I'm doing up a Marconiphone 55 portable receiver, which dates from 1929. It's nothing special - a bog-standard straight five powered by batteries, but it's pre-1935 and in my opinion is worth preserving. Anyway, what I like about this cabinet is that it is made from solid oak. Well....most of it is. For some bizarre reason the front panel is oak-veneered plywood and for the life of me I cannot work out why!
I could easily understand it if the front panel was intended to be in burr wood, or if there was some reason why a solid hardwood panel couldn't be used. But neither of these things apply. Why make the rest of the cabinet in solid oak, but put a plywood panel on the front? I'm convinced the panel is original, as is the veneer too.
I'm at a loss to explain it.
Nick
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I piece of thin, solid timber that wide would be very prone to warping and/or splitting.
— Joe
Mm. The panel is only 10" x 14" and the cut-out piece above is 3/8th thick so that would have been thick enough. But I think you have hit the nail on the head Joe. Cutting lots of 3/8th thick hardwood would have been quite tough on a fretsaw blade so they would have wanted something thinner and then of course they would fall foul of the risk you point out. So they went for 5-ply which is about 1/4" and simply veneered it. Thanks for getting to the answer
Nick.
I'd agree with Joe's view. For a start, for a wide oak board to not warp in would need to be 'quarter sawn', so would need to be from a tree twice the width on the panel. (Little timber is quarter sawn as it's wasteful). Plywood is much more stable in wide panels, and depending on how the veneer is cut ('rift' or peeled), attractive effects can be had which don't arise with sawn timber.
If you look at modern solid oak furniture - very much in vogue of late - you'll see that the wide boards are made up of strips glued together with alternating grain arrangements to counteract the risk of warping. Cynics might say it's down for cheapness as they can use less mature trees, but to cut and prepare boards 75mm wide, and glue them together into boards maybe 600cms wide isn't a cost-cutting process. (If furniture makers want to cut costs, they use veneered MDF). Fact is, you end up with a stable board, which wouldn't happen with a cross sawn board of that width, which in any event, would have to come from a tree maybe 200 years old, seasoned 'in stick' for several years.
Unfortunately Nick, when your set is fully restored, you won't be able to use that hackneyed TV advert boast 'There's no veneer in 'ere'!
Good luck with the restoration.
Strength....the fretwork cutouts would have a weak point and might split at the thinnest points if it was one piece of oak, plus wide oak is more expensive, I used to cut the stuff from the sawlogs when I had the sawmill.
Lawrence.
Well. I have my answer. Thanks guys, everything you say makes a lot of sense.
So, now I need to re-veneer the front panel. Think I'll be getting those veneer hammers out David
Nick
(09-10-2015, 05:44 PM)SurreyNick Wrote: [ -> ]Think I'll be getting those veneer hammers out David
Nick
Your first task will be finding them Nick!
Ha,ha,ha. You're not wrong there David
I'm going to have to sneak into the garage when she who must be obeyed goes out, carefully hunt around AND THEN TURN EVERYTHING OUT ONTO THE FLOOR! She won't notice and if she does, well....
"I have no idea how that happened love. Perhaps the dogs got in here when I was doing the housework"
Large (ish) thin timber panels would normally be set floating in a grooved frame to allow for expansion/contraction etc, quarter sawn is more stable from a warp/bending aspect due to the elimination of tangential shrinkage due to the way it's sawn, there is radial shrinkage though, it's a lot less than tangential but it will still move, hence the grooved frame, same when laying timber floors, an expansion gap should be left around the edges of the floor, normally covered by the skirting board, same goes for chipboard flooring, if not and the timber or chipboard gets damp or wet for any reason then the floor can blow.
So.... A grooved frame for the panel means extra cost and if it's floating (free to move within the grooves) then mechanical resonances might occur from the loudspeaker unless some form of damping was built in....hence veneer on plywood cheap and effective.
I cut some quarter sawn stuff from saw logs when I was in the saw milling game, not much call for it though in my case, there's a lot of waste if doing true quarter sawn.
This is me slabbing a large lump of Sitka Spruce with my old chainsaw mill, if you look close you can see that I slabbed it just off the quarter, if I had turned that slab through 90 degrees clockwise and cut it into 1" boards then the second board up from the bottom would have been a true quarter sawn board after the pith had been removed.
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Lawrence.