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Three-Legged Knock-Down Sawhorse by ProfMuggs on December 7, 2010

Table of Contents

Three-Legged Knock-Down Sawhorse ...... 1

Intro: Three-Legged Knock-Down Sawhorse ...... 2

Step 1: Design ...... 3

File Downloads ...... 5

Step 2: & ...... 5

Step 3: A-Frame Leg ...... 7

Step 4: Mono Leg ...... 10

Step 5: Spine ...... 13

Step 6: Finished Product ...... 14

Step 7: Update: Handle and Holds ...... 17

Step 8: Updated Finished Product ...... 20

Related Instructables ...... 21

Advertisements ...... 22

Comments ...... 22

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Intro: Three-Legged Knock-Down Sawhorse The more projects I make, the more I realize that my rickety old sawhorses are inadequate. I think that I am limited by the strength and sturdiness of these sawhorses and I feel like I am always compensating for them. Because these sawhorses are so unstable, I set out to make the most ideal and functional replacements I could.

Ideally, my new sawhorses would be extremely sturdy and collapsible. That way I could take it anywhere and easily put them out of the way in my small workshop. I have a reprint of a woodworking book from the 70's that showed a couple different designs for sawhorses. The one that interested me most was a 3 legged design that touted its sturdiness on uneven ground. My backyard is very uneven and I often have trouble setting up tables or my sawhorses. I reposition them again and again until they stop wobbling.

Unfortunately, the book only had a rough drawing of a 3-legged sawhorse. I looked around the internet but I didn't find any plans for a 3 legged sawhorse, so I had to design my own. I decided I wanted to make my design include knock-down legs, so they could be taken off for storage or transport. I used the following links as guides for the standard parts and adapted a traditional knock-down design to suit my needs.

Knock down Sawhorses The Richard Standard Knock-Down Sawhorse

Other designs 39 Free Sawhorse Plans

Update: 3 Legged Sawbench Design

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. These brackets no longer hold the legs straight in any direction. 2. Sometimes the 2' width of these sawhorses has been a problem for me.

Step 1: Design Most sawhorses have the legs set out at 15º for stability. I decided to make the A-Frame legs splayed out 15º, and make that frame and the mono-leg splayed out 15º from each other. The idea was to make this as stable as it could be while still being a 3 legged sawhorse.

To get the length of the legs, you can use these equations or you can just use this calculator . I knew I wanted to make the sawhorse 30" tall, and I knew all 3 angles of 1 the triangles (90º + 15º + 75º = 180º). For the single leg, I ran it through the calculator once and got a leg length of 31.05829"(31 /16 "). For the 2 legged end, I used that 3 result and solved for the hypotenuse again which gave me 32.15391" (32 /16 ). This number gives me the length of the compound mitered legs.

For a detailed blueprint, open the attached PDF.

Image Notes 1. Once I was done, I drew up some blueprints with more detail than the Instructable. If you want to see the full size original, download the PDF below.

Image Notes 1. 2" x 8" board. I decided not to taper the leg this way on the final design. 2. 2" x 6 " board 3. 2" x 4" board 4. 2" x 4" board 5. 2" x 4" board 6. 2" x 4" board 7. This is the final design I went with. It is simplified from my previous designs, but still has some tricky angles to cut. 8. 2" x 6" board

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. I was kinda making this up as I went along. I didn't know where I was going to put the braces for the A-Frame until I how much 2 x 4 stock I had left.

Image Notes 1. Shorter notch. 2. Taller notch. 3. This idea was to add a stowable bench dog on the ends of the spine. This way if I was using the horses on a hill like my backyard, I wouldn't have to worry about the work sliding off the side. One way the block would line up flush with the top of the spine, the other side would sit a half inch proud of the other board.

