Luthier Tips du Jour - Bolt on Mortise and Tenon Neck Joint

Luthier and Instructor, Robert O'Brien, shows how to make a bolt on mortise and tenon neck joint for attaching a guitar neck to the body.

[@waltersguitars3336]

Love this guy I’ve been building Guitars now for 10 years if it wasn’t for Rob O’Brien I would never be able to get it done. This man turned me into a master Luthier. The best content on the Internet!!!!! Thank you Mr. Robert O’Brien you are the man!!! When people ask me how I learned how to build guitars I tell him I went to school of Robert O’Brien!!

[@OBrienGuitars]

Thank you for the compliment. All the best to you and yours and happy building!

[@demolitionwilliams7419]

That's awesome

[@brad42948]

Great that you show things slowly and in detail!

[@Archtops]

As always your videos are clear and concise without any distractions. Great teacher! Thank you Robert!

[@redrock1963]

@ 3:44 "I tighten the screws until I hear a crack......I then I back off the screws about a quarter turn". Really everyone......no comments. That's comedy gold right there people.

[@OBrienGuitars]

Glad you caught that one and thanks for watching.

[@fugalibrana]

I love this method!! Since I started to make steel string guitars with this method (even Harp Guitars, with more tension) necks are more stable. Instead, I prefer to make it all by hand, I trust more in my hand skills than a powertool. Thanks for the video! Cheers from Finland 😊

[@JPumpkinKing]

Love how you use "skoche" a lot in you videos! It's a word I rarely hear, but love to hear.

[@ricklatouch2263]

I built a OOO style steel string acoustic about 25 years ago under the tutelage of luthier Tom Knatt. This was the method we used. In 25 years the neck hasn’t required removal but if it ever does it will be a simple procedure.

[@andreapoliti3110]

Magnificent neck coupling system!

[@MAPIOH]

I love the way u build.. Like the Aircraft Technology..👍👍👍

[@sirgreggins8824]

Thanks Rob. you da man. I've learned a lot from these vids. Never would've used fish glue without you. It's my favorite glue for guitars. stuff is great and doesn't smell horrible like hide glue

[@antoniogirardeli50]

O Robert e o cara, passei uma semana com ele em Araguari MG na oficina do Luciano Borges, quanta saudade!!!!

[@OBrienGuitars]

The fretboard extension is glued to the soundboard. I then level and refret the fretboard on this guitar. I also only use a 30 foot radius on the soundboard.

[@tyfude]

@OBrienGuitars Thanks for your time and quick response! This helps me understand the process. I have gleaned much from your instruction. I am currently on this step of my first build. Your clarity and humor have helped me persevere! To clarify, I have one of the pre-slotted and radius fingerboards from LMI. I'll glue it with the drop off at the the transition, then level it with a sanding stick after the neck is set and glued as you mentioned (without defeating the radius)? Thanks for your help.

[@OBrienGuitars]

@tyfude Thanks for the compliments. When leveling the fretboard I let the fretboard extension taper off from the neck to body joint about a 64th to a 32nd. BTW, I have a google chat group where we discuss things like this. let me know if you want access.

[@chester2cows]

If you don't have the router setup you can also do this using a forstner bit in a drill press, setting the depth and width close and cleaning with a sharp chisel. This is easier to do if you put the back on last and use a piece of wood clamped to the drill press table to rest the neck block flatly on it while drilling. You can also drill the bolt holes at the same time and easily place and remove the neck while doing the fitting. Matching the hole positions on the neck and the body becomes easy. Not sure if there is any reason why not to attach the back after the neck fitting has been done, it is sure easier to to attach and remove the bolts with the back off while fitting the neck.

[@car5car5]

Very smart way to install neck. Using 3 bolts would be better, because it would let neck to be adjustable side to side and up/down.

[@OBrienGuitars]

@johncharnock I use 1/2 inch aluminum tubing and 3/8 inch threaded rod. Use a wingnut and a washer to adjust the spreader. All items are available at your local lutherie supply warehouse.

