Paul Reed Smith (PRS) Travel Size guitar build

[TSK]

Hello everyone,

I wanted to share a project that I'm working on... PRS inspired/style Travel Size guitar build. 

Disclaimer: I'm new to guitar building and mods... So, will likely be asking around for advice for learning and lurking around all the cool projects, gear, and axes here.

Anyhow, inspiration for my project is my own CU22 model, though, it'll be more like a CE type (with bolt-on neck).   

Of a travel size, the body portion is essentially the size of a regular sheet a paper, at 8.5"W x 11.75"L.   The neck will feature 24 frets at 25.5" scale length.  Attached are some pics to share.

And some progress videos as well

Part 1: https://youtu.be/TpcWkaX64eg 

Part 2: https://youtu.be/rmdxkFaUScM

 

In the next steps, I plan on setting the neck angle break and establishing the neck plane. I'll be routing all of the cavities.  First time going through these steps... so am a bit nervous to not wreck the nice wood I have. I appreciate any tips/constructive comments you all might have. 

thanks for viewing!

-Tony

[ScottR]

18 hours ago, TSK said:

So, will likely be asking around for advice for learning and lurking around all the cool projects, gear, and axes here.

Welcome to the forum Tony!

Bring it on, we love to watch and offer advice. First piece of advice: if this is your first time routing highly figured wood, and what you've got is certainly that....and gorgeous, use some off cuts and set up some test routes so you can get a feel of how the router behaves and how that figured wood reacts. Getting a bit of practice will help calm the nerves as well!

SR

[JayT]

Judging by the paper bridge template is this going to feature string through? I don't think I've ever seen a PRS with string through- should be very cool! 

[TSK]

3 hours ago, ScottR said:

Welcome to the forum Tony!

Bring it on, we love to watch and offer advice. First piece of advice: if this is your first time routing highly figured wood, and what you've got is certainly that....and gorgeous, use some off cuts and set up some test routes so you can get a feel of how the router behaves and how that figured wood reacts. Getting a bit of practice will help calm the nerves as well!

SR

great advice!

[TSK]

3 hours ago, JayT said:

Judging by the paper bridge template is this going to feature string through? I don't think I've ever seen a PRS with string through- should be very cool! 

Yes!  string-thru.  I talk a little about in the Part 1 video.   For the upcoming Part 3 vid, I'll show what my approach is on the back side (very simple). 

[TSK]

I have a question for consideration of a next step...

ackground: The maple bolt-on neck that I'll be using has a short tenon. I'm now thinking about extending that tenon longer to underneath the neck PU. The neck will still be bolt on (via screw and threaded insert); but, with the bolts farther apart (length-wise) to minimize rocking/torquing (that's the idea, at least). Was thinking of gluing on an tenon extension piece that is about 2" longer from scrap maple. Eventually, will apply two bolts into the extended piece and two bolts into the original part. Would be using Titebond glue for the extended tenon piece. Question: Would this help for a stronger neck joint, or not really? (this affects a next step of routing the neck pocket ... hopefully just once! lol)

thoughts?

Thanks in advance!

[Bizman62]

27 minutes ago, TSK said:

Was thinking of gluing on an tenon extension piece that is about 2" longer from scrap maple

End grain glue joints aren't strong so I'd call that a waste of time. On Fender guitars the neck cavity is only 7 cm long and only one side has full length support, the cutaway area covers only the very corner. On Superstrats the contact area is even smaller as they've cut one corner off for better reach to the upmost frets. Judging by the width of the neck pickup on your drawing there's more than 7 cm reserved for the heel so there should be no issues regarding strength.

Just remember that no matter how deep your neck cavity is and how deep your neck intrudes the body, the distance from the nut to the 12th fret has to be the same as the distance from the 12th fret to the bridge.

[TSK]

10 hours ago, Bizman62 said:

End grain glue joints aren't strong so I'd call that a waste of time. On Fender guitars the neck cavity is only 7 cm long and only one side has full length support, the cutaway area covers only the very corner. On Superstrats the contact area is even smaller as they've cut one corner off for better reach to the upmost frets. Judging by the width of the neck pickup on your drawing there's more than 7 cm reserved for the heel so there should be no issues regarding strength.