Image Notes 1. Originally the idea was to make it stackable as well. The notch would catch on the spine, the outer ledge on the single leg would catch on the inner ledge of http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ the double legs. 2. Stackable would have been nice, but more work than its worth since it comes apart easily. 3. I decided on 36" wide after I had been kicking around ideas for much wider horses. My last set was only 2' wide, so I figured I could use the extra space. I came to my senses when I realized there wasn't room for anything this large in my workshop. 4. This notch would have matched up with the top of the lower sawhorse if they were stacked.

Image Notes 1. I found this example in a book, but there were no measurements. Also, this is a saw bench, not a saw horse, so I decided to make my own.

File Downloads

3 Legged Sawhorse blueprint.pdf (405 KB) [NOTE: When saving, if you see .tmp as the file ext, rename it to '3 Legged Sawhorse blueprint.pdf'] Step 2: Lumber & Tools Lumber One problem I had with my last sawhorses was the wood getting bleached and brittle. When I made them, I didn't expect to use them outdoors as much as I did. This time around I am using pressure treated lumber so they will stand up to the weather if necessary.

The other main problem was the galvanized brackets that I used to put them together. They get bent over time and don't hold the wood tight. By using a knock-down design, I will eliminate these brackets.

I made everything from 2 inch pressure treated stock. Specifically, I used 2 x 6's for the spine, 2 x 4's for the 2 legged side, and 2 x 8's for the single leg side. I had a bunch of 2 x 6 lumber left over from an earlier project, so I only had to buy one 2 x 8. I ripped everything else down from the 2 x 6's. For the last pieces, the leg brackets, I just ripped down all the scrap pieces left over from the other steps to 2" x 2".

When you are measuring and designing something like this, it helps to be familiar with the actual thicknesses and widths of standard lumber sizes. Take a look at this page for more information.

Tools Because of all the angles involved in this design, I absolutely needed my Craftsman compound miter saw. I got this saw as a hand-me-down from my cousin, so I am not sure how old it is, but it still works great. The legs of the A-Frame leg in particular couldn't have been cut without a compound miter saw.

Because I was reusing 2 x 6 lumber and making 2 x 4's out of it, I needed my Craftsman 10 in. . I've ripped down lumber with my , and it is a big hassle to do any more than 1 or 2 boards. With the table saw, once the fence is set, I can repeat the same cut again and again with minimal effort. This was especially important to make the 2 x 2 leg brackets out of the scrap wood.

My older model compound miter saw doesn't have the slider feature that the newer like this one have. This means I can't cut anything wider than about 6" and less if its a miter cut. For these cuts I had to resort to my circular saw.

You will also need a good , a sharp set of drill bits and a few medium sized quick release bar clamps. A good hand saw and or coping saw will also be handy. To measure, you will probably need a steel framing square, measuring tape and a woodworking protractor.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. When I got this saw from my cousin, it was missing the dust bag. I use this one from my palm that fits, but fills up quickly.

Image Notes 1. Since I am making this out of pressure treated lumber, I chose to use exterior screws. I have also heard that the chemicals used to preserve pressure treated wood can break down other types of fasteners.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Step 3: A-Frame Leg 3 To start the A-Frame leg, I set the blade on my compound miter saw to 15º miter and 15º bevel. I then cut four 32 /16 " lengths of 2 x 4 stock. I made the first cut to 3 establish the angle at one end, then measured the 32 /16 inches and made the cut with the blade set at the same angle. All 4 legs can be cut with the blade set the same way and the legs can be flipped around to give you the opposite angles.

Next, measure out the plumb cut where the legs meet at the top. Since the legs are on a 15º angle, I wanted to get the most contact between the legs and spine for 3 strength. This required using the triangle calculator again to find the length of the edge that would form the groove for the spine. I made marks at 1 /32 " on the end and 7 1 5 /26 " on the side to leave a smooth 5 /4 " surface. For this cut I used my compound miter saw with no angle or bevel.

Next I clamped a scrap of 2 x 6 where the spine would go and attached the 2 cross pieces. The two cross pieces will have 15º angles on each side, slanting in at the top like an isosceles trapezoid . The top cross piece has a 15º bevel on the top edge to accept the spine.

