Finish turning the bowl

[cwearing]

In her book Judy Ditmer uses a faceplate for both rough and finish turning. Placement of the faceplate on the foot can be adjusted to account for warping. What is the best procedure to allow for distortion of the spigot if a chuck is used?

:cool2: :mad:

 

[TurningDog]

This is a big can of worms to deal with and there is no best way to rechuck a bowl except the way you choose to use, the bowl distorts and will be slightly out of true no matter what you do. You have 2 choices when rechucking, profiled jaws or dovetail and those were the same two choices you had in the begining. When the bowl distorts it distorts both the spiggot or recess which ever method you use and despite what some whining wanna be perfectionists tell you it is not the jaws that matter but your skill in turning as to how well the bowl rechucks.

 

[Andy Coates]

finishing

Hello there,

My method...which won't be the same as everybodies...is to use a dovetail recess with a small centre mark. If the recess is badly distorted when the bowl's dry...and often it isn't bad enough to be a problem...I mount on a cushioned jam chuck, bring the revolving centre into the centre mark, and recut the outermost inside edge of the dovetail using a skew. If you cut all your dovetails too the smallest diameter your four jaw chuck wil mount, you'll have plenty of scope for enlarging it to make it true again later.

Once you've done that remount on the chuck...check your speed is low...and away you go!

It just occured to me that I do a similar thing with spigot mounted bowls...

This time, when you first turn the bowl, make the spigot a little larger than the optimun diameter...this way, when it distorts you'll have plenty to cut away to true it up without ending up with a too small spigot to finish it off..

Happy bowls

Andy

 

[MichaelMouse]

You have 2 choices when rechucking, profiled jaws or dovetail and those were the same two choices you had in the begining. When the bowl distorts it distorts both the spiggot or recess which ever method you use and despite what some whining wanna be perfectionists tell you it is not the jaws that matter but your skill in turning as to how well the bowl rechucks.

There is a third, of which I am quite fond. Turning on the pin chuck, as I do, I find it an easy matter to punch the center round and mount as it was originally. Rarely is there enough distortion in the old center to make a significant difference in re-centering. Since the pin chuck allows you to cantilever the piece after rounding, it's an easy matter to turn the mortise or tenon round again. If you're a tenon type, be sure to leave the original tenon oversize, or you may run out of grip. BTDT

 

[Charlie Knighton]

spiggot

"When the bowl distorts it distorts both the spiggot or recess"

has anybody tried to use a el cheapo hose clamp to keep the spiggot from distorting??????????

 

[TurningDog]

"When the bowl distorts it distorts both the spiggot or recess"

has anybody tried to use a el cheapo hose clamp to keep the spiggot from distorting??????????

yeah had that idea did a dozen large bog oak burl bowls and cracked at the base of the spiggot of each one and the amount of CA I had to use to put a dozen 5 inch diameter tenons it back on securely was rather pricey.

 

[john lucas]

I start my bowls between centers so their is a center mark in the back of the tenon or if I choose to make recess I leave a 3/4" tenon that still has the center mark. This allows me to remount the bowl between a jam chuck and the center mark so that I can true up the tenon or recess for remounting.
For reverse turning a bowl check out http://www.cumberlandwoodturners.com/tips.asp
Click on the methods for reverse turning bowls. I've covered most of them in this article. If you have any others let me know and I'll try to get them put in with this article.

 

[Jeff Jilg]

I also roughout bowls between centers. Then, months later, it gets remounted between centers using the previous center mark. Then the tenon gets recut for mounting in the chuck.

You might lose a little bit of wood if the bowl is not perfectly realigned but it doesn't matter that much. Once you eyeball a few of them when remounting you can get it pretty close. I just did this remounting process today on 2 ash bowls that were roughed out in 2003. Works great.

 

[George Van Beynen]

There is a third, of which I am quite fond. Turning on the pin chuck, as I do, I find it an easy matter to punch the center round and mount as it was originally. Rarely is there enough distortion in the old center to make a significant difference in re-centering. Since the pin chuck allows you to cantilever the piece after rounding, it's an easy matter to turn the mortise or tenon round again. If you're a tenon type, be sure to leave the original tenon oversize, or you may run out of grip. BTDT

Michael, how much depth would be required for an approximately 18x8 burl if a pin chuck is used? Does it require a shoulder to index on or does it just hang when a tailstock is not in use?
I have been roughing some burl caps and i think this would be an easy way to get the cap face balanced perpendicular to the lathe bed.

 

[MichaelMouse]

An 18x8 burl sounds like a bit of a drive-by gloat to me.

Pin chucks I have are about an inch and a half in length, and I make sure to bottom them in a Forstner hole. No real external shoulder, but the internal inch and a half depth with a one-inch bottom seems to hold proof against the largest I can turn, especially as I'm using my tailstock until the very last, when the piece is at its most balanced and its lowest weight. If you're making wingy things rather than near-rounds, it might be best to start on a faceplate. Lot of weight in a piece of wood that big, and if too much is on one side, it can work against the hold and loosen it.

Be sure to reinforce the post after drying on a burl. Cracks and pockets can ruin your day if you're not careful. Same holds for faceplates. Make sure those screws have wood to work with, not bark.

No chance you could reduce those to 16" to fit my lathe and send them over?

 

[George Van Beynen]

Sounds like I will have to finally give in and get one. I think it will be handy in a lot of situations, especially natural edge. I usually use the tailstock to the end as you have taught me so I think it would work well other than off the end with the Vicmarc outboard tool rest where the faceplate would be safer.


"No chance you could reduce those to 16" to fit my lathe and send them over?"

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