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post #1 of 13 Old 04-26-2012, 10:49 PM Thread Starter
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hard time finding TRUE center

I an new to this site. I have been turning f. or a couple years has a hoppey,Iam not a expert but iam not bad at it. My question is does anyone have a trick to finding true center?My center finding tools are useless unless the wood cut true and square.I measure the size on both sides and split it in half.But it doesnt seem to be cutting it, i made a vase out of maple marble, the piece i didnt cut it came that way.The wood was cut to were it looked crooked, So center on one end didnt seem the same has the other end.So I get low spots and iam getting low spots in a bloodwood bowl iam making.So iam open for ideas to find true center. Thank you chris
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post #2 of 13 Old 04-26-2012, 11:18 PM
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Draw diagonals from the corners, should get you close. Use a compass (the kind for drawing circles) to give you a rough circle. Should get you close. Pics of your problems might help.

That bowl was perfect right up until that last cut...
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post #3 of 13 Old 04-26-2012, 11:24 PM Thread Starter
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whats going on is,when i do my finish cuts half of the piece is clean cut the other half is still rough.Is that from not being center?
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post #4 of 13 Old 04-26-2012, 11:29 PM
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There is no true center of a crooked piece of wood. The only shapes that have a center like you're talking about are ones with perfectly machined edges, like dowels and straight rectangular stock. Unfortunately, with an odd shape like a branch, it's a guessing game. You should be able to get some pretty good guesses, but you really can't expect to mount everything up perfectly.

The problem you're describing is because there are high and low spots in the wood that you're turning. You have to turn all of the high spots down to the low spots, then go from there. Once it's trued up, finding the centers should be pretty easy. That oddly shaped block of wood that is about 8" in diameter isn't going to get you an 8" bowl. It'll probably get you a 6" bowl though. You have to plan for some waste is all of your turnings.
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post #5 of 13 Old 04-26-2012, 11:33 PM
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whats going on is,when i do my finish cuts half of the piece is clean cut the other half is still rough.Is that from not being center?
Finish cuts? Once it's turned and you're about ready to apply whatever finish you want?

Are you turning the piece, then taking it out of the chuck, then rechucking it? If you rechuck in a different orientation, it will turn differently and seem off centered. You have to mark the piece and always put that mark back in the chuck in the same orientation. For example, once I get the piece chucked and trued up, I put jaw #1 on the top, then mark the piece where the center of jaw #1 is on my chuck. That way, if I take it off for any reason, I can get it back on in the same position.
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post #6 of 13 Old 04-26-2012, 11:45 PM
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sawdustfactory is right. the only way to get close enough to centre is cross corners marking. But if you got a thickness planner " for small projects " or depending on the size of thickness planner you use. measure the smallest deminsions, and gradually plane the largest sides, to reach your smallest size, flipping over side to side, try not to remove all the material from oneside, keep planning until you reach the measurement you want, then slowly plane four sides, 1/64" at a time, just to smooth all sides. then cross corner mark. now you are perfectly square and dead centre.( Hint ), once you are square and if you are for example turning spindles, it is safer for you to chafer four sides. your chisel will not dig into your wood, and spoil your work piece. it is petter to have eight sides then four sides. Chafer only needs to be around 1/2". Hope some of this info works for you. Good luck with your projects and be safe.
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post #7 of 13 Old 04-26-2012, 11:53 PM
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Just got a bunch of apple limbs. Cut most for smoking but have some for turning. What should I do?
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post #8 of 13 Old 04-27-2012, 08:35 AM
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Just got a bunch of apple limbs. Cut most for smoking but have some for turning. What should I do?
I've been making some nice bottle stoppers from my Maine apple branches.






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post #9 of 13 Old 04-27-2012, 09:00 AM
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have you run your live center to your drive spur and see if they meet! but if you are rough turning something and than going back after time and returning them, the wood will warp a little. causing you to have those issues. is the wood green or dry?
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post #10 of 13 Old 04-27-2012, 02:12 PM
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but if you are rough turning something and than going back after time and returning them, the wood will warp a little. causing you to have those issues. is the wood green or dry?
Kind of what I was thinking ... if the wood is wet, you don't even need to reverse it or re-chuck it. The wood can warp and distort if you simply look the other way for a few minutes. But then you typically get 2 patches of rough in between the 2 patches of smooth (if the blank was cut in the standard "half cylinder" orientation for face work.)

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post #11 of 13 Old 04-27-2012, 02:58 PM
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Kind of what I was thinking ... if the wood is wet, you don't even need to reverse it or re-chuck it. The wood can warp and distort if you simply look the other way for a few minutes. But then you typically get 2 patches of rough in between the 2 patches of smooth (if the blank was cut in the standard "half cylinder" orientation for face work.)
i just finished a spalted maple bowl, it was around 15 percent, i wanted the warp look to it thats why i did this, but that being said, when i was finish turning it, my front edge of the bowl had to be resurfaced right before i finished sanding it because it warped within prob. 5 mins or less. looks cool tho, but that is my guess on the issues at hand. if you rough turn a bowl and don't want warping to happen the wood has to be stable, around 8-9 percent moisture or lower anything higher than that will most certainly crack or warp on you! hope that helps out
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post #12 of 13 Old 04-27-2012, 10:29 PM
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Finding centre.
Set an arc slightly longer than the radius of a "rough" circle made on the block. Scribe an arc with the compasses centred on the perimeter from 4 or more spots on the perimeter. You will end up with a small polygon/rectangle around the true centre. You can eyeball the centre in this and drill the hole for a screw chuck or dray a more accurate circle on this centre.
It works and quickly.
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post #13 of 13 Old 04-29-2012, 06:27 PM Thread Starter
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have you run your live center to your drive spur and see if they meet! but if you are rough turning something and than going back after time and returning them, the wood will warp a little. causing you to have those issues. is the wood green or dry?
I dont know why i didnt think of that!My lathe is a 12'' c-man the kind with the key way at the bottom and the bed is just a post, so that could be it!I have a 1930's power king lathe that i iam starting to restore.It has a flat bed and you can alligne the tailstock like my south bend metal lathe, I wanna get the going.I really like the vintage machines.but everybody has helped me with the info so thank you. And the wood should be dry,and i do it a little bit at time over the week between work and my 5yr old its hard to get alot of time

Last edited by cms83; 04-29-2012 at 06:30 PM.
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