Image Notes 1. All 4 legs (2 sawhorses) can be cut with the saw set to the same angle and bevel.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes Image Notes 1. No bevel or angle on this cut, just hold it tight against the fence. 1. Scrap of 2 x 6 representing the spine. 2. Plumb cut.

Image Notes Image Notes 1. The corresponding plumb cuts of the two legs with their mitered ends to 1. Legs elevated until the top is in line with the spine scrap. match the angle of the spine.

Image Notes 1. Two identical stretchers. 15" for each sawhorse.

Image Notes 1. I had one piece of 2 x 4 left that was 30" wide, so I cut it down to make two 15" pieces with the ends mitered to 15 degrees.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes Image Notes 1. Clamp a piece of cereal box cardboard in here or the joint will be too tight to 1. I lined everything up and clamped it to attach the lower stretcher first. slide the spine in.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes Image Notes 1. 2 x 4 ripped at a 15 degree bevel to match the spine that will lay on it. 15 1. In the finished product the spine will not stick out this far, but this was the best degree mitered ends. way to line up the tops of the legs with the spine and attach the top stretcher at the right height.

Step 4: Mono Leg I cut two legs at the same time, one for each horse. I had to use my circular saw because my compound miter saw can't cut boards wider than 6" or so. I set the saw to 1 cut a 15º bevel cut and cut the very end off the board to establish the first angle. I measured out 31 /16 " and made my next cut. I cut the next leg to the same length, making sure that the bevels on the ends were parallel to each other. You are looking for something like a long parallelogram , not a trapezoid .

To cut the notch in the top to fit the spine, I used a coping saw and a woodworking protractor to check the angle I was cutting. You could use a jigsaw, but mine recently broke and I have not replaced it with a better one .

Image Notes 1. 15 degree bevel.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. First cut to establish the 15 degree bevel.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. These two 2 x 8 board will be used for the single leg end. I beveled the ends at a 15 degree angle because it will be leaning at that angle. This way it will have a solid footing on the ground and will add stability to work laid on top of the horse.

Image Notes Image Notes 1. 15 degree bevel for the crosscut. 1. You can't see the trailing edge, but this is the 2 x 8 board that I crosscut on a 15 degree bevel. The trough of this cut will have to have that same angle.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes Image Notes 1. Coping saw held at a 15 degree angle. 1. I followed my lines with a circular saw on the leading edge side (as pictured). I 2. Woodworking protractor for checking the angle while cutting. finished the cuts with a hand saw that I held upside down (teeth up) while I checked the angle with a woodworking protractor. I finished the bottom cut with a coping saw while still checking the angle.

Step 5: Spine Until this point, I hadn't decided what I was going to do to make the brackets that the legs would slide into. I decided to take all the various scraps of 2" stock that I had and rip them down to 1.5" wide and thick on my table saw. I ended up with a lot of little pieces that were just barely long enough to use.

With these pieces of 2" x 2" (1.5" x 1.5"), I setup a stop block on my compound miter saw and mitered both ends of the blocks to 15º.

I aligned the lower edge of the outer bracket with the edge of the spine. This way the legs will be spread out as wide as possible for maximum stability. I alternated where the screws went on each side, so they wouldn't make contact with each other. Make sure you are attaching them on a 15º angle and that you are leaving 1.5" for the leg to slide into.

Image Notes Image Notes 1. 36" for the spine. 1. I took all of the scraps from all of the other steps and ripped them down to 2 x 2 (1.5" x 1.5"). These will be the braces for the legs.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. Stop block clamped at the right length saves you from having to measure every cut.

Image Notes 1. 15 degrees. 2. 15 degrees.

Step 6: Finished Product I really like the way this project turned out. I especially like the way the tops of the leg brackets make a little tabletop that you could rest tools on. If you were only using one sawhorse, you could use the tops of these leg joins to balance boards the long way down the spine.