Just remember that no matter how deep your neck cavity is and how deep your neck intrudes the body, the distance from the nut to the 12th fret has to be the same as the distance from the 12th fret to the bridge.

Bizman62, Thanks for chiming in. I'd like to pick your brain some more, please....

 

Re: Scale length. Yep! Am constantly making sure I have enough body to maintain my 25.5" scale length.

Re: weak end grain glue joint.  Thanks for this... didn't think about this aspect. Please see attached pic (some of the dimensions are approximate, not exact).  Of my intended Course of Action (COA) #2, it would make sense that the joint of a not very thick tenon extension wouldn't be strong enough to put half my bolts into.  That said, what do you think about my COA #3?  For COA#3, I'd still add an extension. However, I would bolt into the original part, though would shorten the distance of the bolts (M5 hex bolts into threaded insert). I figured that if I could tighten the bolts enough; then, the extended tenon could help to minimize any tendency for the neck to torque around the bolt joint area. That way, of my real intention, I can I also minimize how much the neck heel pocket that extrudes out from the body.     (my reasons for an extended tenon is more for better stability of the neck and minimize heel pocket extrusion).

 

thoughts?      thanks again!

 

 

[curtisa]

If you're not afraid of a little metal work, what about something like the bolt-on neck joint used by Yamaha for some of their 90s-era Pacifica models?:

[Bizman62]

Judging by the dimensions given COA #3 should suffice even without an extension. As I said in my previous post Fender uses about 7 cm long neck pockets which is less than 3". Your drawing shows an almost 4" (10 cm) even with the less extruded neck pocket. Then again, Fender neck bolts are 2" apart lenght vise.

One option for a deeper neck pocket would be installing the bridge closer to the edge. That might also improve balance a bit. Half an inch would be a lot!

The metal lip @curtisa suggested is interesting and would certainly work. Then again, a 3" deep pocket whereof the last inch is supported on both sides and 2.5" on the upper side has worked for Fender for more than half a century. For the record, the neck pocket of a dual cutaway LP junior is 2.75" deep with both sides supported.

[TSK]

14 hours ago, curtisa said:

If you're not afraid of a little metal work, what about something like the bolt-on neck joint used by Yamaha for some of their 90s-era Pacifica models?:

Interesting.... it's definitely making me think about it more.

I'm guessing that's aluminum?

Hypothetically, If going this route.... I could minimize the part extruding from body to only 1" (or enough for me to fit my bolt/washer). One concern I have is that I would still need to route that cavity area out of the body. Once dropping the neck in from the top, it seems there would be a void of wood above the metal extension (minimizing sustain support). ... Unless, I still glue on a wood extension and then use the aluminum plate to re-enforce that joint.   sounds a bit Frankenstein-ish, hahaha.   

totally welcome additional thoughts!  lol   

[TSK]

13 hours ago, Bizman62 said:

Judging by the dimensions given COA #3 should suffice even without an extension. As I said in my previous post Fender uses about 7 cm long neck pockets which is less than 3". Your drawing shows an almost 4" (10 cm) even with the less extruded neck pocket. Then again, Fender neck bolts are 2" apart lenght vise.

One option for a deeper neck pocket would be installing the bridge closer to the edge. That might also improve balance a bit. Half an inch would be a lot!

The metal lip @curtisa suggested is interesting and would certainly work. Then again, a 3" deep pocket whereof the last inch is supported on both sides and 2.5" on the upper side has worked for Fender for more than half a century. For the record, the neck pocket of a dual cutaway LP junior is 2.75" deep with both sides supported.

@Bizman62     If working with the neck as-is (not metal plate, not extended tenon); then, Maybe I could plan for a 2.5" length pocket. I could move the neck slightly toward the pickup by 1/16" (to 2/16" max) and push back my bridge short of the point where the top carve would slope significantly (to avoid overhang).  This way, the neck heel would sit a good 1" into the body, with the rest of the supporting neck pocket extruding only 1.5" from the body.  If making a rounded pocket (like PRS silver sky), then I could probably add another 1/4" (though, not sure this would make a true difference since, the neck would tend to torque away from it).

thoughts about my response to @curtisa  ?

