Checking Neck Angle

[jerryk]

Hello,

I found an old forum post from somebody who built a Saga kit and found that the neck
angle was not good. He fixed it by fabricating a shim for the fretboard.

A good low action is important to me; I have tendinitis from years of computer programming.

How does one check the neck angle? I envision temporarily putting it together and
lightly stretching one string. Or just laying a ruler over the fretboard to see if the bridge
height works out?

- Jerry Kaidor

[bart mcneil]

Why are you asking? does yours have a neck problem? a bent neck? or what?

That might have been me from the old post on shimming, because i did it and it worked. Although I am sure others have done it.


I am guessing that you are using an adjustable bridge, or are you? if so and it is too high at its lowest setting for the low action you want, then the first thing I would try is to make or buy a non-adjustable bridge or two and and manually adjusting it to the height you want. I would only consider making that shim if I was certain I could not find or make a lower bridge to suit my playing style.

To find the bridge height you want I would use a metal straight edge from the nut (top) to the desired height of your ideal bridge and work from that measurement as your desired bridge height. of course you can buy a non-adjustable bridge or make your own from maple or whatever wood you choose. See frets.com for how to sand the bridge for best full contact with the mando top. I suspect you will find that your problem is pretty easily solved without necessarily shimming your fret board.

[jerryk]

Why are you asking?

*** Sorry, I should have been more specific. There really is no problem. I just ordered a Saga kit from IV. I believe I did find your
old post. That alerted me to the possibility of the kit having a faulty neck angle out of the box, and the desirability of measuring it up front instead of just gluing it together and accepting what I get.

Does the factory joint on the Saga kit have enough slop to adjust it out? I would imagine that
the dowel pins fix the angle pretty precisely.

[jerryk]

Reviewing the Siminoff book, I think the way to get it perfect would be to build a simple wooden jig to hold the body at 6 degrees,
lay the neck flat, and if the dowel holes don't match up, drill them slightly oversize with a drill press.

[bart mcneil]

The neck joint on the kits is not the problem. it is built in such a way that, if you follow instructions religiously you should do fine. On one of mine the neck joint wood was split and though i attempted to glue it back in proper alignment it remained slightly off and the slightest misalignment can be too much on these kits or any mando. But the joint is pre-fit in the manufacturing process before the holes for the dowel rods are drilled. This allows for a flawless fit in almost all cases. The neck/body joint is clearly the most critical joint in the mando. But these kits have made that problem a non-problem for the most part. if something goes wrong it will likely not be that joint if they are still making them as they were when I built mine.

"Does the factory joint on the Saga kit have enough slop to adjust it out? I would imagine that
the dowel pins fix the angle pretty precisely."

As close to perfect that a wooden product can get. There should be no slop at all. In construction you can fit the neck and body together without glue if you want to test it, but I suspect it will be unnecessary. Enough folks have built these that we can answer any problem you might run into in putting these together..

[jerryk]

One of yours? How many of these kits have you built?

[High Lonesome Valley]

I know with a violin you measure the fingerboard height at the end of the fingerboard to the body.

Does anyone do this with mandolins?

[Michael Lewis]

Put a straight edge on the neck and project it to the bridge position, and measure from the straight edge to the top. If you don't have the fingerboard on the neck you must allow for it's thickness, plus about 1/8" (3mm) for the 'action' above the frets. Ideal bridge height is between 3/4" and 7/8" (18mm - 22mm).

If you draw this out as a side view of the instrument it will help you get the forms and relationships in your mind, and things usually go much more smoothly after that.

[bart mcneil]

"One of yours? How many of these kits have you built?"

I have built three. an oval hole, and two standard f hole ones. I built three because I was interested in experimenting with varying tone by re-graduating the tops and back beyond what is standard for these kits.. Very interesting and careful re-graduating does improve tone significantly. On one I over did it and the mando collapsed under string tension so i learned a lot on that one.

[HoGo]

When I fit the neck to body I measure with ordinary straightedge against neck (without f/b). The end of straightedge should project just about 1/2" above the center of bridge position. This coupled with typical 3/16" fingerboard and mandolin frets plus standard setup results in standard bridge height like Michael Lewis noted above.

[Bernie Daniel]

When I fit the neck to body I measure with ordinary straightedge against neck (without f/b). The end of straightedge should project just about 1/2" above the center of bridge position. This coupled with typical 3/16" fingerboard and mandolin frets plus standard setup results in standard bridge height like Michael Lewis noted above.

Slightly OT but if you were doing that very same measurement on the neck (w/out fretboard) on a 25" scale arch top guitar how high should the straight edge project above the bridge location?

[Mike Conner]

Bernie, On my 25" archtop I targeted a 1" total string height above the front plate.

I make dummy necks out of framing lumber to verify the neck angle and resulting bridge height prior to committing to the good neck blank. The Macassar ebony fretboards I am using are a bit more than the standard 1/4" thick, and I like them that way. I clamp the fingerboard to the dummy neck, then try to account for the fret heights and the action above them for the strings, maybe 3/16" .

So, if I am doing the math right...

Total height 1"
- Action and frets 3/16, maybe 1/4" ?
- Thickness of fretboard 1/4"
------------------------ --------------
.. yields a distance from top of front plate to neck plane w/o fretboard about 1/2" ??
It's got me thinking though. I have two builds started, a GOM and a 25" archtop guitar. I'm going to pay more attention to the measurements and post back later....

[Bernie Daniel]

Bernie, On my 25" archtop I targeted a 1" total string height above the front plate.

I make dummy necks out of framing lumber to verify the neck angle and resulting bridge height prior to committing to the good neck blank. The Macassar ebony fretboards I am using are a bit more than the standard 1/4" thick, and I like them that way. I clamp the fingerboard to the dummy neck, then try to account for the fret heights and the action above them for the strings, maybe 3/16" .

So, if I am doing the math right...

Total height 1"
- Action and frets 3/16, maybe 1/4" ?
- Thickness of fretboard 1/4"
------------------------ --------------
.. yields a distance from top of front plate to neck plane w/o fretboard about 1/2" ??
It's got me thinking though. I have two builds started, a GOM and a 25" archtop guitar. I'm going to pay more attention to the measurements and post back later....

Thanks a lot! Great information! The1/2" would be a good target is use -- should be close enough that a set up could bring things to a good playing configuration?

I have used LMI for two Macassar fret board blanks for cutting out mandocello boards and both have been 1/4" thick. In the end both mandocelli have strings about 1" above the top board at the bridge -- just like you suggest.:)

[jerryk]

"One of yours? How many of these kits have you built?"

On one I over did it and the mando collapsed under string tension so i learned a lot on that one.

*** So what thickness of top would you recommend to make sure it *doesnt* collapse?

The kit arrived yesterday. I popped open the box, verified that it was indeed a mandolin kit, closed it up, and
went back to reading the manual and sourcing supplies.

- Jerry K