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Gerald Ross
 
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Default Restoring bowl dovetails

Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.
--
Gerald Ross
Cochran, GA

A day without radiation is a day
without sunshine.





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tdup2
 
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Default Restoring bowl dovetails

I would be interested in a jig to do that on the router. I would think that
would be quicker than having to redo the jaws on my chuck.

Tim

"Gerald Ross" wrote in message
...
Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.
--
Gerald Ross
Cochran, GA

A day without radiation is a day
without sunshine.





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tdup2
 
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Default Restoring bowl dovetails

I would be interested in a jig to do that on the router. I would think that
would be quicker than having to redo the jaws on my chuck.

Tim

"Gerald Ross" wrote in message
...
Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.
--
Gerald Ross
Cochran, GA

A day without radiation is a day
without sunshine.





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Bill Rubenstein
 
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Default Restoring bowl dovetails

It seems to me that the lathe is the right tool to true up the dovetail
-- not a router.

Make a small jam chuck -- maybe 3 or so inches in diameter. Your blank
should also have the hole caused by your tail center visible; that will
make centering it easier but is not completely necessary.

Mount it between the jam chuck and the tail stock, top of the bowl to
the headstock side and then cleaning up the dovetail is a piece of cake.
If it is small then you might need to make a small special cutter to
get to it but I'd say this is the way to go.

Bill

tdup2 wrote:
I would be interested in a jig to do that on the router. I would think that
would be quicker than having to redo the jaws on my chuck.

Tim

"Gerald Ross" wrote in message
...
Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.
--
Gerald Ross
Cochran, GA

A day without radiation is a day
without sunshine.





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robo hippy
 
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Default Restoring bowl dovetails

Gerald,
It sounds like a good idea, even if I don't return my warped bowls. I
was wondering how the jig would sit stable on a bowl bottom that is
also warped?
robo hippy
Gerald Ross wrote:
Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.
--
Gerald Ross
Cochran, GA

A day without radiation is a day
without sunshine.





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George
 
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Default Restoring bowl dovetails


"Gerald Ross" wrote in message
...
Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.


Have you ever considered using a pin chuck for roughing and leaving the
pillar intact in the drying bowl? Makes an easy recenter because the hole
remains full size in the direction of the grain, guiding the bit to center
and removing the face grain symmetrically.

Additional benefit in that you can re-turn the outside and bottom to
circular toward the headstock with no interference. It can also provide you
with support by snugging the tailstock up after re-chucking in the dovetail,
allowing a faster hogging rate as you turn the interior for thickness and
circularity. Protects the turning from an accidental dismount until it's at
its lightest and best balance, too. Pictures of the procedure, using both
pin chuck and pin jaws at http://personalpages.tds.net/~upgeorge/index.html
for your examination.

14 degree bit, easily obtainable, will work as well. At a quarter inch
depth the degree difference is certainly within the elastic limit of the
wood.


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George
 
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Default Restoring bowl dovetails


"robo hippy" wrote in message
ups.com...
Gerald,
It sounds like a good idea, even if I don't return my warped bowls. I
was wondering how the jig would sit stable on a bowl bottom that is
also warped?


Anything on three points will sit steady. With an adjustable point, should
be able to regain parallel with the original bottom.


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Gerald Ross
 
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Default Restoring bowl dovetails

George wrote:
"Gerald Ross" wrote in message
...
Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.


Have you ever considered using a pin chuck for roughing and leaving the
pillar intact in the drying bowl? Makes an easy recenter because the hole
remains full size in the direction of the grain, guiding the bit to center
and removing the face grain symmetrically.

Additional benefit in that you can re-turn the outside and bottom to
circular toward the headstock with no interference. It can also provide you
with support by snugging the tailstock up after re-chucking in the dovetail,
allowing a faster hogging rate as you turn the interior for thickness and
circularity. Protects the turning from an accidental dismount until it's at
its lightest and best balance, too. Pictures of the procedure, using both
pin chuck and pin jaws at http://personalpages.tds.net/~upgeorge/index.html
for your examination.

14 degree bit, easily obtainable, will work as well. At a quarter inch
depth the degree difference is certainly within the elastic limit of the
wood.


