I am the eggman,
They are the eggmen
- I Am The Walrus, The Beatles
Modifications to a miter jack for accurately cutting both miters and tenons
|Modified miter jack|
Modified miter jack rear side.
The magnetized flat surface provides a reference for 90° cuts such as tenon shoulders or removing the waste on the outer edges of the tails of a dovetail joint.
The Purpose of a Miter JackSuppose you are making a frame and panel door and would like to make a miter joint for a stuck moulding rail that has a tenon.
This rail contains not only the tenon, but a stuck moulding with a miter.
A stuck moulding is a moulding that is integral to the piece rather than applied or glued
Behemoth miter jack.
Note that this miter jack has a vertical surface in the rear, unlike the smaller one above.
The vertical surface can be used for 90° cuts.
Each of the above miter jacks are useful, but have some limitations. The smaller one can only be used on its angled surface to make miters. The larger one is unwieldy and requires a massive chisel or slick.
People who have not used a miter jack often ask how the surfaces don't get marred when using planes, saws and chisels. To preserve the surface, you could:
- Apply cardstock or wood to the angled surfaces and replace them when damaged.
- Use a saw with no set
- Be careful and slow when using a plane or chisel
In general, the above works to prevent the surface from becoming damaged. But, every now and then, the surface becomes dinged despite my efforts. For the modified miter jack, I went about adding a couple of features:
- Embedded magnets and steel plates on the rear 90° surface that grabs the saw for a flush.cut
- A modified block plane with rails attached to the plane
- A surface protector made of ash for the mitered worksurface
Building the souped up miter jack
A 3/4" dowel is made using the Stanley 77 dowel maker
|The end of the square stock needs to be tapered to pass through the dowel maker|
|Part of the stock is left intact to serve as the handle|
|Alternatively, a rounder plane or even a stail engine could be used to fashion the rod.|
|Screw box (die)|
Base. The sliding central portion is trapped by the angled outer edges like a sliding dovetail. Screws were placed only temporarily to help with fitting and gluing of the outer boards.
|Since I don't own a table saw, the angled edges were made using a shooting board|
|The tip of the threaded rod is made into a cylinder on the lathe.|
|Clevis pin inserted through a hole in end of rod|
|Copper pipe fitted to end|
One screw on each side is placed from underneath the bottom board, through the outer board and into the fixed outer jaw
Block plane modification
|After using the block plane with add on rails. No need to worry about damaging this antique.|
Perfect 90° cuts using magnetic plates
When The Beatles' Hello Goodbye single came out, it was a #1 hit. On the B side was I Am The Walrus, not as popular at first but it grew on us.
When I first used a miter jack, I didn't pay attention to the rear side. But, side B of the miter jack, the rear end, has proven even more useful for me than side A after modifying it a bit.
I tried using the back side (vertical face) of the miter jack to cut tenon shoulders, but even the no set saw would occasionally dig into the surface. To correct this problem, 3/4" magnets were installed along with steel plates. The zero set flexible saw (from Lee Valley Tools) is then grabbed by these magnets and gives quite a clean cut.
|Three quarter inch countersunk neodymium magnets|
|Steel plates fashioned from old saw blades|
|Steel plates magnetically adhered to vertical surface|
Cutting a tenon with mitered stuck moulding using the miter jack
|The no set saw gets grabbed by the magnetized steel plates serves as a guide to position the stock|
The saw blade can be positioned quite accurately to remove half of the scribed line..
|Tenon shoulder cut. The saw stays true.|
|Cheeks removed with a moving fillester plane (one of several methods to remove the cheeks).|
Another foolproof device. The magnetic Veritas right angle saw
guide assures a right angle cut of the ends off the tenon.
|A chisel is used to miter the moulding.|