Threads cut in a walnut post

[4DThinker]

Cut another hub nut today hoping for better results. Tighter fit, but identical slant of the nut when it threads on. My side cutting V-bit isn't long enough to try a deeper cut to see if that helps on the bottom of the threads. GRRR.

[MiloScott]

Cut another hub nut today hoping for better results. Tighter fit, but identical slant of the nut when it threads on. My side cutting V-bit isn't long enough to try a deeper cut to see if that helps on the bottom of the threads. GRRR.

What side cutting bit are you using?

[4DThinker]

Magnate 796. Bought from amazon: https://www.amazon.com/dp/B00LNUJ0UM?re ... asin_title

[MiloScott]

Magnate 796. Bought from amazon: https://www.amazon.com/dp/B00LNUJ0UM?re ... asin_title

Here is a longer version - 751. Remove the bearing and grind off the nub.
https://www.magnate.net/ProductDetails. ... ctCode=751

[4DThinker]

Appreciate the link, but my router is limited with a 1/4" chuck and that bit had a 1/2" shaft. I plan on trying again with a deeper 1.25" cut. I think I can still grip the bit leaving that much under the chuck. I'll post results later today.

[4DThinker]

Third try was the charm. Set the depth of the threading toolpath 1/4" deeper and prayed that the bit wouldn't slip out of the chuck. So I've got a working hub nut with LH threads now, and just need to find another 3/4" thick scrap of red oak to make a good one with RH threads.
4D

[MiloScott]

Third try was the charm. Set the depth of the threading toolpath 1/4" deeper and prayed that the bit wouldn't slip out of the chuck. So I've got a working hub nut with LH threads now, and just need to find another 3/4" thick scrap of red oak to make a good one with RH threads.
4D

Did the full depth cut on the nut fix the crooked bolt portion?

[4DThinker]

Yes. The problem was the toolpath moving inward before finishing the thread cut, leaving a bit projecting into the opening and keeping the post from going through perpendicularly. If I'd had the threads tighter with less slop the post wouldn't have even been able to screw through.

[4DThinker]

I now have two hub nuts that work and sit level relative to the vertical post. RH and LH threads. One from red oak and other from an ash scrap I had.
There is about 1/16" of play between post and nuts. It looks like I could reduce the starting diameter by 1/16" and still have nuts that would screw down the post. As the post is walnut, I'll likely make two more nuts that fit tighter from walnut as I finalize the design. The oak and ash nuts I can use to prototype the strap connections and overall idea.

[Jimcad]

Getting there.
Keep us posted.

Jim

[4DThinker]

Thanks Jim. Using one of the early test hub to check how well my webbing strap connection(s) will work. Hole for a 5mm pin done with a #9 drill bit seems the best fit so far.

Final will use 1" wide straps. These are unused straps I made for my TV tray table designs.
Friction in hole seems enough to keep the pins in place with no tendency to fall out. Once there is tension on the cables that tension will surely keep the pins in place.

[4DThinker]

The underside of the table top.

Ball socket in the center for the post top, actually to be cut in an inset block of HDPE.
Slot near the edges for the strap ends that will run down to a hub nut. Straps will be held in place by a 5mm pin dropped into a slot 90° from the straps. Push the strap end through, slip a pin through the grommet, then pull back until the pin bottoms out in its slot.
4D

[Jimcad]

Show us the finished item please.
Not sure I'm following it yet.
I didn't say I was clever !

Jim

[4DThinker]

Test socket cut in a scrap of HDPE I had. Wanted to make sure the CNC could cut it without melting, and the post ends would fit and spin easily.

Fit was perfect. The post can spin easily in the socket. This scrap was 1" thick and the socket was cut 5/8" deep. I've ordered some 5/8" thick HDPE to cut the final sockets that will inset into the table top and base to "capture" the post between. I'll reduce the socket depth to 1/2" on those. A bit more of the post ends will show.
4D

[4DThinker]

Spent most of the morning waiting on my CNC to cut the table top out. All the details are on the bottom of it.

A mix of moulding and profile cuts. Contouring the surface with the moulding toolpath took the most time. The board was 15/16" thick and now tapers down to 5/8" at the edge. Slots are where straps will attach. Hard to see in the photo but I used the moulding toolpath to round over the inner edge of the 4 slots. The straps will wrap over that edge.
4D