Woodworks by John
CGF II, Certified Grumble Framer Level 2
Many times I've seen posts about how folks cut their miters and I often think about sharing what I do. Since I was cutting some molding today figured it's the perfect time to take some pictures and pass this along. I don't do a lot of volume so this works great for me. It's extremely accurate and I think many shops can't justify that dual miter CTD unit so this is for you. It starts with a table saw and a sled you make yourself. I'd suggest something stable like Baltic birch plywood. You can use hardwood strips that fit in the miter gauge slots but I prefer to use UHMW polyethylene, it's stable, slippery, and you can drill/tap it to attach the sled.
Here's the basic procedure; start with a piece of ply about 16"x20" and attach a straight piece of wood at least an inch thick and 3" wide to the front. If you look at the pictures, the ply is centered between the two miter slots. Attach one runner first, then the other side trying to eliminate any slop -- don't want any side to side movement. Next, raise the blade about an inch and cut into the sled about half way. The key to this jig is that the support block you place the molding against must be 90 degrees. You can use a miter gauge or protractor to make the point of the support block line up with the kerf in the plywood when you cut half way into the sled. I only screw this block on because in time you may want to replace it.
Here's the beauty of this sled. Even if the blade doesn't line up exactly with the support block, you're cutting one side of the frame on the left of it and the other side of the frame on the right of it. Theoretically, if your support block is off and cuts a 44 degree angle on the left, the right would be 46 degrees so you end up with a 90 degree corner.
You can add an aluminum ruler and definitely some sort of stop block to the right side to insure that both sides of the frame will be the same length. Clamps too will help hold the stock and prevent it from creeping when you cut. I used this type of sled in my classes and only attached sandpaper to the support block and my students had no problem with it for smaller pieces. You may notice that I've had to increase the height of the front piece because I had some pretty thick molding to cut.
Setting it up is pretty straight forward. I always cut the longest piece first (you can wood shorter but it's hard to stretch!) and cut the miter on the left side of the sled. I measure inside the rabbet and draw a line for the required length. To play it safe, I'll set the stop block and allow about an inch extra. Make the cut, measure the length and then move the stop block to cut off the extra. Once I establish this baseline measurement the stop block can be moved accordingly for all the other pieces that need to be cut.
This method works for me, using a tablesaw means less vibration in the blade than most miter saws and gives a nice cut. It seems a little difficult to explain but if you look at the photos, hopefully it'll make sense. If not, send me a message and I'll try to clarify.
Here's the basic procedure; start with a piece of ply about 16"x20" and attach a straight piece of wood at least an inch thick and 3" wide to the front. If you look at the pictures, the ply is centered between the two miter slots. Attach one runner first, then the other side trying to eliminate any slop -- don't want any side to side movement. Next, raise the blade about an inch and cut into the sled about half way. The key to this jig is that the support block you place the molding against must be 90 degrees. You can use a miter gauge or protractor to make the point of the support block line up with the kerf in the plywood when you cut half way into the sled. I only screw this block on because in time you may want to replace it.
Here's the beauty of this sled. Even if the blade doesn't line up exactly with the support block, you're cutting one side of the frame on the left of it and the other side of the frame on the right of it. Theoretically, if your support block is off and cuts a 44 degree angle on the left, the right would be 46 degrees so you end up with a 90 degree corner.
You can add an aluminum ruler and definitely some sort of stop block to the right side to insure that both sides of the frame will be the same length. Clamps too will help hold the stock and prevent it from creeping when you cut. I used this type of sled in my classes and only attached sandpaper to the support block and my students had no problem with it for smaller pieces. You may notice that I've had to increase the height of the front piece because I had some pretty thick molding to cut.
Setting it up is pretty straight forward. I always cut the longest piece first (you can wood shorter but it's hard to stretch!) and cut the miter on the left side of the sled. I measure inside the rabbet and draw a line for the required length. To play it safe, I'll set the stop block and allow about an inch extra. Make the cut, measure the length and then move the stop block to cut off the extra. Once I establish this baseline measurement the stop block can be moved accordingly for all the other pieces that need to be cut.
This method works for me, using a tablesaw means less vibration in the blade than most miter saws and gives a nice cut. It seems a little difficult to explain but if you look at the photos, hopefully it'll make sense. If not, send me a message and I'll try to clarify.