Thanks! I do use a pin chuck and leave the pillar until the last thing
while roughing. Never thought about leaving it until finish turning.
Shows my age. The 15 degree bit was easy to find, but only in 1/4 shaft.

--
Gerald Ross
Cochran, GA

A diplomat thinks twice before saying
nothing.





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Gerald Ross
 
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Default Restoring bowl dovetails

Here it is.

Making the jig. Two pieces of 1/4 masonite 1 ft square. Base of scrap
3/4 wood 1 ft. square. Drilled 1/4" pilot hole in center of both pieces
of masonite. Cut 1 1/4" hole in one with hole saw, 5" in second piece
with fly cutter on drill press. Glued pieces of masonite together. Cut
corners in top & bottom pieces to hold rubber bands. The bottom piece of
masonite is just a stiffener and the 5" hole gives clearance for bowl
bottom.

Used 15 deg. dovetail bit in router with a 5/8 guide bushing.

procedure. Sand bottom of bowl flat and top fairly flat on 4" belt
sander. Invert bowl on base of jig, center masonite guide on dovetail
recess of bowl and hold with rubber bands on corners. Adjust depth of
bit to touch bottom of dovetail recess and route slowly letting guide
bushing guide the router. A soft start router and slowest speed is the
way to go. I stop frequently and blow the dust out so it won't interfere
with the guide bushing.

Pictures in ABPW. This is only a prototype to see if it was feasible. It
has worked well for me for the few weeks I have used it. The masonite is
a little flexible and a better clamping method would probably help.

I like George's method of leaving the center pillar, but I have a pile
of drying bowls that do not have it so for those that warp, it is this
or the cole jaws and they do not work so well if the rim is also warped.


--
Gerald Ross
Cochran, GA

A diplomat thinks twice before saying
nothing.





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George
 
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Default Restoring bowl dovetails


"Gerald Ross" wrote in message
...

procedure. Sand bottom of bowl flat and top fairly flat on 4" belt sander.
Invert bowl on base of jig, center masonite guide on dovetail recess of
bowl and hold with rubber bands on corners. Adjust depth of bit to touch
bottom of dovetail recess and route slowly letting guide bushing guide the
router. A soft start router and slowest speed is the way to go. I stop
frequently and blow the dust out so it won't interfere with the guide
bushing.


Seems you could use a bottoming bit, the same jig and bushing for level
rather than fussing with sanding? Then go two steps up in the bushing and
work your dovetail. With the longer shanks on 1/2" bits, you could easily
go to 1/2 stock and avoid the flex.

I'd wedge for level and tack with hot glue for down below.




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Gerald Ross
 
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Default Restoring bowl dovetails

George wrote:
"Gerald Ross" wrote in message
...

procedure. Sand bottom of bowl flat and top fairly flat on 4" belt sander.
Invert bowl on base of jig, center masonite guide on dovetail recess of
bowl and hold with rubber bands on corners. Adjust depth of bit to touch
bottom of dovetail recess and route slowly letting guide bushing guide the
router. A soft start router and slowest speed is the way to go. I stop
frequently and blow the dust out so it won't interfere with the guide
bushing.


Seems you could use a bottoming bit, the same jig and bushing for level
rather than fussing with sanding? Then go two steps up in the bushing and
work your dovetail. With the longer shanks on 1/2" bits, you could easily
go to 1/2 stock and avoid the flex.

I'd wedge for level and tack with hot glue for down below.


You lost me. How can I level the bottom if the jig is resting on it? The
dovetail bit does cut on the bottom, and levels the bottom of the
recess. On the bowls I've done with it, it takes about 2 seconds to
knock the bottom flat on the sander. It does not seem necessary to level
the top of the bowl.

--
Gerald Ross
Cochran, GA

A dirty book is rarely dusty.





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George
 
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Default Restoring bowl dovetails


"Gerald Ross" wrote in message
...
George wrote:
"Gerald Ross" wrote in message
...

procedure. Sand bottom of bowl flat and top fairly flat on 4" belt
sander. Invert bowl on base of jig, center masonite guide on dovetail
recess of bowl and hold with rubber bands on corners. Adjust depth of
bit to touch bottom of dovetail recess and route slowly letting guide
bushing guide the router. A soft start router and slowest speed is the
way to go. I stop frequently and blow the dust out so it won't interfere
with the guide bushing.


