Need Help with a Curved Box Tower Design

[jmik26]

I am in the planning stages of the Modula MTM or the Nat P's. I want to build curved cabinets but wanted to see if anybody could verify the volume to ensure I am on the right track. Below is what I got laying things out on Bobcad. Maybe a bit unorthodox but its the only way I new to get my point across. I basically made a 7x11 rectangle then added points from there. I extruded the design 31" high and measured to calculate 2503.72 (cubic inches??) and divided by 1728 to get 1.4489 cubic feet? I understand it doesn't take into consideration speakers, bracing, etc... Thanks in advance... Jeff

[snmhanson]

I'd be happy to give it a whack. Just to confirm, inside dimensions are 7" wide at front, 5" wide at back and 8" wide at the wide point of the speaker? Also, looks like the 5.5" measurement the mid-point making the speaker 11" deep, right? Would you use the same 22" height as in the design? Did you use a specific radius for the curve? If so, let me know what it is and whether it is the radius for the outside or the curve or the inside of the curve? If you can get that info I could draw it up on Autocad and get a pretty accurate measurement for you.

Matt

[snmhanson]

Deleted and reposted below...

[jmik26]

Sweet, that would be awesome....

7" Wide front = correct
5" Wide back = correct
8" wide half way through cabinet = correct
11" deep = correct

Height = 31"
Radius = 15.807" from the inside.

Thanks, Jeff

[jmik26]

I had Autocad open so I made a quick drawing using the parameters in the post before and came up with an 11" internal radius. Volume came out to be 1.13 cubic feet or 31.97 liters. Just slightly larger than the design.

Hope this helps.

Matt

Was that with 22" height or 31"?

[jmik26]

This is what I came up with.

[snmhanson]

I reran the calcs - I was using 22" as an internal measurement before (and I had made one other error which I realized about ten seconds after posting). Anyway, with 31" as the internal height the results I come up with are 1.45 SF and 40.98 liters. If 31" is outside height dimension and 30.5 is inside I come up with 1.42 and 40.32.

Matt

[jmik26]

Awesome, so it seems I'm on the right track 8) ... Thanks for your help.... Jeff

[nikbrewer]

what are your plans on skinning them? I have used 1/2" or 3/4" kerfed mdf, with a later of 1/8" masonite to smooth it out

[jmik26]

I scrapped the curved cabinets. I tried kerfing 1/2 mdf with little success. If I had two extra people helping me or built some pretty serious jigs It would have worked but I ran out of patients. There is always next build...

[Jim85IROC]

There's always the option of laminating thinner pieces of MDF. For curved cabinets, I'd rather do 3-4 layers of 1/4" MDF instead of kerf cutting thicker stuff. It should be much easier, plus stronger.

[jmik26]

I would agree on the using skinner stock instead of kerfs. I was kerfing almost 3/4 of the way through the 1/2" MDF and it was still hard to bend, any more then that I might as well glued strips, lol. I even though about 4 or 5 layers of luan.

[nikbrewer]

they make a bending plywood. I used the 3/8" thick, 2 layers, lots of glue between,then skin with masonite. I have had fine luck with kerfing 3/4" even. How tight was the radius?

[jmik26]

they make a bending plywood. I used the 3/8" thick, 2 layers, lots of glue between,then skin with masonite. I have had fine luck with kerfing 3/4" even. How tight was the radius?

34.289" radius

[john trials]

I would agree on the using skinner stock instead of kerfs. I was kerfing almost 3/4 of the way through the 1/2" MDF and it was still hard to bend, any more then that I might as well glued strips, lol. I even though about 4 or 5 layers of luan.

I've never tried bending MDF, but it appears you have to cut more than 3/4 of the way through (from the photos in this link). Here is a cool thread about bending MDF: http://techtalk.parts-express.com/sh...highlight=kerf

[jmik26]

Here is a cool thread about bending MDF: http://techtalk.parts-express.com/sh...highlight=kerf

Cool indeed, thanks... Jeff