Are you building a deck, fence, lean-to, or other structure and using 6x6s for support? Cutting posts with hand or power tools can be challenging and frustrating, especially if they’re already set in concrete. If you’re trying to figure out how to cut 6×6 posts so the tops are all level, or they all have the same angle, here are some helpful suggestions.
To cut a 6×6 post, measure the length and use a square and pencil to scribe a line, rotate the post 90°, and extend the line. Repeat until the cut line is on all faces. Use the lines to guide the saw as you cut through the post. A DIY jig is also helpful for accurate cuts.
In this article, we’ll explain how to cut 6×6 posts using different tools, and how to do straight and angle cuts, and notches. We’ll explain how to use a jig for consistent and accurate cuts and offer some safety tips too. Our goal is to provide you with useful information to help you complete your project.
How to Cut a 6×6 Post
There are different ways to accurately cut a 6×6 post. The more stable the post, the less vibration, and easier it is to accurately cut. Posts that can be cut to length prior to use are less challenging than those that are already set upright in concrete. Make sure the end of the post you are measuring from is square or level, if it isn’t cut square, you’ll need to fix it before cutting it to length.
To cut a 6×6 to length, lay it horizontally on a solid, preferably flat surface and at a height that is easy to work at. Measure the length and use a pencil or marker with a set square to scribe a straight cut line on one face. Roll the 6×6 and draw connected cut lines on the other 3 faces. The lines should intersect at the corners of the post, if they don’t, remeasure.
Having lines fully around the post makes it easier to keep your saw cut square, but it is important to keep the post from moving too. Clamp it or have a second set of hands hold it firmly in place. A 6×6 is 5-1/2” x 5-1/2” in actual dimensions, so the type of saw used determines how the cut is made. Some require the post or saw to be rotated from face to face, and others cut straight through from one face.
Pro Note: All cuts to pressure-treated lumber should be treated with wood preservatives to protect exposed wood. If posts are set in concrete, ensure the concrete has set for 48-hours or more, and use a stable ladder or base as a platform from which to cut.
Using a hand saw is an age-old way to cut wood. With the 6×6 resting and secure on a flat surface at a comfortable height, grip the post at the cut line with your free hand. Draw the saw along the line and begin your cut.
Use the lines on the sides to guide the saw as you cut. Depending on the surface you are cutting on, the post may need to be rolled to finish the through cut.
Using a circular saw necessitates the rolling of the 6×6 from one side to another and still requires a different saw to finish the cut. When set for the maximum depth, a 6-½” circular saw has a cut depth of 2-1/8” and a 7-1/4” blade saw will cut to a depth of 2-1/2”. That leaves between 1-1/4” and 1/2″ to finish with another saw type. There are larger circular saws on the market for purchase or to rent if you wish.
Set the circular saw for the maximum depth and align the blade with the scribed line. Use a rafter square as a guide for the saw base plate or shoe to keep the blade aligned with the cut – grip the 6×6 and the square to keep them secure.
Complete the first cut, rotate the post 90° and align the blade in the kerf of the previous cut, set the square in place as a guide, and complete the cut. Repeat for the remaining sides. Use a handsaw or reciprocating saw with a long blade held flush to the line side of the kerf to complete the cut.
With the cut line scribed on all four faces of the post, place the 6×6 tight to the fence, back gate, or featherboard. Make sure the post is properly supported at both ends to prevent binding and align the blade with the cut line. Hold or clamp the post, power up your miter saw, and make the cut as deep as possible.
A 10” miter saw will cut about 3” deep and a 12” miter 4” deep, so the post will need to be rotated. Lift and shut off the saw, rotate the 6×6 90° or 180°, hold flush with the fence, lower and align the blade with the kerf or line, and cut. Repeat until the cut is completed.
Many reciprocating saws use 6” blades, but there are blades up to 12” long which may be compatible with your saw. The thicker and longer the blade, the less flexible and straighter the cut. The blade should have 6 to 11 teeth per inch (TPI) for cutting wood and 12 to 18 TPI if you want a smoother finish. Reciprocating saws are available corded or battery-powered too, making them a versatile tool.