Seems you could use a bottoming bit, the same jig and bushing for level
rather than fussing with sanding? Then go two steps up in the bushing
and work your dovetail. With the longer shanks on 1/2" bits, you could
easily go to 1/2 stock and avoid the flex.

I'd wedge for level and tack with hot glue for down below.

You lost me. How can I level the bottom if the jig is resting on it? The
dovetail bit does cut on the bottom, and levels the bottom of the recess.
On the bowls I've done with it, it takes about 2 seconds to knock the
bottom flat on the sander. It does not seem necessary to level the top of
the bowl.


Rest the jig on the table or whatever via the three legs straddling the
bowl. I hate belt sanders, gave mine to the school after rounding over and
gouging everything I touched with it. Now a block plane....


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Bill Rubenstein
 
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Default Restoring bowl dovetails

This whole discussion seems to me to elucidate a lot of hard ways to
solve an easy problem. The lathe is the right tool for the job.

Bill

George wrote:
"Gerald Ross" wrote in message
...
George wrote:
"Gerald Ross" wrote in message
...
procedure. Sand bottom of bowl flat and top fairly flat on 4" belt
sander. Invert bowl on base of jig, center masonite guide on dovetail
recess of bowl and hold with rubber bands on corners. Adjust depth of
bit to touch bottom of dovetail recess and route slowly letting guide
bushing guide the router. A soft start router and slowest speed is the
way to go. I stop frequently and blow the dust out so it won't interfere
with the guide bushing.
Seems you could use a bottoming bit, the same jig and bushing for level
rather than fussing with sanding? Then go two steps up in the bushing
and work your dovetail. With the longer shanks on 1/2" bits, you could
easily go to 1/2 stock and avoid the flex.

I'd wedge for level and tack with hot glue for down below.

You lost me. How can I level the bottom if the jig is resting on it? The
dovetail bit does cut on the bottom, and levels the bottom of the recess.
On the bowls I've done with it, it takes about 2 seconds to knock the
bottom flat on the sander. It does not seem necessary to level the top of
the bowl.


Rest the jig on the table or whatever via the three legs straddling the
bowl. I hate belt sanders, gave mine to the school after rounding over and
gouging everything I touched with it. Now a block plane....


  #14   Report Post  
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Gerald Ross
 
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Default Restoring bowl dovetails

Bill Rubenstein wrote:
It seems to me that the lathe is the right tool to true up the dovetail
-- not a router.

Make a small jam chuck -- maybe 3 or so inches in diameter. Your blank
should also have the hole caused by your tail center visible; that will
make centering it easier but is not completely necessary.

Mount it between the jam chuck and the tail stock, top of the bowl to
the headstock side and then cleaning up the dovetail is a piece of cake.
If it is small then you might need to make a small special cutter to
get to it but I'd say this is the way to go.

Bill


Have you ever actually done this?

--
Gerald Ross
Cochran, GA

A dirty book is rarely dusty.





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Bill Rubenstein
 
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Default Restoring bowl dovetails

On every bowl I do. The only difference is that I use a tenon instead
of a dovetail -- much more secure in my opinion. If I used a dovetail
I'd need a small tool to get in given the interference of the tailstock.
This is another justification for using a tenon instead of a dovetail.
It would make no difference in the finished product because I'd get
rid of either.

Bill

Gerald Ross wrote:
Bill Rubenstein wrote:
It seems to me that the lathe is the right tool to true up the
dovetail -- not a router.

Make a small jam chuck -- maybe 3 or so inches in diameter. Your
blank should also have the hole caused by your tail center visible;
that will make centering it easier but is not completely necessary.

Mount it between the jam chuck and the tail stock, top of the bowl to
the headstock side and then cleaning up the dovetail is a piece of
cake. If it is small then you might need to make a small special
cutter to get to it but I'd say this is the way to go.

Bill


Have you ever actually done this?



