rough turnig green wood with a chuck

[Charles M Gillingham]

I've been turning for about 5 years. I have an old powermatic(circa 1960's) lathe with a vicmark chuck. I have acquired a good quantity of green "Flame" Box elder. The wood is beautiful and I'm anxious to try some of it. I usually turn, using the chuck to hold the piece in a recess/hole I've turned in the base of the future bowl. I wanted to rough turn a bowl and let it dry for awhile before I do the final shaping, sand and finish but I'm afraid the recess will warp while drying and I won't be able to resume turning in the recess when it's dryer. Could you offer other way the accomplish this.

cg

 

[john lucas]

I am assuming that you are starting the bowl mounted with the face toward the headstock. Once you've turned the recess and everything else, before you take it off the lathe bring your tailstock up and let the center point punch a hole in the center of the turning.
Now when everything is dry and warped put a rubber sink stopper over your chuck. Place the face of the bowl over the chuck and bring the tailstock up to engage the center point you put there earlier. Then simply true up the opening. You may have to make a special tool to reach in there. It's easy to do using an old screwdriver. Just heat it and bend about 1/2" or so to the left a little. Then grind a scraper sort of tip on it. You can reach in and reshape the warped opening until it's round enough to accept your chuck.

 

[Jake Gevorgian]

Hey John, I think Charles can't do that, because he has hollowed the inside of the bowl.

Maybe, instead of the sink rubber thing, you can create a large faceplate type of board, mounted on the chuck, that has pencil lines at every 1" increments. Then put the recessed with the center line against the tailstock and adjust the bowl's opening side against that large round board with 1" increments, placing them pretty much equally on all sides of the pencil mark. Then, cut some pieces of wood and, using hot melting glue, secure the opening side of the bowl with the large circular board. Then using John's suggested tool, just true the recess for the chuck.

 

[Ed_McDonnell]

How about using a tenon instead of a recess?

If you can, then cut a tenon on the blank and mark the center of the tenon as described by John. Then after you rough out the interior of the bowl (using the tenon in the chuck to hold the blank), use the same technique to mark the center of the interior of the bowl.

When you are ready to finish the bowl, mount it between centers (using your marks) and true up the tenon. You don't need any special tools to true up the tenon and it's pretty easy to remove the tenon when you are done turning the bowl. You also have the option to turn the tenon into a nice foot / pedestal (or even carved feet) if you like, instead of just removing it.

Ed

 

[Jake Gevorgian]

Here is what I had in mind in a pictorial view. See the attachment.

 

[dbonertz]

What John and Ed describe is the fastest and easiest way to true up a recess or tenon. What Jake shows you would need to true the face for it will warp as well as the tenon or recess. I personally use a tenon because it is easier for me to true up than a recess with the tail stock in the way although many do it that way, with a recess, and it works.

 

[Charles M Gillingham]

Thank you for your quick replies and you have given me a few directions I can experiment with. I've never turned using a tenon, rubber stopper in the chuck or making an attachment to hold the rim of the bowl in the chuck. It's nice to have someone to get some ideas from.

cg

 

[MichaelMouse]

I usually turn, using the chuck to hold the piece in a recess/hole I've turned in the base of the future bowl. I wanted to rough turn a bowl and let it dry for awhile before I do the final shaping, sand and finish but I'm afraid the recess will warp while drying and I won't be able to resume turning in the recess when it's dryer. Could you offer other way the accomplish this.

Think about the other end, because the wood will contract as it cures. Matter of fact, it is an early indicator of readiness to re-turn. http://i35.photobucket.com/albums/d160/GoodOnesGone/Picture-Package-14.jpg Shows what the normal is for a ~2" recess. I then weigh and check for equilibrium.

Now regarding the other end. I use a pin chuck to start almost every bowl. Just too easy (and FAR safer than starting on a spur) to start that way, and I don't have to change jaws on the chuck. At $70 I have the most-used chuck in my inventory. Beauty is, the hole is still 1" along the grain, even though it's a sixteenth narrower across. This makes it easy to drop a Forstner down the mortise, at which point I can mount just as it was when green and turn for round. I just need to open the mortise in the bottom a bit to get it perfectly round. Beauty is, it's almost perfectly centered on all but the most outrageously configured wood.

If you have pin jaws for your chuck - Teknatool type which don't chew the wood - you can start smaller stuff on them. If you like that "woodworm" screw, you may use that. Just leave a pillar in for remounting when you rough. After you're circular, you can finish up the bottom before removing the rest of the inside. http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=BottomHoldProcess.mp4

http://s35.photobucket.com/albums/d160/GoodOnesGone/?action=view&current=150Sand.mp4

Consider how much safer it is to keep the piece between centers until it's circular inside and out, and as light as it's going to get. You can hog hard when hollowing, and even take a hook or two without losing the whole thing!

 

[Charles M Gillingham]

Michael,

I find leaving a post in the hollowed side of the bowl a very helpful idea. I have two pin chucks and I'll try the technique this week. You mentioned weighing and checking equilibrium. Do mean weighing the wood green and weighing before re-turning? Equilibrium=checking for round? Thanks for the comments.

cg

 

[MichaelMouse]

Michael,

I find leaving a post in the hollowed side of the bowl a very helpful idea. I have two pin chucks and I'll try the technique this week. You mentioned weighing and checking equilibrium. Do mean weighing the wood green and weighing before re-turning? Equilibrium=checking for round? Thanks for the comments.

