BR928 Posted May 9, 2011 Author Share Posted May 9, 2011 Very nice build. I have two questions if you don't mind - 1. Which CNC system do you use? 2. The curved sides of the horn appear to be oak plywood or oak veneer covered and not bendable plywood. What exactly are they made of and how did you bend them? Thanks, I have a ShopBot CNC w/ 5HP Colombo Spindle. The sides are oak plywood. The wood is cut, steamed for an hour and bent over a form over night. There is some springback but that is easily overcome when the sides are inserted in dados in the top and bottom. Quote Link to comment Share on other sites More sharing options...
BR928 Posted May 21, 2011 Author Share Posted May 21, 2011 After edge banding all the plywood I can get started on the cabinet assembly. Quote Link to comment Share on other sites More sharing options...
BR928 Posted May 21, 2011 Author Share Posted May 21, 2011 Buscuits and pocket screws with butt joints make assembly simple and easy to keep square. Quote Link to comment Share on other sites More sharing options...
TheEvan Posted May 22, 2011 Share Posted May 22, 2011 Absolutely audacious, Stan! Quote Link to comment Share on other sites More sharing options...
BR928 Posted May 27, 2011 Author Share Posted May 27, 2011 I got the motorboards attached along with the ports. I painted the interior of the ports to get a better contrast when the enclosure is finished. I used threaded 1/4-20 inserts so I can mount the woofer internally for a cleaner look. Quote Link to comment Share on other sites More sharing options...
BR928 Posted May 27, 2011 Author Share Posted May 27, 2011 Starting to take shape. Quote Link to comment Share on other sites More sharing options...
KanedaK Posted May 28, 2011 Share Posted May 28, 2011 Those look great! can't wait to see the final result!![] Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 3, 2011 Author Share Posted June 3, 2011 I put some color on the cabinets. Only one coat of tung oil so far. I hope to start assembling the tractrix horns this weekend. Quote Link to comment Share on other sites More sharing options...
Arash Posted June 4, 2011 Share Posted June 4, 2011 completely Heritage as if came from ancient Greece nice work I have a question... I have a pair of boxes nearly in same dimensions of Cornwalls... they have veneer on them but som eparts are crashed and broken... How can I repair them or at least paint them for piano black? tnx Quote Link to comment Share on other sites More sharing options...
bigrfish Posted June 4, 2011 Share Posted June 4, 2011 interesting, do you have links to the good Doctors work? Best regards Moray James. Moray James, Please pardon the delay in answering you. I do not have any useful links, but he did chronicle the process in some detail here in the forums. Search for DBB Cornscala. He goes by the screen name JWC here, and his avatar is a smiling amplifier with red eyebrows and goatee! The best approach would be to read after his work here and contact him directly, I would suppose. I am convinced his design is one of the best. He is highly dedicated and pays attention, which qualities I admire and respect greatly. If you do decide to build them, I predict you will be pleased with the result. All the best, Chuck Quote Link to comment Share on other sites More sharing options...
moray james Posted June 4, 2011 Share Posted June 4, 2011 Thanks and no worries, looking good by the way. Best regards Moray Jamse. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 5, 2011 Author Share Posted June 5, 2011 With the cabinets about finished and it's time to build the tractrix horns. All of the problems were figured out building the prototypes so this should go pretty fast. I thought I would share the steps I used to build them. The parts are all cut on a CNC router. I first built a fixture to hold the material at a fixed angle while they were cut. This was done to keep from having to cut compound angles, which a 3 axis CNC can't do. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 5, 2011 Author Share Posted June 5, 2011 The angle calculated from ALK's program for a 7"x20" horn is 23.4 deg. Half of that is 11.7 so that is the angle of the fixture. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 5, 2011 Author Share Posted June 5, 2011 Next a prefinished blank is secured to the fixture. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 5, 2011 Author Share Posted June 5, 2011 Dados to hold the sides are cut. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 5, 2011 Author Share Posted June 5, 2011 Some alignment holes are cut and the center piece is secured before the outside cut. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 5, 2011 Author Share Posted June 5, 2011 The sides were previously cut, steamed and formed. They are prefinished and will be placed in the dados in the top and bottom. A couple of braces need to be cut before I can assemble them. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 11, 2011 Author Share Posted June 11, 2011 I got the front and rear braces cut today. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 11, 2011 Author Share Posted June 11, 2011 Here are the major components of the horn. Quote Link to comment Share on other sites More sharing options...
BR928 Posted June 11, 2011 Author Share Posted June 11, 2011 The first step of the assembly is to attach the mouth braces after beveling the edge to match the final curve of the side. Quote Link to comment Share on other sites More sharing options...
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