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william kossack
 
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Default Restoring bowl dovetails

I use this approach also. Its fast and simple

Bill Rubenstein wrote:
On every bowl I do. The only difference is that I use a tenon instead
of a dovetail -- much more secure in my opinion. If I used a dovetail
I'd need a small tool to get in given the interference of the tailstock.
This is another justification for using a tenon instead of a dovetail.
It would make no difference in the finished product because I'd get rid
of either.

Bill

Gerald Ross wrote:

Bill Rubenstein wrote:

It seems to me that the lathe is the right tool to true up the
dovetail -- not a router.

Make a small jam chuck -- maybe 3 or so inches in diameter. Your
blank should also have the hole caused by your tail center visible;
that will make centering it easier but is not completely necessary.

Mount it between the jam chuck and the tail stock, top of the bowl to
the headstock side and then cleaning up the dovetail is a piece of
cake. If it is small then you might need to make a small special
cutter to get to it but I'd say this is the way to go.

Bill



Have you ever actually done this?

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mac davis
 
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Default Restoring bowl dovetails

On Sun, 25 Jun 2006 15:13:58 -0400, Gerald Ross wrote:

Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.


Looks like a good idea, if I could find a router under all the bowls and
shavings.. lol

Personally, I'd rather do it on the lathe, feeling that the end really would be
true to the bottom... I'd be sort of afraid that your new or cleaned up recess
might not be the center of a warped bowl any more, and the bowl would really
spin awkwardly..

I find that it's pretty fast using a jam or vacuum chuck and the live center
without the point... holds the bowl and is adjustable for allowance of warp and
lets you do a little truing and cleanup while you're at it.. YMWV
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
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mac davis
 
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Default Restoring bowl dovetails

On 25 Jun 2006 17:31:27 -0700, "robo hippy" wrote:

Gerald,
It sounds like a good idea, even if I don't return my warped bowls. I
was wondering how the jig would sit stable on a bowl bottom that is
also warped?
robo hippy


Ok, Reed... let's assume that you mean "re-turn".. lol

My concern on a warped bowl, and I think that was the motivation for using this
jig, would be the TOP of the bowl more than the actual recess..

One of the reasons that I went to a vacuum system was that when a bowl is nicely
warped, it won't sit flush in a cole/jumbo jaw setup... which makes it hard to
hold and harder to do anything to the bottom of the bowl..

Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
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mac davis
 
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Default Restoring bowl dovetails

On Mon, 26 Jun 2006 08:00:33 -0400, Gerald Ross wrote:

snip
Thanks! I do use a pin chuck and leave the pillar until the last thing
while roughing. Never thought about leaving it until finish turning.
Shows my age. The 15 degree bit was easy to find, but only in 1/4 shaft.


Gerald... I'd rather ask a dumb question that make a dumber mistake, so I'll ask
what kind of chuck you use?

My guess is a Nova?
The Oneway series would require a straight bit, I think?
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
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Gerald Ross
 
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Default Restoring bowl dovetails

mac davis wrote:
On Sun, 25 Jun 2006 15:13:58 -0400, Gerald Ross wrote:

Some bowls dry with a usable dovetail pretty much intact, some wind up
with an oval hole. I often chuck them in the cole jaws and re-do the
dovetail before finish turning. Recently I made a jig to round up the
dovetail with a router. This requires a 15 degree dovetail bit but has
worked well for me. If anyone is interested I can do the pictures &
description.


Looks like a good idea, if I could find a router under all the bowls and
shavings.. lol

Personally, I'd rather do it on the lathe, feeling that the end really would be
true to the bottom... I'd be sort of afraid that your new or cleaned up recess
might not be the center of a warped bowl any more, and the bowl would really
spin awkwardly..

I find that it's pretty fast using a jam or vacuum chuck and the live center
without the point... holds the bowl and is adjustable for allowance of warp and
lets you do a little truing and cleanup while you're at it.. YMWV
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm


My live center is 1 1/2" diameter and most of my dovetail recesses are
about 2". My dovetail scraper is straight and the tailstock is in the
way. Even if I had a 1/4" wide dovetail scraper with a dogleg shaft, I
don't believe I could center it as well as laying a template over the
oval one.

