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PostPosted: Mon Nov 27, 2017 1:02 pm 
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Koa
Koa
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Joined: Thu Dec 18, 2008 11:42 am
Posts: 1087
Location: Hudson, MA
First name: Kevin
Last Name: Quine
City: Hudson
State: MA
Country: Usa
Focus: Build
Status: Amateur
A buddy loaned me his Duolian from the 30's It's in OK shape with a nice gray crystallized finish but the action is way too high to play well.
The neck looks pretty straight but tipped forward at the body joint. Seems like its a common problem with old National guitars so I said I'd see if I can fix it up for him. I'm no expert in Nationals....is there anything really scary about a neck reset?
How do I get the neck off? Are the screws hidden under the dot markers? Do I have to adjust the neck stick as well as the heel? Should I un-glue the neck stick to reset it?
Any tips would be appreciated. I've built several non-reso guitars so setting a neck isn't too big a deal. But I don't want to get in over my head with a guitar I don't own eek


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PostPosted: Mon Nov 27, 2017 1:37 pm 
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Koa
Koa

Joined: Thu Nov 04, 2010 1:46 pm
Posts: 899
First name: Freeman
Last Name: Keller
Focus: Build
Status: Amateur
Kevin, I have a spider bridge Dobro from the '30's and a 1980 Dobro Duolian. Both guitars have neck sticks, however they are slightly different. Here is a picture of the Duolian

Image

The neck extends into the body (much like a banjo) and the tailpiece screw goes into the end of it. There are two small mushrooms that support it to the back - you can move, shim or trim them. The heel end is not glued or attached in any way and you are correct, there are one or two screws under a couple of the f/b extension dots that holds the extension down to the top.

You will do about 99 percent of your action adjustment with the neck angle - you don't have much wiggle room at the saddle. You can file the slots a tiny bit but get the angle as close as you can first. Remember that there are a bunch of compromises in setting up a resonator based on how you plan to tune and play it. here are a couple of pics of mine

Image

Image

Image

In the last picture the straightedge is resting on the frets, I'm measuring the 6th string action. This particular guitar has about 16 inch f/b radius (which I don't like) and is set up for a lot of slide playing


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PostPosted: Mon Nov 27, 2017 3:07 pm 
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Koa
Koa
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Joined: Thu Dec 18, 2008 11:42 am
Posts: 1087
Location: Hudson, MA
First name: Kevin
Last Name: Quine
City: Hudson
State: MA
Country: Usa
Focus: Build
Status: Amateur
Thanks Freeman. I definitely can't do much adjustment with the saddle....looks like someone already trimmed that down before.
Can I get the dot markers out with some heat? I was thinking of using a soldering iron and a needle to get them out.
What's a good 12th fret action for a Duolian? The National website says they are set to 3/32" today. But, between the fat fat neck and small frets on this old model I'm not sure if I should go lower.


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PostPosted: Mon Nov 27, 2017 4:24 pm 
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Koa
Koa

Joined: Thu Nov 04, 2010 1:46 pm
Posts: 899
First name: Freeman
Last Name: Keller
Focus: Build
Status: Amateur
As I recall heat works but I can't remember which of the dots has the screws under them. I think I ended up destroying them and putting in new ones. I've had the neck off both my spider and biscuit bridge resos and its been a while.

3/32 (0.095) would be a good goal but you might not be able to get there. Most old reso's have little or no fingerboard radius - that is great for playing slide but not too good for fretting. I think I end up with about 0.075 on the first string to about 0.095 on the 6th - I play a mix of slide and fretted and I try to keep it as flat as I can. Most resonators don't have any string compensation - the saddle is right at the scale so they tend to play really sharp. You can push the break point as far to the back of the saddle as possible - I've seen people go thru all kinds of gyrations to get better intonation. Obviously it doesn't matter with a slide.

If the cone is wonky this could be a good time to upgrade to a new NRP hot rod cone and a new biscuit/saddle. Would love to see some pictures


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