 

Also, for the neck joint, I’ll be inserting M5-sized stainless steel threaded bolts through the body neck pocket into matching M5 threaded brass inserts installed into the neck heel. Am trying to figure out how close to the outside edge of the neck heel that I could place the threaded insert and still have enough wood for strong grip.  Question: what minimum distance should there be between the outside of the threaded insert and the edge of the neck heel?

I was planning for maybe 1/8”… sufficient or not enough wood?

 

[curtisa]

6 hours ago, TSK said:

I'm guessing that's aluminum?

Yes, I believe aluminium was used on the originals.

 

6 hours ago, TSK said:

One concern I have is that I would still need to route that cavity area out of the body. Once dropping the neck in from the top, it seems there would be a void of wood above the metal extension (minimizing sustain support).

I believe the metal tongue used in the Pacificas was located immediately underneath the neck pickup, which was exposed by the pickup cavity. While this doesn't create much of a neck pocket that encloses the sides and back of the neck in the traditional sense, I don't think the Pacifica was ever labelled as a guitar with an apparent lack of sustain due to minimal coupling between the neck and body. Take from that whatever tone voodoo you will

 

6 hours ago, TSK said:

I was planning for maybe 1/8”… sufficient or not enough wood?

I'm having trouble visualising what you're describing, but I would've thought you need enough meat surrounding the threaded insert to prevent the sides of the neck from being split outwards by the insert itself. Is there any particular reason why you are using inserts over common woodthread screws?

Based on your COA1-3 diagrams above, the only option of the three that is practical is to use the first. Any option that has you grafting on a heel extension made from timber will not be suitable as there is no easy way to extend the endgrain of the neck in a way that is strong enough to act as the primary neck attachment point. The drawings also indicate that the pocket sides are extended upwards towards the nut as a thin sliver of timber, which will likely snap away leaving the neck sides exposed.

The problem is not helped by the shape of the PRS body itself. The area in between the cutaways is significantly less than the area and shape of a traditional Strat for which your bolt-on neck is intended. On a Strat (and its derivatives) the heel itself has enough real estate for a pocket to naturally exist in the body. The PRS has pretty much nothing underneath the point at which the neck meets the body and relies on the neck attachment point being naturally much deeper into the body, which also relies on the neck blank being much longer past the end of the fretboard

I suspect that if a Pacifica-esque metal extension tongue is not used the only real way of making a prefab bolt-on neck work with the PRS body style at such a small scale is to have the heel footprint the same size and shape as the neck itself, and simply bolt the neck to the flat ledge created by this extension to the body (a la, COA#1 minus the pocket sidewall extensions you have drawn). It will unfortunately look a bit clumsy, but it will stand up to the stresses involved without risking coming apart under string tension.

[Bizman62]

10 hours ago, TSK said:

I was planning for maybe 1/8”… sufficient or not enough wood?

Any screw or insert that close to the edge of end grain would worry me. 1/4" seems more like an industrial standard.

RE the aluminium plate, as you can see in the images the metal allows for screws being right at the edge to fasten the plate firmly enough. The main issue with bolt on necks is that they're made out of a 1" thick plank. If the heel was 2" thick you could substitute the metal lip with a 1" wooden lip glued to the heel - actually ½" would do, the total heel being 1½". That's how they do it at PRS except that they do it out of one piece.

[Bizman62]

On this early 80's dual cutaway Eko the extension of the neck pocket is 1 1/4" and the side supported area 1½", which makes 2 3/4" in total. The neck is glued on. Notice that the fretboard is longer than the neck! The guitar has fallen from the stand so badly that there's cracks both sides of the upper neck, the headstock being saved only because the neck is  a three piece laminate.The lines on the joint are scraping marks as at some point someone had painted the guitar matte grey using regular indoors wall paint over the lacquer. Luckily it came off with a plastic scraper!

Anyhow, if future taking apart is not mandatory a glue joint should be strong enough within the dimensions you want.

[TSK]

@Bizman62 and @curtisa

thanks for your guys' expertise and advice (I truly appreciate you lending me your valuable time). Being new at this, perhaps I've been overthinking it (lol). 

@Bizman62, I plan on keep this neck as a bolt on, in case I need to remove it for whatever reason (e.g., per travel constraints, refinement/replacement of neck, etc.).

