HowTo: Drum Top Table technique?

[Absinthe]

I do not want to buy "bendable plywood", however, I am not opposed to kerfing regular plywood. I am also ok using solid wood.

The question is: (well two of them I guess)

How do I do it with kerfing plywood?
How do I do it with solid wood?

In both cases, I understand the super basics.

I know I have to cut some number of kerf cuts, some depth and some distances apart... All those variables have to be formulaic based on size, thickness, radius etc.. How to I calculate them?
I know I cut pieces of solid wood to make a sexagon/octagon/decagon.... dodecagon... whatever... But stock thickness calculations for such a thing, also must be calculated on similar factors.. How do I calculate those?

Thanks in advance.

-- Abs

 

[Jeff]

What's wrong with using bending plywood? You don't want to buy a 4' x 8' sheet with a lot of leftover stuff?

Bending plywood has all of the layers in the same direction, that's why it bends easily, but regular plywood has each ply at 90 degrees to each other so maybe it doesn't bend so well. Solid wood with the kerf cut might bend easier.

I don't know. I did find this calculator but haven't figured it out yet.

https://www.blocklayer.com/kerf-spacingeng.aspx

 

[JohnnyR]

Thanks for the link, pretty cool!

 

[Absinthe]

Great link. I am not religiously opposed to bendable plywood, just never saw it for sale anywhere I have been, and the thought of ordering something like that shipped sounds like an expensive proposition.. I will ask about it at Klingspore today since I have to go there anyway.

 

[Jeff]

Pretty interesting stuff. Columbia sent me a free small sample awhile back and it was fun to play with (bends pretty easily with all of the plys in one direction).

https://www.columbiaforestproducts.com/product/columbia-radius-bending-plywood/

 

[Absinthe]

Picked up about 20 lbs of maple from the scrap bin. I asked about the bendable plywood and they had no idea what I was talking about. SMFT. I will keep an eye out.

 

[Jeff]

You probably talked to the wrong clueless person at Klingspor.

I'd call a Columbia Forest products local NC salesman first just to ask about it. Then go back to Klingspor to enlighten them: "This is what bendable plywood is and here's how you can order a sheet for me."

Columbia Forest Products corporate is in Greensboro.

https://www.columbiaforestproducts.com/contact-us/contact-columbia-forest-products/?fid=5

 

[McRabbet]

I've made excellent smooth bends with conventional Baltic Birch plywood in both 1/2" and 3/4" (metric equivalents) with equally spaced saw kerfs to a depth 1/8" short of the thickness. Spacing is determined by the radius, but closer spacing than required to bring the bent plywood kerfs together is preferred. I have made smooth curved panels with 12" radius over 4" to 18" lengths. Bending just takes patience and a curved form on the benchtop is best.

 

[Absinthe]

I've tried to enlighten them on EZ Smart before, they don't seem to be receptive to my suggestions of enlightenment. I did contact CFP, but I will contact some of the online places to see where things can be gotten from.

 

[Jeff]

I did contact CFP,

...and...? What is their suggestion on how to buy a single sheet or two?

 

[Graywolf]

The hardwood store carries bendable plywood, and they carry vertical and horizontal orientations.

 

[srhardwoods]

Check with A&M in Charlotte, I get all my supplies from the Richmond brand, and they carry it.

 

[Absinthe]

Just contacted them for a market sample

 

[Absinthe]

I will have to look up their hours and such

 

[Jeff]

The hardwood store carries bendable plywood, and they carry vertical and horizontal orientations.

Thanks. It's way at the bottom of their plywood page. Luan (3/8", 4 x 8) at $44.

 

[Roy G]

Have you considered resawing some wood into thin strips and laminating them around a form?

Roy G

 

[Absinthe]

I have considered many things. I guess I am hoping to hear from someone who has done one with some suggestions on what worked and what didn't. I so prefer to learn from someone else's mistakes than reinventing the wheel and making all the same ones