[@OBrienGuitars]

Tiago, (this is my son's name too) I like a gap of 3.5mm at the saddle location when a straightedge is placed along the neck without the fretboard. For my set up with a fretboard thickness of about 6,5mm and a bridge height if about 10mm this works well. It is true the fretboard extension will have to be pushed down about 1/32 inch to glue to the soundboard. When leveling/radiusing the fretboard this goes away but I still like about 1/64 drop off on the fretboard extension. Hope this helps.

[@RickMcQuay]

I'm doing my first mortise and tenon neck and this was super helpful, thanks.

[@OBrienGuitars]

@johncharnock You are correct. However, cutting in one pass is dangerous and not necessary. I use a guide bushing in the router. This eliminates the need for a bearing on the actual bit.

[@gengar678]

first of all thx for all the great info. How do you solve the space underneath the fretboardextension? As you show due to the angle of the neck you will have a slight gap underneath this extension. Most brands will have the extension glued directly on the top though.

[@tiagofiao]

Hi Obrien! First of all, thank you very much for your videos! Congratulations! They are amazing! I’m from Brazil and I’m building viola caipira and classic guitar as a hobby, so far! Your videos are helping us very much! Well, I have two questions about the gap of 3,5 mm of the neck and the bridge.

[@tyfude]

Hi Robert. Considering neck angle, (1:40) you align the bevel so that the plain of the neck leaves a small gap at the top of the sound hole. It has been my understanding that the neck and soundboard angle should equal180 degrees. It would seem, if I leave this gap, then there would be a slight bow in the finger board as it transitions from the neck to the sound board rather than being flat. If you have the time, any clarification would be excellent! I have truly enjoyed your tutorials. Thanks!

[@OBrienGuitars]

No trade secret at all. I clearly show this in my videos and in great detail in my online guitar building courses available via my website. I do not know what the exact angle is as I have never measured it. Most builders use an angle that works with the top radius and bridge and saddle height they choose to give them the correct action. For my building sequence, 30 foot radius and approx 10mm bridge height a slight neck angle is all I need to get the set up I look for on my guitars.

[@OBrienGuitars]

@alianstuff Thank you. I am glad you enjoyed the video. Happy Building!

[@OBrienGuitars]

The fretboard extension on my guitars, and most guitars for that matter, is not flat. It tapers down about a 64th to a 32nd from the 14th fret to the soundhole.

[@bigsbyfreak]

Great video I sent it to some friends who want to built guitars with this way.

[@OBrienGuitars]

if it needs to be tapered down because it is going up then you can use a block plane to make sure it tapers down. My experience has been that on my guitars it doesn't need to be tapered cause it already slopes down from the body joint.

[@jeancarlosfarias4540]

Parabéns pela obra de arte, ainda chega lá!

[@OBrienGuitars]

@garciaorganization I prefer the bolt on mortise and tenon cause it is easier, no compound angles like a dovetail.

[@OBrienGuitars]

Thanks. I would probably go a bit lower because I would probably use a bridge a bit thinner than I normally use. I would shoot more towards the 2.5mm

[@dasfabrik]

Hi OBrien! Thanks alot for all you amazing videos. Sooo helpful in my first build. Question: Will the measurements of the gap (2.5mm - 3.5mm) still be the same on a 12 fret parlor guitar? Im thinking that the value should be a bit lower, because of the bridge being further away from the top of the body..? Regards form Denmark!

[@OBrienGuitars]

For some that probably is the best option. Others may find great satisfaction in making their own guitar.

[@LUCKYB.]

I never knew how a bolt on neck was really done .. I always thought they were only Dove tailed . thanks . do you have a series of A to Z in making an acustic Guitar out ?

[@sirgreggins8824]

When you mark the angle at the 14th fret you say "notice how it is not a 90 degree angle." Does that mean that when you route the tenon the heel should sit on the guitar matching that slight angle slight angle or should that be 90 degrees?

[@OBrienGuitars]

@sirgreggins8824 Not sure I understand your question. The shoulders of the tenon are not at 90 degrees.