No sense weighing the wood when green. What you do is wait until you observe indications that the wood may be equalized, then weigh. Weigh again after maybe 5 days to see if it's the same. if so, and the shop's been steady, it's ready. The shrink is my favorite indicator, though kissing the wood is also a good one. Wood still losing will feel a bit cooler than the board you know is done. your lips are pretty sensitive, it turns out. Why mom used them to check your forehead!

Mine from bestwoodtools.com http://i35.photobucket.com/albums/d160/GoodOnesGone/Chuck-Sheet.jpg

The only part of the old Masterchuck I would recommend. http://i35.photobucket.com/albums/d160/GoodOnesGone/Old-Chuck.jpg As you can see, two kids worth of turning for tuition took its toll!

When you're ready, use the gouge and parting tool like this. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=PillarSmall.mp4 Remember to snug your hold before you give up any help from the tailstock. Words to live by using a chuck in any wood orientation.

Then peel it out, leaving a 1/2" "button" on the bottom so you don't twist the wood fiber out and leave a dimple. Gouge and/or sandpaper the very last. This shows where the pillar was, just prior to refining the bottom. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=CherryPeelIn.mp4

 

[Mark Levitski]

Whew, you guys make it sound way more complicated than it has been for me. Rough out the bowl and let it dry. Then repeat putting it between whatever centers you like to use for this and true up the recess or tenon for the chuck. Voila-- re-turn and finish it. The tips that have been given for re-centering it are very good. However, as long as you left enough "beef" in your roughout, it does not need to be perfectly re-centered. Try to leave the rough tenon large enough that when you go to true it up when dry it still fits in the same size jaws on your chuck. For a recess (I don't use this too often), I guess you would need to not make it too large to begin with so that the same jaws when expended more will still hold the piece.

 

[dbonertz]

Mark,
Everyone is giving basically the same advice you are with the exception of why not run your tail stock into the tenon or recess before pulling it off of the lathe to mark a center spot. Truth is one should be using their tail stock to rough out a blank anyway so the center should already be marked on the tenon or recess. That way one does not need to leave an abundance of beef which can contribute to a bowl cracking while drying. MM's system works with a tower also and is easy to do but not practical if you are going to core the blank. Ahh so many ways to turn a simple bowl.

 

[MichaelMouse]

long as you left enough "beef" in your roughout, it does not need to be perfectly re-centered.

Absolutely true. However, wouldn't it be nice to KNOW that you can dead center up on the cured piece and have the safety of turning between centers along with the option to cantilever and do the bottom without interference?

Thick walls cure more slowly, and since the wood contracts upon itself, are more likely to develop stress leading to full cracks. Like the book says, half as thick cures three times as fast. My experience as well. When it has to be ready in the short term, cut thin and it will be.

The method works for coring if you keep long jaws available. Might lose one bowl in the nest providing for the jaws, but I don't give more than cordwood price for what I turn, so coring makes little sense. Wood grows on trees.

 

[dbonertz]

Curious Michael how your method of the tower/post works with coring. You can't have the tower/post inside and pull a core since you have turned the inside to shavings making the tower leaving nothing for a core. Our precious wood does grow on trees so make the most out of it and don't waste it.

 

[Charles M Gillingham]

I rough turned a bowl blank yesterday using the tower method Michael suggested. We'll see how it works when it drys. You all have shared some of your knowledge with me and offered a few tips on drying, weighing, using centers ( which I marked) and a new meaning of what a pin vise is. Never seen a pin vise like yours. Much different than my 4 jaw, pin vise. i see where the name comes from.
As to coring; I don't own the equipment, it seems a bit pricey and limiting as to what your final design will be. Generally, I don't buy wood or cut trees solely for bowl turning. I use wood destined for the fire or rotting. This box elder was a blow down, brought home for firewood by an employee of a tree company, who found it of poor quality. I happened to stop and ask if I could have some and was given all that I wanted. 2 1/2 ' dia. rounds, 16"s thick.

Anyone want to venture to guess what a 8" bowl, 4" deep and 1" thick will take to dry in a high desert climate?

Thanks for all you help.

cg

 

[MichaelMouse]

Curious Michael how your method of the tower/post works with coring. You can't have the tower/post inside and pull a core since you have turned the inside to shavings making the tower leaving nothing for a core. Our precious wood does grow on trees so make the most out of it and don't waste it.

Simple enough. You take out a core, drop a one inch by half inch deep hole in what will become the inside center of the next bowl. It will become the hole for your pin jaws when the piece is cured. Core two and so forth. Do your measurements first, so you don't end up with something that hits the headstock, though even at that you're no worse off than you were without the inside hold. Since trees are our main crop here, we welcome the opportunity to make use of what makes lousy lumber by turning and carving the short, misshapen and knotty.

One inch thick is a LOT on an 8" bowl with a simple cross-grain design. You'd probably be safe with a lot less, unless it's that #%^*& madrone. Depending on shape, you could blow the bottom quickly. One inch at >=70 relative moving to ~50 after two weeks will be ready in six weeks if it's light wood, eight to ten if dense.

 

[Charles M Gillingham]

I understand "that #%^*& madrone". The only other time I've turned green was with Madrone. I had a 6' rooster tail coming off the piece and I needed windshield wipers. In the end, it continued to warp and twist for a year or so.

cg

 

[dbonertz]

"Simple enough. You take out a core, drop a one inch by half inch deep hole in what will become the inside center of the next bowl. It will become the hole for your pin jaws when the piece is cured. Core two and so forth. Do your measurements first, so you don't end up with something that hits the headstock, though even at that you're no worse off than you were without the inside hold."

Seems like extra steps for what a jamb chuck will accomplish without drilling. Like I said so many ways to turn a simple bowl. Not to many wrong ways but many right ways.