Am now thinking that I'll leave the neck heel as-is per the following plan pic.  (This part has actually held me up from moving forward. perhaps keeping it simple is best for now)  Will move the neck just a tad closer into the body (and moving the bridge back slightly to maintain the scale length). The wood underneath the heel will be about 5.5/8" to 6/8" thick.  In the neck heel, I'll leave at least 1/4" of wood around the outer edge of each M5 threaded insert. Of the extruded pocket, I will sand down the shaped block ever so slightly (1mm?) to where I can establish a line across the neck heel from one cut-away corner to the other side (just after the 22nd fret). Neck angle will be 2.5-deg (same as my Custom 22). 

What do you think... sufficient support with this plan?    

[curtisa]

Provided you're not also scaling down the body thickness to match the reduced overall size, I reckon that will be fine.

[Bizman62]

To me that looks solid enough compared to the factory made bolt on instruments I have. An angled neck plate might further spread the stress from the extruding part of the pocket to the actual body.

[TSK]

7 hours ago, Bizman62 said:

To me that looks solid enough compared to the factory made bolt on instruments I have. An angled neck plate might further spread the stress from the extruding part of the pocket to the actual body.

 

@Bizman62 I originally considered this type of angle neck plate, but then desired a more flush/non-plate look on the back.    Will be using this bolt set, which has a flat bottom washer.

 

[Bizman62]

That certainly looks nicer and most likely won't break anything as it's a proven method in guitar building.

[TSK]

51 minutes ago, Bizman62 said:

That certainly looks nicer and most likely won't break anything as it's a proven method in guitar building.

okay!, good to know (wheww!)    I had seen some other non-flat/rounded hollow washers with a thin edge... but figured that might cut into the wood and cause uneven/reduce tightness.  

[Bizman62]

Bear in mind, though, that the countersunk washers take off some wood so the bottom of the neck pocket has to be both thick and tough enough. The plate sits on the surface and as I said it evens the load. Then again, we're talking about some 3 mm or 1/8" more or less in thickness. The bottom of the pocket seems to be in the ballpark of 1" +/- 1/8". - How on Earth can you live with the fractions?

[TSK]

2 hours ago, Bizman62 said:

Bear in mind, though, that the countersunk washers take off some wood so the bottom of the neck pocket has to be both thick and tough enough. The plate sits on the surface and as I said it evens the load. Then again, we're talking about some 3 mm or 1/8" more or less in thickness. The bottom of the pocket seems to be in the ballpark of 1" +/- 1/8". - How on Earth can you live with the fractions?

@Bizman62

Great points! 

here's a side view of the above plan to try and to illustrate thickness (hopefully I had converted the numbers correctly )

Though the wood thickness is minimized at the four bolt-thru locations from the 3mm thick washers, I'm hoping that the remaining and majority surrounding areas will have retained max and sufficient thickness and strength of the African Mahogany to hold well (that and with a low action).  thoughts?

 

[Bizman62]

That looks sturdy enough. As I previously said, the neck cavity bottoms of my bolt on guitars are about 1" (25mm) thick but I just took a look on my 70's Aria Diamond "1820" bass. It's got two horns and and extrusion like your plan. The inner bolts are barely within the body. What really caught my eye is that the extrusion is only about 3/4" (18 mm) thick. Again, there's a neck plate which may or may not affect strength.

I'd say it ends up to the properties of the mahogany. The species per se can only give a clue, an offcut right at the end of the extrusion will tell how the very piece acts. Drill a hole the size of the bolts at 1/4" from the edge, stick a pin or nail in and pry. Also you can use a punch tool for testing the softness. If it breaks like balsa use a neck plate.

[Andyjr1515]

For 'normal' medium strength timbers I have a rule of thumb that the pocket can go down to 1/2" (12mm) pretty safely.  In fact, just been working on a Status bass - walnut - and that was 10mm before the insert recesses!

Just a point, @TSK.  I'm pretty sure the inserts you picture are designed for metal and the external thread depth won't be wide enough to spread the load when you really bolt up tight - it is likely to strip out the insert. 

You would be better finding some decent quality ones designed for wood which have a coarser and wider thread.  These leave plenty of wood in the bore hole taking the strain.  These are the type I personally use:

 

There are some where the thread is even wider and those are even better