Re-installing a brass nut on my LP Studio.

Hi Everyone,


Not sure if this is the most appropriate section for this thread, but anyway, I was doing some work on my Gibson USA Les Paul Studio guitar last night, basically re-installing a brass nut on it, now although the brass nut itself is thick enough to fit in the nut shelf, but, I found that the nut shelf was cut a bit too deep for the brass nut to sit so that the 1st-fret action was high enough to allow the strings to ring cleanly without buzzing against the first fret, so I did some thinking and decided to try making a shim out of some rosewood that a local Darwin Luthier gave me, the last time I tried installing the brass nut I used some pieces of clear plastic to make a shim, but I ended up gluing the nut in at a funny angle relative to the surface of the fretboard so that it wasn't at 90 degrees to it, this played havoc with the individual string-intonation.

After roughly cutting the new rosewood shim to size, I used some 80-grit sandpaper and a vernier caliper with a digital readout to carefully sand the rosewood shim down to the correct thickness to allow the nut to sit in the nut shelf to get the 1st-fret action correct, as it turned out the rosewood shim needed to be sanded down to a thickness of 1.2 mm, after that I glued the new rosewood shim to the bottom of the nut shelf using some Aquadhere PVA wood glue, I think I had a win cause the nut looks like it is sitting square relative to the surface of the fretboard, anyway, I'm happy with it, I left it to dry overnight last night, and I'm going to be gluing the nut into position today, just need to pop up to the service station to buy some suitable glue, PVA glue isn't strong enough to glue the nut into position because it won't bond to brass, so I was thinking of going with either Superglue or some 2-part Epoxy.

I might go with the two-part epoxy since Superglue dries fast and I want to make sure I have time to get the brass nut positioned correctly before the glue dries, otherwise I'll have to remove the nut and re-do everything again.

I'm also seriously thinking of upgrading the stock bridge and tailpiece on my LP Studio to a Babicz Full Contact bridge system (I might go for a gold one if I can afford it), the stock bridge has some lose parts that I reckon are causing some tuning instability issues.

I've also decided to go ahead and upgrade the tuners to a set of 3-a-side TonePros Kluson Locking-Tuners, I managed to find a set on eBay but they are chrome ones, so, in that case I'm going to go with a chrome Babicz Full Contact Tune O Matic Bridge, the guitar should still look cool with the chrome hardware, I'm going to keep the stock pickups because I love the sound of them.

Have you glued the nut on yet, Doc? I've glued brass nuts on before with PVA and they've lasted years without any issues. But if you're having problems, I'd use a couple of spots of CA - you wound need to coat all the surfaces or it may make it very hard to remove if you need to. Likewise, I'd avoid epoxy, because you definitely won't get it off again without doing damage to the wood.

I doubt the bridge is the cause of your tuning issues, 99.9% of the time it's the nut that needs sorting and fine sanding and polishing. Even on plastic and bone nuts you can polish up the slots with a few strands of string that's been soaked in some Brasso - for that extra-low friction feel. What's the string break angle like on the bridge? To improve it you need to lower the tailpiece as low as it will go without any of the strings touching the rear edge of the bridge. You should still be able to slide a thin piece of paper between the strings and the edge of the bridge.

One thing I do with my bridges and tailpieces is wrap some PTFE plumber's tape around the threads that screw into the inserts. They are usually quite a sloppy fit, but a few turns of PTFE tape takes up the slack and they don't rattle around any more after that. Before you remove the posts, note how much thread is showing so don't wrap the tape any higher than that, so that you can't see the tape once it's screwed in.

The looseness of the threads is all part of the wide tolerances applied in mass-guitar manufacturing these days, so that if the posts holes aren't drilled at the exact distance apart, or at a slight angle, then the bridge and/or tailpiece can still be persuaded to fit on the posts. After wrapping the posts in PTFE tape you may find it harder to fit the bridge or tailpiece back on, but then they sit there and often the pressure keeps the bridge and tailpiece in place, even with no strings fitted. It's hard to say if it makes any positive difference to the sustain or tone, but it certainly doesn't degrade it and I do feel that tuning stability is improved.

I did this on my Maestro trem equipped Flying V, among a couple of other adjustments to firmly hold things in place on the trem, and now it's as stable as a well adjusted Strat trem.

So I'd fit the nut, lightly run over the slots with increasing grades of wet'n'dry - 400 upwards - and have a go at polishing the slots with a Brasso soaked string. Then get some of the PTFE tape, wrap it on your bridge (if it's not the thin threaded post type that's screwed directly into the wood) and tailpiece threads, put it all back together, adjust the string break angle and see how it goes.

Quote:

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Originally Posted by Simon Barden

Have you glued the nut on yet, Doc? I've glued brass nuts on before with PVA and they've lasted years without any issues. But if you're having problems, I'd use a couple of spots of CA - you wound need to coat all the surfaces or it may make it very hard to remove if you need to. Likewise, I'd avoid epoxy, because you definitely won't get it off again without doing damage to the wood.

