Replies

1. 
   Biscardi | Apr 19, 2006 05:21am | #1

   I found a drawing for a Duncan Phyfe table. If that is along the lines of what you want let me know and I can mail you a xerox.

   Frank

1. 
   DonStephan | Apr 19, 2006 03:56pm | #3

   If you could just reply with the length and width of the top and base that would be very helpful. Thank you.

2. 
   ring | Apr 19, 2006 12:09pm | #2

   Don,

   I've done only a handful of these over the years, and I don't have any guideline for figuring the base size.  I can tell you that the critical thing you need to watch for is that a person who leans heavily on one edge of the table should not be able to tip it.  This will depend on the weight of the table as well as the perimeter of floor that the base covers.  The only practical thing I can suggest is to mock up a base after the top is made, and use a overlarge crisscross on the floor for stability.  Start to shorten the arms of that cross until it becomes unstable, and you will know the minimum base size you need.

   DR

1. 
   DonStephan | Apr 19, 2006 03:58pm | #4

   I agaree completely a mockup would be the best way to determine the size of the base. Unfortunately the interior decorator and client are going to want firm dimensions before approving the project, and there won't be an opportunity to revise the design of the base later.

3. 
   JohnWW | Apr 19, 2006 06:35pm | #5

   The physics of the problem are simple, as the base gets narrower, the table will get less and less stable.  This is true whether the table is on four legs or on a pedestal base. 

   The question doesn't typically come up on four legged tables because the basic design forces the legs out close to the four corners, automatically creating a stable base.

   So to achieve a stable pedestal base the bottom needs to extend out close to the perimeter of the top, especially across the narrower dimension, a 36 inch base width is probably the minimum, but I'd go wider if at all possible. 

   The length wise dimension can come in some, maybe 12 inches shorter on each end and still be stable, but you won't be able to come in far enough to leave full clearance to push in a chair from the ends.

   The second way to achieve stability is to lower the center of gravity by weighting the base but this usually requires a lot of weight creating other design problems and creating a piece of furniture that can be difficult to move.

   Is the design based on a single large column centered in a 78" by 42" top?  This isn't a common design because it is very difficult to achieve a table of this style that is stable, easy to sit at, and sturdy. 

   The typical rectangular table on a pedestal base will use two smaller pedestals using the basic proportions seen in the classic Shaker style dining room tables.  Some of the Shaker tables have a narrower base crosswise than I recommended above, but I suspect that they aren't as stable as most people would desire.

   A final point, pedestal tables have to deal with a lot higher stress on the joinery than most other furniture, so a weak design will create a lot of problems that can take the fun and profits out of a job.

   John White, Shop Manager, Fine Woodworking Magazine 

4. 
   jimmy | Apr 19, 2006 06:40pm | #6

   Would a split pedestal work in your design?  This way both ends of the table will be properly supported.  Kinda long to be supported only in the middle...Jimmy

1. 
   DonStephan | Apr 19, 2006 08:38pm | #7

   Thanks for the additional input. The rough sketch faxed to me includes a single turned vase-shaped column between the top and base. I have some concerns about the relatively narrow top of the column as well.Haven't found any drawings in my woodworking books, but at a store this morning the only example of a solid base had the radius of the top only about 12" longer than the radius of the base. The top of the dining chairs around the table would not reach the tabletop because of the size of the base. The two four-legged pedestal bases extended to within about 8-10" of the "drip line" of the round top.