Didn't take too long.  I cut a single plug using the CNC from a cherry scrap. Cut it in half and glued each in the bottom end of the incorrect slots.  When the glue dries I'll recut the slot where it was supposed to be, roughly 5mm higher up on the legs. 

4D

All fixed.  Flush cut the patches, did  a little sanding to clean up the surface.  Put the inner legs one at a time back on the CNC and cut the slots again, although in the  right place this time. 

Left to do is holes for the binding bolts that will hold the straps in.  If interested in what I'm aiming to do see here:

https://4dfurniture.blogspot.com/2024/03/tension-straps-vs-tension-cable.html

 

4D 

Edited April 7, 20242 yr by 4DThinker

Wrong and Patched. 

Recut.

Second try was a little offset from the first.  Hard to zero exactly the same on any piece removed then replaced on the CNC.   Close enough though, and won't be noticed behind the strap and under the table between the legs.

4D

Got the binding bolt holes cut for the straps this morning.  Double checked before starting and checked again once the toolpaths were loaded that they would be cut in the right place.  Have to make the straps with grommets on each end, but that shouldn't take more than 2 tries to get them just the right length.  Once those are done and verified I can glue the inner legs to the stretchers, put a radius on the outside of the outer legs, and sand it all to get ready for a finish.  Considering Danish oil. Always have liked how cherry reacts to it.   

4D

First try with straps.  Doesn't look bad, but base is spread out too much.  Next try the straps will be 1/4" shorter. 

I like the army green straps with the cherry wood. 

4D

Edited April 7, 20242 yr by 4DThinker

Does it fold out multiple ways? Looks like the ledger strip is on the bottom side of the top unless I'm crazy which may be true if you can prove it beyond a shadow of doubt in court.

5 minutes ago, Grandpadave52 said:

Does it fold out multiple ways?

Yep.  That feature is what the patent for it is about. 

Flip the top over, pull the leg frame through to turn it inside out. Advantage of asymmetric X leg configuration. 

4D

Playing with the macro feature of my camera.  This is what the ends of the straps looks like with a grommet in them.  For this application as tension straps in the folding x-frame TV tray table their ability to pivot around the binding bolt that holds them in the slot is critical. 

The grommet kit I bought came with a punch  intended to use with leather or cardboard or similar sheet materials, but NOT nylon or poly straps/webbing.   I found I could put the punch in my drill press, then manually turn it while pressing down to cut a clean hole in the webbing. 

4D

Edited April 8, 20242 yr by 4DThinker

At one end or the other, depending on which way the stand is unfolded, the straps bend sharply out of the slot to go around then toward the other leg.   This is a CNC cut I plan to do to each slot, on the side they exit their slot from, to take the sharp edge off.

Moulding toolpath in Aspire.  1/8" round nosed bit. 

4D

Results from the moulding toolpath cut:

Now no sharp edges for the straps to rub against.  Outside edges of the legs are already rounded over. 

 

I'll officially declare that all the machining, fabrication steps of this build are done. Legs have all been sanded down  to 220 grit.  The top needs more attention and will be the most interacted with part, so it'll get sanded to 300 or better before getting a Danish oil finish. 

 

The first two TV tray tables I made with no CNC help. That until I changed the 2nd one to straps between top stretcher and back edge of the top.   This cherry  version much relied on the precision available with my CNC.  I could have done the binding holes and slots and such without the CNC, but the need for very precise positioning encouraged use of the CNC.  The pivot bolts were the surprising new feature, and were far easiest to be made on the rotary axis of my CNC.  Had I had a precision metal lathe I could have used it, but that is one tool I don't have. 

4D

Started putting Danish oil on the Cherry parts.  Bought the oil at my local True Value where it was $2 more than their advertised web site price.  Not much of a true value IMO.  Took it home anyway.

 

Left my Chevy Bolt out on the driveway and set up a folding table in my garage for the finishing work.  Big denim tarp over the table.   

First coat.  This evening I'll put a second coat on everything.  Personally I like the color/look of the cherry. 

4D

Edited April 9, 20242 yr by 4DThinker

Agree, cherry has a nice, rich, soothing color which will so gradually darken with age.

Yep.  Can't argue with the look of cherry. 

I was sort of surprised how well balanced the leg frame was hanging from the binding bolt hole for the straps.  2nd happy discovery with their location which leads me to believe it must be mystical perfection.    An arbitrary 5" below the pivot bolt hole with arbitrary 3/4" straps rather than the 1" webbing I started with and might have used. That position leaves the straps just below where the top folds down to when the stand folds flat. Perfectly out of the way to not interfere with the folded up parts. A little kismet. 

4D

Test shots.  Need better photo lights.

4D

Most excellent 4D! Your final decision on strap width and color really complements the overall design and finish. This one is a keeper for sure.

20 hours ago, Grandpadave52 said:

Your final decision on strap width ... complements the overall design and finish. 

The 3/4" wide straps, and their location 5" down from the pivot point on the legs turned out freakishly perfect.  When I first put the parts together with the new straps I was delighted to see how the straps ended up just below where the top ends up when folded flat.  Had the straps been 1" wide they would have been just under the edge of the top. Any higher in position they would have been crushed under the top.  Any lower and they would have been longer than they needed to be.  This kind of verification that something is just right is very satisfying.  I never drew up the parts folded up like the photo shows, and where the straps fell relative to the top was never part of the design intent. 

The other freaky coincidence was that the location of the straps was also the balance center of the inner leg frame. 

Anywhere higher or lower on the legs and I couldn't have hung it safely like this to dry. 

4D

Edited April 12, 20242 yr by 4DThinker

Just now, 4DThinker said:

 

Anywhere higher or lower on the legs and I couldn't have hung it safely like this to dry. 

4D

That's just good planning, right?!! 

Just now, difalkner said:

That's just good planning, right?!! 

Kismet.  Perhaps a coagulation of details I'd come across before but didn't consciously connect. 

Now I'm bored again.  Lined up the three prototypes and it looks like I need a walnut one and a maple one to finish the set of 5. I've got two more ideas for outer leg variations.  

Low resolution quick image or the three.  Ordered some 500w photo bulbs which should be here Monday.  Plan on setting up a backdrop in my garage now that the temps are warming up. I've dug out my photo flood set of lights and want to see if I can remember how to get some real nice images of these. 

I know I have enough Maple to make one out of.  I might have enough dark walnut but will need to check.  I can always pay too much and buy another piece at my local Menards if I get around to wanting some more. 

4D

collect the whole set!!