I doubt the bridge is the cause of your tuning issues, 99.9% of the time it's the nut that needs sorting and fine sanding and polishing. Even on plastic and bone nuts you can polish up the slots with a few strands of string that's been soaked in some Brasso - for that extra-low friction feel. What's the string break angle like on the bridge? To improve it you need to lower the tailpiece as low as it will go without any of the strings touching the rear edge of the bridge. You should still be able to slide a thin piece of paper between the strings and the edge of the bridge.

One thing I do with my bridges and tailpieces is wrap some PTFE plumber's tape around the threads that screw into the inserts. They are usually quite a sloppy fit, but a few turns of PTFE tape takes up the slack and they don't rattle around any more after that. Before you remove the posts, note how much thread is showing so don't wrap the tape any higher than that, so that you can't see the tape once it's screwed in.

The looseness of the threads is all part of the wide tolerances applied in mass-guitar manufacturing these days, so that if the posts holes aren't drilled at the exact distance apart, or at a slight angle, then the bridge and/or tailpiece can still be persuaded to fit on the posts. After wrapping the posts in PTFE tape you may find it harder to fit the bridge or tailpiece back on, but then they sit there and often the pressure keeps the bridge and tailpiece in place, even with no strings fitted. It's hard to say if it makes any positive difference to the sustain or tone, but it certainly doesn't degrade it and I do feel that tuning stability is improved.

I did this on my Maestro trem equipped Flying V, among a couple of other adjustments to firmly hold things in place on the trem, and now it's as stable as a well adjusted Strat trem.

So I'd fit the nut, lightly run over the slots with increasing grades of wet'n'dry - 400 upwards - and have a go at polishing the slots with a Brasso soaked string. Then get some of the PTFE tape, wrap it on your bridge (if it's not the thin threaded post type that's screwed directly into the wood) and tailpiece threads, put it all back together, adjust the string break angle and see how it goes.

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I haven't glued the nut in yet, I was going to do it today but I found out that the service station didn't have any 2-part epoxy in stock, nor did they have any CA glue either, I've got plenty of PVA glue though, so I'll give it a try first before I use CA glue or epoxy, I actually was having second thoughts about using CA glue or epoxy anyway, I've got a small red container of some special nut slot lubricant, called Super Vee Superglide, which I'll try putting in the nut slots of the Brass nut, it is specially formulated to help reduce friction.


Update:

I've just gone ahead and glued the nut in with some PVA glue, I'm assuming that I'll need to give it a good amount of time to dry before I put strings on the guitar, that's fine cause I don't have any spare strings, or money to buy some, I'll buy a new set of strings some time next week.


I've just had a look at the glued-in brass nut under a magnifying glass and it looks like I've got it right this time round, it looks to me like the front-edge of the nut where the scale-length starts is sitting 90 degrees (ie, perpendicular) with respect to the surface of the fretboard, and not leaning at a funny angle, so I'm happy with that, the ends of the Brass nut feel like they're flush with the neck too, so I'm pretty relieved.

But the slots need to be smooth as you can get them first, otherwise it's like oiling sandpaper - a slight improvement but still rough.

I normally use at least the two E strings to hold the nut down under pressure whilst it's drying. I'd then give it a full day to harden before using the guitar in anger.

Quote:

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Originally Posted by Simon Barden

But the slots need to be smooth as you can get them first, otherwise it's like oiling sandpaper - a slight improvement but still rough.

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I think I've got some 1200 grit sandpaper somewhere that I can use to smooth the nut slots, although they do appear to be smooth enough.

Just fold it over and do a light pull-through a couple of times. Doesn't hurt to ensure it is smooth.

Quote:

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Originally Posted by Simon Barden

I normally use at least the two E strings to hold the nut down under pressure whilst it's drying. I'd then give it a full day to harden before using the guitar in anger.

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It'll probably be a few days till I can buy some new strings for the guitar so I really don't mind waiting for the glue to properly harden, so that's fine with me, I've got a few other guitars I can play in the meantime, so it all works out, I'm feeling pretty happy that my LP Studio guitar will be playable again, cause I just got my Marshall amp sounding much better than it had been for a few weeks, it turned out to be a couple of Chinese 12AX7 B valves that had gone bad, which was the cause of the amp sounding a bit weak, the two Chinese 12AX7B valves formed the four Triode gain-stages in the preamp section, the result was that the three-band EQ in the overdrive channel wasn't as effective as it should have been, I replaced the two Chinese 12AX7 B valves with a couple of known good ones and the amp sounded much better afterwards like a Marshall amp should sound, with all those nice midrange harmonics, even the Resonance control was working like it was supposed to.


Note that by "bad" I meant that the two Chinese 12AX7 B valves had lost their ability to produce gain, the filaments still lit up, but I'm suspecting that they went low in emission, they don't look like they went gassy because the getter on the inside of the glass envelope is still silvery in appearance.

Quote:

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Originally Posted by Simon Barden

Just fold it over and do a light pull-through a couple of times. Doesn't hurt to ensure it is smooth.

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Will do once the glue has fully dried, and before I install the new strings.

I really don't like no-name Chinese valves. I've never heard a good one yet. Several of them I've had you could hear them physically rattle. The one that came in a Fender Champ 600 was probably the worst as you could hear it over the amp! At least ones with a known brand name on them will have been properly quality checked and be of a higher quality to start with.

