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 The
Thien Router Table Circle Jig
Design Copyright (c) 2005
Phil Thien
If you want to make your
own Thien Cyclone Separator Lid, you're gonna
need to make circles. Of course, there are all sorts of reasons
you may need to make circles (or holes, this jig makes those,
too). And there are all sorts of ways to make both. But
this jig is easy and foolproof.
Using the jig to make a circle
(1) Drill a 1/4" pilot
hole as the center of your circle. (2) Adjust the jig's pivot
to the correct radius for the desired circle. (3) Use the jig
as a compass and (using a pencil) draw an outline of your circle on
the wood. (4) Rough-cut the circle (leaving about
1/16" of material) with a jig saw or (if you have one) a
bandsaw. (5) Finally, using a 1/2" (diameter) flush-trim
bit in your router table along with the jig, perfectly finish-trim
your circle.
Using the jig to make a hole
(1) Drill a 1/4" pilot
hole as the center of your hole. (2) Adjust the jig's pivot to
the correct radius for the desired hole. (3) Use the jig as a
compass and (using a pencil) draw an outline of your hole on the
wood. (4) Drill a 1/2" starter hole just inside of
the pencilled outline. (5) Finally, using your router table
with a 1/4" flush-trim bit (inserted through the starter hole),
along with the jig, cut your hole. NOTE: As
you finish the hole, the center pivot point will be unsupported which
can lead to a ragged finish to your hole. I suggest inserting
pieces of 1/4" dowel in the bit's cutting path as you progress
to keep the middle (waste) centered in the hole.
I realize this page is
short on details but it should provide enough information to make
your own jig.
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Detail shot of the
pivot. This was made using: (1) Knob with a 5/16"
threaded hole, (2) 5/16" t-nut (from Woodcraft), (3) 5/16"
brass all-thread that was turned down to 1/4" at the end (I just
chucked it in the drill press and filed the threads off), (4) Some
washers. I will try to add better pics of the pivot shortly.
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The business end of the
jig. There is a 1/2" diameter radius in the end to catch
the larger flush bit for making circles, and a 1/4" radius on
the inside to catch the smaller bit when making holes.
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Making a circle for one my
of Thien Cyclone Separator lids.
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Detail shot: The wood
is pushed against the bit and spun. The bearing rides in the
jig and creates a perfect circle.
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--Phil
phil@cgallery.com
This page has been viewed 59583 times.
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I consider this design
my unique intellectual property, and reserve all rights.
Please
do not take credit for my work by submitting this design to
magazines as a "reader's tip." I realize that this
design will appeal to woodworkers and is something that can be made
in your
shop.
If you want to make one for your own use, please be my guest.
If you want to mass-produce them, please contact me first. |
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