Vintage mandolin - fitting new strings

[MagentaGiant1]

2 days ago I strung a 1930s mandolin for the first time in probably at leaat 20 years. It's my first mandolin and I'm a complete beginner with trying to fix them.

I bought a set of light D'addario gauge strings, my thoughts being to not over stress the instrument after so long without the tension. Apart from one or two strings slipping on the pegs a little due to a hurried job when stringing, which I'll likely redo today, its now holding its tune reasonably well. The bridge is set to the correct intonation as far as my knowledge allows, with the 12th fret on each string being the octave above open.
The main issue I have is that whenever I try and strum even a basic G chord, the strings are extremely sensitive to pitch bending. Only an extremely light amount of pressure, to barely get the strings to touch the fret, keeps the fretted strings in pitch with the open strings to form the chord. Any excess pressure and the pitch bends very fast to make the chord out of tune. Even when all strings are in tune with one another when open

Have I missed a step in the setup of the mandolin to cause this? Or is it a common mandolin quirk that I'll have to adapt to? The action on the strings is high due to the design on the body and bridge height, but not excessively so in my opinion.

What do you think?

[Fretbear]

Sounds like the nut could need to be lowered. Light strings on mandolins tend to be hard to keep in tune, but you were right to start off with something on the light side to begin with.

[MagentaGiant1]

Thanks for the swift response. I'm fairly sure that lowering the nut won't be able to help. The instrument has a zero fret, so a lowered nut would be negated by this would it not?
If a lowered but is the solution, is that a job that can be done myself or only by an experienced luthier?

[spufman]

You're right, with a zero fret, lowering the nut won't help. Possibly that zero fret it too high or possibly your neck is a bit bowed. If you have a truss rod, carefully tightening (while maybe assisting by manually flattening) should help.

[MagentaGiant1]

Thanks. Is it possible that a zero fret that is too low is causing it? Or by all frets being too tall? Because to fret a string to the point where the string touches the fret board bends the strings probably a good 1mm. When looking closely you can physically see the string tighten, thus causing the pitch bend. Do the light gauge strings accentuate the problem?

[bennyb]

The strings are not supposed to touch the fretboard. You should only use sufficient pressure at the fret to get good tone. You may be too heavy handed to use light gauge, or you may be able to lighten your touch. Sounds like the frets are in good condition if they're 1 mm above the fretboard. Try playing without the heavy grip and see if you can get that to work.

[MysTiK PiKn]

Search for Rob Meldrum Setup book - member here provides this for free if you email and ask for it.

Sounds like action is too high. Try lowering bridge, if it's adjustable (w little wheels beneath the saddle.????)

Reduce string tension before adjusting.

Truss rod????? Do you have one???? see www,frets.com (lots of info there + section on truss rods)

If you have pitch bend issue - then how can you set intonation? Recheck that. ????

It often seems that mandos settle for an hour or a day or maybe more, after any adjustments - unstrung for a couple decades will be settling into sudden tension (which is higher on mandos than on guitars, etc.)

The zero fret is likely "good enough" for now; until things settle down. Lower the bridge, and adjust up or down until you have reasonably low string heights, with maybe almost a trace of buzz. There's a lot going on here - we have no pictures. Get that setup info and do one thing at a time until you can see what's happening. Keep tension lowered for actual adjustments - those strings are going to be up and down getting a workout before this is stabilized.

Post a picture - we don't know anything about this except it's old. Some oldies are unplayable - sorry to say that; but reality gets in the way sometimes. Pictures? What is it? Brand? A-style? F-style? Flat? etc. Need more info.

[Willie Poole]

I would try setting the bridge at a position where the noted 7th fret is the same as the note of the string below it, (A string on 7th would be an E, same as the open E string)...If you don`t play way up the neck that is the best way to really check it out for what you want...some mandolins are not built perfect as far as the fret spacing goes in the olden days...

A little more info might help some of the other members on here, like what make mandolin is it, I assume with an ) fret it is not American made...

[MagentaGiant1]

The Mandolin is a Czech built Radiotone that was sold through a London retailer from what I understand.

There's no truss rod in the neck, just solid wood. But from my view the neck is completely straight with no bowing or warp. This may be my first mandolin but I'm also a guitar and bass player (hence the heavy touch). I'm aware that a lighter touch is required for mandolin which I'm working on, but the level at which the pitch bend is occuring,makes me think it's something more.

