Introduction: Ultra Precise Miter Sled for Table Saws
Making picture frames is a fun way to get into woodworking as they are very expensive to have custom made. That being said, if you want to make lots of them, or if you want to sell the frames yourself, making a jig is essential. I recently had a client ask me to make 4 frames and that was enough of an inspiration to make this jig. Because this jig slides on top of your table saw, it is also referred to as a table saw sled, in case you were wondering!
Beyond making perfect 45° cuts (as shown in the picture), there are two things that make this jig great. The first is that you can cut the miters either before or after cutting a rabbit (rebate) out. The second is that you can make repeatable cuts of the same dimension over and over again using the 45° stop block.
In this post I will show you how I made this sled, which is inspired by Fine Woodworking Magazine (here is their video: https://www.finewoodworking.com/2012/08/07/special...) and by David Piccuito of Make Something, who made an instructables post in 2015 https://www.instructables.com/id/How-to-Make-a-Pic... I believe that changes I have made to the design (cut out of the back, extension wing and clear top on the stop block) make the miter sled even easier and more fun to use.
Don't forget to check out the video above and if you have any questions, please feel free to ask them in the comments below.
Below are links to tools and materials I used in this article. It is either the exact tool/supply or something very close.
Plywood in three thicknesses: 3/4", 1/4" and 1/8"
Hardwood for runners (size this up on your table saw but generally you will need something at least 1/2” thick and 1” wide)
If you don’t want to fuss with making some runners you can also buy the ZeroPlay Miter Bars from MicroJig
Dimes (or washers)
Some kind of weight (I used a brake rotor)
Digital caliper or other precise measuring gauge
Machine screws and nuts
Note: The links above are affiliate links, meaning, at no additional cost to you, I may earn a commission if you click through and make a purchase.
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Step 1: Cutting the Plywood for the Base
I went to my local home depot and picked up a 24"x48" panel of 19mm(3/4") Baltic Birch Plywood.
I first cut it to 15" wide using my table saw.
I then measured 36" on the long side and cut it to length using my circular saw. A quick tip I picked up recently was to use my speed square as a fence to ensure that my circular saw stays straight.
If I were to to this again, instead of cutting it to length, I would have cut out the optional extension wing seen in the sketch up drawing.
Also, at this point it would have been a good idea to cut out the back portion (also seen in the sketch up drawing), but I didn't realize the sled would be so tippy when I built it, so I ended up cutting it later.
Step 2: Making Hardwood Runners
If you are like me and you keep every single piece of scrap wood no matter what the size, you are in luck! Now is a time to use some of those thing scraps of wood you have laying around.
I grabbed some cherry that was approximately 1/2" thick. I set up the fence on my table saw to be a bit wider than the slots of my table saw. I micro-adjusted the fence (read: tapped it gently) and cut the strip of wood. I then tested it in the slot. If it fit I was done (but of course it didn't fit on the first try). I then repeated this (gentle tap, cut, try) until it slid in nicely.
It is really important to use hardwood (vs. softwood) for these runners. Hardwoods will resist changing size more than softwoods and they are less likely to have residual sap.
If you are not like me, and don't have any scrap wood, you can always purchase the ZeroPlay Miter Bars from MicroJig
Step 3: Prepare for Glue-up
I had to rummage through my pockets and try to come up with some spare change. I found some dimes, but if you happen to be in the USA, they still have pennies, so that could work too. Basically what you are looking for is something to raise the height of your runners so they will contact the sled base. You could find some washers as long as they fit in your table saw slots.
I stacked them up the slot so that the runner will be just protruding over the table top.
I then set the fence about 15" from the blade (adjust as required) and clamped my speed square to the fence. This will allow me to line up the sled base at exactly 45° from the blade.
Step 4: Glue the Runners to the Base
I put the runners on top of the stacked dimes and added some glue.
I made sure the weight (brake rotor) I was going to use was handy, and then placed the sled base on the table top. It is really important to ensure that the base is lined up with the speed square and that the blade lines up with the corner of the base.
If you ended up using the pattern from the first step to cut out the extension wing, just make a mark at 36" and line up the blade with that mark.
You will see in the picture that I had runners that were sticking out of the slot. I suggest cutting them so that they don't hang over as there is no way to ensure that they stay parallel with the slots. (which then causes complications later, but don't ask me how I know)
Step 5: Flush-cutting, Waxing and Testing the Base
After waiting overnight for the glue to set, I grabbed the base and checked out the runners. Everything looked good, so I collected my dimes. This is an important step, as you don't want to loose money on this project!
I then used my flush cut saw to cut off any of the protruding runner from the base.
I added some paste wax to the bottom of the sled. While this is technically an optional step, I really feel like it is one that needs to be done as it makes the sled glide so much nicer.
Then the make it or break it moment. I raised the blade of my table saw and pushed the sled through. I used my speed square to verify that it was perfectly set up. If for some reason it didn't work out, this is a perfect time to go back to step one and start again.
Step 6: Secure the Runners
Now that everything checks out, I have to securely attach the runners. As much as I like glue, I like to sometimes add screws for that extra level of assurance that things won't move.
