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Building Better Miter Joints
By Eric Knudsen
As an avid woodworker, you know how to make simple miter joints. You also know that it can be tricky to make really good miter joints.
However, there are some simple steps you can take to get better results – perhaps better than the results you're getting now – miter joints that are good enough to use for framing artwork. Granted, it can take extra effort to create miters that are picture-perfect, those without any gaps whatsoever. But you'll likely find the results to be well worth the extra effort.
Now, you can make 45 degree miter cuts all day long -- yet mysteriously, you may still end up with unwanted spaces between the joints. This can be frustrating, especially if you believe you're doing everything right. You may think your miter saw's gage settings are correct. You can measure and lay out your cuts methodically, take painstaking care with saw cuts, and still end up with joints that don't line up. You might even own a fancy new model; a high-dollar compound-miter saw with all the latest features, like laser sights and other goodies... and yet, still cannot come up with tight-fitting miters.
So, what the heck does it take to make a great miter joint? Frankly, it's not just one thing that makes a difference; there are, in fact, several things to consider. Firstly, let's clarify a key aspect of making great-looking miter joints; there's more to it than precise saw cuts. Sure, accuracy is critical. That goes without saying. But, there are other factors involved; the key to making better miter joints involves the steps you take just before – and, just after you make the actual miter cuts on your saw.
With this in mind, let's take a closer look at these important steps, starting with a couple of things you should do before you start making saw cuts: Before you turn the saw switch “on,” the very first thing you want to do, is triple-check the settings on your power miter saw. Yes, this gets back to the accuracy detail, but this is only part of the issue. Just because you made a 45 degree cut on your miter saw, doesn't necessarily mean that you actually end up with a 45 degree cut. It might actually be 44 degrees, or 46 degrees.
The point is, how do you know that your saw settings are accurate? That's the question you should ask yourself. You must have some way of checking the gage on your saw, either with an angle finder, caliper, or other device. Check your owner's manual, ask the dealer (where you bought your saw), or visit the manufacturer's website and get some technical support. Until you can be absolutely certain of you miter saw settings and have a reliable way to check it, don't assume that the saws' settings are correct. If they're off just a half a degree, you will have gaps in your miter joints.
Here's a quick-'n-easy way to check your miter saw gage settings: take a couple of 1 x 4 scraps of pine (about 12 to 16 inches long each), and mark them both to 45 degrees, using a sharp pencil and a combination square. Next, set your saw gage to 45 degrees, stack them, and cut both pieces at the same time. Then, join the two pieces together with glue and a few finish nails or brads.
Finally, check the miter joint you just made against a framing square; your 45 degree miter joint should match-up precisely to the framing square. If it's just slightly off, you'll need adjust the gage plate somehow. Many saws have face plates that can be unscrewed and adjusted. Other models will require different kinds of adjustments. Once again, check the owner's manual for specific instructions on how to do this task.
Now, let's go over some of the things you can do after your miter cuts are made: When gluing-up miter joints, try using some small, triangular “helper” blocks on the inside corners. These blocks really ease the joint-building process; they help control the joint while you work on it, and keep the pieces of wood from slipping. Also, get in the habit of using pads; like small, 1/4-inch thick wood blocks and heavy cardboard pieces. If any cardboard happens to stick to the glue, it can easily be sanded away later.
If you notice a slight gap between two boards while trying to get a miter joint to match up, try holding one of the mitered ends against a drum sander, being careful only to remove a tiny bit of material. If you don't own a drum sander, just use a piece of 120 grit sandpaper that's been stapled to a scrap of 1 x 4 lumber. You can actually “cheat” the joint a little bit, if needed, by “back-cutting” with the sandpaper. Tilt the joint edge slightly away from the edge of the sandpaper while sanding. This should help to eliminate any minute gaps in the joint.
To help you get precise cuts on your miter saw, use the saw's hold-down clamps, which are typically mounted to the saw's fence. These clamps must be purchased separately for some models. For tough miter joints on pressure-treated lumber (like exterior decks), try using a few dabs of “quick-grab” construction adhesive. Apply adhesive onto the inside mitered edges, and clamp the joint in two places. After the glue dries, fasten the joint tightly with galvanized screws or nails.
If you really want to give yourself an edge for building miter joints, pick up a set of miter clamps, for about $20 apiece. These specialty clamps will help keep miter joints tight, and prevent them from slipping apart while gluing. Picture framing shops and other woodworking professionals use these clamps with great results.
A final tip: keep in mind that mitered joints on stained woodwork will require a higher level of attention than painted projects; with stained wood, you want to match up the wood grains closely on the two mitered pieces, for appearance sake, whereas it's not nearly as critical to match up wood grains on painted work. Plan your work accordingly.
The difference between mediocre miter joints and really good miter joints is all about the extra steps you take. A small amount of extra effort can mean the difference between the kind of joints you can be proud to show, or, would rather hide. Whether you're building miter joints for highly visual crown moldings, or just for simple baseboard trim, you'll get the better results by following these simple steps.
