How would you make this?

[smorgasbord]

Here's the end product:


It's a rectangular block 45mm x 100mm x 300mm (say).


Essentially, I want to cut the faces in blue:

From the end, if you could see the middle, it'd look like:

The ends remain 45x100, but the middle is that parallelogram that fits inside that 45x100 envelope.

Here's another view:


If I were only doing half, it'd look like:


I'm thinking bandsaw with some kind of sled, but not sure how to calculate what angles to position the piece at. Each blue triangular face is flat, so I think if I line things up right I can just push the sled though. But calculating angles and then jigging up are my challenges.

Anyone up for guiding me?

 

[Packard]

I would make it in two pieces and join them in the middle after making the taper cuts on the table saw. A couple of dominoes or 3 dowels to strengthen the butt joint.

Special jigs and the jointer might work also. But two sections, definitely.

 

[Michael Kellough]

Router sled.

Simple kind with a flat platform and generous slot down the middle rather than constricting rails.
Need a stop that takes into account the router base and bit sizes.

You’ll need four different jigs that hold the ends of the stick. Only two if you make the jigs symmetrical so they can be inverted to hold the work for the opposite end (end referring to the section from the midpoint intersection out to the actual end). Since you are working with cad it she fairly easy. Hard part will be figuring out the best way to hold the ends. Since the ends will not be coplanar with the router sled the mortises in the holding jigs will have to be larger or…?

Finish up with psa sandpaper on a hard flat platen. Cut the abrasive into small strips and apply in a chevron pattern to allow some space for waste dust to accumulate. Since there is no “give” from the platen without the chevron dust will quickly accumulate and prevent the “sander” from being coplanar with the desired plane.
Or, keep a stiff brush on hand to wipe the dust of the abrasive every other stroke.

 

[Michael Kellough]

…I think you could do it with just two end jigs.

But forgot to mention above that the workpiece has to be longer than final to account for the stock that is buried in the end jigs.

Mount the work and cut one triangle.
Roll the workpiece and cut a second triangle on the same end.

Swap the workpiece end for end and repeat above.

Then remove the end jigs and turn them around but keeping them on the made ends of the router sled.
Now the four remaining cuts can be made on the square edges as above.

 

[Michael Kellough]

…also, the lateral stop that determines the “belt line” in the center of the piece needs to be finely adjustable on both ends.

Or like you mentioned, bandsaw and hand tools.

 

[Packard]

I predict that any solution that does not include parting the piece in half prior to machining and then reassembling afterwards will require extreme craftsmanship and likely will betrayed by the smallest lapse there of.

Show this drawing to an experienced machinist and ask his approach. I suspect he will agree: 2 pieces and assemble.

Note: The pictured component more resembles a machined part that a woodworking part, which is why I suggested showing the images to a machinist.

 

[smorgasbord]

I don't think I want to risk making this in two pieces, as the leg is very structural.
I may just do the Nakashima Conoid thing, as shown in this post:

S

Post in thread 'Seeking your ideas for: A) Slab desk and B) Small Night Table'

Saturday at 11:38 PM

On the decorative treatment I mentioned above, right now the angled leg is rectangular in cross-section. On Nakashima's Conoid tables with splayed legs, he brought in the sides in kind of a straight-edge hour-glass shape:


Another angle:



Now, my single leg is angled further (25º), but it's the same basic idea with the bridle joint at the bottom stretcher.

Any thoughts on this, or perhaps some other shape?
I do want to keep the leg full cross-section at both top and bottom for structural reasons, but the leg itself is 45mm thick by 100mm across, which has got...

• smorgasbord

Basically, just trim off the edges into a straight-line hourglass. Or, maybe just leave it rectangular. Sometimes doing less is best.

 

[Michael Kellough]

Less. I wouldn’t make a change except maybe raise the belt line a little.

 

[smorgasbord]

maybe raise the belt line a little.

What do you mean by that? What's a belt line in this situation?

 

[Packard]

Turn the flat surfaces as indicated by the blue sections, into continuous curved surfaces. I believe a custom template attached to the work piece and run through either a router table or a shaper would work.

However, the abrupt angle in the middle will be an issue if made in one piece.

The same template concept could make the flat surfaces but would yield a radius in the middle. That could be cleaned up with a chisel, jack plane or a file. To make it look perfect will require skill, however.

 

[Vondawg]

He has the skill

 

[Crazyraceguy]

I don't think I want to risk making this in two pieces, as the leg is very structural.
I may just do the Nakashima Conoid thing, as shown in this post:

S

Post in thread 'Seeking your ideas for: A) Slab desk and B) Small Night Table'

Saturday at 11:38 PM

On the decorative treatment I mentioned above, right now the angled leg is rectangular in cross-section. On Nakashima's Conoid tables with splayed legs, he brought in the sides in kind of a straight-edge hour-glass shape:


Another angle:



Now, my single leg is angled further (25º), but it's the same basic idea with the bridle joint at the bottom stretcher.

Any thoughts on this, or perhaps some other shape?
I do want to keep the leg full cross-section at both top and bottom for structural reasons, but the leg itself is 45mm thick by 100mm across, which has got...

• smorgasbord

Basically, just trim off the edges into a straight-line hourglass. Or, maybe just leave it rectangular. Sometimes doing less is best.

I don't think I would worry about the two-piece issue, since the load is straight down. I would, however, do the joinery first. Lay out the diamond shape, to be sure of the placement, then you still have nice square faces to reference.

 

[smorgasbord]

The leg is at a 65º angle to the horizontal, so the force isn't in-line with the leg.

I'm going to do the Nakashima pinch. Then I might do another pinch on the thickness after trying it out on a piece of scrap.

 

[Michael Kellough]

The narrowest point “the pinch” is the belt line.