The intonation set-up is not perfect, but is roughly accurate. It certainly isn't too far out. Furthermore, there are markings on the body where the bridge has sat before, and the 12th fret intonation check lines up to this area even if it isn't millimetre perfect. The book sounds excellent, but unless the user mentioned is British or at a stretch European, it's unlikely that it will be able to solve my problems. The bridge has the dials that adjust the height and they're at the lowest finger tight position.

I've posted the pictures which should hopefully answer some questions. It has plenty of scuff marks as would be expected form an 80yr old instrument, but seems structurally sound in every way. I can take, and upload more pictures if required of whatever is requested

Thanks for all the help

[Jim Adwell]

The action looks way too high to me.

[bennyb]

Action looks high to me too. It looks like the bridge is too tall for the current neck-body geometry. With light gauge strings, you could have action of .060 inch at the 12th fret(even lower if everything is well set up). That's 1.5mm if you measure like that. It may be that the neck block(head block) has rotated some over the years from string tension. To lower the action, you could file the string notches deeper into the saddle if there's enough "meat" to do so without compromising strength, or you take it off the base by refitting the base to the top, again if there's enough wood. Or you could fit a new bridge, probably the most logical choice. The problem with modifying the existing bridge is that you have to take twice as much off the bridge to get the desired lowering at the 12th fret. So to get 20 thou at the 12th fret, you have to take 40 thou off at the bridge; and it looks like you may want more that that.

Just to be extra clear(ha), the action we're talking about is measured from the top of the fret to the bottom of the string.

Good luck, benny

[darrylicshon]

I agree that action is too high for me

[acousticphd]

The action looks way too high to me.

Yep; your action is about a mile too high at the first fret, and more like 8 miles too high by the middle of the FB.
It is a good set of pictures and I think helps make the difficulty fairly clear. The bridge is standing much too tall, as evidenced by the 3rd-to-last photo. The good news is that, based on photo 5 (if the strings are at proper full tension), the fingerboard plane looks very flat and straight.

The next step is to lower your bridge - a lot. It looks like an adjustable bridge that is already sitting on the thumbscrews, as low as it will adjust. My approach here would be to deepen each bridge saddle slot until the action is right, then remove the bridge and remove unnecessary saddle material, and replace.

First, tune to pitch; this is important because you want to set your action height with the mandolin fully settled in to normal tension.

1) Refer to the setup guide(s) and video(s) already mentioned above, but here would be a short description of my approach:

2) Measure the action carefully, to at least 64ths" precision, at the 12th fret. Be sure you have a good ruler to do this.
3) Assuming you want to achieve about 5-6 64ths" action at the 12th fret, estimate how much it needs to be lowered at the 12th.
Keep in mind it should be a little higher on the G side (~6/64" to start) and lower on the E side (~5/64").
4) Deepen the slots at the bridge saddle by about 2X this amount. Do this one string at a time, with a needle or triangular file, or better yet, a proper nut slotting file. Lift the string out of the slot, and lay it just to the side, and deepen the slot. Be sure to angle its pitch back toward the tailpiece. As you go, keep returning the string to the slot, and check your progress, remeasuring action frequently. Take as much possible care not to overshoot your depth - you can make fine adjustment to the slot depth and saddle adjustment later.
5) When finished, recheck the intonation of the G and E strings and adjust bridge position, and mark the position of the bridge feet with tape.
6) Remove bridge, and sand/file the saddle top down until the slots are maybe 1mm deep. Start by sanding the saddle ~flat, to create a flat "shelf" ~1/8" wide, then continue to lower/shape/flatten until the slot marks just barely show.
7) At this point, I would create a basic saddle compensation pattern, copying the standard design of mandolin bridge saddles; ie, E string forward, A string set back ~1mm, D string forward, G string set back 1-2 mm).
8) Replace the bridge, tune up, and basically go through the whole setup again. First, intonate the G and E strings, adjusting bridge
position. Then remeasure the action, making more adjustments to slot depth, then adjust saddle positions if necessary.

[lenf12]

I would first decide on a "medium" gauge set of new strings before you go through an entire setup with strings that may be too light for the mandolin and for your guitar playing style. Then follow the above advice. It's all good.

Len B.
Clearwater, FL

[allenhopkins]

OMG is your action high! The neck may be at the wrong pitch, and it'll take a serious lowering of the bridge (see acousticphd's Post #13) to get you where you need to be.

