jorjen Posted February 10, 2007 Share Posted February 10, 2007 I would like to start with a couple of apologies. First, I know I promised to post this thread many, many months ago when I built the horns. Sorry for the delay. Second, had I given more thought to it prior to construction, I would have taken more detailed "action" photos of cutting, sanding and assembly procedures. Did'nt think about doing a thread until after completion. Now, as with any project, there is more than one way to skin a cat. The procedures I used were due in part to my extreme lack of woodworking tools. This project could have been completed much easier and in far less time had that been different. So, just kind of had to fly by the seat of my pants. Her we go with the first photo. Just a basic layout of the top/bottom horn flare using dimensioning provided in the Edgar article. Wanted to try cutting the plates on CNC, so I layed it out on paper to have something to show my CNC guy. More on using CNC for this procedure later. Probably will do it different next time. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Next, constuction of the forming jig. This is critical, as construction/assembly of the horn really cannot be completed without it. You will see how it is used in the next few photos. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Next... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Next photo... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Completed jig.... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Another... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Top and bottom plates cut on CNC from half inch Russian Birch Ply. Ready for first sanding. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Notice in this picture of the flared top and bottom plates the "point to point" jump of the cutter head. This is due to close to half inch increments of the flare in the tooling program. One could spend more time and extrapolate additional dimensions between the existing numbers for a finer, smoother arc for the cutter head to avoid the "point to point" problem. In my case I will freehand the plates on a scroll saw or bandsaw in the future. Just kind of wanted to see how CNC would do with this procedure. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 To avoid gaps on the inside of the horn at the joints that would require filling, I decided to construct angled jigs that could be tacked to the plates at the proper angle to allow for sanding on a table belt sander that would provide for a nice clean sidewall to top/bottom plate joint. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Another picture of plates ready for edge sanding... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Top and bottom plates properly angle sanded. Jigs removed... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Another shot... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 One more... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Top and bottom plates tacked onto forming jig by brad with gun at low pressure... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Different view... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 For the side walls of the horn I used 3/8" bendable plywood. This material is somewhat soft with wide open pores when bent to this extreme. I will not use this material again. Next time, I will laminate 2 layers of 1/8" Russian/Finnish/Baltic Birch Ply to form the sidewalls. First applying one layer and then the other. Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Bendable Plywood sides attached to top and bottom plates with Gorilla Glue and brads... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 And another.... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Sidewalls cut and sanded flush with outside of top and bottom paltes... Quote Link to comment Share on other sites More sharing options...
jorjen Posted February 10, 2007 Author Share Posted February 10, 2007 Another shot after sanding... Quote Link to comment Share on other sites More sharing options...
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