Quote:

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Originally Posted by Simon Barden

I really don't like no-name Chinese valves. I've never heard a good one yet. Several of them I've had you could hear them physically rattle. The one that came in a Fender Champ 600 was probably the worst as you could hear it over the amp! At least ones with a known brand name on them will have been properly quality checked and be of a higher quality to start with.

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One of these days I'm going to have to invest in a good valve testing rig, and learn how to sort through all the good ones from the bad ones, I'm going to be ordering a set of three new 12AX7 valves from Evatco soon, the ones in my Marshall are just to keep it useable till the new ones arrive in the post, I was thinking of ordering either a set of three Sovtek 12AX7 LPS valves, or a set of Electro Harmonix 12AX7EH valves, or maybe some JJs, I want to get ones that are high gain but low-microphonic and low noise, so maybe ones with small anodes might be good since they tend to be low-microphonic, might even end up ordering three Sovtek 12AX7WA valves.

Orange do the cheapest and most versatile valve tester that I know of, but it's still expensive and worthwhile only if you do a lot of amp servicing. Don't know what the valve supply situation is like in Australia, but there area a couple of UK suppliers (probably more but these are the biggest outlets) that pre-test the valves and match them up, often into low, medium and high gain sets. It's often variations on the standard valves that end up having the lowest microphonics or highest gain. A valve spec for a 12AX7 valve means it should have a maximum gain of 100, but often ends up less. And even the same manufacturer's valves will have a variation in actual gain. Here's a site I just found that does a good comparison of the different available types of 12AX7s. https://www.amplifiedparts.com/tech-...ent-made-tubes

Worth noting how many of the different brand's offerings are all the same Chinese-made valve, with the same electrical and sound characteristics. So you may as well find the cheapest brand you can find if you decide to try one of those valves.

Quote:

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Originally Posted by Simon Barden

Orange do the cheapest and most versatile valve tester that I know of, but it's still expensive and worthwhile only if you do a lot of amp servicing. Don't know what the valve supply situation is like in Australia, but there area a couple of UK suppliers (probably more but these are the biggest outlets) that pre-test the valves and match them up, often into low, medium and high gain sets. It's often variations on the standard valves that end up having the lowest microphonics or highest gain. A valve spec for a 12AX7 valve means it should have a maximum gain of 100, but often ends up less. And even the same manufacturer's valves will have a variation in actual gain. Here's a site I just found that does a good comparison of the different available types of 12AX7s. https://www.amplifiedparts.com/tech-...ent-made-tubes

Worth noting how many of the different brand's offerings are all the same Chinese-made valve, with the same electrical and sound characteristics. So you may as well find the cheapest brand you can find if you decide to try one of those valves.

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Cheers for the website link, I downloaded a copy of the pdf of the comparison table, I've decided that I'm going to see if I can order three of those 12AX7/B759 - Genalex Gold Lion, Gold Pin valves, I know that they are a bit expensive but so is my Marshall amp, and I reckon it deserves some decent preamp valves to get it to sound it's best, so I'm prepared to spend the money.


I tried creating an account with that website (amplifiedparts.com) but it won't let me log in even if I use the exact username and password I chose when I created the account, so, I'm going to try ordering the new preamp valves from Evatco since I was able to successfully create an account with them, the new preamp valves will end up costing me about $160.00 all up but I'm not really too worried about that at all.

Update:

So, I've just re-strung my Gibson USA Les Paul Studio guitar up with my usual Elixir 46-10 gauge strings, and it looks like I've got the nut height, and consequently the 1st-fret action, well and truly nailed, fretting strings just behind the first fret feels good, I don't seem to be getting any fret-buzzing at all on the first fret either, all I need to do is get the 12th-fret action correct and then I'll be happy with it, oh yeah, I just did a quick play through my Marshall amp's clean, overdrive, and boosted-overdrive channels and the guitar is sounding pretty nice and lively so far too.

That's good news.

I've got the action at the 12th fret on my LP Studio set as per Gibson factory specs (5/64 for the low E-string and 3/64 for the high E-string), the guitar seems to be playing well and I've got the string intonation for each string adjusted as close to spot-on as I can get it (the A-string was a bit finicky to adjust but I got there in the end)so the guitar is playing as well as it can, I think it's ready for taking to uni next week, in that case, I'm calling it "job finished".

Update:

I found that the Brass nut I installed on my LP Studio seemed to be causing the strings to bind in the string slots, so I re-shaped the back of the nut after lightly tapping it free from the PVA glue (very glad I used the PVA glue rather than 2-part epoxy), anyway, after re-shaping the back of the Brass nut to hopefully reduce the string-binding, I glued the nut back into place and re-strung the guitar, it didn't seem to make much difference, so I'm going to try replacing the Brass nut with a Bone one that I've ordered from Stewmac, unfortunately they are out of stock but Stewmac will send it to me once they have some in stock, I've actually ordered two of them and the string-spacing is standard Gibson spec which is a bit wider than the string spacing on the Brass nut.