How concerned to be about cracks along the neck?
 

https://imgur.com/a/NKaGBsm

I am just getting into jazz guitar. Ordered my first archtop. A washburn j600. It was used and the seller alleged it to be in excellent condition. When I opened it up I checked it over and found two cracks along the neck starting just at the nut. One follows where the fretboard meets the wood of the neck and the other goes into the neck and down about an inch and a half. The intonation is good, but I never know how much to be concerned of hairline cracks. What do you guys think? Lesson learned about buying used guitars online, nothing to worry about, or something to try to get a return on? Thanks in advance.

https://imgur.com/a/NKaGBsm

Image of the crack

That would really bother me! I vote to send it back for a refund.

The second picture could look like the fretboard separating, but the other picture clearly shows the crack extending down the body of the neck . Someone dropped that poor guitar and it is broken. I would consider it the same as breaking off the head, as that looks like almost what happened.
String tension is going to pull and continue to make that worse.
I bet it can be repaired, but It should have been fully disclosed and discounted. You shouldn’t have to deal with or pay for it unless you agreed to that upfront.
Send it back. Make sure they reimburse any shipping costs.

Sadly, I think this is the case ☝️

Very! The worst place for a crack! I stay away from neck cracks altogether.

Send it back.

I had a similar issue with a much higher priced guitar. The seller convinced me to keep it with a personal guarantee for a year. The cracks got much worse and he disappeared. Send it back.

Brian

I agree. Send it back.

I’d be VERY concerned.

I know this may be a moot point by now: I agree with other posters, the cracks look structural. The guitar must have fallen on its face at one point.

One way to fix it is to gently open up the crack by carefully bending the head back a bit, (I woudl use a long clamp to do this in a controlled manner), then inject plenty of yellow aliphatic glue into the crack.

Clamp tightly with cauls, clean up the squeeze out. and let it dry for a day or 3.
the resulting glue joint will be stronger than the original wood.
Once the crack is glued, the outwards appearance can be refinished.
In a way it is lucky that the crack is "long" and mostly parallel with the grain.

What do you think about this crack? Story goes it was fixed 15 years ago by a luthier. It's an Eastman 800 series. Neck is straight, seems to play fine. I'm considering buying it....

https://i.imgur.com/gLKGaO0.jpg

https://i.imgur.com/JqbJyle.jpg

Nope pass this one by. Unless it is $100 or less.

That's some story. If a real luthier fixed it you wouldn't be able to see it. A great big nope from me.

If it was half or less of it's otherwise value, I'd probably buy it if I liked it. If it's stable, it's a decent repair. Extremely hard to make a headstock off repair invisible with a transparent finish. It will probably play and sound and make you as happy as any other guitar of that make/model, but it's resale value is now lousy. Sometimes that's important but I never sell guitars.