The Miter Jack is a fixture that is a combination of a vise and shooting board, and is used to precisely trim work pieces to 90, 45 and 22.5 degrees. The work piece is clamped in the vise jaws and the large jaws become the reference surfaces for either a plane or chisel. The miter jack can be mounted with either side facing up; one side for square cuts and the other for miter cuts. The large mounting bracket will accept a holdfast in both positions, and when cutting miters, also needs to be pinched between bench dogs of a workbench. The advantage of the miter jack when shooting is that a conventional plane can be used in the normal fashion. This makes it easier to plane and to monitor progress. It is also easy to tweak angles by shifting the work piece in the jaws. It will stay put regardless of whether it is sitting flat on the ramps. Planing can also be preformed in any direction, a big plus if working with molding to avoid grain blow out.
For doing 22.5 degree miters, there is an auxiliary jaw that is engaged with a hook when the jaws are closed. This auxiliary jaw then opens with the main jaw, creating the 22.5 degree angle between the jaw and top face.
The miter jack demands an advanced technique to use to avoid damaging the jaws, and losing its built in accuracy. Tools must be sharp and cuts taken light and controlled. When using a plane, progress needs to be closely monitored to avoid cutting into the jaws. Using the plane held on a sharp skew will help ensure the plane doesn’t dig in on either side. The user should stop planing when the work piece is still slightly proud of the jaws by a shaving or so. Another technique that is safer is to use a wide, long chisel and pare flush to the jaws after getting close with a plane. By keeping the chisel flat against the jaws, there is little risk of cutting into them.
Tenon shoulders can be accurately pared all around in one set up using a chisel. Even angled tenons can be done this way. In short, the miter jack is a very accurate tool that will enhance the work of most any hand tool user.
Our miter jack is made of European beech, and is built using the hardware kit from Benchcrafted. Overall length of the main body is 20 1/2″, with a clamping capacity of about 7″ and a jaw depth of 5″. A mounting bracket and a wrench to facilitate opening and closing of the jaw are included. These are complex vises to make, and demand a high degree of precision to ensure accuracy. The basic vise is finished to a high degree, while the wrench and mounting bracket are left more rough, like the original miter jacks, having been finished with rasps and a paring chisel.
We are not planning to stock this as an off the shelf item, but will be made to order in small batches. Currently, we have enough orders for our first run, but likely will be making more due to strong interest. Price is $995 plus shipping costs, base on the customer’s location. A deposit of $100 will be collected before production begins, with the balance due upon completion. For a video demonstration, check out this link from Benchcrafted.