Matt Jackson | September 03, 2018


YouTube // Framing

A Bajillion Carpentry Tips Using Basic Sawhorse Building as an Excuse

 

These simple, strong sawhorses incorporate many carpentry skills and structural lessons

 

Master carpenter Matt Jackson delivers a master class in carpentry basics by building a pair of super strong sawhorses, which he calls apprentice ponies. They are a great skill builder in these areas

  • Material selection
  • Marking, measuring, layout
  • Cutting
  • Assembly tasks

 

Other benefits of this design and process:

  • Incredibly strong and relatively lightweight
  • Made from standard 2x4s and plywood scrap
  • Sturdy configuration for stability and unencumbered workflow
  • Inexpensive, durable, and expendable
  • Ideal surface for company logo and branding!

 

Features:

  • Accurate cuts for tight-fitting parts that eliminate wobble
  • Legs cut at 12-degree angle for no-gap fit and practical footprint
  • Nipped foot minimize splintering
  • Screw type, placement, and driving with stress engineering in mind increases strength
  • Plywood gussets won't split
  • Subtle mortise in bottom rail makes a better fit for the legs
  • Attentive material selection eliminates weak spots in the wood

 

Materials:

  • Six straight 2x4s
  • A scrap of plywood for gussets
  • 20 #8 x 3-inch torx drive construction screws (I-beam)
  • 24 3 inch torx lag screws (legs to I-beam)
  • 16 #8 x 1-3/4 inch torx drive construction screws (gussets to legs)
  •  A scrap of sheathing, about 2 feet by 4 feet, for layout, measuring, and angles

 

Cut the I-beam parts

Choose three 2x4s and cut in half. Dimension lumber is longer than the length specified, which allows it to be cut in half for two four-foot pieces (in this case). Cut both ends for a clean surface rather than the rough sawmill-cut surface.

Select the two cleanest boards, those with the fewest knots, as the upright pieces of the I-beams. These boards carry the most weight, and fewer knots make the wood stronger. Mark centers on the ends of the I-beams. 

Center-marking tip (6:59)

Guesstimate the center point by placing the pencil roughly near the center and holding your finger as a fence against the 2x4, and then scribing the end.

Flip the board and remark the same distance. This illustrates how far off your guesstimate was and allows you to dial in the center quickly: put your pencil between the lines and mark it.

Notch the bottom flanges of the I-beam to add a significant amount of strength by increasing the contact surface area of the joints. Begin by drawing the I-beam to scale on the scrap sheathing, taking into consideration the height of the sawhorses, 32 inches in this case.

Tack a nail at the intersection of the I-beam's web and top flange. This nail will be a pivot point for a 2x4 to get an accurate scribe. Pivot a 2x4 from a wide angle toward vertical with a speed square pushed against it. When the angle on the speed square reads 12 degrees, scribe the edge of the 2x4 using a sharp pencil. Stand the 2x4 on edge and scribe the opposite side.

With the leg location lines drawn, draw beveled top (which is an extension of the bottom of the I-joist upper flange).

Stand the I-joist lower flange in its outline on the template and mark the beveled intersection. Use a sharp pencil.

Mark 4 inches and 7 inches from each end of the piece to indicate where each of the notches will be. Square the marks across the face of both bottom flanges.

Transfer the notch marks from the ends of the boards to the area within the notch location lines. Connect the location marks on the edges of the boards to complete the notch layout.

Cut a straight line between the mark on the bottom and the mark on the top using a pull saw. Cut the outside edges and then cut a series of identical kerfs between them. 

Knock some of the waste out with a sharp edge of a hammer and clean up with a sharp chisel.

 

Assemble the I-beam

Draw a center line along the top flange of the I-beam and mark screw locations at 3 inches from the end, the center, and between those screws. Pilot holes make the screw placement cleaner, and it reduces splintering when using splinter-prone wood, like hem-fir.

Line up the center lines that you marked earlier on the ends of the flanges and web and screw them together with #* 3-inch construction screws. Bury the heads about a quarter inch, or so so they are less likely to get hit with a saw blade.

 

Shape the legs

Bevel the top of a leg to 12 degrees and use the pattern to scribe the length. Each face will run long point to short point for the bevels.

Attach a temporary scrap to the end of this first leg and use it as a pattern with a fence to scribe the other seven legs to be identical lengths.

Nip the sharp angle off the edges of the bottom cuts to eliminate splintering later. A 33-degree cut will make a perfect 45-degree angle on the bottoms. Trim one edge and mark the throat plate of the miter saw to keep the bevel consistent between legs.

To bevel, the edges, too, line up the ends with a straight edge and clamp the legs together. Use a block plane to clean up the edges.

Slide the top of a leg into the beveled notch and mark three screw locations: at the top center of the leg and two screws placed 3/4 inch in from the edge to drive screws into the bottom flange. Self-tapping construction lag screws don't require drilling, but it sucks to split wood at this stage of the process, so Matt recommends pre-drilling the screw holes through the leg only.

Use the holes to mark locations on the remaining seven legs. Drill all of the holes.

 

Assemble the sawhorses

Insert a leg into the beveled notch in the I-beam, tight against the top flange, and drive the lag screws. Repeat the process with the second leg on the first side.

Flip the horse over and attach the legs. Assemble the second sawhorse.

Rip the gusset stock to four inches wide, and cut a 12-degree angle on one end. The simplest way to get an accurate pattern is to lay the sawhorse upside-down on a work surface and scribe the gusset. Cut a little extra off the length so that the ends of the gussets set back slightly from the corners of the legs. Use this as a pattern to cut the remaining three gussets.

Knock exposed edges down with a sanding block to reduce splintering later on.

Use a counter-sink bit to predrill holes in the gussets, centered on the legs and about 3/4 inch from the edges. Drive screws through the holes to complete the sawhorses.

 

(24:38) Matt brought the apprentice saw-ponies to his local lumber yard to see how much weight they could hold. It turns out, they can carry quite a bit—about 8 tons.

EIGHT TONS!

 

Tune in later when Matt builds a pair of journeyman saw horses with a splayed leg and tool shelf.

 

—Matt Jackson is a master carpenter, remodeler, SketchUp Wiz, YouTuber, and contributing editor to ProTradeCraft. He lives and works in Rapid City, South Dakota. 

 

Comments

My Dad was a custom home builder in the 60’s. He employed 10 full time carpenters. Whenever he hired a new carpenter, he asked the individual to build him 2 saw horses.  He had them make them using 1x4 for legs & top & bottom of the “I” for which he used a 2x4. He like the light weight horse and said that if a carpenter could build this type of saw horses he was not only a craftsman but understood many aspects of joinery. 

Great anecdote Doyle... thanks for posting it here.  Those were the days when a worker's resume was tangible, not subject to meaningless 'filler' and accolades. The potential employee didn't get to take the wood home and bring back finished sawhorses the next day.  Either you can build a pair of sawhorses or you can't.   They would have been built on site with the tools on hand.  An instant assessment of the quality of those little ponies told employers like your Dad everything they needed to know (and then some) to hire or pass on a prospect.

Best, Matt

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