Banjo Hangout Logo
Banjo Hangout Logo

Premier Sponsors

213
Banjo Lovers Online


Feb 3, 2023 - 5:22:46 AM

wilson88

Germany

6 posts since 10/4/2022

Hello Guys i need your Help,

I got a inexpensive China Banjo with a Brass Tone Ring and it actually is quite decent. Action slighty high at 4mm. I checked the Pot assembly and Theres a Strange Shim between Pot and Neck. I cant say If its Wood, Tape or Cork or some stuff. Should i remove it? I want the Most Tone ofc. Fitting is as expected Not very good but i guess it could be a decent Instrument (actually is) when the Neck/Pot is fitted properly. U think it helps to remove this Shim? Also im thinking of trying topfit the Neck but im Not quite Sure i can make it Work. Would you bother?

Regards

Edited by - wilson88 on 02/03/2023 05:24:14

Feb 3, 2023 - 5:25:23 AM
likes this

1725 posts since 10/12/2011

Folks shim necks to get a better neck angle versus recutting the heel of the neck. This is more than likely what your seeing. Folks use wood, credit cards, and all kind of stuff. I prefer wood if I shim.  Personally I recut heels and get the best fit I can. 

Edited by - buckholler on 02/03/2023 05:26:41

Feb 3, 2023 - 8:44:42 AM

4756 posts since 5/29/2011

You are saying that the action is a little high. If you remove the shim it will be even higher. On an inexpensive banjo it is more prudent to shim the neck than to go to the trouble and time to fit the heel.

Feb 3, 2023 - 2:19:39 PM
like this

13959 posts since 6/2/2008

The effect of removing the shim will depend on where the shim is located. If it's at the bottom of the heel then removing it should lower the action. If it's toward the top of the heel -- especially if it's above the lag bolt (assuming a cheap banjo has only one) that should tend to raise the action.

If your banjo has two lag bolts, shimming at the bottom one raises action, shimming at the top one lowers it. Removing shims from those locations has the opposite effects.

I think at least two of my good banjos have shims. I haven't wanted to have the heels permanently altered.

Feb 4, 2023 - 9:10:45 AM
likes this

wilson88

Germany

6 posts since 10/4/2022

thanks all. the shim is only a patch at the bottom end of the heel where it meets the pot. all the other surface of the neck doesn't touch the pot except the fretboard at the tension hoop. i think going forward i'll try to get rid of this shim and see how it goes. it should bĀ“give me slightly lower action as well.

Feb 4, 2023 - 9:43:22 AM

13959 posts since 6/2/2008

Worst case -- I think -- is you remove the shim and the action gets so low you get fret buzz. But then, the fix is relatively easy and a possible improvement in sound: get the next size taller bridge. If your bridge is 5/8-in, that means .656 (21/32). Or maybe all the way to 11/16. If your bridge is a low 1/2-inch, then the most common taller bridge will be the standard 5/8. Some makers offer 9/16. I think Richie Dotson offers a .600.

Well -- another fix is Stew-Mac's angled shims. With one of those you could shim the whole mating  surface of the heel so that when the neck is re-attached, the angle is changed with the entire heel making contact. I'd go with a new bridge.

Your 4mm string height is .157 inch, or about 1/32-inch higher than 1/8, which seems to be the most common. If the shim is really thin, that's the amount I'd expect the action to come down. If you can get it below 1/8-inch without fret buzz you'll probably find that comfortable.

Good luck.

Feb 4, 2023 - 11:00:50 AM
likes this

Alex Z

USA

5182 posts since 12/7/2006
Online Now

"Action slightly high at 4mm."

Question:  At what fret is the 4 mm, assuming it is the distance between the top of the fret and the bottom of the strings?  12th fret, 22nd fret?

If the 12th fret action is to be raised or lowered by 1/32" (.79 mm), then the bridge would have to be raised or lowered by double that , or 2/32"  (1.58 mm).

If the 22nd fret action is to be raised or lowered by 1/32" (.79) mm, then the bridge would have to be raised or lowered approximately by 1.33 x 1/32, or 1.05 mm.

Hope this helps.

First step is to remove the shim;  then reassess.  The contact between fretboard and tension hoop is part of the geometry, and we don't know yet how any change in that contact will affect the neck angle when the shim is removed.  

Edited by - Alex Z on 02/04/2023 11:01:31

Feb 4, 2023 - 11:06:03 AM

13959 posts since 6/2/2008

quote:
Originally posted by Alex Z

First step is to remove the shim;  then reassess.  The contact between fretboard and tension hoop is part of the geometry, and we don't know yet how any change in that contact will affect the neck angle when the shim is removed.  


This is an excellent observation!

The contact at the tension hoop may be why the only contact of the heel to the rim is at the bottom where the shim is located. That is: contact at the hoop is interfering with contact on the rim. So maybe the entire face of the heel needs to be shimmed to push the fretboard away from the hoop.

Feb 4, 2023 - 2:24:07 PM
like this

15206 posts since 6/29/2005

Shimming is a perfectly valid way to adjust the action of a banjo. A banjo with a properly made wooden shim is just as good as one with the heel altered—maybe better because altering the heel can cause a host of problems not caused by the insertion of a little sliver of wood.

In my world, playability and a good action is more important than preserving the setup of a banjo, that may have not been done right in the first place.

I would not have the end of the fingerboard pressing against the tension hoop.

Feb 4, 2023 - 2:46:26 PM
Players Union Member

RioStat

USA

6024 posts since 10/12/2009
Online Now

Here's the "shim" photo from the OP's homepage


 

Feb 4, 2023 - 4:18:11 PM

Alex Z

USA

5182 posts since 12/7/2006
Online Now

No problem. Tune down the strings. Loosen the coordinator rod a half turn, remove the shim, tighten the co-rod. Retune. 
 

Remeasure action height. Note if fingerboard is still touching tension hoop, and if so is the tension hoop is bent in at that spot. 

Feb 5, 2023 - 8:58:02 AM

13959 posts since 6/2/2008

I would expect removing that shm to both lower action and move the fretboard away from the tension hoop. Whether it will move enough in that direction to eliminate contact, I can't know from what I see. But I believe it will move in the right direction.

As I've already mentioned, shimming the full face of the heel may be enough to provide desired action and clearance at the hoop. If the shim is the same thickness top-to-bottom, then the neck angle should be the same as it was unshimmed. I think.

This doesn't look like the cheapest of the cheap import banjos, so good setup should be achievable.

Good luck.

Hangout Network Help

View All Topics  |  View Categories

Hide these ads: join the Players Union!
0.1875