Top radius and neck angle relationship

[tippie53]

Now the intial set up video shows how the fretboard plane is critical to the action and playability of the guitar.
You have one major variable in that it is hard to know how much the top will rise.
If you over radius the top you can actually loose a lot in the added tension on the top restricting the optimum exchange of the string energy.
As you set the neck the point is you want the straight edge from the fretboard to be about 3/8 of an inch off the top at the point of the saddle , if you use a full radius or not , The top will rise a bit so if you make your bridge to set 1/16 of an inch under the straight edge you should be able to get the action perfect

[kinspeed]

Now the intial set up video shows how the fretboard plane is critical to the action and playability of the guitar.
You have one major variable in that it is hard to know how much the top will rise.
If you over radius the top you can actually loose a lot in the added tension on the top restricting the optimum exchange of the string energy.
As you set the neck the point is you want the straight edge from the fretboard to be about 3/8 of an inch off the top at the point of the saddle , if you use a full radius or not , The top will rise a bit so if you make your bridge to set 1/16 of an inch under the straight edge you should be able to get the action perfect

Can anyone tell me on average how much the top will rise? I know it's variable but someone should have an average, right? Thank you!!!

[tippie53]

it depends about 3/32 so figure 1/16 to 1/8 in you should be ok.
feel free to call me

[kinspeed]

it depends about 3/32 so figure 1/16 to 1/8 in you should be ok.
feel free to call me

Thank you Sir!

[Ben-Had]

Now the intial set up video shows how the fretboard plane is critical to the action and playability of the guitar.
You have one major variable in that it is hard to know how much the top will rise.
If you over radius the top you can actually loose a lot in the added tension on the top restricting the optimum exchange of the string energy.
As you set the neck the point is you want the straight edge from the fretboard to be about 3/8 of an inch off the top at the point of the saddle , if you use a full radius or not , The top will rise a bit so if you make your bridge to set 1/16 of an inch under the straight edge you should be able to get the action perfect

Can anyone tell me on average how much the top will rise? I know it's variable but someone should have an average, right? Thank you!!!

Too many variables which is why you want to end up in the "ideal" range so when you complete your final setup it ends up where you want. If you use a run/rise calculator and fill in the numbers you start with (i.e. distance from body joint to saddle location and the top radius) you will get a number for the rise. But what that doesn't take into account is top stiffness, bracing stiffness, hot close you hit those target numbers, etc. which will impact that actual rise. That's why in the end adjusting the bridge thickness and saddle height are necessary (in most builds).

[tippie53]

As Ben points out , this is a variable. Until you have made a few guitars you don't have a clue what will happen. It depends on your top and the bracing pattern.
If you making a CF Martin kit you can expect a solid 1/16 in scalloped braces lean more to the 1/8 in side, So for the crux of this lets say your straight edge is 3/8 in off the top and your bridge is the same. You can take a bit off the bridge ad go with 5/16 on the bridge.
if the top comes up 1/16 and you add 9/64 for a saddle that would set your height at about 7/16 at the bridge. That is within acceptable limits.

If you set the straight edge 7/16 your at the 1/2 point
so you see you have a bit of a tolerance. I would say on your first guitar set up in this range of 1/16 without the frets the frets will add another 1/32 so your right in the middle.

[kinspeed]

So, I think I have this simplified. Radius your top, flatten the upper bought from the neck block to the apex (between the soundhole and bridge), straight edge the neck to measure the distance between the straight edge and top (at the point of the bridge), floss the neck joint to get the proper meaasurement and build your bridge accordingly. It seems like I'm missing something in my simplification?

[MaineGeezer]

... if you make your bridge to set 1/16 of an inch under the straight edge you should be able to get the action perfect

That is pretty much what I aim for. After completing only two guitars so far, it's preposterous to think I know what I'm doing, but here is how my guitars assay out. I make the bridge 3/8" thick. I set the neck so a straightedge on top of the fretted neck just clears the top of the bridge -- John's 1/16" dimension. With whatever top rise I get and with the action adjusted correctly, the required saddle height turns out to be "reasonable." (The break angle of the strings is "reasonable" and there is enough saddle height to allow for some trimming if, over time, the action gets nigher.)

[ruby@magpage.com]

This is indeed the most critical part of construction. I think you have the concept, but getting the job done in a consistent and simple manner is another matter. Here is a method I have used that works well:

http://www.luthiersforum.com/forum/view ... 17&t=25931

The method works well enough regardless of the radius you use for your top, telling me that getting onto the ballpark is all that is needed here. Remember that even Martin has a choice of 3 different thicknesses of bridge when everything is done and the bridge gets glued on.

In the 7 I have built, the first one I got lucky on, 2 and 3 I had to play with, 4, 5 and 7 were pretty much right on using this system, and 6 was a uke which has a flat top and is therefore dead easy.

Good luck

Ed

[kinspeed]

Thank you very much for the help. I appreciate the link. This one thing is the most complicated for me to fully understand.