This was a fun project for me. It was an excuse to get more familiar with features of my tools that I don't use very often and I think the sawhorses will come in very handy around my house.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. I like how the joints make this little tabletop on both ends.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. The new one is a foot longer, but they are both the same height. This way if I ever need to resurrect the old rickety sawhorses because I need more support, I can use them with the new ones.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Step 7: Update: Handle and Clamp Holds Handle After I used these sawhorses for a few projects, I noticed that there wasn't a good place to grip the mono-leg. To fix this I added a rounded cutout at the same height as the bottom edge of the top cross-piece on the A-frame leg. With this change, the sawhorse is easily movable.

I removed one mono leg and lined it up against the other A-frame. I drew a line marking the underside of the top cross piece. I decided that the best size for this hole was 3 3 3 /8 " long and 1 /4 " wide. I drilled 2 holes side by side with a 1 3/4" hole saw and I angled the drill 15° so your hand can get a good grip on it. To connect the 2 holes, 1 I used a jigsaw with the blade set to a 15° angle. I smoothed the hole with a handheld and a /4 " roundover bit with a guide bearing. This makes the hole very comfortable to hold.

Clamp Holds Because the spine was made of 2 x 6 lumber, most clamps are too small secure anything to the sawhorse. To fix this, I drilled 3 holes in the sides of the spine. This allows me to use average size clamps without any problem. Since the spine is 36" long, I put the first hole in the center, 18" from either side. The other 2 holes I put 10" from the ends to avoid the leg joints.

Image Notes 1. 1 3/4" hole saw. This one isn't deep enough to drill straight through the wood. I drilled the center hole straight through and completed cutting the hole from the other side.

Image Notes 1. I cut two holes next to each other with a hole saw. I held the drill at a 15 degree angle to match the bevel cuts on the top and bottom of the leg. I started each hole on the first side, then finished them from the other side. I cleaned up the hole with a jigsaw. I rounded the corner to make it a smooth handle with a 1/4" roundover bit.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Image Notes 1. Jigsaw on 15 degree bevel.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Step 8: Updated Finished Product

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Related Instructables

Portable and Perfect Shorty Saw Adjustable Sawhorse made DIY Ping Pong Sawhorses: Horse by Sawhorses from pallets by Table by adjustable and Strong, Light, ausable tablesawed mkaercher knock-down Quick-Build (Photos) by design by Sawhorse by briangrabski loftyduck clemensee

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/ Advertisements Comments

9 comments Add Comment

chipper35 says: Nov 15, 2012. 8:28 AM REPLY Intelligent, simple (and, actually kinda nice looking!)...... great project here!!

steliart says: Jan 31, 2011. 9:50 PM REPLY Very nice, thumbs up

buteomont says: Dec 25, 2010. 7:54 AM REPLY Excellent idea. I'm going to make a couple.

cyprian916 says: Dec 22, 2010. 10:30 PM REPLY pretty good i bet you wish you had had a saw horse for this project though. ;)

Dream Dragon says: Dec 21, 2010. 3:24 AM REPLY Favourited, Voted, Five Stars, etc. An excellent project.

Greasetattoo says: Dec 20, 2010. 3:08 PM REPLY Hey Jim, You got my vote... Trade... Thanks for the kind comments!

Phil B says: Dec 20, 2010. 5:43 AM REPLY Thank you. The three-legged design makes the sawhorse stable, even if the ground surface below rolls. This would be especially helpful when used on a lawn.

Dream Dragon says: Dec 20, 2010. 5:49 AM REPLY It would do, unlike a four legged one, or a table. You KNOW they're always going to have one leg adrift and start rocking.

For stacking them could you not switch them end for end so that the single leg falls between the double legs?

Dream Dragon says: Dec 20, 2010. 5:43 AM REPLY I'm sure it's a fine for sawing, but I can see possibilities beyond such mundane "work-a-day" uses. It seems like an eminently stable and useful structure for all kinds of furniture. Thank you for posting it.

http://www.instructables.com/id/Three-Legged-Knock-Down-Sawhorse/