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Air-dried blanks

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Chris152

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I want to let air-dried boards (about 2" thickness) acclimatise to a centrally heated house before I turn it.
Is there any advantage to cutting into rounds and waxing the edge over just letting the boards sit in the house (assuming the ends of the boards aren't splitting)? Would it be any quicker/ more stable cut to rounds?
Thanks, C.
 

Paul Hannaby

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If you cut and seal, it will take just as long to reach equilibrium. If you want to speed up the process, rough turn what you want to make with it first. That way you effectively reduce the thickness of wood.
 

Chris152

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The boards are still waiting and seem to have reached about 15% mc (I just cut a piece and used a meter that seems fairly accurate). Reading online, I found this:
'As a rough guide to the amount of clearance that should be allowed it is found that most common timbers will shrink by 1.5% to 2% across the grain with a fall in MC of 5%. '
(Brian Clifford at http://www.turningtools.co.uk/howdry/howdry.html)
The plan's to turn my boards into bowls, nothing remotely elaborate or precise, and mostly not big on account of faults running along the boards. If Clifford's rough guide holds for this beech, 1.5 - 2% isn't much movement/ distortion, so I might go ahead and start turning.

Question: do people usually turn air-dried wood for such things as bowls (no lids or things like that) without acclimatising/ drying further?
 

CHJ

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Chris152":mnwot3do said:
…...
Question: do people usually turn air-dried wood for such things as bowls (no lids or things like that) without acclimatising/ drying further?

Everything I've Turned this Year so far has been in the range 10-12% moisture, measured on cut face from rounds cut from slabbed/split logs that have been drying for several years.

You should get away with Platters and Bowls at 15% but be aware of possibility of uneven base if they move, suggest you do as Paul suggested and partially turn a blank and leave for a couple of weeks then remount and finish off if you are in doubt. Or adjust base design to negate warping risk.
Mind you, re-cutting a 'green' turned blank is an art in its own right due to the interrupted tool contact etc. when rounding out.

Turned in one (without roughing out first and acclimatising) at 10-12% as I'm doing you get movement between body and lid enough to cause enough ovality to effect lid fit if it is rotated, answer is to design interface to give the appearance of a reasonable location without excessive slop.


I check any of my lidded items that may have a problem after a week or so to make sure they are still reasonable and if not (rare, had 2 last year) I rework the odd recess/spigot.
 

Chris152

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CHJ":15mec5kb said:
be aware of possibility of uneven base if they move, suggest you do as Paul suggested and partially turn a blank and leave for a couple of weeks then remount and finish off if you are in doubt.
I've never remounted and returned a bowl - is the easiest method placing the inside against a dome attached to the chuck/ headstock and using the tailstock to hold the base? Is there an easy method for doing it once the diameter's larger than the swing will allow - one of those plates with adjustable holds?
Thanks.

ps I'm thinking of your comment on the possibility of a distorted foot ring, Chas - I'm not thinking to re-turn the whole bowl.

pps I've read through this (re-mounting-roughed-bowls-t74664.html) but don't think it's helping me think about how to re-shape a foot with mortice?
 

Chris152

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I read around and decided that as I just want to return the foot ring due to distortion, a donut chuck was the way to go. I have the rear section made with a face ring attached and have been working on the front part this morning. I cut it with multiple drill holes (which made quite a mess of the underside) and then a flexible saw, but now want to turn the inner face (face up in the photo) so it's even and fits more-or-less onto the underside of a bowl (with anti-slip mat between).
Can you turn a piece of ply like this well enough? (I'll be attaching it reversed to the rear section to turn.) Sharp gouge and fine cuts? Or will it make an even worse mess?
_MG_8318.jpg
 

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CHJ

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Ply turns reasonably easily, High quality Ply and its Adhesive may take the edge off tools quickly. If edges are too friable then soak in sanding sealer before final cuts.

Be careful with cheaper (DIY Shed) Ply) adhesive is often not the best and it can delaminate if cross section area is small.
Not a problem in your application but if used as spigot jaws etc. will fail with ease.
 

Chris152

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Thanks Chas - definitely not good quality ply (Wickes) but hopefully it'll be ok - and with a mat between the chuck and bowl, finish doesn't need to be perfect. I'll soak a bit of sanding sealer into the wood before turning and on final cuts, if necessary.
 

CHJ

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This is where you need care with Ply, thick Ply would on the face of it be ideal for this sort of application but the bond between layers over such small areas can be very week. These had to be soaked in Thin CA to strengthen them for use without them 'snapping off' when in use.
 

Robbo3

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Turning plywood, or at least getting rid of the bulk, is a good use of carbide tipped tools & save the repeated sharpening of HSS tools.
 

Chris152

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Thanks Robbo - I used a carbide tool to turn both the inner face of hole in the outer board and the edges of both boards to round. Worked well, and the chuck works a treat.
IMG_1711 (1).jpg

IMG_1715.jpg
 

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Chris152

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All turned at about 15% mc, they seem pretty stable when brought into a centrally heated house, with a little movement noticeable on the larger bowls (I only had to re-turn the foot on one).
_MG_8327.jpg

Thanks for the advice and guidance, all.
 

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Dalboy

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Chris if you make a small hole in the centre of the doughnut chuck say about 1" diameter you can use that to centre a jam type chuck if you ever do natural edge bowls
 

Chris152

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The chuck won't fit over the bed/ bars, Derek - so I think I'd need to make another chuck for that (if I understand)?
 

CHJ

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Chris, if I've got Derek's idea correctly he's suggesting you make a location hole in your rear plate to take a domed plug when needed , something like this I use for holding with the tailstock :-


Then your Donut chuck can trap a natural edge bowl in there regardless of the top edges being irregular should you ever do one.
Donut Plug.jpg
 

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Dalboy

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Chas has got it in one. I may need to make a donut chuck at some stage but only for my larger bowls that will not fit over the bed
 

Chris152

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Got it! And I guess I can just change the bolts for longer ones if the bowl's a bit deeper than it'll hold at the moment.
Thanks both, and that's a great suggestion Derek.
 

CHJ

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Chris152":2byx4rru said:
And I guess I can just change the bolts for longer ones if the bowl's a bit deeper than it'll hold at the moment.
Some lengths of threaded rod (studding) in the shop stock and some nuts and 'penny washers' are always useful to have to hand.
 

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