Neck pocket hole size

[petermwright]

I've hit a few bumps in the road with my current DIY build, one of which is this...

As supplied, the holes in the neck pocket were a pretty tight fit with the screws (I can't remember if I could actually get them through or not). In any case, I didn't want the screws binding in there, so I drilled the holes out a bit to widen them. I fitted the neck, and then found that even when the neck was mounted it would sometimes shift very slightly. I found that doing the screws up tighter (pretty much as tight as I could get it with a normal screwdriver) stopped it moving. But I've never needed to do up neck screws that tight before, and am concerned about over-tightening.

So I took the neck off again, and I noticed that one of the holes in particular has thread marks inside it, which suggests it actually is binding. I'm not sure what to do, really. I can widen the holes more to stop it binding, but I wonder if that will make it more likely to shift around.

How tight should the neck screws be in the neck pocket holes? And what should I do?

 

[MonetBass]

When the holes don't line up properly as seems to be the case here, I would recommend:
1. Drill out the neck holes
2. Glue in hardwood dowels
3. Re-drill the neck holes to line up with the body holes
Here's another thread on the same topic: https://www.talkbass.com/threads/re-drilling-screw-holes-on-a-bolt-on-neck.1124389/

 

[MotorCityMinion]

Chuck up the same size screw in a drill and ream that one hole out in the body. You can also shim the walls of the pocket with scotch tape if you want to tighten up the fit. Shouldn't be necessary though.

 

[petermwright]

When the holes don't line up properly as seems to be the case here, I would recommend:
1. Drill out the neck holes
2. Glue in hardwood dowels
3. Re-drill the neck holes to line up with the body holes
Here's another thread on the same topic: https://www.talkbass.com/threads/re-drilling-screw-holes-on-a-bolt-on-neck.1124389/

I wondered if it might come to this.

And if the neck holes line up properly, is it ok for the body holes to have a bit of space around the screws?

 

[MonetBass]

I wondered if it might come to this.

And if the neck holes line up properly, is it ok for the body holes to have a bit of space around the screws?

That is expected, yes.

 

[petermwright]

That is expected, yes.

Ok, and do you think the old matchsticks and glue routine is not going to cut it for the neck?

 

[RSBBass]

If you have thread marks on the hole in the pocket, the hole is too small. Grab a round file and make it a bit bigger inn the area where the thread marks were. If that doesn't cure your problem, consider using threaded inserts.

 

[petermwright]

If you have thread marks on the hole in the pocket, the hole is too small. Grab a round file and make it a bit bigger inn the area where the thread marks were. If that doesn't cure your problem, consider using threaded inserts.

I think it's not so much that the hole is too small, but rather that it isn't perfectly lined up with the neck hole.

 

[MonetBass]

Ok, and do you think the old matchsticks and glue routine is not going to cut it for the neck?

Because of the stress on the neck screws, that won't be enough.

 

[petermwright]

Because of the stress on the neck screws, that won't be enough.

It does raise the question - as RSBBass points out - if it’s ok for the hole to on the big side, why not just widen the pocket pole so that it doesn’t bind, and lines up with the neck hole?

 

[Turnaround]

I've hit a few bumps in the road with my current DIY build, one of which is this...

As supplied, the holes in the neck pocket were a pretty tight fit with the screws (I can't remember if I could actually get them through or not). In any case, I didn't want the screws binding in there, so I drilled the holes out a bit to widen them. I fitted the neck, and then found that even when the neck was mounted it would sometimes shift very slightly. I found that doing the screws up tighter (pretty much as tight as I could get it with a normal screwdriver) stopped it moving. But I've never needed to do up neck screws that tight before, and am concerned about over-tightening.

So I took the neck off again, and I noticed that one of the holes in particular has thread marks inside it, which suggests it actually is binding. I'm not sure what to do, really. I can widen the holes more to stop it binding, but I wonder if that will make it more likely to shift around.

How tight should the neck screws be in the neck pocket holes? And what should I do?

With the neck off, turn the screws in their holes in the body. So long as they can continue to turn after fully seated they are good - no need to drill out further.

EDIT - I see others suggesting that the body holes don't line up with the neck holes. I didn't read that in the original description. We need to establish this for sure before deciding on a course of action.

 

[petermwright]

With the neck off, turn the screws in their holes in the body. So long as they can continue to turn after fully seated they are good - no need to drill out further.

