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truing a dried bowl

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Forum topic by Karda posted 11-17-2019 06:12 PM 515 views 0 times favorited 21 replies Add to Favorites Watch
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Karda

1816 posts in 1113 days


11-17-2019 06:12 PM

Hi, i am turning some bowls that have been dried and are ready to finish. How do you true up a bowl when nothing is true. Even the tenons or recesses are out of shape thanks


21 replies so far

View bilyo's profile

bilyo

906 posts in 1661 days


#1 posted 11-17-2019 11:13 PM

I almost always make a recessed bottom with dovetailed inside edge for my chuck jaws to clamp into. Yes. After drying, they are usually out of round. When its time to finish them up, I experiment with positions until I find a place where they turn the best. I mark the spot and go. If it is too badly out of round, I will turn it around and, using the original centering point from when I made the bottom recess and with the spur drive inside the bowl, I true up the dovetail edge and then put it back onto the chuck.

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MrUnix

7529 posts in 2758 days


#2 posted 11-17-2019 11:59 PM

Use or make a jam chuck and true up the tennon/recess first, then proceed as normal. I pretty much always leave the ‘dimple’ that the center made when originally turned, just for that reason.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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Karda

1816 posts in 1113 days


#3 posted 11-18-2019 02:16 AM

i usually have a dimple on the tenon but never inside, I’ll have to start. i really don’t like tenons but i can’t make a recess really nice, can’t. Besides I sign in the recess. I can’t seem to get a clean dovetail

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OSU55

2450 posts in 2548 days


#4 posted 11-18-2019 01:21 PM

I use tenons and leave the original dimple from turning the green blank between centers. I use the tenon dimple in the tailstock live center and jamb chucks to align the dried bowl between centers and true up the tenon and bowl bottom. Recesses/mortices are very difficult to reach with this method to retrue, one of the main reasons I dont like them.

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bilyo

906 posts in 1661 days


#5 posted 11-18-2019 02:32 PM

I made a special tool ground at an angle so that I can get in close to the tail stock and cut both the edge and bottom of the tenon. It leaves a small circle around the tail stock that i later clean out with chisel and small sanding disk. Works great.

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Karda

1816 posts in 1113 days


#6 posted 11-18-2019 04:41 PM

ok thanks

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Karda

1816 posts in 1113 days


#7 posted 12-01-2019 03:58 AM

OK I have learned to true the tenon, But this wood is very dry and very hard. every time i touch the tool to the wood it kicks and bucks and slams the tool rest, but it does very little cutting what am I doing wrong. i am really getting frustrated. Ive got a lot of bowl drying

View Nubsnstubs's profile

Nubsnstubs

1632 posts in 2289 days


#8 posted 12-01-2019 01:29 PM

Mike, more than likely your blank is out of round causing what you describe as a Bronc Ride. When you can pass the 8 seconds, you could possibly have gotten the blank round enough to start finishing it.

Another possibility coupled with the Bronc ride is your tool rest might be too low, adding to the rough ride. Verify things are in order, then approach it carefully, and finish the piece.

What is the starting speed you’re using to do this finish turning? ............ Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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Jack Lewis

522 posts in 1637 days


#9 posted 12-01-2019 04:20 PM

In the future, leave just enough meat on the inside bottom for a dimple and drive center also. Then mount dimples between drive center and live center until you make the tenon true. Even if you prefer recesses, remount between drive centers until you can true the recess.
OR! as an alternative, finish the bowl green and let it warp, VERY interesting!

-- "PLUMBER'S BUTT! Get over it, everybody has one"

View Planeman40's profile

Planeman40

1467 posts in 3320 days


#10 posted 12-01-2019 07:16 PM

Sometimes wood appears to be dry on the outside but is still wet inside. Many bowl turners that use wood from the forest pre-turn a bowl or object getting it close to the final shape, then remove the wood to let it sit for a while, like a few weeks or months, and dry out. They then remount and turn to the final size and shape.

-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

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Karda

1816 posts in 1113 days


#11 posted 12-01-2019 11:43 PM

Hi, Jerry the tool rest could be part of it but fro the time i started truing the tenon these dry pieces make the tool jump. Not all the time, on the sides i was able to get smooth cuts but on convex cures its rough. from the cut pattern on the one I am doing now I think I might tun the wall to thin because of the way it is warped. My turnning speed is 750, can’t go lower and the bowl was rough turned in 7/19

View MrUnix's profile

MrUnix

7529 posts in 2758 days


#12 posted 12-01-2019 11:54 PM

Kind of stating the obvious, but it’s really not very different than turning a rough blank.. it will buck a bit until rounded out. Just make sure your tools are sharp and go slow.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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Karda

1816 posts in 1113 days


#13 posted 12-02-2019 01:42 AM

ok just wish i knew how to prevent the tool from bangen on the rest one end is pitted and I will have to redress it. A machinist I am not

View Nubsnstubs's profile

Nubsnstubs

1632 posts in 2289 days


#14 posted 12-02-2019 02:36 AM

If you are right handed, apply a little more downward pressure to the tool on the rest. It shouldn’t bounce, but kick back some as the blank rotates. As it gets rounder, the kick backs should stop and then you should be getting good long curls…... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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MrUnix

7529 posts in 2758 days


#15 posted 12-02-2019 02:41 AM

What Jerry sez… it shouldn’t ‘bounce’ at all. And any pitting on the tool rest can usually be easily taken care of with a metal file or similar.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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