Interior beveled squares

[ear3]

I'm exploring taking a commission to build some display pedestals, but the desired specs look to be a bit more trouble than my schedule permits me to deal with at the moment.  I wanted to lay it out here though and get a sense of how you guys might do this work.

You'll see in the examples pictured below that it involves constructing a normal four sided pedestal, but that there be one or two interior boxes the purpose of which is to display a book.

[attachimg=1]

[attachimg=2]

The main pedestal will be constructed from mahogany veneered plywood, but what the artists want is for there to be a seamless transition between the pedestal and the interior box.  This would call for doing a 45 degree bevel joint on the cutout, and then constructing the interior box with matching bevels to join and thus hide the plywood edge.  I could see maybe being able to pull this off on the second pedestal -- say, use a 45 degree chamfering bit to finish the edges of the two cutouts, with a scrapwood guide for the router bit bearing applied with double sided tape to the outside of the pedestal, and then work by hand with a chisel to square the corners while continuing the 45 degree bevel.  But I don't see being able to pull off with any degree of precision the same operation for the cutout for the first pedestal, which, as you see, spans two sides of the pedestal.

An intermediate solution might be to edge band the cutout, and then just build the interior box with straight 90 degree edges.  This would still involve some hand tool precision to square the corners, but again, this still gets into some pretty tricky work on the second first pedestal.  And it's not clear in my mind whether this would even look good, as one would definitely see the abrupt transition between the edge banding and the veneer face of the interior box.

I was considering asking for some slight modifications in the design to make it more straightforward to execute, something where the interior box would be more like a prefabbed insert that would sit slightly proud or overhang the edge of the pedestal, the way, say, a sink nests into the cutout of a countertop.

What do you guys think?  Is there perhaps an easier solution I haven't thought of?

 

[bnaboatbuilder]

Since the main issue arises from covering exposed plywood edging, design it with solid mahogany. The cost can't be much different when you consider the extra time dealing with the plywood edges versus less time on solid wood that may have a slightly higher cost. A sheet of 3/4" mahogany ply is $100-150 depending on location etc. How many board feet of 4/4 mahogany would you need? Khaya is about $6/bd ft locally for me.

 

[ear3]

That's a good suggestion that I was thinking about as well.  The pedestals are 12x12x40 -- so as long as I can get some 4/4 boards that were >12" I might be in business.

It would take 3 sheets of plywood to do the pedestals, so let's say $350-$400 for ply construction.  For all three pedestals it's about 50 65 board feet.  If I use Sapele, which I can get for around $6-$7 a board foot (maybe a hair more for boards that wide), then we're looking at not that much more in materials cost, and certainly A LOT less in labor.

At the lumber yard I regularly go to in the Bronx (Rosenzweig), I see wide Ribbon stripe Sapele and 5/4 flat cut all the time, but when I was there earlier this week sourcing materials for some shadowboxes I'm building for the same artists there was a limited amount of 4/4 flat cut sapele in that width -- I guess I'll have to call around.

I'd still be interested to know how you guys might do it if I stuck with plywood.

Since the main issue arises from covering exposed plywood edging, design it with solid mahogany. The cost can't be much different when you consider the extra time dealing with the plywood edges versus less time on solid wood that may have a slightly higher cost. A sheet of 3/4" mahogany ply is $100-150 depending on location etc. How many board feet of 4/4 mahogany would you need? Khaya is about $6/bd ft locally for me.

 

[bnaboatbuilder]

If you do go with solid wood, I would suggest not using 12" wide boards but glue up narrower pieces. That makes a much more stable board. I like the very subtle or almost invisible edge lamination look than the veneering patterns of ply.

If staying with plywood, cut out the book nooks first, cut all the miters and assemble the boxes. Then once you see the plywood edging, I think it will look straightforward. The side nook will be the one that requires the left edge to be covered, probably the only complicated part of it all. The depth of the nooks will be more than 3/4" I would assume. So increasing the depth of the nook will need to done before the edge veneering anyway. I would use a hide glue for the veneers instead of standard wood glue (Titebond). Easier when performing the final finish, oil, poly, whatever.

