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Picture of Three-Legged Knock-Down Sawhorse
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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



 
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Step 1: Design

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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 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 1/16"). For the 2 legged end, I used that result and solved for the hypotenuse again which gave me 32.15391" (32 3/16). This number gives me the length of the compound mitered legs.

For a detailed blueprint, open the attached PDF.

Step 2: Lumber & Tools

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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. table saw. I've ripped down lumber with my circular saw, 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 saws 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 drill, a sharp set of drill bits and a few medium sized quick release bar clamps. A good hand saw and jigsaw or coping saw will also be handy. To measure, you will probably need a steel framing square, measuring tape and a woodworking protractor.

Step 3: A-Frame Leg

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 3/16" lengths of  2 x 4 stock. I made the first cut to establish the angle at one end, then measured the 32 3/16 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 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 3/32" on the end and 5 7/26" on the side to leave a smooth 5 1/4" 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.

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 cut a 15º bevel cut and cut the very end off the board to establish the first angle. I measured out 31 1/16" 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.

Step 5: Spine

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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.

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.

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 3/8" long and 1 3/4" 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, I used a jigsaw with the blade set to a 15° angle. I smoothed the hole with a handheld router and a 1/4" 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.

Step 8: Updated Finished Product

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Thanks ProfMuggs! I got them done.

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Copperace3 months ago

Sure glad I found this. I am looking for a set of legs for a very heavy Texas table my friend Cliff and I cut out of some 6' round table tops I found at auction real cheap. I think adding a foot or two of length should bring them up to "bar" height and still remain stable. And double as saw horses since I am tall.

The stability and knock-down ability are my two main considerations. I think you have saved my bacon!!! When I get my "roun-tuit" lined up I hope to post a photo or two. Thank you for taking the time for photos and write-up!!!

ProfMuggs (author)  Copperace3 months ago

Thanks, I'm glad you like it. If you are looking for a particular height, I recommend using the triangle calculator I linked to on step 3. It makes everything a lot easier.

I bookmarked the calculator and will be using it shortly! Again, thanks.

softbid9 months ago

The plan is great and so is the instructable. I will be making a pair of these this weekend. I do plan to screw a 2x4 across the top to add a clamping surface and a sacrificial strip for circular saw action :) Thanks !

ProfMuggs (author)  softbid9 months ago

Good idea! I have a few ideas for add-on pieces that could make these more useful, but unfortunately I haven't gotten to them. Please post pictures of your finished project?

Great plans! I made a pretty rough slot in the 2x8 leg so I used a scrap piece to make a platform for the top piece, which doubled a carrying handle.
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ProfMuggs (author)  syntheseiser9 months ago

Very nice! Sorry I missed this comment until now. Since I posted this I built a set for my friend and he was able to take them apart and fit them in the trunk of his car. I also moved and had to put them in storage for a while and the ability to take them apart really came in handy.

Hi,

Can someone enlighten me how to make the 15 degree cut on the mono leg with the coping saw. I am new to wood cutting, this is my first real project, so pardon my ignorance.

Thank you

ProfMuggs (author)  csnbharathi1 year ago

I didn't go into enough detail there. I actually used a circular saw to cut down the grain but stopped short of the end so I didn't overrun the bottom of the cuts. I started the cut on the acute angled side to prevent overrunning the bottom on the other side as well. I used the coping saw to follow the cuts I already started and end cleanly on the marks on both sides of the board. I then turned the the corner with the coping saw and followed the bottom edge on a15 degree bevel. I used a tool like a sliding T bevel to compare the angle I was cutting to a reference as I went.

I hope that helps.

Thank You! Yes it did help.

This project seems to be the most challenging among all, I learnt a lot when trying, still a long way to go. The pics you posted are really awesome and thanks for the detailed reply.

Do you have any other interesting plans for me to follow, do you have a blog that i could use?

Thanks again

svalkov11 year ago
Great design. One thing comes to my mind- why not make few more holes on the single leg- that way will be lighter to carry and wont lose lots of strength!
Damnatory1 year ago
Excellent instructable. Decided I needed a set of saw horses, so this was a perfect first project for my budding wood hobby. Super sturdy, and though mine aren't as nice as yours, they are actually sort of nice looking for saw horses.
ProfMuggs (author)  Damnatory1 year ago
Thanks a lot. Do you have any pics you can post?
Hawkeye_bkj2 years ago
I really like this style of saw horse. Thank you for posting it. I did have one idea, have a 2x4 laying flat screwed onto the top of the horizontal piece to use as a sacrificial board so you don't have to remake the cross piece.
paganwonder2 years ago
Good design. I tended to use plywood gussets on the legs to avoid splitting of 2X bracing. I also found nails have more lateral resiliency than self-threading screws (screws would break occasionally). That being said- I regularly loaded 'horses' of this design with 1500# of lumber...I don't necessarily recommend this practice! (it was production expediency and we took risks a sane person would not)
chipper352 years ago
Intelligent, simple (and, actually kinda nice looking!).......great project here!!
Very nice, thumbs up
buteomont4 years ago
Excellent idea. I'm going to make a couple.
cyprian9164 years ago
pretty good i bet you wish you had had a saw horse for this project though. ;)
Favourited, Voted, Five Stars, etc. An excellent project.
Hey Jim,
You got my vote...
Trade...
Thanks for the kind comments!
Phil B4 years ago
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.
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?
I'm sure it's a fine tool 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.