Chris Friesen wrote:
On 11/27/2009 01:13 PM, -MIKE- wrote:

I know the OP had stated that be was trying to center the bushing, but
we had taken a tangent, discussing how to get a round base perfectly
centered with the bit.

One possibility would be to use a trammel bar of the same radius as the
base plate. This gets attached to some bar stock that is chucked up in
the collet and threaded internally. When the edge of the trammel bar is
aligned with the edge of the base plate all the way around, you're centered.

If you get close when drilling your holes through the base and use
pan-head screws, you'll have a bit of wiggle room to get it perfectly
aligned.

Chris


I have a compass scribe that is already configured in a manner you
describe.
The point's is held in a round cast section that might be 1/4" diameter,
which would chuck-up in the router.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

Gerald Ross wrote:

Mark & Juanita wrote:
.... snip

For those who haven't yet looked at this, it is well worth the look.
Very
clever -- Gerald, this is something that seems to be marketable.



I had it made for my own use and liked it so I sent drawings and
pictures to
Lee Valley. They researched it and found something like it already on
the market somewhere.


Would sure like to find it. I looked at the Bosch cone, it's too small
for all uses, it appears useful only for centering a bushing.

--

There is never a situation where having more rounds is a disadvantage

Rob Leatham

Mark & Juanita wrote:
Gerald Ross wrote:

Snip

Would sure like to find it. I looked at the Bosch cone, it's too small
for all uses, it appears useful only for centering a bushing.


Do you know a machinist? I turned a wood pattern and showed it to a
friend who has a machine shop as a hobby. He quoted me $50-65 to make
one from steel. Two or three months later he brought it to me. He was
embarassed that it had taken so long and refused any payment. I did
give his wife a nice bowl.

I would send you the pattern I turned, but can't seem to lay my hands
on it right now.

--
Gerald Ross
Cochran, GA

All I want is a LITTLE more than I can
spend!

On Sat, 28 Nov 2009 07:54:15 -0500, the infamous Gerald Ross
scrawled the following:

Mark & Juanita wrote:
Gerald Ross wrote:

Snip

Would sure like to find it. I looked at the Bosch cone, it's too small
for all uses, it appears useful only for centering a bushing.


Do you know a machinist? I turned a wood pattern and showed it to a
friend who has a machine shop as a hobby. He quoted me $50-65 to make
one from steel. Two or three months later he brought it to me. He was
embarassed that it had taken so long and refused any payment. I did
give his wife a nice bowl.

Um, a real friend wouldn't have quoted you a price like that. It's a
happy ten minute job (including smoothing and waxing) and a couple
bucks worth of steel.


I would send you the pattern I turned, but can't seem to lay my hands
on it right now.

Y'mean a 1-1/4" diameter rod tapered at 45 degrees down to 1/2", then
kept that diameter for 2"? Who needs a plan or a pattern?

If he kept a tit on the cone end, it could double as a toy top!

--
Some days, it's not even worth chewing through the restraints.

Gerald Ross wrote:

Mark & Juanita wrote:
Gerald Ross wrote:

Snip

Would sure like to find it. I looked at the Bosch cone, it's too small
for all uses, it appears useful only for centering a bushing.


Do you know a machinist? I turned a wood pattern and showed it to a
friend who has a machine shop as a hobby. He quoted me $50-65 to make
one from steel. Two or three months later he brought it to me. He was
embarassed that it had taken so long and refused any payment. I did
give his wife a nice bowl.


I'll have to hunt one down. I do like the approach.

I would send you the pattern I turned, but can't seem to lay my hands
on it right now.


--

There is never a situation where having more rounds is a disadvantage

Rob Leatham

On Nov 27, 11:41*am, Chris Friesen wrote:
On 11/27/2009 01:13 PM, -MIKE- wrote:

I know the OP had stated that be was trying to center the bushing, but
we had taken a tangent, discussing how to get a round base perfectly
centered with the bit.

One possibility would be to use a trammel bar of the same radius as the
base plate. *

To make a base plate to match an existing router, I used a dowel pin
in the
target router, and a matching-diameter carbide bit in the primary
router.

With a raw phenolic plate attached to the target with three flathead
screws
in countersinked holes (which is self-centering after remounting), I
first
used the target router to drill a center hole, then chucked the steel
dowel in the target and routed the edge of the plate with the primary
router, with the dowel as my guide. I did a rough cut with a bit of
brass tube over the dowel, then removed that tube and made the finish
cut.

Hmmm. If I chucked the dowel in a holesaw's pilot, maybe I could
make a stepped hole in the base suitable for router guides?