Folks, this is not a new religion I'm preaching, just a report of
something I tried and found it works using what I already had on hand,
other than the router bit. If you have a system that works for you, keep
it. I used to use tenons exclusively, and lost a few bowls that departed
the lathe. I have so far not lost any off a dovetail chuck but it
probably will happen. Repairing an out of round tenon is surely easier
than a dovetail recess so comparing the methods of doing so doesn't
really work.

--
Gerald Ross
Cochran, GA

A dirty book is rarely dusty.





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robo hippy
 
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Default Restoring bowl dovetails

Well, I will try again. I must have missed the post button the first
time. When I got my first chuck, I started using a tenon, but had some
problems with the jaws eating pieces of the tenon. I then started
experimenting with the mortice idea. I did have a few problems with
things coming off, and breaking the shoulders, but learned what size of
shoulder was necessary, how deep the mortice should be, how much torque
to put on the chuck, and how close of a fit was necessary tor the chuck
to hold. I can core an 18 inch diameter bowl with the McNaughton system
with no problems and no tailstock. I am very agressive when roughing
out a bowl. With a 'properly' cut mortice, it will not come off. I
never use the tailstock as it isn't necessary. The only down side to
not using the tailstock is that all of the vibration from turning goes
to the headstock. I wore out the headstock bearings on my PM3520 in 5
years. I now have a Laguna 16HD bandsaw that makes the blanks much more
balanced and smoother than the chainsawn blalks that I did for 5 years.
This should make this set of headstock bearings last a lot longer. I
will let you know when they fail.
robo hippy
Fred Holder wrote:
I agree with Bill, I use a tenon instead of a recess. Many years ago, I
sometimes used a recess until a fellow brought in a bowl to the club meeting
that was split in half because he had tightened his chuck too much using a
recess. After that, I never again used a recess only a tenon.

When re-turning a rough turned bowl, I open my chuck jaws quite a bit and place
the inside of the bowl over the chuck. I then bring up the tailstock with a live
center and clean up the dovetail on the tenon. Because I always start my bowls
originally between the face of the jaws of the chuck and a live center to turn
the original tenon and the outside of the bowl, I have a center point for
remounting after the rough turned bowl has dried. I keep this center point all
of the way through until the final turning of the foot on a jam fit chuck or a
vacuum chuck.

Fred Holder
http://www.fholder.com



In article , Bill Rubenstein
says...

On every bowl I do. The only difference is that I use a tenon instead
of a dovetail -- much more secure in my opinion. If I used a dovetail
I'd need a small tool to get in given the interference of the tailstock.
This is another justification for using a tenon instead of a dovetail.
It would make no difference in the finished product because I'd get
rid of either.

Bill

Gerald Ross wrote:
Bill Rubenstein wrote:
It seems to me that the lathe is the right tool to true up the
dovetail -- not a router.




Make a small jam chuck -- maybe 3 or so inches in diameter. Your
blank should also have the hole caused by your tail center visible;
that will make centering it easier but is not completely necessary.

Mount it between the jam chuck and the tail stock, top of the bowl to
the headstock side and then cleaning up the dovetail is a piece of
cake. If it is small then you might need to make a small special
cutter to get to it but I'd say this is the way to go.

Bill

Have you ever actually done this?


  #22   Report Post  
Posted to rec.crafts.woodturning
George
 
Posts: n/a
Default Restoring bowl dovetails


"mac davis" wrote in message
...
One of the reasons that I went to a vacuum system was that when a bowl is
nicely
warped, it won't sit flush in a cole/jumbo jaw setup... which makes it
hard to
hold and harder to do anything to the bottom of the bowl..


LOVE that pin chuck. No fooling around. Re-turns are on center and capable
of being held there by the pin chuck for prefancying the bottom before
reversing if you care to after rounding the outside.

Plus, it's there when you reverse to become that third hand and the
tailstock your vacuum chuck.


  #23   Report Post  
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George
 
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Default Restoring bowl dovetails


"Gerald Ross" wrote in message
...

