Archtop Floating Bridges and Intonation

[Etienne Rambert]

I was fooling around with my archtop. I moved the bridge to lower the action a tad. I moved it toward the tailpiece.

 

Wow! Action was only slightly lower. But the intonation went wierdly down. I could tune the strings to A440. At the 7th fret though, on each string, the intonation was flat about 1/4 tone. Open chords played beautifully.

 

So I moved the bridge back to where the luthier had originally placed it. Perfect tune & perfect intonation again.

 

I'm wondering what is the purpose of a floating bridge at all, if you can't move it around without affecting intonation? BTW, the brass screws that supposedly lower & raise action are not hand-turnable. That's wierd too.

 

Any experience with these issues or comments?

 

[guitarist21]

Warning: I know nothing about what I'm going to say. I'm speculating.

 

My initial thought is a logistical one. Archtop-style floating bridges take the strings of the guitar way farther away from the body itself than do flat-top glued-on bridges. So floating bridges are taller, and therefore easier to break off (increased leverage) when changing strings, say. So if you glue it and then accidentally break it off, which you would be more likely to do than with a regular old flat-top, you probably take a bunch of the finish or maybe even the wood with you.

 

Like I said though, I'm just guessing. Interested to see people's thoughts.

 

Ellen

[mikeSF]

Marcellis,

if i understood your post, it sounds like you slid the bridge toward the tailpiece to try to lower the action (presumably taking advantage of the slope of the arched top, right?). This threw out your intonation because you ended up increasing the speaking length of the strings.

 

Adjusting action at the bridge is actually accomplished by turning the thumbwheels to raise or lower the saddle (i assume you have a 2-pc carved bridge, right?), OR (more permanently) by shaving wood from the bridge saddle. You said that yours do not adjust or at least do not adjust easily by hand, right? they are supposed to. you may try loosening the strings to reduce the downbearing on the bridge and then try again, OR remove the bridge and force the issue with tools. I usually apply a little wax to the threads which makes them turn easily with finger pressure. are there thumbwheels on those brass screws? maybe they are missing and the bridge saddle is just resting on the bridge base. a decent replacement floating bridge may be ordered from stewart macdonald for reasonable $$.

 

the longitudinal movement of the floating bridge is for adjusting intonation, not action. I've found that any time i make a change to string gauge or set, it requires at least a little adjustment of the intonation on a floating bridge, YMMV.

 

as long as you are at it, consider the radius of the bridge saddle in your action adjustments. a properly radiused bridge will equate to an easy to play guitar, sometimes more so than simple up/down general action adjustments.

 

good luck!

[mikeSF]

Warning: I know nothing about what I'm going to say. I'm speculating. My initial thought is a logistical one. Archtop-style floating bridges take the strings of the guitar way farther away from the body itself than do flat-top glued-on bridges. So floating bridges are taller, and therefore easier to break off (increased leverage) when changing strings, say. So if you glue it and then accidentally break it off, which you would be more likely to do than with a regular old flat-top, you probably take a bunch of the finish or maybe even the wood with you. Like I said though, I'm just guessing. Interested to see people's thoughts. Ellen

 

hey Ellen. to your point, i'd offer that in addition to having the ability to adjust intonation easily at will, a floating bridge also offers the conveniece of easy replacement. i've come to understand that a chunky bridge base has a dampening effect on the top and a very slim base allows more voice, etc...it is easy to swap in replacement bridges if it is not glued to the top. also, the purists in this department would cringe at drilling holes or driving mounting srews or glueing anything to a beautiful arched top.

I feel that way to at least some degree but have found i much prefer the amplified sound of a routed humbucker on a carved top, so the sawing of a gigantic pickup hole in an otherwise beautiful carved piece of spruce does not bother me in the least.

[Etienne Rambert]

MikeSF:

Marcellis, if i understood your post, it sounds like you slid the bridge toward the tailpiece to try to lower the action (presumably taking advantage of the slope of the arched top, right?). This threw out your intonation because you ended up increasing the speaking length of the strings.

 

 

Exactly right.

 

Adjusting action at the bridge is actually accomplished by turning the thumbwheels to raise or lower the saddle (i assume you have a 2-pc carved bridge, right?), OR (more permanently) by shaving wood from the bridge saddle. You said that yours do not adjust or at least do not adjust easily by hand, right? they are supposed to.

 

 

Thanks for that. I'm glad you told me that. It seems to me like thumb-wheels should be able to be manipulated by thumbs. My wheels are immobile.

 

I am going to loosen the strings again and see if I can get them mobile.

I really love this guitar. An archtop is a whole new experience. And plugged in - I'm Scotty Less - not Moore.

 

My archtop action is already pretty fast. But I'm comparing the archtop to my Guild F-65ce. And I've never played any kind of acoustic with a neck like this Guild.

[Runn3r]

beautiful guitars Marcellis

 

absolute works of art.

 

[guitarist21]

 

Thanks for that. I'm glad you told me that. It seems to me like thumb-wheels should be able to be manipulated by thumbs. My wheels are immobile.

 

 

Sure they're not all the way down? Because that would certainly make them immobile.

 

Ellen

[mikeSF]

 

Okay cool. That makes sense. Thanks! Sure they're not all the way down? Because that would certainly make them immobile. Ellen

 

 

or possibly stripped. i've seen that too.

[Etienne Rambert]

 

Sure they're not all the way down? Because that would certainly make them immobile. Ellen

 

 

 

I can't turn them either direction. I think I need to disassemble the bridge and put some oil or wax on them. The action is good right now. But I want action like I have on my F-65ce Guild. Archtops should have really fast necks.

 

Thanks Ellen & also Mike SF & Steve-0 (smack dab in the middle of Luzy-Anna)

too, for the off-line tip.

[S~R~O]

I can't turn them either direction. I think I need to disassemble the bridge and put some oil or wax on them. The action is good right now. But I want action like I have on my F-65ce Guild. Archtops should have really fast necks. Thanks Ellen & also Mike SF & Steve-0 (smack dab in the middle of Luzy-Anna) too, for the off-line tip.

 

 

Well You can make the Tripp back up this way...We can fix your Guitar...and do some Jammin with Samilyn......

[Etienne Rambert]

Update-

 

I got one of the thumb wheels to turn. So I assume the other will. (It's flush against the pickguard right now). But it turns in the direction of raising the action.

 

I checked the action tonight. 2 business cards/12th fret - perfect.

Just like I requested from the luthier.

 

But it still feels more difficult to play than my F-65ce. But I guess that's true of every other acoustic guitar I've ever played.

 

The archtop has a bigger neck than the F-65ce. Wider nut length, too 0I think.

 

If I want to lower the archtop action further, the thumb wheels are non-starters. That leaves Steve-0's suggestion of sandpaper. Which I'll ask the luthier to try.

 

I'll tell him 1 business card at the 12th fret. He'll think I'm insane - or just incredibly spoiled.

 

I could sand on the bridge myself. But labor is cheap over here. Might as well have someone who knows what he's doing do it.

 

2 biz cards isn't bad. But the F-65 plays like a hot knife into butter. It's effortless up & down the neck.