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Cornwall construction material?


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All:

A couple of things if I may:

1) What was the name of the thread that included the ACAD Cornwall drawings? I cannot recall....

2) In "general" (and I hope someone can elaborate), were the Cornwall cabinets plywood? If they did switch to MDF, when was it, and on what speaker type (I and II? II only?). I have a set of 1976 Cornwall I's that I am going to cut new cabs for on CNC (all plywood), but I wanted to know if other materials were used.

Thanks all!

Chris

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Regarding the plywood versus MDF debate.

Aside from what materials the originals were manufactured from...the differences in materials are more practical.

Plywood is much more resilient then MDF. It does not chip as easily and it is certainly more resistant to moisture then MDF.

But MDF also has superior anti-resonant characterisitcs, and in many ways , it is easier to 'machine' (but I would beware the dust from either!).

So a primary focus should be upon the enviroment in which it will be used and the design in which it will be utilized! And it may be productive to select the material most suited to that intended application.

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From the beginning the original Cornwall II and the Cornwall through 1983 were 100% plywood excluding glue blocks, as previously described, with one exception. On the early models 3/4" pine was used as the connection (I can't think of the right term at the moment) between the sides and what the back screws into and I'd bet also for the same connection to the motorboard. It dries out and shrinks. At some point 1973-74?? they began to use the scrape plywood in its place and it doesn't shrink as much.

Either at the beginning or early in the life of the Cornwall II (1980's version) MDF was used. See the Klipsch link below and look toward the bottom.

http://www.klipsch.com/product/product.aspx?cid=115&s=specs

Now before someone also looks at Klipsch's site at the "Cornwall" and sees it also says MDF, It's WRONG and the picture is WRONG too.

Others have owned more and older Cornwalls, but I have owned 5 pair. The oldest a 1974 and the youngest 1990. I've seen over a hundred and what I've said above "IS FACT JACK"!

I have never seen 1" of either material used, nor heard it referred to by any credible source.

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3/4" always. I've got em from three decades. NEVER MDF, ALWAYS plywood

Think it was a mods thread of title, Lets start a Cornwall Drawing.

Here 'tis http://forums.klipsch.com/idealbb/view.asp?topicID=60171&forumID=71&catID=19&search=1&searchstring=&sessionID={44F7ED1B-FCDA-474F-AF15-6BEB6AC98D1D}

Michael

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May I ask how much you are spending on the CNC router?

I would just go to home Depot with a list of wood panel sizes and have them cut them for you. You would just need a jig saw to cut the motorboard openings.

jc

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For others who are building a cornwall, you may find the above mentioned thread helpful. However, from a build standpoint, it may not be enough. I ended up buying a pair of Corns to better understand the build.

I have an FTP server with pics of my Cornwall refinishing project. It also includes documents such as a list of wood panels that your can take to Home Depot and have them cut for you. You would just need to cut the 3/4 inch strips of wood yourself in the store. These are the "mounting" pieces.

You would have to "jig" the openings in the motorboard. The reason I have all this stuff is because I built me a pair of Cornscalas and I had to understand the Cornwall inside and out.

ftp://www.jwcullison.com/Cornwall/

Personally, I wouldn't consider building a Cornwall after hearing a Cornscala. It is the same cost! Same drivers! Also more versatile for tweaking. Now if you want a PWK original built by you...I can understand.

jc

Motorboard1.jpg

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On 6/8/2005 10:29:58 PM jwcullison wrote:

I would just go to home Depot with a list of wood panel sizes and have them cut them for you. You would just need a jig saw to cut the motorboard openings.

You are aware that Home Depot only does "rough cuts" meaning they don't guarantee any accuracy greater than 1/4". From my experience with them, they aren't going to give you peices that fit together well. I found a local lumber yard with a mill shop. They charged me $20-30 a sheet (in addition to the cost of the 49" by 97" sheet) to do precision straight cuts that were guaranteed. I did route all the opening myself though. Anyhow, being that MDF is so tough on saw blades (and that it saved me a lot of time) I considered it money WELL spent!

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Chris,

I think Jim E. used ACAD to make the drawings. Perhaps you could get those files from him. It might be easier to generate your code that way. (then again, maybe not)

Marvel

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JC:

The CNC machine is at work; I am a production supervisor at a cabinet shop, so no biggie either generating the code and/or cutting panels in my spare time. Management basically told me, "if you want to use the equipment for your own projects, go ahead".

Marvel:

Yeah, a good suggestion, would be a good idea to start with something already done than regenerate it. Besides, if Jim would let me use the ACAD files, I could probably cut him a cabinet or two gratis.

Chris

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BSbutton:

Sure, I don't see why not. I guess the first question would be - what style? I know some motorboards have two port slots, and some three. I also assume these would need to be 3/4" plywood as well (as opposed to MDF), true? Painted semi gloss black or bare wood? How many do you need?

Chris

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Chris (popbumper),

I'm quite willing to share the cad file(s) with you. I would need to know what file type you would need as I am not aware of any cam programs that translate acad files directly. I have the three port version layed out in Autocad Mechanical 3-D or 2-D dwg files. I could also supply you with dxf format files. DXF might be the best bet as it was intended to be a universal file exchange format. If nothing else I could generate a high res PDF file.

If it is of any interest, I have drawn the La Scala and the Belle Klipsch in cad as well.

I am personally not interested in building a Cornwall but a Belle would work.

Jim

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Jim:

We use BobCAD version 20 into which ACAD .dwg format can be directly translated. I need the 2d stuff; I would like to see what you have as far as Cornwall and Belle drawings, please write me offline to discuss further. It would be fun to cut a Belle!

Chris

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