[@liloukulele5238]

another excellent instructional video (with a little humor throw in for good measure!) I have a problem; I have a neck that was cut to use wood dowel pins. I am thinking to align the neck and body (without plates installed), drill a pilot hole to locate the holes on the neck and install brass inserts in the heel then screw in from the body...do you think this is structural sound?...this is for a uku. Thanks!

[@OBrienGuitars]

Threaded inserts will work fine on a uke. Some folks only use one.

[@liloukulele5238]

@@OBrienGuitars Thanks so much for the reply! I really appreciate that you reach out and reply...(so many don't).

[@OBrienGuitars]

@@liloukulele5238 My pleasure. Happy Building!

[@liloukulele5238]

@@OBrienGuitars Thank you Sir! Along with being a master luthier, teacher; you are a gentleman.

[@OBrienGuitars]

@sirgreggins8824 It really doesn't matter what size you use as long as you use a bit and guide bushing that give you the results you want. For what I do I have found that the 5/8 O.D guide bushing and the 1/2 straight cut bit work well.

[@tiagofiao]

1 - Why leave this difference? How would it help? 2 - When glue the fingerboard on the neck, would have a gap between the fingerboard and the body on the part before the soundboard hole, correct? How to solve this gap? Thank you very much! Best regards, Tiago

[@OBrienGuitars]

@garciaorganization Yes it could, but why not just use the traditional Spanish heel?

[@azcomum]

Olá Robert! Porque você instala o braço desnivelado em relação ao top? Esses 2,5 ou 3,5mm influenciam na sonoridade ou apenas na montagem? Estou construindo um violão baseado em seus vídeos e esta é minha única dúvida. Posso instalar o braço reto-nivelado ao top? Obrigado e parabéns pelos vídeos. Farei o possível para estar em sua turma aqui em SP

[@OBrienGuitars]

Wagner Venâncio O braço fica nivelado com o tampo mas por causa do angulo do braço na junta fica um vão de 3.5mm no cavalete ao esticar uma regua ao longo do braço até o cavalete.

[@sirgreggins8824]

Any suggestions on how to avoid a bump in the soundboard where the fretboard extention glues on?

[@seasonedtoker]

hi! question about neck angle. in your video you had a neck without a fingerboard and you said if you put a straightedge on it it should sit right on the bridge. how to determine a proper neck angle on a already built guitar?

[@sirgreggins8824]

So i got ahead of myself> Rookie mistake= i don't have an access hole to the truss rod and i have the body glued up. any suggestions on how to do that with the body closed?

[@jeteye97]

Question: Since the bolts have relatively little bearing area on the neck block compared to the glued up area on a set neck, does the neck block need to be thicker or wider or have specific grain orientation to maintain strength in this joint?

[@timbreraguitars]

Robert, pensa em fazer outra turma aqui no Brasil? Tenho interesse em participar se for o caso. Como consigo mais informações referente aos cursos? Você disponibiliza o projeto dos gabaritos desse vídeo? Grato

[@micron001]

Have started my first build & love your vids! Drawing on many years in maintenance to suggest you file the weld, then test the rod. Weld penetration could be marginal and the mass you remove might be what kept it together during the test. If quality testing is required, the time to test is ALWAYS after alteration. Also, after seeing you do what I've read about, I'm surprised more force is not used to test. At the same 1/4 turn, the torque applied will be much higher when it is called on to deflect a neck, thus more strain on the weld. Maybe a rod testing jig is in order! But then, the torque applied would be the most consistent basis for measurement and luthiers would have to purchase torque wrenches. Probably not going to happen...

[@OBrienGuitars]

This is a good point and well taken. Thanks.

[@micron001]

OBrienGuitars Whoops! Had 2 tabs open. Comment was supposed to be for your truss rod video.

[@sirgreggins8824]

when gluing on the fretboard extention how do we make sure its flat, since the neck angles back and is not 90 degrees?

[@umbalaba]

Dear O'BrianGuitar, I guess your angling of the tenon must have something to do with the desired string hight over the fret board. Cumpiano & Natelson does not seem to angle their tenon ("Guitarmaking - tradition & technology"). The StewMac jig loosely suggests an angle of 1-1/2 to 2 degrees. I suspect your precise angling of the tenon is a trade secret. I really appreciate, that you share it with us. Thank you. Yet, could you elaborate on what the point of the angled tenon is, please sir?

