter table length as the final cut length. The tables give theoretical centerline length, not the finished length after ridge reduction and overhang adjustments.
- Applying the hip and valley table to jack rafters. Jack rafters have their own shortening ratios, and confusing the two tables produces rafters that land short or long.
- Setting the speed square to the wrong scale on the degree gauge. Pitch marks and degree marks are different reference systems, so aligning the wrong one creates angle errors of several degrees.
- Ignoring the overhang addition. The birdsmouth and tail cut need to be measured from the outside of the wall line, not from the theoretical rafter length.
- Skipping the stair rise check. The rafter book’s stair charts include total rise validation, which prevents landing on a ceiling slope or building steps that violate headroom clearance.
The Verdict: The Right Speed Square and Rafter Book Combo
After an exhaustive comparison of the Swanson catalog and budget alternatives, the practical recommendation is straightforward. For a weekend remodeler or DIY carpenter, the SWANSON S0101 7 Inch Speed Square, Blue with the Little Blue Book is the ultimate all-around purchase. Its low price, massive review base, and straightforward manual make it the default choice for general layout work.
For a professional roofer who wants the Big 12-inch layout capability alongside the compact 7-inch, the SWANSON SW1201K Value Pack is the better per-dollar value. Buyers who want the black embossed scale and pro-specific guide should choose the Swanson Speed Square Pro 7-inch, as its upgraded legibility pays off in low-light attic work and fast production framing.
The rafter book is not a promotional insert; it is a working manual that turns the speed square from a simple angle-marking tool into a complete roof framing system. Pair the right square with the right book, and the layout errors that plague amateur roof framing disappear. For those already invested in the Swanson ecosystem, the book is already in the box—take the time to read it, apply its tables, and the next roof project will move from guesswork to measured precision.