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  • #31
    ... he used a flat bottomed 3mm (.118) for the rough cut and a 1mm (.039) ball end for the finish cut..."

    Did he say why he used such small cutters? I can see he may have been concerned about damaging the Birdseye pattern, but 1mm seems excessively small. The Surface foot/minute number for a 1mm diameter cutter at 18000 RPM is less than 200, if my quick math is correct. If I recall correctly it should be well over 4000 SF/M. I probably should check that as I haven't looked at the numbers for wood in years.

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    • #32
      Originally posted by randyohoh View Post
      Regarding 3D data for drivers, it would be an easy task for a speaker manufacturer to create a model of the outer shape of a speaker without giving away any top secret design information which is in the inside.
      I don't imagine any serious manufacturer not designing prototype in the digital domain. Slicing of part of the frame or just ballparking the rest of the driver is really not an issue. For example, motor can be drawn as a set of cylinders with no details at all. For a fabricator, my interests are thickness and size of the frame and location of the screw holes. It's not a big deal to draw in cad prior to fabricating speaker cabinet but having a drawing handy would save time.
      I modeled another port opening, also for PE flared port and cut it yesterday (4" port) so I now have 3D models for 3" and 4" ports that I can import in other fabrication projects.

      Originally posted by TN Allen View Post
      ... he used a flat bottomed 3mm (.118) for the rough cut and a 1mm (.039) ball end for the finish cut..."

      Did he say why he used such small cutters? I can see he may have been concerned about damaging the Birdseye pattern, but 1mm seems excessively small. The Surface foot/minute number for a 1mm diameter cutter at 18000 RPM is less than 200, if my quick math is correct. If I recall correctly it should be well over 4000 SF/M. I probably should check that as I haven't looked at the numbers for wood in years.
      Yeah, 1mm is very small. Considering that ball mill only cuts with the point on the spherical cutting edge. Perhaps he is using vibration of the cutter to create sort of fuzzy surface that in fact is easy to sand.
      I read about it in old article how cutter vibration can actually create smoother finish.
      http://www.diy-ny.com/

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      • #33
        Isn't it amazing that a 1mm ball mill can be ground, and probably in Carbide? I didn't know about that effect of vibration, do you recall where you read it?

        Regarding design files, there have been times a reasonably complete file would have been helpful to work out clearances inside the envlosure and center distances between throat openings in double waveguides. I usually model the drivers if I have them to measure, and if I need to, but, it seems like a nuisance compared to having a stock manufacturers file. The data sheets PE publishes are good, but don't provide all of the dimensions.

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        • #34
          Although I've been back in the last few months, I had a long break from the board and coming back to see Roman using a RAAL tweeter in his build is amusing to say the least.

          Roman, which one are you using and why did you decide on a RAAL?
          Last edited by Ray Tremblay; 07-16-2017, 06:41 PM.
          Being defeated is often a temporary condition. Giving up is what makes it permanent.

          The Merlots
          Scanspeak R2904/7000's,
          Scanspeak 15M/4531K00's, Dayton RSS265HF-4's,
          MiniDSP 2x8, class D amplification

          Sennheiser HD650's

          Comment


          • #35
            Originally posted by Ray Tremblay View Post
            Although I've been back in the last few months, I had a long break form the board and coming back to see Roman using a RAAL tweeter in his build is amusing to say the least.

            Roman, which one are you using and why did you decide on a RAAL?
            If you look at the post #10, I've explained that this design is by Rick Craig and I am just showing of my CNC and veneering skills. Also, few guys here are now equipped with CNC routers or have access to them and it is a useful discussion as far as subtractive digital fabrication goes.
            While Raal XR20 is a good tweeter I never had a strong desire to use it myself. First of all, I prefer line arrays to conventional speaker design. Requirements for a ribbon tweeter are different. Secondly, I am the only US dealer for Viawave tweeters and GRS145 crosses lower and cost half as much. So, there's no particular reason for me to use Raal unless a customer wants me to design something with it.
            http://www.diy-ny.com/

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            • #36
              Originally posted by TN Allen View Post
              I didn't know about that effect of vibration, do you recall where you read it?
              It was Soviet machinist manual from 1965.
              http://www.diy-ny.com/

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              • #37
                Originally posted by r-carpenter View Post
                Thanks guys.

                The design was developed by Rick Craig for a customer in MN.
                Lucidita is the name of this speaker.
                Instead of working from paper drawings I decided to just 3D model and lay out the parts.
                Veneer is Makore. Initially we were going to use figured Bubinga but to be honest, I am not a fan and at the same time I was able to source a small bundle of Makore from the local veneer dealer.
                Unfortunately, I am not going to get to listen to this design. Shipping Accuton over state line twice is not the best idea, considering it's ceramic and exuberantly expensive.
                Hopefully the quality of the cabinetwork will fit the selection of drivers.
                Oh, so you're just building the cabinets for Rick. Got it.
                Being defeated is often a temporary condition. Giving up is what makes it permanent.

                The Merlots
                Scanspeak R2904/7000's,
                Scanspeak 15M/4531K00's, Dayton RSS265HF-4's,
                MiniDSP 2x8, class D amplification

                Sennheiser HD650's

                Comment


                • #38
                  Originally posted by r-carpenter View Post

                  It was Soviet machinist manual from 1965.
                  Thanks Roman, I'll think on that one, interesting.

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