Neck Tenon Design Help!

[sai the explorer]

So I'm building an electric solid body 5 string mandolin (13.5" scale) as my first build. Because plans/blueprints for such instruments are few and far between, I've had to figure out most of the design myself as well, adding to my woes. Currently, I'm trying to design the neck tenon for a set neck join, and I had a couple of questions that you guys might know the answer to.

Is it fair to assume that the longer I make the tenon, the shorter the "lip" forming the heelblock of the neck needs to be? (sorry, my vocabulary is probably all wrong)

Also, from what I recall, the mortises and tenons on builds that I've seen seem to have rounded corners, rather than ending in sharp 90 degree angles. Is this a matter of preference, or does this add to the strength of the join in a significant way?

To give you some context, right now I am planning to have the neck attach at the 10th fret and have the tenon extend all the way to the end of the fretboard (20th fret) (dimensions of the pocket are 1.25" x 3.25").

[ihocky2]

I'm not an expert on set necks so I can't offer too much help here. But as for the rounded corner question, at least when I build I use a rounded corner because I route the mortise and the router bit leaves a radiused corner. It's far faster and easier to round the corner of the tenon than to square up the inside corner of the mortise. If I were using a mortising machine I would probably stay with square corners, but then templates don't work so well and you won't get as tight of a joint.

[Ken Bennett]

I'm confused. Why would your neck tenon be any different from a standard mandolin?

I'm assuming that you mean 10-string instead of 5-string. 5-course would be the correct term. A normal mandolin has 8 strings arranged in 4 courses, 2 strings per course.

So your 10-string just has a slightly wider neck than an 8-string. Why not simply make the tenon proportionally wider?

[sai the explorer]

I'm confused. Why would your neck tenon be any different from a standard mandolin?

I'm assuming that you mean 10-string instead of 5-string. 5-course would be the correct term. A normal mandolin has 8 strings arranged in 4 courses, 2 strings per course.

So your 10-string just has a slightly wider neck than an 8-string. Why not simply make the tenon proportionally wider?

The mandolin I'm making is actually just 5 single strings, not 10 double.

So all my basic plans are essentially scaled down designs from plans for a Les Paul. I don't really have access to solid body mandolin plans, so I'm basing them off of a combination of these Les Paul plans and measurements taken from a mediocrely made 5-string electric mandolin I have. The neck joint on the mandolin I have right now is some sort of set neck, but I can't really tell how far the tenon extends into the body. The scaled tenon length I got from the Les Paul stops at about the the 14th fret or so, and my fretboard has 20 frets. I was basically wondering if I should extend the tenon even further into the body just because I can (I have the space and neck blank length to do it). Is there any benefit to making the tenon as long as possible?

[SwedishLuthier]

Is it fair to assume that the longer I make the tenon, the shorter the "lip" forming the heelblock of the neck needs to be? (sorry, my vocabulary is probably all wrong)

I'm not following you here. Try to explain a bit more what the problem is

Also, from what I recall, the mortises and tenons on builds that I've seen seem to have rounded corners, rather than ending in sharp 90 degree angles. Is this a matter of preference, or does this add to the strength of the join in a significant way?

That is only to make it easier from a production stand point. Rout out the pocket (with a round bit of cause) and the pocket will have round corners. Take the tennon to the belt sander and the tennon will have matching corners in a second. Much faster that to try to make "a square hole"

I'm confused. Why would your neck tenon be any different from a standard mandolin?

I *think* he is making it more in the veins of an electric guitar tenon compared to a dove tail tenon found on acoustic guitars and mandolins.

I'm assuming that you mean 10-string instead of 5-string. 5-course would be the correct term. A normal mandolin has 8 strings arranged in 4 courses, 2 strings per course.

Electric mandolins often dont use that double coures of strings, but a single string for each note