Can't really tell from the pic -- and I'm no repair person -- but the instrument's top may have "dished" in a bit between neck and soundhole, which would elevate the neck angle. If so, getting heavier strings may well be the exact wrong way to go, as they'll exert more tension on the neck and pull it forward.

You can't adjust your bridge any lower, so you'll have to rework it -- or get a lower one, probably non-adjustable, since the adjustment posts and thumb-wheels set a certain minimum height for an adjustable bridge. Is that the bridge that came with the instrument, or did you buy a new one? A Czech mandolin from the 1930's may not have been equipped with an adjustable bridge, for all I know.

You're significantly stretching out the strings to get them down to the fingerboard, hence the "pitch bend" phenomenon. If you can correct the problem through bridge modification or replacement, the instrument could be playable. I'd expect that it's not a valuable enough mandolin to warrant a neck re-set...?

[Rick Lindstrom]

Are the strings silk and steel? If so, that could be adding to the problem. As others have pointed out, the string action it far too high, and that's what you need to deal with first.

If you decide to lower it, taking the bridge down enough that the string clearance at the 12th fret is about the height that it is now at the first fret would be a good approximate place to start.

[David Houchens]

Find something a 1/16" or so and lay it on the 12th fret. Lay a straight edge on your finger board and see where this contacts the bridge. It may be that you can't use a bridge this low. Another option would be to remove the finger board, and glue a long thin wedge between it and the neck. It would make the neck a little thicker front to back, but give you some bridge height which usually relates to more volume and in some cases better sound.

[MysTiK PiKn]

OMG is your action high! The neck may be at the wrong pitch, and it'll take a serious lowering of the bridge (see acousticphd's Post #13) to get you where you need to be.
.... You can't adjust your bridge any lower, so you'll have to rework it -- or get a lower one, probably non-adjustable, since the adjustment posts and thumb-wheels set a certain minimum height for an adjustable bridge. Is that the bridge that came with the instrument,....????

I had the "mile high bridge" problem on my old Harmony. Original bridge collapsed. Bought new adj. rosewood bridge - and it was 2x the height needed. Solution was to throw away the wheelies, [glue the top saddle to the bottom base], making a "one-piece bridge". but it still needed fitting to the top. After fitting it was still too high. So I kept the fitted lower part, and started sanding, and also "shaping" from the (now-glued) saddle. Rough grit sandpaper made it quick. Fine sandpaper made it pretty, and I rounded all the ugly corners, and former wheelie holes, etc. and shaped it - it was quite beautiful. It was solid rosewood, I oiled and polished it.

BUT - you can always go lower - but you can't go higher, (unless you use shims). So, you sand lower slowly and slower, as you get close to exact perfect fit and height. You can incorporate the intonation items from post 13 also. Sculpture. It all gets very perfectionistic as you get it close.

This will give you what you want as long as the top is stable - and I would just assume the top is ok, because you really don't want to go there, except as last resort (top collapse).

Bryce's straight edge ruler idea will indicate how much you need to remove to get in the low action ballpark.

As you get to low action, you likely will need a light fret flat-filing. the zero fret is likely pretty darn close already.

It's a nice looking mando - and worth the effort to launch the rocket.

One other thing - you could get ANY straight-ish piece of any wood (or a stick), and set it in place of the bridge, just as an indicator of desired height ballpark. And you could actually test playability with that. (roughly, of course).

Also nobody said it yet, but those locator bridge marks on the top, are within maybe an 1/8" or worse of actual inton'd location. Those are just 'wear marks'.

- thanx for good pix -

[MysTiK PiKn]

Getting Close
see green line.

[MagentaGiant1]

I think I'm probably going to try and get a new bridge for my mandolin then. I have no idea if the bridge is original, but given the how solid the rest of the body is, my instinct is that the neck hasn't moved too much if at all. It's completely structurally sound other than needing a dab of wood glue to stick some edging trim back down. Furthermore, the gap between the higher end of the fret board and the top of the instrument is near parallel, so would have been one heck of a coincidence for it to have rested there.
A non adjustable bridge probably seems like the way to go, simply because the height difference is so great.
After looking carefully at the tail piece as well, I believe the bridge isn't original anyway. The height of the bridge means that the strings are pulled up too high and that the hinged tail piece in the photos rubs on the strings slightly, and I can't believe this is part of the original design.