My live center is 1 1/2" diameter and most of my dovetail recesses are
about 2". My dovetail scraper is straight and the tailstock is in the way.
Even if I had a 1/4" wide dovetail scraper with a dogleg shaft, I don't
believe I could center it as well as laying a template over the oval one.


Leave a pillar next time you're roughing and give the pin chuck a shot.
Only "special" thing about leaving one is making sure you have a bevel to
steady when plunging and pulling center to rim for hogging. Pictures
available, though there's nothing earth-shattering there.


Folks, this is not a new religion I'm preaching, just a report of
something I tried and found it works using what I already had on hand,
other than the router bit. If you have a system that works for you, keep
it. I used to use tenons exclusively, and lost a few bowls that departed
the lathe. I have so far not lost any off a dovetail chuck but it probably
will happen. Repairing an out of round tenon is surely easier than a
dovetail recess so comparing the methods of doing so doesn't really work.


I find the tenon loses bowl depth, behaves poorly in wet sapwood (abysmally
with crush types), and of course, unless you use smooth jaws, takes an extra
step to make things presentable after you have your work sanded up and
ready. Fred mentions how to misuse a chuck in either mode by
overtightening. Dovetail people normally relearn quickly what wood workers
have always known, that a round peg in a round hole will split wood, because
it presses evenly all around. Of course that's also the strength of the
smooth jaw - doesn't require that you smash wood to get a grip, just a snug
fit.

I'm chopping dovetail mortises for a set of KD shelves this morning. In
this case through tails, but fox-wedged tenons are a feature in furniture
the world around. Same principle as an internal dovetail.


  #24   Report Post  
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mac davis
 
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Default Restoring bowl dovetails

On Tue, 27 Jun 2006 13:20:51 -0400, Gerald Ross wrote:

mac davis wrote:
On Mon, 26 Jun 2006 08:00:33 -0400, Gerald Ross wrote:


Gerald... I'd rather ask a dumb question that make a dumber mistake, so I'll ask
what kind of chuck you use?

My guess is a Nova?
The Oneway series would require a straight bit, I think?
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm


It is a Nova. How would you make a dovetail recess with a straight bit?


That was my point... Oneway uses a straight jaw, Nova a dovetail..

BTW: Please don't feel like I (and the others) are taking pot shots at you..
You opened up a good topic with an idea that you had and we're commenting..
please don't feel flamed or anything..

(picture of jaws on ABPW for clarification)
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
  #25   Report Post  
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william kossack
 
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Default Restoring bowl dovetails

the trick with any jaw set is learning how to cut the edge so the jaws
fit correctly. I usually put the piece onto the jaws and then look
closely to see how much of the wood is making contact with the jaws.

When I've had problems with a chunk coming loose it can usually be
traced back to the surface I prepared. One time I was turning some
olive wood and had to repeatedly remount the bow. It turned out that I
had done a bad job (too much of a hurry) of preparing the tenon

mac davis wrote:
On Tue, 27 Jun 2006 13:20:51 -0400, Gerald Ross wrote:


mac davis wrote:

On Mon, 26 Jun 2006 08:00:33 -0400, Gerald Ross wrote:




Gerald... I'd rather ask a dumb question that make a dumber mistake, so I'll ask
what kind of chuck you use?

My guess is a Nova?
The Oneway series would require a straight bit, I think?
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm


It is a Nova. How would you make a dovetail recess with a straight bit?



That was my point... Oneway uses a straight jaw, Nova a dovetail..

BTW: Please don't feel like I (and the others) are taking pot shots at you..
You opened up a good topic with an idea that you had and we're commenting..
please don't feel flamed or anything..

(picture of jaws on ABPW for clarification)
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm



  #26   Report Post  
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Gerald Ross
 
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Default Restoring bowl dovetails

mac davis wrote:
On Tue, 27 Jun 2006 13:20:51 -0400, Gerald Ross wrote:

mac davis wrote:
On Mon, 26 Jun 2006 08:00:33 -0400, Gerald Ross wrote:


Gerald... I'd rather ask a dumb question that make a dumber mistake, so I'll ask
what kind of chuck you use?

My guess is a Nova?
The Oneway series would require a straight bit, I think?
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm


It is a Nova. How would you make a dovetail recess with a straight bit?


