oreos40
21st August 2012, 11:50 AM
Thought I would post another one. This one is a circle cutting jig. it can be used for bowl blanks too. Many available jigs are fixed so youhave to set the blank in against the blade and then turn the blank to cut it. This allows you to mount the blank and then advance it into the cut. Once against the table stop the blank is spun giving you a perfect circle. It also has a captive guide on the inboard edge of the table which keeps the jig from falling off or popping out of the miter slot while loading.
All dimensions will vary for adaptation. The piece of angle is attached to the inboard edge of the table with the upper leg horizontal and flush with the top of the table. It can remain in place even when the jig is not in use. The guide block is fastned to the bottom of the jig so that the trough hooks under the horizontal leg of the above angle. Once placed this cam be fastened permanently to the jig. The T slot nut bar has two threaded holes there are several ways to use them.
1. one is used for a set screw to lock the nutbar in place and the other is used for a pointed center or a plug made to fit your application, IE 1 1/2" plug fastened to the jig to allow a 1 1/2" hole pre-drilled in the center of your project to be indexed on.
2. the same hole can be used for guide and lock if the spline of the nut-bar is cut shallower than the minor slot dimension of the T slot.
The slot in the top is of course to allow blade travel in the direction of cut to enter the blank this slot has to extend at least to the center of the guide slot.
The guide bar is fastened to the bottom of the jig in the appropriate location.
The last piece is fastened to the edge of the jig on the operators side. The third hole in this peice is to thread in a thumb screw that will stop travel when the cutting edge of the blade is exactly at the tangent of your desired circle.
All dimensions will vary for adaptation. The piece of angle is attached to the inboard edge of the table with the upper leg horizontal and flush with the top of the table. It can remain in place even when the jig is not in use. The guide block is fastned to the bottom of the jig so that the trough hooks under the horizontal leg of the above angle. Once placed this cam be fastened permanently to the jig. The T slot nut bar has two threaded holes there are several ways to use them.
1. one is used for a set screw to lock the nutbar in place and the other is used for a pointed center or a plug made to fit your application, IE 1 1/2" plug fastened to the jig to allow a 1 1/2" hole pre-drilled in the center of your project to be indexed on.
2. the same hole can be used for guide and lock if the spline of the nut-bar is cut shallower than the minor slot dimension of the T slot.
The slot in the top is of course to allow blade travel in the direction of cut to enter the blank this slot has to extend at least to the center of the guide slot.
The guide bar is fastened to the bottom of the jig in the appropriate location.
The last piece is fastened to the edge of the jig on the operators side. The third hole in this peice is to thread in a thumb screw that will stop travel when the cutting edge of the blade is exactly at the tangent of your desired circle.