Freeman Keller

Something I posted at another forum

Evaluating a used Martin (or any other) guitar. | Telecaster Guitar Forum (tdpri.com)

44 minutes ago, kwakatak said:

OT: Hello, Freeman! I was looking for your old archtop build thread to reference. It's good to see you! How've you been?

Neil, I'm good, a whole lot older but still crazy after all these years.   All of my old HC threads used Photobucket links which have gone bad and I've pretty much switched allegiance to a different forum, if you are interested in my latest archtop build

Lets build something that looks like an L5 archtop | Telecaster Guitar Forum (tdpri.com)

And to the original poster, if you are curious about building your acoustic with the minimum tools I might be able to help.   

Chambered bodies are done fairly frequently on electric guitars and you could certainly make it an acoustic.   It is very wasteful of wood, particularly if you go the full depth of an acoustic (2 inches is pretty shallow).      Basically most of your sides will be very thin end grain which is pretty weak, particularly in the neck block area.   End grain will look kind of funky and is harder to finish, it wants to absorb more of whatever you put on it.  

You'll probably want to make some pretty good templates for both the outer and inner routs.   If you do them in  two parts joined at a center seam (like two bent sides) you can cut them on a band saw - still dealing with end grain but might be easier than routing.

Bending does involve several steps that are tricky for a new builder, you need to thickness the sides to 0.060 or 0.070, put together some sort of hot pipe and molds and then do the actual bending.    Buying a kit or having someone bend the sides is a very good option - I built a couple of kits when I was first getting started and still play them.

So bottom line, its certainly doable but not the way I would choose.   

GluBoost Applications Guide

On 9/9/2022 at 3:14 PM, BeeLectro said:

I don't recommend anyone do this. Warranties don't concern me. I've got so many guitars that if I wreck one I'll cry and have a funeral but I'll get over it.

 

Anyway, here's what happened. It's a 2018 OM-21, bought it new but it had been hanging in the shop for over a year. I've had good luck buying guitars that've hung in the shop for a while, they've already opened up, they don't change much.

 After a couple years I think my tone preferences changed and I wished it had more bass, a stronger low E string. My other OM is a hog custom shop and can double as a dread.

 I remember exchanging some emails with Bryan Kimsey many years ago, he said you can tune the body by shaving the back braces. So now I decided to give it a try.

 

 This is not for the faint of heart. The tools I used are a Dremel with a 36" extension for initial deep cutting with a coarse sanding barrel. Also a 50 grit sanding disk cut in half and attached to an oak square stock as a handle. The disk is sturdy to begin with so it keeps it's shape and doesn't wear out. And a flashlight.

 

Working blind inside the guitar is a little stressful, especially with a power tool. I practiced on a cheaper guitar first, my workmanship was terrible but the sonic results were excellent. I moved on to the OM-21. 

 

Bass notes have longer wavelengths, and the notes I wanted to bring out are below open A. So the only brace I shaved is the longest of the lower bout, side to side back brace. I started at the outermost ends by the curf and gradually worked towards the middle, stopping now and then to give it a listen. I ended up thinning it down considerably, leaving about 1/8" or less at the outer ends and tapering up in the middle.

 The theory, is that shaving the outer ends will bring out the lowest frequencies.

 

It was a complete success. The bass is big and warm and consistent all the way up the neck. This consistency up the neck was a pleasant surprise. There's a few other sonic surprises that are somewhat ethereal, as describing tone is impossible, but the character overall is more interesting. Most standard series Martins produce a tone like a soft fluffy halo around each note. This mod made the halo a little more prominent.

 

Here's a few pics.

Wow, I don't come around here much anymore but I happened to stop by the other day and saw this.   Wow.

I'm not really sure where to start commenting but I will say that I am very glad your modification was a success.   But I do have issues with a few of the things you said.   Its too bad you didn't take some sound clips before and after the mod - I would love to hear each of the open strings played before and after (with the same strings, pick, recorder, yadda yadda).   Double blind listening tests are always interesting...

