Posted by BillEpstein [ 12.75.72.79 ] on December 29, 2003 at 17:57:21:
In Reply to: Methods of work posted by lon on December 29, 2003 at 16:00:40:
Yeah, Appleton! One of my drinking buddies at U of C got thrown out of Lawrence.
Really the Jasper is so easy that there's no reason to use a jig saw. I can't cut a proper circle with a jigsaw and that's important because the biggest hurdle we face is the fact that the friggin speaker manufacturers design there flanges as tho' we were using screws w/o t-nuts. Well we are using t-nuts you rat bastards!
Anyway, forget all the math that you see in the brochure. I did. Use a 1/4" double flute mortising bit, solid carbide if you can afford it and try to get an upshear bit.
With the 1/4" bit the holes in the jig will exactly correspond with the size you need. When in doubt cut a sixteenth bigger as the holes are generally smaller, not larger.
If you are using a driver for the first time I would recommend making a test cut out to see if you do have room for the fasteners at the size you select.
For small sizes that cause the pin to be under the router base be sure to drill the pivot hole deep enough to accept the length of the pin. Otherwise you'll be stuck with a spinning bit and the router wont sit on the workpiece.
I don't use a plunge router with it. My plunger is a Freund and the Jasper won't fit. I have the jig on my P-C 690 and there it stays.
If you're new to the router carefully drill a hole just inside the circumference that will accept the bit. Then you put the router flat and posiiton it before you hit the on switch. A better method that requires some practice and confidence and which is probbaly desparate ly UNSAFE is to pull the pin out far enough that the router bit will not touch the work but the pin will enter the hole. Turn it on and press down. This is not only faster but eliminates the need to drill a hole that may cause problems when you finish up the cut. Or be outside the circumference.
Please be careful, tho'. Best is a plunge router like the P-C 690 plunge base. The P-c and DeWalt 2 hp plungers a re krap. The Bosch is pretty good and the P-C Speedmatic is aces.
Okay, adjust the depth of cut so you miss going completely thru by the proverbial pubic hair. Further, make sure the pin goes thru the workpiece and on thru a scrap piece underneath. Both these steps will keep you from having a "keyhole" in the circle when you're done. The offf cut will still be attached by that p-hair; turn the workpiece over and you will see a gopher track from the point of the bit. Tap around the edges. The offcut will release more or less cleanly w/o tearout.
I need another beer.
[ Craftsmen Forum ] [ Help ]