Archtop bridge is as low as it can go - options?

[Tom Karol]

I have a new oval-hole archtop mandolin with which I'm very pleased. But there's a significant issue/problem ... or is there? I posted this over at The Mandolin Cafe, but whatever answer would apply to an archtop guitar should apply here as well.

I've tweaked the set-up with my preferred string-set so that it's darn near perfect in terms of neck relief, action height, intonation, playability, and clear buzz-free sound all over the fingerboard.

BUT ...

I've lowered the bridge all the way down so that the bottom of the saddle portion firmly abuts the top of the base portion (see picture below). While the instrument plays well as is, I'd like to try lowering the bridge still a bit more, but I can't! Do I have any options? If so, what are they?

I have local access to a competent string instrument tech and even a fine luthier should that become necessary, and I'm willing to spend a few bucks since I do like the instrument. (A neck reset, however, would not be worth it.)

Anyway, here are my thoughts; would any of these work?:

1) Have the tech remove some material from the bottom of the saddle to allow more room to be lowered before it hits the top of the base - wouldn't need to be much. That seems like the simple solution, but am I over-simplifying?
2) Have the luthier remove material from the bottom of the bridge base and then reshape it to again fit the arch of the top.
3) Get a new bridge or have one made by the luthier and have it properly installed. (But how will that solve the problem?)

If I have to accept it the way it is now, it won't be a tragedy, but I'd still like to make it exactly the way I want it if feasible. Anyone have any thoughts? Thanks!

[P4guitar]

Numbers #1 and #2 look quite doable at home. #2 is best done with double stick tape and sandpaper (Fitting the bridge to an archtop guitar).

[Jimmy blue note]

I would not remove anything from the foot of the bridge, there looks to be a well fitted match there.
Yes you could remove material both from the bottom of the saddle and you will need to remove material from the saddle that contacts the thumb wheels. Be careful here because you don't want to round out that surface. You want that interface to sit squarely on the thumb wheel. It's very easy to round off the bottom surface and that'll result in rocking and unsteady seating which will effect your intonation and the ability of the bridge to efficiently transmit the energy to the top plate. That's why I clamp firmly in a vice and use a chisel, checking it with a straight edge and square.

Another option you don't mention is to cut the slots deeper into the existing saddle. This will seat the string deeper into the saddle. No harm here. This is a technique I've seen luthiers, including Benedetto, use and it assures a solid seating of the string in the bridge, sometimes below the level of the top of the saddle. This option doesn't reduce the mass of the saddle piece and preserves the strength of the carved saddle piece. But you'll need a set of nut files matched for the diameter of each string. Cut with a slight cant off the 90 degree (slight back angle) to assure a solid one point contact at the leading edge of the saddle. You need to do this to avoid 'sitar-ing' effect of a less than clean break angle.
I've actually come to be an advocate of this option. It gives a very solid string seating and a strong bridge.

[Tom Karol]

Wow, you guys are great - thanks so much! So I'm not up the proverbial creek with this! I'll have the fix done professionally.

[deacon Mark]

Tom. this is easy you can do it yourself. Just get some say 220 sandpaper. Take the saddle off and do just as JBN said, sand the bottom of the saddle. Just looking at it you can easily remove the wood underneath between the post and still not disturb the depth of the wheel post position. You have plenty of room to work with. Then you set it back up where it was can adjust down if needed. Just take off saddle and tape some 220 sandpaper down on a perfectly flat surface. Your best bet for a perfectly flat surface is a large piece of square steel put down on a level surface. You can get this at any box store for small change. You could even use a thick metal precision ruler that was wider than the bridge. Tape the sandpaper and go. Do it yourself.

I have not heard from you in awhile hope all is well my old friend!

[nevershouldhavesoldit]

It looks to me like the limiting factor is that the knurled nuts are all the way down on the threaded posts. If that’s the case, removing wood from the bottom of the saddle will not change this and there will simply be more space between the bottom of the saddle and the base. But if the saddle is against the base now, it’d be necessary to trim the bottom of the saddle to allow it to drop if wood is removed where it contacts the knurled nuts (which, as already suggested, is one way to add adjustment space).

Another alternative would be to use thinner nuts under the bridge. This, too, would require wood removal from the bottom of the saddle to make room for lowering it.

Whenever I see this problem, I want to know why it happened. The instrument was almost certainly made with a normal range of adjustment. So something went awry over time. I’ve seen this happen on guitars that had neck problems and either needed a reset to correct the angle or had enough bowing to keep the action too high with the bridge all the way down. I don’t think it can develop unless something is wrong.

[Jimmy blue note]

Whenever I see this problem, I want to know why it happened. The instrument was almost certainly made with a normal range of adjustment. So something went awry over time. I’ve seen this happen on guitars that had neck problems and either needed a reset to correct the angle or had enough bowing to keep the action too high with the bridge all the way down. I don’t think it can develop unless something is wrong.

It's not a given that instruments are set up with enough clearance for adjustment. Having worked at the factory end, the retail store end and the customer end doing repairs for customers, I've seen PLENTY of instruments that haven't had any room for adjustment. That includes truss rod travel, bridge height on flat tops, bridge height on archtops, ukes and mandolins.

They are assembled on a production line. If it doesn't play and it's caught by QC, good for the customer. If it plays but there's no room for adjustment, that is not grounds for rejection if it can make it to the showroom floor and be turned into cash.
More so for instruments like mandolins and low-mid range guitars.