Something else that is equally interesting is that there is now software that will let you compare two sound notes both in the time domain and the frequency domain.    I have been using one that was especially designed for luthiers when I make modifications - here are two waveforms of the same guitar with a plastic and a bone saddle, this is A2 on the open fifth string, the fundamental is 110 hz

Having something like that and the sound clips would get around the inability you are having describing what you really hear.

OK, just so everyone knows what you are talking about I believe that you are shaving the lower back brace, sometimes call B4.  This is an OM that I built for a HC forum member some years ago, there are two shapes for that brace that Martin has used over the years.   One is wide and flat, the other is fairly skinny and tall like this one.

That brace has two main functions - it keeps the back from splitting as the plate moves with humidity and it holds the 16 foot radius of the back's dome.    Remember that the stiffness of a brace is the cube of its height, by removing one half of the height you reduce the stiffness (and strength) by a factor of 8.    

Some builders do attempt to "voice" the backs of their guitars and certainly that is a worthwhile endeavor - I've never felt that it made that much difference in any tap tones so I mostly just follow traditional designs (like Martins) and they seem to work fine.

I'm intrigued by your discussion of wave length as it relates to your brace shaving,   We know that the length of a wave is simply equal to its speed in whatever medium (air, wood, etc) divided by its frequency in hertz.    I don't know if you are talking about the note in air inside the box or propagating thru the wood - the speed of sound in air is 343 meters/sec, generic wood is 4150 m/sec.   That means your A2 (open fifth string) has a wave length of 3.2 meters in air, 38 meters in wood.   Your low E2 string would be 4.2 meters in air and 50 in wood.    Compare those with the length of that brace which is less than a half a meter, its pretty hard to believe that you are dramatically affecting the wave length - I guess I don't believe your theory.

Your comments about halos around the notes looses me completely.   If you are talking about all of the partials you can see how they changed in the saddle swap but the fundamental and first octave are pretty much the same.

I'll make one last comment before I crawl back in my hole.   Bryan Kimsey is (was, he is not taking new work) a very talented and somewhat controversial luthier and repair technician.   One of the things that he does is after market scallop Martin guitars from the 1970's.   This was often considered a low period for Martin's guitars - because of a lot of warranty issues they had gradually beefed up the size of TOP braces and bridge plate from what they were doing in the so called Golden Era before the war.   Bryan's claim to fame was replacing the big rosewood bridge plate with a smaller maple one and shaving braces thru the sound hole to make them more like the pre war guitars, often completely removing the popsicle brace.   Obviously it voided warranty and there were many people who were critical of his ideas.   However I happen to own a Kimseyfied 1974 D-18.   When Bryan reset the neck on it and refretted it he also replaced the bridgeplate and scalloped the braces (we left the popsicle alone).   I don't belief the work changed the sound significantly but it certainly made it a heck of a lot louder.    I did make some recordings before and after, people who have heard them agree that its hard to tell much difference except volume (and of course that can be playing style as much as anything).     As far as back braces, I've never heard Bryan say anything about modifying them, only fixing them when they break.

In the end it doesn't matter and I'll leave the good folks at HCAG  to think what they think.   I had a lot of good friends here and see that a couple are still around - hi to you all.   I'm still building guitars and stirring up trouble.   Life is good

On 7/8/2022 at 8:29 PM, bluzboy said:

 

Looks too heavy for my tastes, but that is a thing of beauty!

And nice seeing you again, Freeman.  It's been years! 

Its all chambered but still pretty heavy.    And thanks, I haven't been here in a long time.   Friend Gardo posted at another forum that good old HC had met its final demise and I was curious.   Apparently it didn't really happen (yet)  - once upon a time this was a regular hang.

Home made 6/12 watt 6L6 amp.   Just finished building a spring reverb, need to make an oak box for it.

Does it make a difference that its the only amp I've played?   Oh, and there's that old barncaster again.

Hundred year old Douglas fir

There are a few more of these out there somewhere....

Have not built a jumbo (yet).   Did build this one, not an acoustic so I guess it doesn't count

Very different from each from each other in lots of ways - size, scale, strings, tuning

Slick, "painting" a guitar body is not a trivial subject, and is one of the most difficult aspect of building a guitar.   You need to decide on a finishing product, preparation, method of application, final sanding and buffing.    One of the reasons so many hand applied finishes are popular with do it yourself finishers is because it is so difficult to get a professional finish.

This is a great resource and does cover setting up your spray gun and compressor, but it is primarily focused on traditional lacquer finishes

Depending on your wood you may need to fill the pores to get a smooth finish (it is very unlikely your guitar body actually is maple, it might have a maple cap however).   If in fact your body is maple it would be a shame to cover it with an opaque finish like white.    Dan does discuss some traditional white finishes but, again, he is mixing the colors with lacquer.

The cardinal rule for any finishing question, and it goes double here, is to do all of your practice and experimenting on scraps of the same wood as your guitar.    Learn your gun and compressor by shooting lots of water or solvent until you are totally comfortable with the settings.   Wear the proper PPE and have fun.

Probably the best kit electric guitar company right now is Precision out of Vancouver BC.  I'm pretty sure they can put together an SG style guitar for you.   One of the nice things is that they don't include a bunch of cheap hardware and electronics that you will just end up throwing away.   There have been some recent build threads of Precision guitars at TDPRI in the Home Depot.

You can fill the holes with dowels and small round pieces of wood - preferably ash.    Since the finish is probably catalyzed poly something you can drop fill with CA, level and knock the gloss off.   The drilling looks like it might have been a tune-o-matic bridge with a Bigsby - measure your hole locations and compare with the engineering drawings of various trems at StewMac or other suppliers.   Putting a trem back on introduces its own problems

You won't be able to hide it but you can make them look better.

The simple answer is that a lap steel is an electric guitar, it makes its sound by the strings moving thru a magnetic field.   A "dobro" is an acoustic guitar, it makes its sound by the cone moving air.   Various kinds of pickups can be added to a "dobro" to amplify it - some are more true to the cone sound.  

I've run a Paul Norman carbon fiber biscuit in my Duolian since 2009.    Lighter than maple, intonation is fine for the combination slide/fretted play.   Paul has sold a variety of compensated saddles for at least that long.   My tricone has a normal Tee bridge, my spider has a spider bridge.

I need to chime in on this.    First, the idea of the flared slide is that it follows the radius of a fretboard which has a lot of radius to it.   When you do slide barres you can get more even pressure on all of the strings.   For most of us who play on acoustics with relatively flat fretboards a cylindrical slide works pretty well.    

If I was using a flared slide (which I don't) I would want the flare closest to my hand so I can control it over the first two strings while doing barres.   When I pull down to use the tip of the slide for single string stuff I would want to use the straighter part.   As others have said, there are many ways to play slide and if someone else puts it on the other way, whatever works.

What might not work too well is the nut extender in Phil's post,   They are designed to raise (and flatten) the strings on a round neck Spanish style guitar for lap style play.   I guess it could be used Spanish style but I've never seen one that way.   Most people who play slide include fretted notes, they would be very difficult to do with a nut extender.    I happen to have one on my old round neck Dobro right now that I go back and forth between lap and Spanish style play.

The capo thing seems like a complete waste but I've got to admit that I've never tried (or seen) one.  If you are playing slide on an electric guitar you are probably tuning up to A or E, why would you want to capo above that?    And I'll be very honest, a good slide player probably does not need excessively high action - I play slide on everything I own with nice reasonable low "fingerstyle" action.   If you want to optimize a guitar for slide (my resonators are slightly higher than my acoustics or my electrics) then do so but there is no need to get carried away.

2 hours ago, gitmo said:

 Of all the mortise tenon schemes that strikes me as strange that application.

Its not a M&T, its a bolted butt joint.   You see them from time to time on ukuleles and its somewhat similar to Taylors NT joint except for the shims and bolt in the fretboard extension.

If Bob is still around and has the neck off he can check the length by knowing that the insert is 1/2 inch long.   If the neck is still on the guitar measure the length of the neck block, add 1/16 for the sides, 1/2 for the insert.  He does not want the bolt to bottom out in the insert.   Also, Bob, you should use Belleville washers under the bolt heads.

4 hours ago, Bob's Guitars said:

I have a C6 in need of 2 bolts,where can I get them???

I just worked on one.   They should be SAE 1/4-20.  The ones I use are 1-1/4 long but that might not be right for an A&L/Seagull.   

For what it is worth, the Eastman OM that I am storing is a 2003 model AC610.   I has a 25.4 scale, is 1-3/4 at the nut and 2-3/16 at the saddle.   That is slightly narrow by Martin's standards and I can see how some players would not like it (including me).   

You've got me curious.   I need to go measure the one I was storing. 

Most OM's are fairly wide necks - the ones that I have built are 1-3/4 at the nut and 2-5/16 at the bridge.    I'll report back when I've measured the Eastman.

Glenn, I have been storing an Eastman OM for a friend who is on an extended trip, I don't remember the model but it is one of the best mass produced guitars that I have played in a long time.   He worked at a local music store and brought a few Eastman models to them, unfortunately I don't think they sold all that well.    I was particularly impressed with some of their hollow body jazz guitars.    Looks like you scored!

I don't mean to jump into your thread.   My laminate trimmer is relatively inexpensive and like I said, for standard "flat" tops and backs I just tape a little shim on it that holds it more or less perpendicular to the side.   I try to follow the stewmac direction but mostly if I hold on tight I can just run around the body.   I have to turn it so the shim is always working but its never failed me.

Note that the shim is thick at the center line of the base and tapers to nothing at the outside edge.

Sorry about your binding issues, Neil.   I learned a long time ago that cheap tools were often a mistake - I bought the hundred dollar StewMac binding router bit set when I built my first guitar and I bought their "precarious" tower rig when I built my first archtop.   Those tools have routed and bound 25 instruments to date and I can honestly say I haven't had a problem.   I keep thinking I should buy a new sharp bit for my next guitar, I think I've amortized the last one.  

Ps - you didn't say if you sealed the edge with shellac or something but I find it helps with chip out and the fuzzies.

I should clarify something.   When I build a flat topped guitar all I need for binding channels is a laminate trimmer and the SM bit set.  It has enough bearings to do any binding/purfling combination I've ever wanted to do.  The top is flat enough that I just use the base of the trimmer, when I do the back I tape a little 5 degree shim on it to compensate for the dome.   As long as I'm careful with the direction of cuts and brush a little shellac on it the channels are nearly perfect.

On an arched or carved top/back instrument the router can't jut ride on the top or back - it needs to float and that's where the precarious tower comes in.   Again, it works perfectly.

Click - now I recognize the name. Glad to hear it is working for you.

As far as the pickup, I am far from knowledgeable - I install what people bring me and I listen to them before giving the guitar back, but I don't personally use a pup and I really don't have an amp or effects to tell much about them. I can tell you how easy they are to install, what problems I have seen, and the comments that I hear back from the users. I'll try to pass any of that along, but otherwise I'm not much help.

There is a discussion at one of the lutherie forums on best methods of amplifying a classical guitar (many folks are recommending the K&K with an external preamp) but one that popped up that is kind of interesting is this guy

https://www.ikmultimedia.com/product...acousticstage/

I wasn't going to link it until I saw your comment about the belt preamp being a possibility - that is how this works. Here is the discussion - note at the bottom that Hesh recommends the Baggs Lyric - in my book that says a lot.

http://luthiersforum.com/forum/viewtopic.php?f=10101&t=51794