[@ROMELUTH]

Olá, sou Brasileiro e luthier apreciei muito seu video gostaria de ter a oportunidade de ter um curso com voce. Abraços.

[@thierryschirk2272]

Salut OBRIEN MERCI pour cette video explicite ,saurait tu m indiquer ou puis je trouver les plan du gabarit pour tenon je souhaiterai en fabriquer un merci d avance Thierry

[@OBrienGuitars]

J'ai des plans disponibles sur mon site web. obrienguitars.com/plans

[@dasfabrik]

Thanks for you answer. How thin would you make the bridge? Thanks again!

[@tiagofiao]

Obrien, your soon has a beautiful name! rs. Thank you so much! It really helps. It was exactly what I was thinking. Again, congratulations for your job and attention! You are helping to develop the luthier art at a global level. I knew that you have been in Brazil, but I did not have opportunity to attend the course, do you have perspective to come back for a new course? One last question, you use the same thickness in the beginning and in the end of the fingerboard (6.5 mm). Um grande abraço

[@sirgreggins8824]

@OBrienGuitars Thanks, I guess i'll glue on the large top brace on when i glue on the popsicle brace and soundhole braces

[@OBrienGuitars]

I use a standard size neck block with the grain running with the grain of the sides.

[@nathandunn5354]

hi i have a epiphone aj-100 im wanting to put a neck off of a epiphone hummingbird can you do that ive sanded down the aj-100 just something to do do you think the neck will work

[@azcomum]

Olá Robert. Apenas para que eu conclua a montagem do braço, qual a espessura da escala sem trastes e do cavalete sem rastilho? Obrigado

[@OBrienGuitars]

Wagner Venâncio se for violão de aço a escala fica em mais ou menos 6.5mm e o cavalete em 9mm ou 10mm

[@OBrienGuitars]

very important if you want the action to be right.

[@OBrienGuitars]

@sirgreggins8824 Glue the braces above the soundhole on a flat surface instead of a radius surface like the braces below the soundhole.

[@OBrienGuitars]

@tyfude The angle of the neck is whatever it needs to be to get the correct gap at the bridge/saddle location. This does cause a slight drop off of the fretboard extension as it transitions from the neck plane to the soundboard. This is why I level my fretboards after they are attached to the neck and soundboard.

[@jonnburton]

Hi Robbie, I was just wondering how the neck joint accomodates the tenon, given that it's angled away slightly. Do you make the mortise slightly oversized (or do you rout that angle into the mortise) or do you shave a bit off the bottom of the tenon?

[@OBrienGuitars]

@johncharnock I use a 1/2 inch straight cut bit with a 17/32 I.D. guide bushing.

[@HRRLutherie]

Can you post a video on dovetails?

[@sirgreggins8824]

Why do you use the 5/8" guide bushing instead of a 1/2"? I watched a video from jsimpson guitars, and he used 1/2" on both, making it basically a flush cut. Just curious why the 5/8".

[@OBrienGuitars]

@sirgreggins8824 oops!! I guess that could happen to anyone. Just do the best you can by going through the soundhole. Good luck.

[@OBrienGuitars]

I have no plans for making this jig. I made mine by trial and error years ago and have fine tuned it over the years.

[@Chrissyb911]

Hi, i have a question i was wondering if you could help me with, im making a replica Gibson Firebird so i bought some plans for it, however these plans are for a set neck and for financial reasons i wanted to build a bolt on neck, is there a way i can convert these plans so that i can still build a bolt on necked guitar?

[@sdearoic]

Really appreciate your wonderful videos! Does the 2.5mm-3.5mm at saddle location change with differant size body? I am building a smaller OOO model and the gap above the soundhole is about 3 times bigger than the one on your video. I use a 25' radius on top. Thanks for the help.

[@OBrienGuitars]

The gap will depend on the radius you use as well as the bridge thickness and saddle height you want. The measurement I mention is what I use on my guitars.

