Hourglass Table Dry Fit

It's all coming together now. With the mortises in the apron stock complete, all the substantial cutting for the table is almost done. Today I dry fit the table together and took the measurements for the lower shelf that I laminated up last week (it turned out fine - i will definitely use this method again.)

With those measurements in hand, sizing the shelf took about 10 minutes and I was able to see the table in its rough final form. Here are the pics:

Thank God for Tivo

I have been gripping over exactly how I was going to cut this mortise in the 45 degree angled surface at the end of the aprons for the hourglass table. My foray into poker chip racks was really just my postponing the cut I had no idea how to make. Then, Tivo saved my sanity.

I have my Tivo set to record Woodworks every weekend and lo and behold, this weekend David Marks was working on a project where he made this exact cut. Here is my adaptation of his method--i built a jig that would hold the apron stock at 45 degrees to the routerbase.

First step is to create a box that can house the apron stock at an angle and accomodate a top that sits parallel to the floor. here is its skeleton, with the top removed.



Here is the entire jig with one of the aprons clamped into place.



The box is not a snug fit for the apron stock, so I wedge it onto place to keep everything square and stable.



And here is a view looking down through the opening in the top of the table at the mortise that is about to be cut. if you look closely, you can see where the mortise has been marked out.



Now cutting the mortise is as simple as using an edge guided router to make the plunge cut. I took special care to make certain that the reference edge of the top is square to the sides of the box, and therefore ultimately square to the piece being cut. Here is the setup:



And here is the result:



For those that are interested, here is David Marks method

Leg Construction - Blanks to finished product

The picture above shows the 3 steps I will be progressing through today. Start with the glued up blanks, then shape the curve on the bandsaw and router table, then taper the legs using the tapering jig. There are lots of ways to do this, and my ways are not likely the best but they work well for me. your mileage may vary.

The first step is to afix the template to the blank. I use double sided turners tape for this--it holds the pieces together well, but is not impossible to remove after use.



Next it is off to the bandsaw to rough cut the shape of the legs. I use this jig i built to make the process as idiot-resistant as possible (nothing, in my experience is truly idiot-Proof).



The jig acts like a poor mans bearing guided router bit. it allows the stock to pass underneath and keeps the bandsaw blade a constant distance from the template. here is a close up of it in action.




after the stock is roughed out on the bandsaw, i use a bearing guided bit (two, actually) to trim it flush with the template. Marc Spagnuolo, aka The Wood Whisperer, just posted a video on template routing curved table legs. One of the issues he adresses is the tearout that comes with trying to flush trim the 'uphill' portion of the grain on a curved piece of stock. He suggests sanding as close to the line as possible for the uphill sections, but i have found this to be time consuming and that it still yields imperfect results. My method avoids 'uphill' cuts altogether. Here is how i do it:

We will employ TWO bearing guided bits in this process. The first step is to determine which sections of the leg will be 'uphill' cuts when the template is on the BOTTOM of the workpiece. i have marked those 'uphill' sections in the pic below so i can avoid them in the first pass. Note that the bit has the bearing on the bottom, and the workpiece is positioned with the template face down. With the bottom bearing bit and the template facing down, i flush trim the DOWNHILL SECTIONS ONLY and then stop.



After that routing is complete, i switch to a bit with the bearing on the top and make the cuts with the template facing UP. the set up is below--note that the X's are still there, as i left these sections rough in the previous pass. through the miracle of Euclidean Geometry, the formerly uphill sections are now downhill, and are flush trimmed without incident (or unsightly tearout.)



the result of the above operations is a perfectly shaped, tearout-free leg. The final step in construction is to taper the planar faces of the legs. I will use the tapered sled i made earlier. First, I afix the leg to the sled with the top against the cleat. the cleat is on the low side of the sled, so i will be removing stock from the foot of the leg as it passes through the planer.