_________________________________________________________
Eric Knudsen is a freelance writer and former restoration contractor from Upstate New York.
However, there are some simple steps you can take to get better results – perhaps better than the results you're getting now – miter joints that are good enough to use for framing artwork. Granted, it can take extra effort to create miters that are picture-perfect, those without any gaps whatsoever. But you'll likely find the results to be well worth the extra effort.
Now, you can make 45 degree miter cuts all day long -- yet mysteriously, you may still end up with unwanted spaces between the joints. This can be frustrating, especially if you believe you're doing everything right. You may think your miter saw's gage settings are correct. You can measure and lay out your cuts methodically, take painstaking care with saw cuts, and still end up with joints that don't line up. You might even own a fancy new model; a high-dollar compound-miter saw with all the latest features, like laser sights and other goodies... and yet, still cannot come up with tight-fitting miters.
So, what the heck does it take to make a great miter joint? Frankly, it's not just one thing that makes a difference; there are, in fact, several things to consider. Firstly, let's clarify a key aspect of making great-looking miter joints; there's more to it than precise saw cuts. Sure, accuracy is critical. That goes without saying. But, there are other factors involved; the key to making better miter joints involves the steps you take just before – and, just after you make the actual miter cuts on your saw.
With this in mind, let's take a closer look at these important steps, starting with a couple of things you should do before you start making saw cuts: Before you turn the saw switch “on,” the very first thing you want to do, is triple-check the settings on your power miter saw. Yes, this gets back to the accuracy detail, but this is only part of the issue. Just because you made a 45 degree cut on your miter saw, doesn't necessarily mean that you actually end up with a 45 degree cut. It might actually be 44 degrees, or 46 degrees.
The point is, how do you know that your saw settings are accurate? That's the question you should ask yourself. You must have some way of checking the gage on your saw, either with an angle finder, caliper, or other device. Check your owner's manual, ask the dealer (where you bought your saw), or visit the manufacturer's website and get some technical support. Until you can be absolutely certain of you miter saw settings and have a reliable way to check it, don't assume that the saws' settings are correct. If they're off just a half a degree, you will have gaps in your miter joints.
Here's a quick-'n-easy way to check your miter saw gage settings: take a couple of 1 x 4 scraps of pine (about 12 to 16 inches long each), and mark them both to 45 degrees, using a sharp pencil and a combination square. Next, set your saw gage to 45 degrees, stack them, and cut both pieces at the same time. Then, join the two pieces together with glue and a few finish nails or brads.
Finally, check the miter joint you just made against a framing square; your 45 degree miter joint should match-up precisely to the framing square. If it's just slightly off, you'll need adjust the gage plate somehow. Many saws have face plates that can be unscrewed and adjusted. Other models will require different kinds of adjustments. Once again, check the owner's manual for specific instructions on how to do this task.
Now, let's go over some of the things you can do after your miter cuts are made: When gluing-up miter joints, try using some small, triangular “helper” blocks on the inside corners. These blocks really ease the joint-building process; they help control the joint while you work on it, and keep the pieces of wood from slipping. Also, get in the habit of using pads; like small, 1/4-inch thick wood blocks and heavy cardboard pieces. If any cardboard happens to stick to the glue, it can easily be sanded away later.
If you notice a slight gap between two boards while trying to get a miter joint to match up, try holding one of the mitered ends against a drum sander, being careful only to remove a tiny bit of material. If you don't own a drum sander, just use a piece of 120 grit sandpaper that's been stapled to a scrap of 1 x 4 lumber. You can actually “cheat” the joint a little bit, if needed, by “back-cutting” with the sandpaper. Tilt the joint edge slightly away from the edge of the sandpaper while sanding. This should help to eliminate any minute gaps in the joint.
To help you get precise cuts on your miter saw, use the saw's hold-down clamps, which are typically mounted to the saw's fence. These clamps must be purchased separately for some models. For tough miter joints on pressure-treated lumber (like exterior decks), try using a few dabs of “quick-grab” construction adhesive. Apply adhesive onto the inside mitered edges, and clamp the joint in two places. After the glue dries, fasten the joint tightly with galvanized screws or nails.
If you really want to give yourself an edge for building miter joints, pick up a set of miter clamps, for about $20 apiece. These specialty clamps will help keep miter joints tight, and prevent them from slipping apart while gluing. Picture framing shops and other woodworking professionals use these clamps with great results.
A final tip: keep in mind that mitered joints on stained woodwork will require a higher level of attention than painted projects; with stained wood, you want to match up the wood grains closely on the two mitered pieces, for appearance sake, whereas it's not nearly as critical to match up wood grains on painted work. Plan your work accordingly.
The difference between mediocre miter joints and really good miter joints is all about the extra steps you take. A small amount of extra effort can mean the difference between the kind of joints you can be proud to show, or, would rather hide. Whether you're building miter joints for highly visual crown moldings, or just for simple baseboard trim, you'll get the better results by following these simple steps.
_________________________________________________________
Eric Knudsen is a freelance writer and former restoration contractor from Upstate New York.