EDIT - I see others suggesting that the body holes don't line up with the neck holes. I didn't read that in the original description. We need to establish this for sure before deciding on a course of action.

The screws all move freely in the holes with the neck not attached. Since there are still thread markings on one or two or the holes, we assume that means that not all of the holes are lined up perfectly.

I will have a look and see if I can work out exactly what’s going on with the positions of the holes.

 

[Turnaround]

The screws all move freely in the holes with the neck not attached. Since there are still thread markings on one or two or the holes, we assume that means that not all of the holes are lined up perfectly.

I will have a look and see if I can work out exactly what’s going on with the positions of the holes.

Cut a piece of card to fit closely in the neck pocket. Hold the neck in place and push the screws through the body holes until the points prick the card. Then you can compare the alignment of the screws to the neck holes by comparing the card to the neck holes.

 

[96tbird]

As for the neck shifting when tightened down, get some self stick sandpaper and paste it into the pocket to add grip.

 

[Lo-E]

It seems like there are two different issues here, both of which should be addressed.

The neck holes aren’t perfectly aligned so you’ll need to drill and dowel (no matchsticks) and re-drill to correct that.

But the movement of the neck is not due to the mounting holes. You have too much space in the neck pocket. You’ll need to shim the sides of the neck pocket so that the fit is nice and snug and the neck is less prone to shifting.

Neck screws are fasteners; if they also need to be positioners, you’re asking a lot of them. Let a good, tight neck pocket fit do the positioning so that the screws only need to hold it down.

 

[96tbird]

It seems like there are two different issues here, both of which should be addressed.

The neck holes aren’t perfectly aligned so you’ll need to drill and dowel (no matchsticks) and re-drill to correct that.

But the movement of the neck is not due to the mounting holes. You have too much space in the neck pocket. You’ll need to shim the sides of the neck pocket so that the fit is nice and snug and the neck is less prone to shifting.

Neck screws are fasteners; if they also need to be positioners, you’re asking a lot of them. Let a good, tight neck pocket fit do the positioning so that the screws only need to hold it down.

Nope. No need to fill the neck holes. The pocket holes as stated are fine.

Nope. No need to shim the sides. Super fine sandpaper pasted in the heel route floor will stop neck shift.

 

[Lo-E]

The pocket holes as stated are fine.

As stated by whom? Nothing in the thread so far has suggested to me that the pocket holes and neck holes are aligned.

Super fine sandpaper pasted in the heel route floor will stop neck shift.

I’m in agreement with you here, but it’s no easier than shimming the sides of the neck pocket for a snug fit, which is my preferred method. Shimming doesn’t require making the neck screws as tight, provides more mechanical support and has no effect upon neck height or angle. The sandpaper method does work, though.

 

[petermwright]

Thanks all for your thoughts, much appreciated.

I've done what Turnaround suggested with the bit of card, and actually as far as I can see, the holes do line up well. So it must be a close run thing.

If the pocket holes don't need to hold it in position, then I'm wondering if there is any reason I shouldn't drill the pocket hole in question out slightly so it doesn't bind, and then use a bit of sandpaper as a side shim?

 

[Lo-E]

Thanks all for your thoughts, much appreciated.

I've done what Turnaround suggested with the bit of card, and actually as far as I can see, the holes do line up well. So it must be a close run thing.

If the pocket holes don't need to hold it in position, then I'm wondering if there is any reason I shouldn't drill the pocket hole in question out slightly so it doesn't bind, and then use a bit of sandpaper as a side shim?

If they align well I don’t see any need to worry about the marks. Maybe just add a little paraffin and call it art.

As for side shims, there’s not really an advantage to using abrasive paper. The abrasive paper would be the ticket for @96tbird ’s preferred method of using it on the floor of the neck pocket to add friction.

 

[petermwright]

If they align well I don’t see any need to worry about the marks. Maybe just add a little paraffin and call it art.

As for side shims, there’s not really an advantage to using abrasive paper. The abrasive paper would be the ticket for @96tbird ’s preferred method of using it on the floor of the neck pocket to add friction.

Ok. My concern about using it on the floor of the neck pocket is that then I'm changing the neck angle. If I wanted to shim it in that way, I'd be more comfortable using a full pocket shim.

Would there be a better material to use for a side shim?