That was my point... Oneway uses a straight jaw, Nova a dovetail..

BTW: Please don't feel like I (and the others) are taking pot shots at you..
You opened up a good topic with an idea that you had and we're commenting..
please don't feel flamed or anything..

(picture of jaws on ABPW for clarification)
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm


I assume these are for grasping a spigot, or tenon. What I am talking
about is jaws that go into a recess with dovetail sides so that it pulls
the piece into the jaws as you tighten them.

When I was using spigot (straight) jaws I rounded oval tenons with a
hole saw. I left the guide drill bit in until the saw got started then
dropped out the drill bit and cut down the length of the spigot. The
original live center hole guided the drill bit for the start. This was
done on a drill press so there was no need to set up a jam chuck or cole
jaws.
--
Gerald Ross
Cochran, GA

A friend in need is someone to avoid.





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mac davis
 
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Default Restoring bowl dovetails

On Wed, 28 Jun 2006 13:26:28 -0400, Gerald Ross wrote:


I assume these are for grasping a spigot, or tenon. What I am talking
about is jaws that go into a recess with dovetail sides so that it pulls
the piece into the jaws as you tighten them.

When I was using spigot (straight) jaws I rounded oval tenons with a
hole saw. I left the guide drill bit in until the saw got started then
dropped out the drill bit and cut down the length of the spigot. The
original live center hole guided the drill bit for the start. This was
done on a drill press so there was no need to set up a jam chuck or cole
jaws.


No, they're for both... The jaws in the picture have a more pronounced "lip"
than on my Oneway jaws, but same theory.... cut the recess at 90 degrees and
expand into it flush..
From what I've seen in the pictures of the Nova line, they have a pretty
definite angle and require a dovetail..

I actually used to cut a dovetail recess for a while because George and others
recommended it.. only to find out that you don't do that with the Oneway jaws...
lol

I think it was Bill Grumbine's DVD where he mentioned using right angle tenons
and recesses for the oneway that made me realize my mistake...
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
  #28   Report Post  
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robo hippy
 
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Default Restoring bowl dovetails

Well, the way I figure it, the more metal from the chuck jaws
contacting the wood the better. If your chuck jaws are straight, then
you want a straight tenon or mortice. If your jaws are dovetailed, then
you want to match that angle EXACTLY. If the angle isn't very close,
then you are putting a lot more pressure on one part of the side than
on the other, and this will cause breakouts, and I speak from
experience. You also want the mortice or tenon to be the same diameter
or as close as possible to it. I bought the idea that angleing the
sides will draw in the jaws to any significant degree. The single
biggest factor in getting the bowl to remount on center, with little or
no wobble, is to leave the scraper or whatever you use to cut the
tenon/dovetail with at the bottom/end of the cut where the jaws will
contact, so that it just barely rubs, removing almost nothing. This
will even it up a lot, because, 1/64 of an inch here can be 1/8 by the
time it gets to the top outside edge of a big bowl.
robo hippy
mac davis wrote:
On Wed, 28 Jun 2006 13:26:28 -0400, Gerald Ross wrote:


I assume these are for grasping a spigot, or tenon. What I am talking
about is jaws that go into a recess with dovetail sides so that it pulls
the piece into the jaws as you tighten them.

When I was using spigot (straight) jaws I rounded oval tenons with a
hole saw. I left the guide drill bit in until the saw got started then
dropped out the drill bit and cut down the length of the spigot. The
original live center hole guided the drill bit for the start. This was
done on a drill press so there was no need to set up a jam chuck or cole
jaws.


No, they're for both... The jaws in the picture have a more pronounced "lip"
than on my Oneway jaws, but same theory.... cut the recess at 90 degrees and
expand into it flush..
From what I've seen in the pictures of the Nova line, they have a pretty
definite angle and require a dovetail..

I actually used to cut a dovetail recess for a while because George and others
recommended it.. only to find out that you don't do that with the Oneway jaws...
lol

I think it was Bill Grumbine's DVD where he mentioned using right angle tenons
and recesses for the oneway that made me realize my mistake...
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm


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