My first Gold Star GF-85 had a pro setup, and it was perfection. Sadly had to sell it back in 2005 when I needed the cash. Fast forward to today, just got a used GF-85 on Ebay. Found the action to be too high , switched the 5/8 bridge for a 1/2 and it improved the action greatly EXCEPT for the low wound D is buzzing. So I had to go back to the 5/8. Would like some advice as to how I can set it up with the 1/2 and not have that one string buzz. Or maybe you would have me go in a different direction bridge wise I am no expert. Ideally I would like 3/64 - 4/64 at the 12th fret . That's what I like my Les Paul at, but perhaps thats an unreasonable goal. (again, I'm no expert) Many thanks !
I would first loosen the co-ordinator rods and then tighten them again, leaving them "neutral". Then check if the action has become lower. If not, or if the action is lower but still (a bit) too high, check if the neck has not got too much neck bow. There should only be a very slight neck bow (the neck should not be completely straight).
Too much neck bow can cause a too high action. The neck bow can be adjusted with the truss rod in the neck.
If nothing helps, you probably need a neck reset. I would argue against using the co-ordinator rods to force the neck keeping the action low. This will put a lot of pressure on the rim, impairing the sound quality and possibly causing the rim to go out of round.
A neck reset would have to be done by a luthier who knows about banjos. Alternatively, you could also put a shim between the neck and the rim, which could also work.
Stick with the 5/8" bridge. If this banjo needs a 1/2" bridge, there is something wrong.
IMO a 5 string banjo, if set up to play bluegrass, does not need to be set up similar to a Les Paul electric guitar as a guide. Two different instruments. Also, just my opinion, but you need more clearance than what a 1/2 inch bridge will give you. Something else needs to be adjusted to get the proper clearance you need.
Ideally I would like 3/64 - 4/64 at the 12th fret . That's what I like my Les Paul at, but perhaps thats an unreasonable goal.
I believe that's an unreasonable goal for banjo.
Gibson spec was 7/64 at 12th according to old posts on the Hangout. 7/64 at 12 will produce close to 1/8 at 22. I believe Deering is 1/8 at 22. Stelling may be 1/8 at 12, which is slightly higher at 22. I believe all of these are considered low action.
I like low action, too, and for a long time had 3/32 (6/64) at the 22nd fret. I now play at closer to 1/8 at 22 with either 5/8 or .656 bridges, depending on the instrument.
So my suggestion is try to play with slightly higher action than you're after so you can keep a standard 5/8 bridge.
If very slight co-rod adjustment won't get you to the action you want, then try shimming the neck at the upper lag bolt. Typical shim materials are wood veneer, credit card, aluminum can or flashing, or brass sheet available from hobby shops. You can actually find this stuff sold as "shim stock."
I agree with above posts that a 5/8 bridge is a minimum for most bluegrass banjos, such as yours. You need pick clearance and get better sound in my opinion. I set my action at 3/32" above the 12th fret, which is low for many, but suits me. With age, I have gone to 11/16 bridges for more string clearance near the neck, but that is a result of less accurate fingers. I still stay with 3/32 over fret 12 by doing my own neck fitting. I think your goal for action will require very gentle picking and result in poor volume compared to what most of us use.
"Ideally I would like 3/64 - 4/64 at the 12th fret . That's what I like my Les Paul at, but perhaps thats an unreasonable goal."
At first, I thought you mean 3/32 - 4/32, which is low to medium for a banjo. But since you mentioned the Les Paul, and the Les Paul is unlikely to be 4/32 = 1/8 at the 12th fret, appears that you do mean 4/64.
Yes, 3/64 - 4/64" is an unreasonable goal for a 5-string banjo played with picks, if the intent is to get clear tone at even a low volume.
The difference between a 1/2 and 5/8 bridge is 1/8, which will make a difference of 1/16 in string height at the 12th fret. If the buzzing D string is the only problem at 1/2" bridge, and 5/8 is too high, then get a custom-made bridge in the middle, 9/16". For $30, you'll be instantly happy.
Some bridges are designed with the fifth string higher (usually for frailing), If nothing else works, and you're getting a custom made bridge, perhaps you could get the 4th string higher. In fact, now that I think of it, have you checked that the 4th string slots in your nut and your bridge are the same height as the others? It might even be as simple as that, and a $5 bridge or $25 nut might solve your problem.
Took it to my friend that owns a music store, he has a lot of experience setting up stringed instruments of all types. We reset both coordinator rods, tweaked the truss rod slightly and fashioned a shim from a Fender light guitar pick. Now it plays nicely, with 5/8 bridge.