Hey all - New to the dobro, but have played roundneck resonators for years. I'm in the process of replacing the cone in my recently acquired Regal. I've got a Beard Legend cone ready to go. The problem I've got is that the cone shelf diameter is a bit small (and probably a bit off-center). Also, the cover plate screw locations are pretty far off. Some of them go into the outer edge of the cone shelf instead of the top of the instrument.
There are plenty of things I'd like to do to get this instrument set up a little better.
First step is to use a 3d-printed jig with a router to get the soundwell dimension up to the 10-9/16" of the cone. Couple of questions -
1) Should I oversize the soundwell diameter? My gut tells me the cone should sit on the cone shelf without any interference from the top. I'm thinking that the best thing (with my garage full of tools) is to get the hole dimension right rather than sand down the cone. I'd like to keep the cone pristine (in case I want to swap it into my roundneck Gretch someday).
2) Should I finish or harden the top surface of the cone shelf? I figured I'd try to sand it to get it flat, but was also thinking it might be good to throw a layer of either superglue or polyurethane so that surface is almost polished flat. I'm not talking about gluing the cone down - Just hardening the surface it sits on. But I'm conflicted about it. I'll almost certainly start with just sanded wood.
3) Brass 4-40 machine screw inserts for the cover plate are also on the menu, but probably need to get this cone in first. Not sure if there are good methods for getting the cover plate positioned properly. The factory sure didn't bother. I think it's off by at least a degree or two.
I've seen some images of other Regal upgrades with opened soundwells, baffles, posts, etc - I may get there, but just starting with the basics of cone and bridge setup to start with. It's my only dobro. What I really need to be doing is to play it. But I can't resist tweaking it just a little first.
Thanks for any advice! ~Ed
I have a Regal that the hole was about 3/8” off center. I cut the sound well out made a new ring out of good plywood redone it all with new post, bracing, etc… I had no choice but to put it back on center cause I wanted my strings over the fret board, among other things. It was worth it it’s held up 13 years.
Oh yea! About the glue on the lip, never heard of that, I suppose it couldn’t hurt, but the cone only really moves when you apply or release string tension. You want the hole a little over size so the edge of the cone don’t spread into it when you bring it up to tune. That’s my take anyway, hope it helped a little.
Your gut is correct. The hole diameter should be oversized to allow for the slight increase in cone diameter when it is compressed by string tension. Make the cone shelf as flat and level as you can. I have had good results with Minwax Wood Hardener. Apply several coats per the directions. Be advised this will result in more brightness and sustain, since the cone shelf will have less damping effect on the cone.
The rim of the cone may not be perfectly flat, so rotate it until you find the fit with minimum rocking and mark the cone so you can easily find the sweet spot again.
Beard uses the machine screw inserts you describe.
First step is done. Enlarged the hole enough to get the cone to sit in with some room. I'll try to attach photos of the jig I used. I also took the height down by a smidge (probably 1/32" or so) just to try and ensure the whole thing is flat (at least relative to the top). I know this will reduce the loading of the cone, but I've got new bridge inserts to install that will let me get that height and loading back up. Sanded the shelf to try and make sure it's as flat as possible.
The first time tensioning the strings, there was a rattle/resonance that was really strange. It sounded like a didgeridoo. Some folks might like that sound, but I didgeridon't. For a bit I thought I had broken the cone or something. De-tensioned the strings, shifted the cone a bit, and re-tuned - Now it's back in playable condition. Maybe loading the cone shifted things to be in contact strangely? Not sure. I did over-tension my high strings initially on the first install.
No surprise - The sustain and volume is better with the new Legend cone. I did the 1/2 turn after snug on the tensioning screw. I'm pretty happy with the sound for the moment, so I'm going to play it as is for a few days.
The strings are definitely a touch lower - My thumbpick is clicking against the coverplate while playing, and that wasn't happening before. I think the bridge inserts will address this, provided I do it right.
RezBluez - Good point about oversize so the loaded cone still has room. I think I accomplished that. Thanks!
SamCy - Thanks for the product suggestion. I'm going to play it as is for a bit, and then do the bridge inserts. If I want more brightness after that (and I suspect I will, based on where it is now), I'll give the wood hardener a shot. Thanks!
Edited by - edhubbell on 04/20/2024 10:59:50
