Author Topic: Excavating trays and table tops?  (Read 7052 times)

chrisstorb

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Re: Excavating trays and table tops?
« Reply #15 on: July 06, 2011, 10:10:22 AM »
Considering larger table tops, 25 ? 35 inches, as opposed to small trays that may be other shapes besides round, evidence seen on original 18th century tables provides much, but not all, of the evidence about how they were made.

Round top tables made in Philadelphia and the surrounding counties (Lancaster city being an exception) have a raised rim ? typically an astragal into a cove ? that is lathe turned and not carved by hand. The shaping of the bottom edge is also done on the lathe. Every table of the scores I?ve examined have four plugged screw holes on the bottom, forming roughly a 12-16 inch square ? evidence of the use of a spider-arm faceplate that must have been something similar to the one in the Dominy?s shop now at Winterthur. On scallop top tables, the lathe is used to turn the bottom edge and the outside of the astragal, and the inner edge of the moulding, the depth of the tray surface is also determined. The rest of the scallop top moulding is, of course, hand carved.

So how is would the remainder of the wood in tray be removed after the rim is turned? The area of the tray next to the rim would need to be cleared with lathe tools to properly turn the rim and this would also set your depth. We?ve concluded that the rest of the tray wood was removed while the top was on the lathe and the lathe tool marks removed with smoothing planes then scrapers. It?s true that no evidence of lathe tool marks is every left on the tray surface so this proposed technique is somewhat speculative ? when we look at engravings of table tops being worked on lathes can you say for sure if just the rim is being worked or the whole top? ? but in practice the technique is quick and efficient. And it needs to be quick because those larger tops start to move when the tray recess is cut ? you turn the rim, then cut out the center in maybe 20 minutes tops and even then I?ll have the cleats ready to screw on the bottom to help control wood movement.

Of course, there are variations in other regions; many tables attributed to Lancaster, Pennsylvania have the rim moulding and bottom edge carved by hand. If they didn?t use a lathe on these areas does it mean they didn?t have access to a lathe? If not how did THEY cut out the tray? Many round table tops made in New England do not have raised lips or sunken trays yet sometimes there is evidence of the half-round edge being turned with plugged screw holes in the bottom from some sort of faceplate.

Hope this helps somewhat, the question that started this off is a real one that hasn?t been addressed in the scholarly publications and the majority of modern how-to books address the problem with routers and such. Hummel?s book ?With Hammer in Hand? really is the one of the few places I?ve seen this dealt with (one sentence in Wheeler and Hayward?s ?Wood Carving? says it all discussing scallop-edge trays, ?To be able to lower almost the whole of the centre recess on the lathe is clearly much quicker than carving or routing away.?)  But get yourself a great wheel, some gouges and scraping tools, move towards the window and then ? turn off your electric lights for atmosphere and great experience.

Chris Storb

albreed

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Re: Excavating trays and table tops?
« Reply #16 on: July 06, 2011, 08:01:10 PM »
Great info, Chris.
Jim- You definitely could go at it with an adze if you were talented and brave. I'm just thinking that if you're only taking off 9/16 or so, you'd want to be really good with it- which is certainly possible.-Al
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chrisstorb

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Re: Excavating trays and table tops?
« Reply #17 on: July 07, 2011, 10:46:39 AM »
Good point Al, and most of the Philadelphia tables have only 1/4 - 5/16 of an inch removed to create the moulded rim. They were trying to leave as much thickness as possible in the top, to allow good purchase for the screws used to attach the top to the iron cross for turning and later to attach the cleats, to maintain a sense of ?weight? or heft, and to protect the top from deforming. If a 15/16 inch board is used for the top, after the interior wood is removed the top can still be 5/8 to 11/16 of an inch thick in the middle.

And boy, putting a premium, highly figured, 35 inch mahogany board on the lathe to turn with no room for error is not for the nervous.

Chris

chairmakerjim

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Re: Excavating trays and table tops?
« Reply #18 on: July 08, 2011, 12:44:26 PM »
Great conversation folks. I guess I'll have to check it on this forum more often.  Best wishes Steve on your project too. 

I should know this, but if we are talking about lathes back then for making a table top up to 3' diameter, were those a type of treadle lathe or maybe even a big wheel lathe? That would be some serious foot power.

It seems like it would be a specialized setup with an outboard side and a faceplate for sure.   

Jim

chrisstorb

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Re: Excavating trays and table tops?
« Reply #19 on: July 11, 2011, 01:51:38 PM »
Yes, I don't think these large tops could be turned without a great wheel lathe. Even the Dominy shop, which was primarily a small family business, had a great wheel lathe with an iron cross on a puppet set-up for table tops even though their surviving table rarely get close to 30 inches in diameter.

Chris