A reciprocating saw cuts in a knife-like manner through wood, except that only the blade moves back and forth not the handle. Draw the lines for the correct length on all 4 faces to guide the blade. The length of the blade determines if the post needs to be rotated. Clamp or have a second pair of hands hold the post firmly in place. Align the blade with the line and start out slowly by gently pulling the trigger.
Ensure the shoe or guide is tight to the wood and the blade stays flush with the line. As the blade cuts in, increase the speed-power with more trigger pressure. A longer thicker blade results in a more accurate cut. Many DIY and contractors also use a guide for a more accurate cut, and to minimize marking up the post by the shoe.
A chainsaw is commonly used to fell trees, so the step to level cutting posts with one isn’t too far-fetched. Scribe the line on each postface where the cut is to be, even though the post won’t need to be rotated. For accurate level cuts, a box-guide made of 2x4s and secured in place to the post is very helpful and prevents the bumper spikes or dogs from marring the post (depending on the orientation of the saw).
Two thin guides fastened to the chain bar which slides on the guides fastened to the post help make the cut smooth. Start the chainsaw, align it with the scribed line and guides, and slowly cut through the log. High revs make a neater cut but beware the upper portion of the 6×6 doesn’t hit you, especially if the post is standing upright.
How to Cut a 6×6 Post at an Angle
Cutting a 6×6 at an angle is similar to cutting it flat at 90°. Measure and mark the height to the base of the angle and to the top of the angle at opposite edges of one face. Connect the marks with a pencil or marker line using a straight edge.
Alternatively, measure to the top or bottom, and use a pivot square, speed square, angle square, protractor, square shooter, sliding T-bevel, bevel protractor, miter guide, or another device to set the desired angle.
Use a rafter square to transfer the lines to the high and low faces and rotate the post 180°. Use a straight edge to connect the high and low lines to form the angled line on the opposing face. Once the lines are complete, use a circular saw to cut the two angled lines, and finish the inside cut with a handsaw or one of the other saw options available.
To bevel cut the top of a post on all four sides for decorative purposes, determine the height or depth of the bevel from the top of the post. Scribe a line with a pencil or marker around the post at the desired location.
Set the angle of the cut and depth on a circular saw, align the blade with the line and keep the base plate or shoe tight to the post and cut. Move the saw from face to face or rotate the 6×6 until the four sides are beveled. A guide or jig is a helpful tool when beveling the top of posts.
How to Cut a Notch in a 6×6 Post
Notching 6x6s for beams or other purposes can be done in different ways and with a variety of tools. The depth, location, and the number of notches are also factors to consider. A notch at the end of a post can be accessed from the face and end, while a notch in the middle only from one surface.
Use a marker or pencil to draw the location and depth of the notch or notches on all sides of the post where applicable. Notches 2-1/2” deep or less can be done with a circular saw, while deeper notches can be completed with a handsaw, reciprocating saw, miter saw, or another option. End cuts can be completed with multiple kerfs and a chisel, or by rotating the post 90° and cutting along the back of the notch from the post end.
Notches in the midspan of a 6×6 can be cut out with multiple kerfs and a chisel – a lot of work if notching multiple posts for a double 2×12 beam. A hand or reciprocating saw works well for deeper cuts, while the reciprocating saw can also be used for cuts along the back. A 10” or 12” miter saw will speed up kerf cuts and can be set to exact depths with the stopper bolt.
Clamping multiple 6x6s together after marking can speed up the process. Use shims to align the top surfaces so they are flush and use the saw of choice to do the work. I’ve seen a beam cutter with a depth jig end-notch twelve 6×6 for a double 2×12 beam in a matter of minutes. It took much longer to set up than to cut, but the overall time was less than doing a couple of notches by hand.
6×6 Post Cutting Jig
There are numerous jigs available on the market and even more DIY plans online to choose from or create your own design for your saw of choice. One of the easiest is a 3-sided box jig made of 1-by stock or 3/4″ plywood that can slide onto or wrap around the post and be clamped or screwed into place. It can be used as a guide for a circular saw, reciprocating saw, handsaw, or even a chainsaw.
