*PING* trusound - making the cones

[AJ]

trusound,

You asked about making the cones. No, I didn't use a lathe, although that's the most obvious way to do it. I cut three sets of 3/4 inch MDF disks, each one 1-1/2 inches in diameter smaller (or larger depending on how you see it) than the previous set. The third set became a template for the other two sets, and I just used a 45 degree router bit to finish them. After that, I stacked and glued them and finish sanded.



Some tips on getting them to match.

First, if you use a jig like the Jasper to cut the disks, don't be concerned about exact size for each set. Once you cut the first disk, just use the incremental accuracy of the jig to make the subsequent sets. It's more important that they're all a little under/over sized than to try and tweak each disk in to some perfect number.

Second, use two routers to rough and finish the angle and once you cut the first set, don't touch the setting on the finish router. This will insure that they're all cut the same, whether they're "perfectly" sized or not. Again, it's more important that they are all incrementally identical than if they have a measurably perfect size.

Third, on the smaller sizes, make a guide ring for the router base. There comes a point where you don't have enough surface area to keep the router stable and a simple ring on the outside makes the small pieces easier to rout. For me this came at about 4.5 inches, where the finish cut would take the diameter down to 3 inches at the small end of the taper.

Here's a picture to help explain that part:



The final piece was a bear There's no easy way to hold it down while you're routing the angle. I ended up buying a 1-1/2 inch dowel and using the protractor on my disk sander, I brought the end of the dowel to a point. Then I just sawed it off and finish sanded it to blend with the rest of the cone after it was glued on.

They came out pretty well.