Diary of an overhauled Dobro

Our story begins with a trusty old Dobro that has seen many years of service and some shoddy repairs. I decided to take on this project as a learning experience and favor for my good buddy and musician Danny "Mudcat" Dudeck. The first time I heard him perform live with this resonator he blew me away. Such an authentic and genuine performance. Sounded like he was coming out of some old windup phonograph. He played and sang solo on his feet in a cafe for 7-8 tables and opened my eyes to what can be done as one person and a resonator guitar. He always mentioned how sick the Dobro was and finally stopped playing it. That's where I stepped in and offered to rescue it. The smile on his face when I handed it back was worth a million dollars. Here's the story of the overhaul with photos. I also installed a new electronic pickup system.

THE BEFORE PHOTO in the case. This sure doesn't look bad from a distance but up close it's a mess.

The next step was to evaluate the Dobro from bow to stern and find every problem that could
affect tone, playability or reliability. I could already hear parts rattling inside so I knew this was going to be a fun one. Almost every screw was rusted and stripped and it took a while just to remove all the parts. Oh boy did I find some things to fix and improve. And that's actually GOOD news.

Hopefully you can see the cone is completely chewed and corroded away on one side and repaired with duct tape. The rim of the sound well is also very rusted and corroded. All of this will have to be fixed. This will be a massive tonal improvement. I can see this  is a metal cone that has been mass produced by stamping method and not the old fashioned spinning method. So this cone probably sounded like a cheap pie plate even when brand new. