Hot rod 2 way truss rod questions

[charles Tauber]

Originally Posted by ZekeM

Haha I also despise fractions. As a machinist I prefer everything measured in thousandths. So much simpler to deal with.

Generally, I use fractions or mm, but for plate and side thicknesses, fret placement and nut slotting. Most woodworking, I find, doesn't really require more precision than that as far as using measuring instruments. Being hygroscopic, wood changes size if you look at it twice.

One exception is these cutting boards I make:



Giving some serious thought to going CNC, which will require decimals.

[arie]

at .375 depth, perhaps the lmi rod is a better choice for you then? it seems to not need that deep of a slot. iirc after extensive catalog surfing, i think i found that they have the lowest profile for a two-way rod.

i too hate fractions. prior to my current job as a mfg engineer, i was a tool/die/mold maker. a steady diet of four place decimals was the norm -but not needed for wood. i find that +/-.002 is pretty easily dealt with and works well for most situations but as stated wood changes with the environment. that's why imo all critical joint cutting and glue up should be done under a humidity controlled environment and preferably the same one during each work session on mature, seasoned wood.

headstock veneer: charles brings up a good point. they can go a long way toward strengthening a headstock along the scarf joint. some builders even use one on the back of the headstock as well.

"I just cant picture how he is managing to get his neck to extend to the upper face brace, far beyond where my headblock ended on my build"

if i am understanding your question correctly, the truss rod slot spans the joint between neck and heelblock. the portion of your heelblock that points towards the tail block is extended to meet the utg. viewed from the side it would look like a sideways "L". some builders even use a insert to form a neck extension. it looks like a sort of "stub". while others go full width. have you ever seen a elevated fretboard? the wood supporting the bottom of the fretboard is actually part of the neck in that situation.

very nice cutting boards btw charles!

[ZekeM]

Charles thank you so very much for the information. It has been super insightful!!!!! I see exactly what you are doing now. Very clever. I think i may give a try to your way if you dont mind me copying your idea there. I can also see how much easier it would be to align the top that way.

As far as CNC machines are concerned, yes you might need to use a decimal or two, or a thousand. If you decide to go with getting yourself into CNC work and need any assistance with the programming or just general knowledge hit me up. I know a thing or two about them. Ive been around them most of my life. When i was in trade school i was in a CNC mill programming competition and came in 1st place in the state and 6th in the country (with a machine i had never used before). So i know my way around the CNC world and would be happy to help you.

Once again thank you so so so very much. Ive learned quite a bit from both you and arie.

[ZekeM]

arie,

I have seen an elevated fret board and that was exactly what i thought of as soon as i saw charles' picture. I am thinking i will do just like his picture and on the neck i will put an extension under the fret board and then carve out the headblock to recieve the extension. therefor extending the truss rod to the soundhole, creating easy acess for adjustment while maintainin the strength and integrity of my head stock.

by the way i cant stand engineers hahaha. im sure since you were a tool and die maker you are one of the few i would get along with. So many engineers these days dont have a clue how things are actually made and they design such rediculous parts. they believe since they spent time in a classroom and got a degree they can draw it on paper which means it will work in real life. I dont get along with those guys very well. I think all engineers should have to work in manufacturing before they can design things. Just my opinion

[arie]

I have seen an elevated fret board and that was exactly what i thought of as soon as i saw charles' picture. I am thinking i will do just like his picture and on the neck i will put an extension under the fret board and then carve out the headblock to recieve the extension. therefor extending the truss rod to the soundhole, creating easy acess for adjustment while maintainin the strength and integrity of my head stock.

this would be a good option for you. i think that taylor does the "stub" extension thing and with the addition of angled shims, they now have the patented "NT" neck joint.


by the way i cant stand engineers hahaha. im sure since you were a tool and die maker you are one of the few i would get along with. So many engineers these days dont have a clue how things are actually made and they design such rediculous parts. they believe since they spent time in a classroom and got a degree they can draw it on paper which means it will work in real life. I dont get along with those guys very well. I think all engineers should have to work in manufacturing before they can design things. Just my opinion

oh jeez don't get me started on today's engineering talent. in nearly 30 years i've done everything from rebuilding machines, to programming 5 axis gantry mills for dod work, to machining rf structures for particle accelerators - and it seems that the talent pool is getting worse. our company employs "interns" for engineers who are the nicest "kids'' but very very green. typically our company suffers through their on the job learning curve and arrogance with the hope that they'll finally get it. i'll be there to bail them out.

good luck with your build and show us some pix when you have a chance

[ZekeM]

I will definitely post pictures. Ill put up a thread in the custom shop section as soon as the back sides and top material get here. Probably early next week. I have decided for sure to do the neck extension thanks to you and charles. hopefully it turns out good. I was quite happy with the first though it had its issues being my first.

Im glad to know there are a few good engineers left out there. especially ones that agree that having a piece of paper from a college in no way qualifies you to start drafting some parts up. Some of the blueprints i get these days make me laugh. One of my favorites had half of the measurements in metric and half in standard and not a tolerence to be seen anywhere hahahah. needless to say i threw it in the trash and told them they needed to make a few changes or they were not gonna be happy with what i made with that print.

[charles Tauber]

Originally Posted by ZekeM

I think i may give a try to your way if you dont mind me copying your idea there.

Unfortunately, I have few original ideas. The methods I use are pretty standard guitar making methods.

i will put an extension under the fret board and then carve out the headblock to recieve the extension

As Arie mentioned, you've arrived at Taylor's neck, or a variation on an archtop neck. There are a few other makers who have done this as well, including Charles Fox, from whom I learned much of the basics: http://www.charlesfoxguitars.com/

I can also see how much easier it would be to align the top that way.

It's not really necessary, but a side benefit of the method - essentially acting like a stop block.

So i know my way around the CNC world and would be happy to help you.

Thank you for your generous offer - I may just take you up on it.

by the way i cant stand engineers hahaha. I think all engineers should have to work in manufacturing before they can design things. Just my opinion

oh jeez don't get me started on today's engineering talent... i'll be there to bail them out.

I'm a mechanical engineer. [ducking for cover]

I started instrument making before going into engineering - actually, it is part of what got me interested in engineering. I spent three years at a hands-on technical college before spending three more to get an engineering degree.

I agree that many graduating engineers have little practical design/manufacturing experience. I see it daily in my job. I'm thankful for guys like you who in my early days bailed me out on more than one occasion.

[jeff crisp]

I find the hot rod to short for easy access from the sound hole. I dont like the idea of burying the allen nut in the neck block, which is required if you wish to extend the other end past the first fret on some of the more standard scale lengths.

Jeff.

[ZekeM]

Oh no engineers are everywhere!!!!

But on a serious note please let me know if you need CNC help I owe you for the great info you have given me.

Those fox guitars are very very nice! I think that im gonna keep my freboard a little closer to the body than he has done though. And yes ill definitely need a longer truss rod since im extending the neck ill have to look into what length i need. Good thing Im assessing this now before ive started cutting. I think overall the neck extension is a far superior design. It will make everything much easier i think and will be very stable as well. Im looking forward to starting. Thanks again everyone

[arie]

Originally Posted by jeff crisp

I find the hot rod to short for easy access from the sound hole. I dont like the idea of burying the allen nut in the neck block, which is required if you wish to extend the other end past the first fret on some of the more standard scale lengths.

Jeff.

doesn't the hot rod come in four different lengths from 12.25" to 24.0"?

i'm kind of a fan of lmi's TRDS rod. shallower slot needed =more wood in the neck in the direction of string pull, you can use a standard router bit or endmill instead of buying their special one or finding a 7/32" diameter cutter, and it has a flat blade on top instead of a shrink wrap coated rod. i feel the the flat blade provides a bit more stable pressure on the neck with less chance of the contact rod deflecting sideways in the slot under tension.

just my .02

[ZekeM]

The hot rod does come in various lengths. I think I'm leaning more toward the lmi or I may just make my own if I can't find the length I need.

So i was thinking about the neck extension and was wondering would it be wise to glue it down as you would the fret board to the sound board? I think that with a snug fit the bolts would hold it in place just fine and if it ever needs a neck reset you wouldn't have to fight glue way down in there. Any thoughts on the matter?

[arie]

i think the usual route for people is to bolt the extension as well. 2 bolts in the heel block and 1 or 2 bolts/screws up into the extension from underneath.

[ZekeM]

Makes sense and I like that way better than glue. I'm so ready to begin this thing now! Thanks again arie.

[jeff crisp]

Originally Posted by arie

doesn't the hot rod come in four different lengths from 12.25" to 24.0"?

i'm kind of a fan of lmi's TRDS rod. shallower slot needed =more wood in the neck in the direction of string pull, you can use a standard router bit or endmill instead of buying their special one or finding a 7/32" diameter cutter, and it has a flat blade on top instead of a shrink wrap coated rod. i feel the the flat blade provides a bit more stable pressure on the neck with less chance of the contact rod deflecting sideways in the slot under tension.

just my .02

I've been using the 14 1/4" on scale lengths up to the 25.5" mark. With the rod starting about a cm from the nut the Allen head remains buried in the neck block. The next size up is 18" which would leave me with the Allen head protruding past the start of the sound hole.

At this point in time I'm favoring the style of Rod you mentioned made locally (Australia) to a length that I would prefer.
(edit) I'm also not keen on the small diameter Allen key required for the stew mac rod. Also I broke one recently but that may have just been heavy handedness on my behalf, I'm not sure.
Jeff.

[jeff crisp]

Originally Posted by arie

i think the usual route for people is to bolt the extension as well. 2 bolts in the heel block and 1 or 2 bolts/screws up into the extension from underneath.

I don't know if the extension bolted to a pocket is the usual route (it may be) but a number of well known builders still glue the extension to the top with a bolt on neck. No doubt pros and cons to both ways.
Jeff.