Any pointers for a bridge to go with? I'm assuming wood, and non adjustable,but is there any brand names I should be looking out for? And how much does the hight vary between different wood bridges, or is this a standard measurement. I can adjust the string action minutely through the positioning with the oval top, but this may also affect intonation.

By the sounds of it though, a new bridge is all that stands between me and a playable 1930's mandolin? Next stop, repairing the original hard case it came with

This forum and the members has been a lifesaver for helping me out

- - - Updated - - -

I think I'm probably going to try and get a new bridge for my mandolin then. I have no idea if the bridge is original, but given the how solid the rest of the body is, my instinct is that the neck hasn't moved too much if at all. It's completely structurally sound other than needing a dab of wood glue to stick some edging trim back down. Furthermore, the gap between the higher end of the fret board and the top of the instrument is near parallel, so would have been one heck of a coincidence for it to have rested there.
A non adjustable bridge probably seems like the way to go, simply because the height difference is so great.
After looking carefully at the tail piece as well, I believe the bridge isn't original anyway. The height of the bridge means that the strings are pulled up too high and that the hinged tail piece in the photos rubs on the strings slightly, and I can't believe this is part of the original design.

Any pointers for a bridge to go with? I'm assuming wood, and non adjustable,but is there any brand names I should be looking out for? And how much does the hight vary between different wood bridges, or is this a standard measurement. I can adjust the string action minutely through the positioning with the oval top, but this may also affect intonation.

By the sounds of it though, a new bridge is all that stands between me and a playable 1930's mandolin? Next stop, repairing the original hard case it came with

This forum and the members has been a lifesaver for helping me out

[MagentaGiant1]

Any idea on a material for a bridge as well? Rosewood? Olive wood? Other? The current one is a kind of rubber

[Shelagh Moore]

As you've concluded, a lower bridge will help a lot and it looks like you will still have plenty of string break angle over a lower bridge from your photo. Suitable blanks are available on line and from some shops but you will need then to fit this to the arched top. That done, it should be eminently playable... I've repaired many far worse!

[Rick Lindstrom]

Any idea on a material for a bridge as well? Rosewood? Olive wood? Other? The current one is a kind of rubber

This mandolin looks like a great candidate for a Red Henry style solid maple bridge that you make yourself. Check it out at Red's website:

http://www.murphymethod.com/index.cf...t&contentId=87

[acousticphd]

For starters, I would recommend you mark and measure the desired final height of your replacement or re-worked bridge, as out, as this will help you shop for the right replacement. First measure how much you need to lower your action, then the bridge height needs to be decreased by 2X that amount. This may not leave enough material in your existing saddle to bear the pressure (as Mystik PiKn's diagram suggests.

It is not easy to find such short bridges designed for archtops. What may work best is a simple low rosewood bridge designed for a flattop, that you will still likely have to shorten, and fit to the top, such as this one:
http://www.ebay.com/itm/Mandolin-Bri...item54193cd1d5

Keep in mind that the 1st fret height may still need to be adjusted as well.

[MysTiK PiKn]

Some kind of rubber? omg Throw that away. It might be plastic. Throw that away too. OR it might be useful as a height indicator if you hack it down somehow. (maybe a first attempt?)

Most any over the counter pre-made will be not only adj bridge, but also too high.

Material s/b hardwood. Many are rosewood or ebony. Red Henry, linked in above post, did experiments that demonstrated HARD maple was best sound. It's debatable, and it gets debated regularly.

Red Henry used to take measurements from people and make a bridge like that - you could contact him on the site - thing is you still have to fit the exact slight curvature of the seemingly flat top - best fit = best sound - often done by taping sandpaper on top, and sand bridge right on the top sandpaper (with tiny little strokes). (it's pretty hard to get perfection) (there was a thread on this a few months ago - search?).

If you aren't confident with woodwork or bridge fit, and want to bypass the trial and error, then a good luthier or repairs person could whip one up for you. But do check out Red's site - some amazing experiments there. That was my guide for converting an over the counter rosewood brdg to a onepiece to a fitted onepiece. It's either tedious or it's art.

(more)
The gap you mentioned under the fingerboard extension - this is where many players w that type mando will attach a strap, perhaps with leather lace under the fb ext. It yields good balance, good clearance, out of the way, and it's cool. You can also make your own strap - tons of threads here about that.