Possible Cracked neck?

[dswn90]

Hi all,

I have purchased a second hand mandolin. I'm worried the neck may have separated from the body.
I've attached some pictures below. It plays fine, it just has quick heavy cracking where the neck joins the body; maybe it was dropped and the impact caused the heavy finish (it's a loar 700...) to crack but the neck to stay intact?

thanks!

[sunburst]

Looks like neck movement in the joint.
I can't tell much about the construction or brand from the pictures, but I suspect that the neck joint was not of the best quality when the mandolin was built and the joint has moved to "take up the slack" in the joint. Maybe it simply moved, maybe it has been overheated to release the glue in the joint, but whatever the cause, it might stay more or less stable as it is for quite some time. I would just play it and keep an eye on the joint for more movement. Also keep tabs on tuning stability. If it tends to go flat, or especially if it suddenly goes flat have a good look at the neck joint.
If it gets worse, have a good luthier/repair person look at it for potential repair.

If it is a brand that uses a hardware neck joint ("bolt-on neck"), check that all fasteners are tight. That may require special tools.

[keme]

Don't worry too much about this. It is most likely a crack in the finish only.Wood will shrink and expand with variations in environment (ambient temperature and humidity). The finish does not easily adapt to this. On even surfaces the stress is distributed evenly, but in corners the stress is focused towards the bend. When the joint "load point" is at a distance from the finished surface, the expanding "gathers leverage". Neck joint is subject to both conditions.

This is not unusual with guitars. My '82 Ibanez dreadnought displayed it from some time in the late '90s, and the '73 Rickenbacker had it when I bought it around '94, and they have served me flawlessly. I use fairly heavy strings (012 flats on the Rick, and 012 "heavy bottom" on the acoustic) so any structural weakness should have surfaced by now.

There are multiple discussions of this type of crack on set-in necks, and the general consensus seems to be that a stress break is more likely to happen elsewhere. The tenon-mortise glue joint is typically very stable.

[jim simpson]

A number of the less expensive brands use 2 dowel sticks for the neck joint. They don't tolerate much in cases of impacts. Not sure about the Loar brand/model.