Seen lots of guitars that had no room for adjustment and I'd say the vast majority of those sold to casual consumers are relying on those customers to never need further adjustment.
I taught guitar at the Adult Education School with a turn over every 16 weeks or so; I saw a LOT of guitars. I'd do action adjustments because it makes it easier for a beginner of course. How many were set up impossibly high from the factory? How many saddles were bottomed out? Countless. How many other teachers would have been able to plane the tops off a flat top bridge and lower the bone saddle? I'd safely say none. Does the guitar maker (or mandolin maker) care, as long as it's deemed playable on Guitar Center floor? Nope.

Luckily, we have a community here that can talk some of this through with the frustrated mando owners. But yeah, we may expect the highest quality standards, but it's far from the norm.

[Tom Karol]

Thanks again to all. I did have the option to return it as defective, but the instrument is otherwise very good for its modest price and you've shown me that fixing this one problem is relatively simple. Will update here when fix is done.

[wintermoon]

I'd take it off the bottom of the bridge base unless there's room at the nut for the strings to be lowered and still have it play well.
NSHSI is correct in that it looks like the thumbwheels are bottomed out so unless you're going to take more off the bottom of the saddle where the wheels are after sanding down the bottom of the flat part, or the tops of the raised areas of the base under the wheels, you're stuck [I wouldn't touch either of those areas]
If you remove it from the bottom of the base where there's a lot of meat it'll solve the problem w/ out compromising the looks of those two areas. If you're not experienced w/that I'd take it to a good luthier as it's a little trickier to sand the curved areas and get good contact as opposed to just sanding the saddle.

[Tom Karol]

I took it to the best luthier I know, Glenn Nelson at Mockingbird Music in Berlin, MA. He's going to take material off the bottom of the bridge base since it's quite beefy (see picture in OP) as well as do whatever additional setup work we agree is advisable. He says it's a particularly good sounding Kentucky (Saga) KM-270, so in spite of the fact that it won't end up being the great value it first seemed to be, it may end up being a keeper even when I choose to aquire a higher-end model down the road. I'll get it back in a week or so.

[Alter]

On an archtop guitar, the sound of a string that rests on the top of a wooden bridge and the sound of one that is in a slot on top of the bridge are quite different. It is easy to test, just move out the string from a slot and tune it again. To me the sound without slots is much better, more bass and more harmonics, at least on my guitars. They do develop small slots sometime from string pressure though..

[Jimmy blue note]

On an archtop guitar, the sound of a string that rests on the top of a wooden bridge and the sound of one that is in a slot on top of the bridge are quite different. It is easy to test, just move out the string from a slot and tune it again. To me the sound without slots is much better, more bass and more harmonics, at least on my guitars. They do develop small slots sometime from string pressure though..

It's funny that you say that. Absolutely I agree that the sounds are different. I like the "embedded" string sound in a wood saddle. I hear a clearer attack and the transients are crystal clear, so for me, I slot the treble strings, and each string has a different (decreasing towards the bass side) depth. But I happen to like this sound. I think it actually encourages harmonics. But to be clear, I'm NOT a flatwound mellow sound guy, I like the sound to pop out and work with the sound of the carved arched wood.
It's very interesting how the inherent sound of a guitar can be changed so considerably by something like this. For me, it's an important part of customizing the sound of an acoustic archtop guitar even if it's amplified.
I cut the slots into a Benedetto B-16 and it changed it from a nice warm, but closed sounding instrument into one where each note, especially in faster runs, sounded and felt clearer.
It really did change the way the instrument actually felt to play. So it's very much an individual thing, and one to be aware of when setting up a wood saddle archtop.

[Tom Karol]

Before:


After:

[wintermoon]

Cool beans Tom, I kinda figured taking it off the bottom would be optimal. If you didn't see the 'before' pic you'd never know.

[unknownguitarplayer]

I had a similar problem with a cheap guitar I bought off the web as an experiment. I was preparing for the bad news the that the repair would cost more than the guitar, but when I showed it to my local guitar tech, he said, "oh yeah, just needs some thinner knurled nuts. I've got some in my scrap box." Turned out to be a 5 minute fix. I hope you have similar luck.

[Freeman Keller]

I'm just going to throw out one more possibility. Many builders feel there is an optimum height for the bridge to get the break angle/down force/ top deflection that they are looking for. That might mean that instead of lowering the bridge to suit the neck you need to reset the neck to suit the bridge.

[Tom Karol]

Unknown & Freeman: Thanks for the on-going commentary/advice, but it's fixed!
The 'Before' picture is how it was then; the 'After' picture is how it is now.
And it plays and sounds great!

[Archie]

Unknown & Freeman: Thanks for the on-going commentary/advice, but it's fixed!
The 'Before' picture is how it was then; the 'After' picture is how it is now.
And it plays and sounds great!

Did you find any noticeable change in sound/tone?

[Archie]

Your best bet for a perfectly flat surface is a large piece of square steel

I’ve always used a piece of thick, or toughened glass, to sharpen my chisels. Usually dead flat.

I dislike the sanding on the guitar top method. The sand paper enlarges the arch due to its inherent thickness and no matter how hard you try, you’ll always rock it when moving back and forth. This usually leads to a high spot in the middle of the base and the contour will be of the arch+ sandpapaer.

You also run the risk of getting ebony particles in between nitro cracks, depending on guitar and age etc..

I know it’s a tried true method but not one I’ve been able to get on with.

[Tom Karol]

Did you find any noticeable change in sound/tone?

Actually, no I don't think so. It sounded good and played well before; I just had no way of lowering the bridge further if I chose to do so. Now the saddle is in the middle of its vertical range of travel.