- cut 2 pieces of 1×6 or 3/4″ plywood into 6-1/4” in length
- cut a third piece 5-1/2” long
- place the 5-1/2” piece against a piece of 6×6 and lay a 6-1/4” piece on top of the 6×6 so it aligns with and overlaps the 5-1/2” board
- screw or nail the two together, ensuring they are flush and square
- roll the 6×6 with the two pieces and lay the other 6-1/4” section on top and align and fasten it to the other end of the 5-1/2” board – making sure all pieces are square and flush
- place the 3-sided box on the 6×6 to be cut, adjusting its location relevant to the cut line in relation to the saw being used
- clamp the open-end tight or screw the jug to prevent movement and saw away the excess
A more versatile jig uses pre-drilled or slotted galvanized angle iron or garage door bracing and some bolts and can be used for horizontal or angled cuts on 6×6 or 4×4 posts. It calls for four 8” to 12” long 1” wide flanged 0.074” thick slotted angle steel. The 8” handles a reciprocating saw and the 12” a handsaw.
- four 8” or 12” long 1” wide flanged 0.074” thick slotted angle steel
- two 8” x 1/4″ carriage bolts with washers and nuts (wingnuts work too)
- four 1” x 1/4″ hex head bolts
- 8 washers for spacers so the saw blade moves freely
- 8 locking washers
- 8 nuts for locking the 4 bolts
- Place two lengths together so they form an 8” or 12” long piece with a 2” wide face. You may need to drill 1/4” holes as close to the ends as possible if there aren’t any that line up there.
- Thread the 1” x 1/4″ bolt with a locking washer through the top piece as close to the end as possible. Slide 2 washers on and insert the bolt through the next steel piece. The two spacer washers should allow a saw or reciprocating blade between the steel pieces if they don’t add another washer. Place another locking washer on and twist and tighten one nut. Use the second nut to lock the first in place, so it can’t vibrate loose.
- Repeat with the other pair of angle iron lengths.
- Align the two sets of connected guides. You want the carriage bolts to thread through so the two pieces stay even. You may need to drill holes to match – one should be 1/2″ from the end, and the other 6” to 7” from the first.
- Thread the carriage bolts through both pieces, slide on the washer, and twist the nut into place until there is about 6” between the two saw guides.
- Hold the two steel guides apart and slide them over the end of the post until the saw opening aligns with the horizontal or angled pencil line. You may want to draw a line where the top of the jig goes so it is easier to see. Tighten the carriage bolts to prevent movement. You can also drive a couple of wood screws through other holes in the top angle iron into the piece being cut off to help secure the jig.
- Slide the 8” or longer reciprocating blade or handsaw between both guide slots and cut. Make sure to keep the shoe of the reciprocating saw tight to the jig.
- Once the cut is made, back the 2 nuts off, remove any screws if used, and remove the cut-off piece and jig.
Safety is always important when using power tools. Make sure to use the proper for the task and that it is in good working order, and you know how to use it. Eyes and ear protection are very important, as is a mask to keep dust out – a sneeze or face full of sawdust during a cut can be problematic. Gloves can be helpful, and so can a helmet – especially if the piece you’re cutting off extends above your head.
Use the appropriate blade for the task and make sure it is sharp. Ensure the power cord is well away from the blade, as are your fingers and other body parts. Don’t over-reach and always use a stable level base when cutting or for standing on when cutting. An extra minute spent clamping, securing, or stabilizing beats a trip to the emergency department.
Wear clothing appropriate for the job and keep strings, scarves, and loose ends away from saws – hoodie strings often appear in emergency reports. If cutting from a ladder or platform, your chest should be above the cut line to maximize saw control and safety. If cut-offs will fall, make sure children and pets are clear of the drop site too.
When cutting a 6×6, measure the length and mark it in the middle of one face or near both edges. Use a square with a pencil or a marker to scribe the cut line on the face. Rotate the post and use the square to transfer the line to the other faces.
Align the saw blade with the line and make the cut, or use a jig to guide the saw for the cut. Hopefully, you have a better idea of how to accurately and safely cut 6×6 posts for your project.