In truth, a mortise is just a square hole. If the joint fails it is usually because too little wood is left around the mortise, so it makes sense to let the location and size of the mortise determine the size of the tenon.
The first thing to consider is where to locate the mortise — too close to the end of a board leaves weak grain that can easily break while making the mortise, or when the finished joint is stressed. The width and depth of the mortise are equally important. When planning a joint, take no more than one-third the thickness of the mortised piece, and make the mortise as deep as you can. The strength of the joint is mainly a function of how far into the mortised piece the tenon goes. That leaves the length of the mortise, or the width of the tenon to be determined.
The tenon will be strongest the closer it is to the size of the piece on which it is made. Make the tenon as wide and thick as possible, and at least half as wide as the overall width of the workpiece. There are five surfaces in a typical mortise. Two of them need to fit just right for the joint to work. Unless you are making a through-mortise, extra space at the ends will let you adjust the position of the piece and easily take it apart after a test fit.
A good joint can be pushed together by hand pressure and stay together when you lift it by the tenoned piece. Layout Rules. Whatever method you use to make your mortises, getting them the right size and in the right spot is critical. With machine methods, it is easy to set where the mortise lies in the thickness, and generally the width of the mortise matches the width of your tool, be it a drill bit, router bit or a chisel.
Depth is also an easy target, especially if your aim is a bit deeper than the tenon length. Unless you are setting up for a large production run, it will likely take less time to mark all your mortises and work to your lines. Getting close by eye will be faster.
If at all possible, gang parts together and mark them as a group. Prepare a story stick and you need only to measure once. Knife lines and marking-gauge lines might take a little longer to make, but the payoff is in cutting the finished edges before you start to excavate and in providing a path for your tools to follow. The Mighty Chisel. In recent years it has become fashionable to write about and demonstrate chopping mortises entirely by hand.
There are two steps to making a mortise — removing the waste and tidying up the edges. The mass of a mortise chisel helps considerably, and if the wood is soft and agreeable, you can hand-chop a mortise in a short amount of time.
After marking out the joint location, there are two general methods for using the chisel to chop out the mortise. The first is to make a cut in the middle area of the space and reverse the direction of the bevel with each cut to create a V-shaped recess. Placing the chisel to start the cut requires some finesse, so this method takes a while. The other method is to start near an end and make a series of cuts in one direction, then lever out the chips and repeat until you reach the desired depth.
When the bulk of the waste is removed, drive the chisel straight down at the ends. The mass of the chisel helps keep it plumb, if you have a loose grip when you place it. If the business end of the chisel is square, that is another aid to keeping it vertical.
And if you position yourself behind the chisel, you will be able to see if it is leaning left or right. You can tell when the chisel has been driven to an optimal depth by the sound and by the amount of resistance you feel. Pry against the bevel to gain leverage and the back and end scrapes the sides as you remove the waste. The process is essentially the same: Make a series of vertical cuts then lever out the waste.
No Shame in Using a Drill. If you look back in old books about woodworking technique, the use of a drill begins to be recommended right about the time that efficient drill bits became readily available. Again, the method you choose depends on the wood you are working with, the number of mortises you need to make and your desire to get the job done.
If your mission is to avoid the spouse and kids, get out your brace and bit and drill a hole to the depth of the mortise at one or both ends. That reduces the need for chopping. If you want to be productive, the more wood you can remove by drilling the better — if you have an efficient and reliable way to power the drill. A drill press, equipped with a fence and a Forstner bit, is ideal.
You can use a bit the exact size of the intended mortise, overlap the holes and be confident that the holes are vertical. This reduces the chisel work to easy paring on the side walls and perhaps a couple of cuts on the ends.
As with the chisel, the important thing is to keep the bit plumb side-to-side, and you can easily see that from the end of the mortise. After drilling you need to pare the side walls with as wide a chisel as you can.
Here are some of the best ones you can go for. It features an X-Y directional table with stops which helps you control the workpiece in the X-Y direction and offers you full control of the workpiece as you bore your mortises. The Jet mortiser is constructed from rugged cast iron and steel, ensuring it will last for as long as you maintain it properly. If you need dedicated workhorse mortiser to produce mortises day in and day out, then this Powermatic T tilt table mortiser will do the job for you.
This Powermatic mortiser is designed to help you quickly cut mortises that are fit tightly with the tenons. The feed lever allows 6 position quick position adjustments which makes it easier to use the mortiser.
It comes equipped with a gas cylinder controlled rack and pinion head raising and lowering mechanism which makes it very easy to operate. Overall, the Powermatic T is one of the best mortiser you can use for making square, and tightly fitting mortises.
If you want to cut mortises for some really large stocks of wood, a chain mortiser like this Makita L is your best bet for the job. It comprises a razor sharp chain power by a powerful This Makita chain mortiser might not be ideal for cabinet making though. So, always try to cut the tenons first before the mortise. Your email address will not be published.
Last updated on September 27th, at am A mortise and tenon joint is one of the most frequently used woodworking joints which has been around for centuries. It has many types, but the basic form is made up of two parts. The mortise and the tenon. To lock the joint together, it can either be glued, wedged or pinned to prevent any movement.
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