[@OBrienGuitars]

If I had a gap of about 2.5mm and a fretboard of about 6.5mm, total 9mm. I would make the bridge in the 8.5mm range. This is starting to get on the thin end of the spectrum but a bridge between 8mm and 10mm will work.

[@sirgreggins8824]

@sirgreggins8824 thanks. I wasn't sure if the was to leave some extra material for fine tuning.

[@HRRLutherie]

How important is it to angle the neck?

[@babuputhiyaparambil8082]

How to bend and thickness of sound boxes side that also need u did well

[@adaviola1]

Adoraria ter uma viola feita por você, mas moro no Brasil.

[@ryandennan8325]

great video. thanks

[@dasfabrik]

Thanks for the advice - much appreciated! Regards, Jacob.

[@newporter42]

I caught the reference to BR-549. Where do I claim my prize?

[@OBrienGuitars]

I prefer doing it afterwards. With my set up I am able to cut the M&T and set the neck angle in one step.

[@boylenkukiboylenkuki8598]

what woods they do it..

[@sirgreggins8824]

Do you recommend a block plane to do this?

[@dyingslowly666]

I was talking about like what fender has done recently with their shredding acoustic it has an electric guitar neck but it's acoustic

[@mr.2minutes161]

2:07 why not 90° angle? what happen if i just make it 90°?

[@OBrienGuitars]

@ROMELUTH Obrigado. Acabei de lançar um curso "online" (via internet) de construção do violão clásico. Vai até meu site para mais informações. Pretendo lançar também um curso via internet para violão de aço mas vai demorar. Também faço aulas particulares na minha oficina em Colorado. Abraços!

[@Owensguitarstudio]

Hi Robert, on a classical would you still add that angle measurement (the "Skoche" - the top to saddle measurement) to the heel or would you just leave it flat?

[@OBrienGuitars]

I leave the saddle slot straight on my classical guitars.

[@hilariogonzalez5787]

No chinguen!es un caso imposible sin los aparatos que se muestran en el vídeo,la construcción de una guitarra acústica!!♦️

[@raquel2012ful]

ola luthier quero pintar meu violao vou passar removedor de tinta e verniz e rancar todo venis vou lixar bem lixadinho e vou passar um verniz tipo fosco igual um takamine que vi a pergunta é aquela borda branca aquele filetinho e danificado na hora do lixamento ou pintura? o psso lixar ele todo e meter tinta

[@OBrienGuitars]

+lilian vitoria uma foto seria mais fácil me dar uma opinião.

[@raquel2012ful]

no seu video o violao que ta sendo construido tem uns filete branco na lateral nao tem ele e prejudicado na lixagem, mas uma pergunta se nao for icomodar muito qual verniz usar verniz acetinado qual pouco vernis ou uma camada grossa prrejudica na sonoridade como funciona goma laca

[@songlessbird1]

I want to use this joint in an elevated fretboard. If i only glue the neck to the body and dont use bolts , will i have problem? I am making a classical guitar.

[@OBrienGuitars]

The bolt on mortise and tenon is designed to be used with bolts. However, you could do a M&T joint with just glue if you wanted. Make sure the joint is tight. Why not just use the Traditional Spanish heel joint?

[@songlessbird1]

The Spanish heel seem way difficult to make an elevated fretboard. Need modified solera and a mistake is hard to correct. I guess I ll try the classic dovetail.

[@mikehasson6146]

Robert - do you sell plans for the tenon jig? I'd like to build one...

[@OBrienGuitars]

Yes, you can find them on the lutherie Academy website. - lutherieacademy.com/plans

[@mikehasson6146]

@@OBrienGuitars Thank you. I took a quick look, it's the "neck angle jig" that is for cutting the tenon, correct? I'll be buying a set soon...

[@OBrienGuitars]

@@mikehasson6146 That is correct.

[@mikehasson6146]

@@OBrienGuitars Thanks for taking the time to reply Robert. And thanks for all the great content as well. I'd love to come take a class with you, but unless I win the lottery, it's not in the budget as I'm retired, and on a fixed income. I'm saving to take some of the online courses! I live not all that far from you, down in western New Mexico. A day's drive if you can handle 10 hours in the seat... If I ever get up your way I'd love to drop in and say hello...