I mark the face of the leg with chalk and in she goes! (low side first)





here is the result, you can see where the taper ends--there is still chalk remaining on the top of the leg. It took about 5 passes to remove ~5/8 of an inch of stock.




once all 4 legs have had their first face tapered, i install a shim so that the opposite face will rest on the sled as though the first side had never been tapered.



I made this shim from a scrap piece of stock using the tapering sled. I passed it through until one end was about 1/16 thick. once the shim is complete, just rotate it end for end and screw it down. Here is it with a leg taped to it, tapered side down.



Pass the legs through the planer as before and you have all 4 sides tapering neatly from 2x2 at the top of the leg to 3/4 x 3/4 at the bottom.

Lower Shelf Assembly

For the lower shelf of the hourglass table, solid wood is not an option. The shelf is bound on all 4 sides by the table legs, and the inevitable expansion and contraction of a solid wood shelf would break the table apart. therefore, I need a piece of 1/2" walnut ply.

I went to my local dealer and of course all they had was 1/4 and 3/4. so i bought 2 pieces of 1/4 and am laminating them to an MDF core. I have never done this before but hear it works well. I'll update if there is any problem.

Starting the Legs, Gluing the Top

Lots of progress on the Hourglass Table over the last few days...

As you many have seen in the background of another pic, I milled the lumber for the legs and top of this table about a week ago.  It is pictured above - the legstock is 1 7/8" square and of varying lengths to fit the template

The first step after milling was to cut the mortises in the pieces of the legstock that will ultimately become the top of each leg.  The position of this piece within the leg lamination is fixed. That is, the top of this segment will always be at the top of the leg so you have a 'reference surfance' from which to cut.  The other pieces are glued together imprecisely, so cutting on them prior to the glue up is not possible.

I worked out the location of the mortises and cut them on my router table using stop blocks and a spiral up-cutting bit.

Once these mortises were cut I could glue up the legs to rough shape, as I did with the prototype.  

While waiting for the glue to dry, I turned my attention to the tabletop.  It will be 3/4" thick and approximately 20x36 in overall dimension. It comes from the same 8/4 stock the legs were made from.  I set aside the best looking 36" of the 8/4 stock and planned to resaw it into 2 10x36 pieces 1" thick.  

Everything went according to plan, until with about 1" left to go on my resaw cut, the board broke under its own internal stress.  one half of the board was so strained, it simply popped the final inch of the resaw cut apart.  one of the resawn boards was so badly warped I was uncertain if i would be able to plane a 3/4" board from it.

Well, turns out I was able to get enough thickness for a usable top.  It is only about 5/8" thick but it is flat and stable.  I edge glued the two boards together after gluing up the legs.  Here is a pic of the final product.

Table Leg Prototype Complete!

Turned out great!  Now to make 4 of them out of walnut...

Hourglass Table Leg Prototype

I milled a douglas fir 4x4 down to 2x2 stock and glued it up so it would conform to my template for the legs of the hourglass table. With the remainder of the stock, i created a tapering sled, which will be used to taper the planar faces of the legs. the final dimensions at the top of the leg are 2x2, and the final dimensions at the foot of the leg are 3/4 x 3/4.

I know that the taper will begin 25" off the ground, and that the thickness of the leg must decrease by 1 1/4" (2 minus 3/4.) To achieve that result, I must taper 5/8" off each side of the leg over the 25" span. Therefore, the top of the tapering sled is pitched at a 5/8" drop over a 25" run. We'll see how things come out.

Update: The leg is out of the clamps and there is a pic below with the template.  Bandsaw, router and planer tomorrow...

Hourglass Table Concept

Here is a concept for a table I am going to build for my wife. She saw a picture in a magazine and i thought I could build it so i am going to give it a shot. I just got a new bandsaw and figured I could put it to good use. I plan to taper the planar faces of each leg using a thickness planer and a tapered sled.

I think the apron is too tall in this mock up. I will probably reduce it by around 40% to make the table feel lighter. I may incorporate a drawer too. The main construction challenge I see is attaching the aprons to the legs--they meet at a 45 degree angle and cutting the joinery will be a challenge.

I'll let you know how this one goes...