 

[ear3]

[member=23087]bnaboatbuilder[/member] Huh...why do you think the two board plank would be more stable vs. a single board?  Even if I reversed the direction of the grain on the two boards making up the planks, wouldn't there be more risk of the sides bowing?

This would add on more labor and materials costs however -- I think generally I can't get 4x4 sapele in anything under 8", so I would have to multiply my materials by at least 1.33, and then there's the extra work of creating all the wide planks.

If you do go with solid wood, I would suggest not using 12" wide boards but glue up narrower pieces. That makes a much more stable board. I like the very subtle or almost invisible edge lamination look than the veneering patterns of ply.

If staying with plywood, cut out the book nooks first, cut all the miters and assemble the boxes. Then once you see the plywood edging, I think it will look straightforward. The side nook will be the one that requires the left edge to be covered, probably the only complicated part of it all. The depth of the nooks will be more than 3/4" I would assume. So increasing the depth of the nook will need to done before the edge veneering anyway. I would use a hide glue for the veneers instead of standard wood glue (Titebond). Easier when performing the final finish, oil, poly, whatever.

 

[Michael Kellough]

With the plunge cut track saw it’s difficult but doable. I wouldn’t want to try it in a garage environment. You’ll need to make test cuts and get good at making backwards plunge cuts or cutting from the other side. Since the load on the inset box is low you can over cut the miters so you only have to finesse the visible joint. Add glue blocks in back.

Make the money sides first and then build the pedestal around.

IMO using solid wood would increase the hassle. I’d use veneered mdf.

 

[Jimdude]

I would cheat. Don't - try to - cut holes, cut all the way through the board. Then take out the middle piece - i.e. the hole - and reassemble the resulting 4 pieces (*) with domino's or  lamellos. After some sanding and finish the cutline should be invisible.

(*) 4 pieces for one hole, of course. You have 2 holes to cut, so you'd have 7 pieces in total.

 

[mwildt]

May have to make sure the storage 'pocket' is deep enough so the book standing there can be on a slight angle so it does not fall out.

If using boards could they be narrow such that just use different lengths as to get the hole ? Not sure if you get what I mean. A little imagination using ascii below. So one long board followed by 3 short ones (top, middle, bottom) one or more to get the width, then a final long one to close the hole. Now you have the Front with the two holes.

III
I I
III
I I
III

 

[bertv]

Plywood all the way. You have a more consistent look of the grain, it is easier to work with and far more stable.
Use veneer to hide the cut out (in)sides.

 

[bnaboatbuilder]

I understand cost/time aspect as far as choice of material, but aesthetics is also just as important. Solid mahogany 9 times out 10 will be way more beautiful than mahogany plywood. Plywood grain is sterile, sometimes lifeless, unless hand selected which is darn near impossible, because a stack will all be coming from the same batch. At that point it is more Ikea and lack the look of real wood. Plus you'll wind up with sharp edges that just can barely be eased without cutting through the veneer edge. Nice thing about edge banding is that the veneer is thicker than regular outer ply veneer thickness. In this situation though, that won't help all that much.

 

[ear3]

Thanks for all the replies.  I asked for some design modifications and got them.

We're going to go plywood, build an interior box for the shelf that will be flush with the pedestal faces, and then trim around the edges with an unobtrusive, thin moulding that I will mill and then apply in door casement fashion.

I agree that hardwood would be the best from an aesthetic standpoint, but it came down to a cost squeeze, so it needs to be ply.

 

[CopperKris]

If I was doing it, I would either redesign for solid mahogany, or at least that one side of the pedestal.  You could cut out the opening the size you want, and laminate a piece to the back of it...as if you laminated it and then chiseled out the vacancy. 

 

[nclemmons]

Edward -

Might be a great project for your Shaper.  You could do a rabbet to almost full plywood depth from the back of the plywood for the book insets.  Shaper should let you leave 1/32 or even 1/64 as a “veneer” and just slide in a box from the back or even 3/8 veneered ply.  I’d probably use MDF Core or even lumber core veneered ply.