[@OBrienGuitars]

@@mikehasson6146 Please do drop in for a cup of Brazilian coffee if you are ever in my neck of the woods.

[@vegane_athee]

Hi! How to make this guitar side angle bevel? Do we have it automatically because the top has a radius and we just have to sand this area to make it flat? Or, if the top is flat, do we have to cut the sides something like one degree angle from a bit higher of the waist?. Or do we make the top thicker where the fretboard will be glued on and we sand the high portion of the guitar to make that angle?

[@OBrienGuitars]

I use a 30 foot radius on my soundboards and rims. The neck angle works for me because I glue the upper braces on a flat surface. Check out my online acoustic guitar building course to see how I do it. obrienguitars.com/courses

[@vegane_athee]

Thanks. :-)

[@juliantaylor7663]

another question, if i'm using a dovetail gluing not bolting do i still need add relief or is that just for bolt on necks

[@OBrienGuitars]

I do not understand your question.

[@juliantaylor7663]

@@OBrienGuitars sorry ill try to rewrite it you mentioned relief around the joint for the bolt on tenon which didn't require glue do you need relief for the dovetail considering the joint will be glued

[@OBrienGuitars]

@@juliantaylor7663 You want the dovetail joint to be tight with no gaps.

[@juliantaylor7663]

OBrienGuitars thanks for your help as always

[@OBrienGuitars]

Yes I do.

[@nathandunn5354]

do you fix guitars do any kinda work on them

[@TW-rn1vn]

What did you do with the truss rod

[@OBrienGuitars]

it gets installed as well by extending the truss rod slot into the block and soundboard.

[@azcomum]

Obrigado Robert, entendi perfeitamente. Mas na hora de colar a escala, como vou compensar o cabelésimo que existe entre a parte de baixo da escala e o tampo? Mais uma vez obrigado

[@OBrienGuitars]

Wagner Venâncio Cola no tampo e depois nivela por cima na hora de arredondar a escala. É só um cabeléssimo mesmo né?

[@timbreraguitars]

Minha dúvida kkk. Obrigado por transmitir conhecimentos tão interessantes, tenho aprendido muito contigo.

[@dyingslowly666]

could you cover how to do a bolt on neck like an electric guitar i want to make an acoustic but with a bolt on neck

[@OBrienGuitars]

I cover an acoustic bolt on neck in my youtube videos. The electric bolt on neck, which is different than the acoustic bolt on neck is covered in detail in my online electric guitar building course with Mike Snider. www.obrienguitars.com/courses

[@juliantaylor7663]

when using a router for the neck joint whether its a tenon or dovetail if youre building a flat top ( no radius on the top) do you still need to have a neck angle?

[@OBrienGuitars]

It depends on the geometry of your guitar. When placing a straightedge along the neck with the fretboard and frets installed I like to see a gap at the bridge location of about 11mm. Do what it takes to get that no matter what radius you have on the top.

[@juliantaylor7663]

OBrienGuitars Thanks for the advice as always Hope you have a great Christmas

[@jonnburton]

@OBrienGuitars OK, thanks.

[@demolitionwilliams7419]

Thankfully this info is very well articulated, but either way, this is overwhelming

[@OBrienGuitars]

@garciaorganization good luck with the build. I have a google group you might find useful. Let me know if you want access.

[@OBrienGuitars]

Sure, Just rout the cavity for the neck and then instead of gluing the neck on bolt it on.

[@Daantjer]

7:50 is it me or does that bolt look too short? After all it has to pass through the thickness of the neckblock?

[@OBrienGuitars]

They are just long enough to get the job done.

[@Daantjer]

@@OBrienGuitars Apparently!

[@ivanfuchs9068]

Hi Robert, Thanks for the video. I m considering making a classical guitar with bolt-on neck. Is it possible to use mortise-tenon jig on clasical guitar(domed top)? ..maybe some thoughts on bolt-on joint on classicals? Thanks again.

[@OBrienGuitars]

Yes, bolt on necks are fine for classical guitars.