Replies

1. 
   SgianDubh | Dec 29, 2002 06:56am | #1

   Make the grooves  10 mm (~3/8") deep. Make the panels a width that equals the distance between the bottom of each groove, but subtract between 5 and 6 mm, e.g., full span available between the bottom of each groove = 370 mm, then make the panel ~ 365 mm wide. I have no real idea what that is in accurate imperial measure. I'll let you do the conversion to inches and fractions. 

   Make the panels a length that almost equals the distance between the bottom of each groove. Just knock off about 1-2 millimetres. There is insignificant expansion to worry about in the panel length, but the top and bottom rail that it fits into might alter in width a bo'hair, so you need some allowance.

   A useful rule of thumb, in imperial measure, and with English oak as a large moving example, is to allow 1/4" per foot width for expansion and contraction, i.e., 1/8" either way. But you do need to make an allowance or two for the season in which the piece is being built, for the difference in general conditions between your workshop and the final location, and lastly for how dry the timber is when you start. It's safest to assume the maximum possible expansion and shrinkage ever likely to occur, and build for it. There's a big difference between a house in Arizona, and three months at sea on a container to Australia from the US as the family moves to a new job.

   I'm trying to work out what size bed you're making. Three panels at 15" wide each, plus two muntins somewhere in the middle at about 2" or so wide, and legs at about 3", still only adds up to a bed about 55" to 57" wide-- of course there may be a stile at either end of the panelling that is attached to the leg which would add about another 4"-- 5" in the width to  ~59" to 61". I'm guessing a double size, or you're using wider rails or panels to get you up to Queen. I don't work much in inches, but that's what my sums come up with anyway, ha, ha. Slainte.

   Some stuff I've made.

   
   

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   Edited 12/29/2002 6:57:14 AM ET by Sgian Dubh

2. 
   BG | Dec 29, 2002 02:08pm | #2

   Wworker,

   What slope will you put on the panel with the table saw?...and will the edge be thin enough to slide in and out of the dado with the expansion/contraction of the wood?

1. 
   wworker | Dec 29, 2002 05:44pm | #3

   BG,

   I'm going to run a some test panels at 5, 6, and 7 degrees to see which looks best for this application. I'm thinking that the flatter the angle the better. I, too, am concerned with the width of the panel where it joins the rails and stiles. I may have to relieve the back side of the panel to accompllish this.

1. 
   BG | Dec 29, 2002 06:06pm | #4

   Wworker,

   I did a 15 degree...lots of burn on the wood...used a thin blade, 24 tooth...lots of clean-up.  Testing makes a lot of sense.  BTW, what wood are you using?

1. 
   wworker | Dec 29, 2002 08:18pm | #5

   I found some curly birdseye maple last time I was in east Texas a couple years ago. It should work well for the bed. The rails, stiles, legs, etc are Honduran mahogany.

1. 
   BG | Dec 29, 2002 09:14pm | #6

   ..sounds beautiful...good luck

3. 
   TomFerreira | Dec 30, 2002 06:37pm | #7

   I have attached my formula for making raised panels on the table saw. Sgain's explaination is correct but the thing to remember using the TS to raise panels is that you will more likely interfere with the slope at the top of the groove before you bottom in the groove. This is beacuse there is no falt area to slide in the groove. The trick is to get the expansion band inside the max available band. As the panel gets wider you need to use a wider groove or a more shallow slope(I don't recomend the later because of scale) to increase the max available so that during periods of very dry conditions you do not see a gap, or during moist conditions you do not tear the frame apart.

   Although the drawing shows this incorrectly, make sure your rabbit on the back allows for the full expansion bandwidth.

   TDF

   
   

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   Edited 12/30/2002 11:35:08 AM ET by Tom Ferreira

   
1. 
   wworker | Dec 30, 2002 10:13pm | #9

   Tom,

   Thanks very much for your advice. Your drawing was especially helpful as it made concrete what was to this point only a rough idea. My finished panels will hopefully look a lot like your drawing which I now have printed out and in the shop.

   Jim Izat

4. 
   Leverone | Dec 30, 2002 07:19pm | #8

   All the previous advice you have received is sound and should help you considerably.  I would like to add two tips of my own, having much experience in the past with tablesaw raised panels and very much past and current experience with highly figured woods:

   First, regardless of the final dimension you plan for your panels' grooves, remember that even with the amount of "give" you will have from relatively soft mahogany, be sure to leave enough thickness of mahogany at the facing side of the grooves in the rails and stiles so that if there should be expansion of panels to the snug point on their "ramp" it will not put so much pressure on the groove as to snap the face off.  Once you determine how much you need to leave in front you can work on the most pleasing angle for your raised panels' ramp.  Remember to factor in whether you intend to leave the panel flush or proud of the frames.  Having a panel proud of the frames is very attractive and adds shadow lines and texture.

   Second, it will be very difficult to raise these panels without some burning of the figured maple.  Practice your final setup on scrap until you are comfortable moving swiftly and smoothly from start to end of cut and you will minimize burning.  Then take advantage of this opportunity to (re)acquaint yourself with the quiet pleasure of using a properly tuned scraper.  If the panels will have shoulders, you can still scrape the ramps by working slowly and not risk altering the sharp edges of the shoulders or of the intersections of the ramps, as sanding often does.

   Good luck!

1. 
   wworker | Dec 30, 2002 10:15pm | #10

   Thanks Tom,

   One of my worries has been working this wood without undue burning or tearout. What is your preference: shouldered or non-shouldered raised panels?

   Jim Izat

5. 
   wworker | Jan 02, 2003 05:06am | #11

   Evening All,

   After much thought and conversations with other wiser woodworkers than I, I've decided to forgo the idea of raising the panels in my frame and panel bed for the following reasons:

   1. Keeping the panels from rattling in the winter as they contract do to low relative humidity is much more difficult with raised panels than it is with a tongue and groove flat panel,

   2. Working with the moderately figured wood I have for the panels is likely to complicate the raising of the panels on my TS which is currently my only option,

   3. With the figure in the wood I'm using for the panels, raising them may be overkill in the design. The wood in the panels is also a contrasting color to the frame (mahogany/maple),

   and

   4. Flat panels will provide a more comfortable surface against which to rest my old back when I read or watch TV in bed.

   I am now at the point where I am going to start cutting joinery tomorrow and I am also indebted to those who gave advice on the width and depth of the groove in which to seat the panels.

   All of the above reasons were brought forth through this, my first, foray into this forum. I have to say that I couldn't be more impressed with the depth and breadth of the knowledge that is represented by the participants here. Though this has been my first question here, it definitely won't be my last

   Many Thanks,

   Jim Izat

   [email protected]

1. 
   TomFerreira | Jan 02, 2003 06:13am | #12

   Jim,

   Good luck with the flat panels. These are also fun to make. I'm not sure that with solid wood panels you will not have the same problem with expansion and contraction causing looseness in the winter, but they are simpler to make. There is a product sold in the catalogs called "space balls" which are simply foam balls which go into the panel grooves to stop them from rattling when they are small. These can be found at Woodcraft and maybe Rockler. I have also used weather stripping to do the same thing.

   Here's the link:

   http://www.rockler.com/ecom7/findprod.cfm?&DID=6&sku=2020

   TDF

   Edited 1/1/2003 10:17:04 PM ET by Tom Ferreira