I first pre-drilled some holes. You can see in the picture that I used a piece of masking tape to act as a depth gauge.
Then I countersunk the holes and added screws. Make sure your screws aren't going to be too long. In my case I used 1" screws.
Step 7: Cut the Ruler
I first marked the ruler on a 45° angle right at the tip. I then set my mitre saw to 45° and cut the tip of the ruler off.
I also cut the last 11" off (so I made a cut at the 37" mark), also at 45° as this extra piece will be used on the short side of the jig.
I then cut the end straight (90°) of the long piece of the ruler.
Step 8: Cut the Support for the Ruler
I used some 1/4" plywood that I had laying around to make the supports. Anything up to 1/2" would work, as long as you have enough to make supports for the ruler and a scrap piece to make the stop block.
I set the fence on my table saw to 1 1/2" and ran the plywood through. I ended up cutting 48" of material, but I could have gotten away with a bit less.
I then made a small piece approximately 2"x6" this will be used to make the stop block.
Step 9: Attach the Supports to the Base
First I marked a line that was 3 1/2" from the two edges. It is really important to get this lined up correctly, so I used my digital calipers.
I then used the ruler as a straight edge and marked the line with a pencil.
I added double sided carpet tape to the bottom of the supports and placed the support down on the line. It is crucial to line this up perfectly. Luckily double sided tape is cheap, so if at first you don't succeed, try, try again!
Step 10: Attaching the Ruler
I added double sided tape to the bottom of the ruler and placed it on top of the support. I made sure to align the 45 degree cut with the blade and the back of the ruler with the back of the support. If everything was done correctly to this point, the
I did the same on the short edge and you will notice that the ruler is flipped around. This side won't need measurements.
I then drilled, countersunk and screwed the ruler to the sled.
Note: If you have a sawstop or other similar blade stopping saw, make sure you either use a wooden ruler or cut extra material off the end of the ruler to ensure the metal does not contact the blade. Metal contacting the blade will result in the brake being applied and I have been told that it isn't a fun experience!
Step 11: Cutting the Back Off the Sled
If you watch the video (at the top of the screen) you will see that the sled ended up being a bit back heavy and tippy before I made this modification. I drew a line between the two supports. (I had to use an offcut of plywood to draw the line as someone had cut up and screwed down my ruler) I then plunge cut with my circular saw and finished up the cut with a hand saw.
It would have been much easier to cut this out before hand!
Step 12: Making the Stop Block - Part 1 - the Bottom
This is the part where I will use that 2"x6" piece of 1/4" plywood from earlier. (don't worry that mine is bigger than 6" in the picture, I cut it down after this shot)
I placed it under the ruler and drew a line. I then took it over to the sander and sanded off a bit of material. I wanted to make sure that it would slide easily under the ruler.
Once that was done, I redrew the line for the next step.
Step 13: Making the Stop Block - Part 1 - the Middle
I found some plywood that was the same thickness as the ruler (in my case it was part of a hollow core door #HollowCoreDoorsAreTheNewPallets)
I cut a piece out that would fit on the bottom of the stop block and then glued it in place.
Step 14: Making the Stop Block - Part 1 - the Top
I had a scrap piece of acrylic that was approximately 2"x6". It was a cut off from a frame I had made. As acrylic is very difficult to adhere to anything, I just used double sided tape to attach it to the rest of the stop block. It will be screwed together in the next step, so it won't be going anywhere!
You will notice that the way this is designed that it now has a slot in it that is the same thickness as the ruler. This makes it so that it can slide up and down the ruler.
Step 15: Making the Stop Block - Part 1 - Assembly
I grabbed my toggle clamps and marked out the location of the holes using a sharpie. I then drilled the holes big enough so that some 8/32 screws would slide in it. I then headed over to the drill press and used a 1/4" forstner bit to drill some recesses for the screws in the bottom of the stop block.
I then turned the stop block over and lined it up against the ruler to make a 45° cut. I turned it over to have less chipping on the acrylic as the sled would act as a zero clearance plate and the cut would be much cleaner.
I pushed the screws through the holes and added the toggle clamps and some nuts. I tightened everything down snugly, but not to tight. If you are worried about this coming apart, you can add some locktite, or locking nuts.
I then slid the stop block along the ruler and adjusted the toggle clamp until it secured the stop block from moving.
Step 16: Enjoy and Make Some Picture Frames
Now your ultra precise miter sled is complete and you can start making repeatable miter cuts all day long! The clear top on the stop block makes it easy to line up the measurements and the extension wing supports the work while you are cutting it. It leads to perfect picture frames every time!
I have included some pictures of the jig being used. Basically you use the short side of the jig to cut the first 45° and then transfer it to the other side. Line up the part you just cut with the stop block, then you can cut the second 45°. Super simple and easy to repeat!
If you want to see it in action you can check out this video which will also be the subject of a future instructables post, so make sure to follow me.
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If you made one, I'd love to see pictures and if you have any questions, please feel free to ask them in the comments below.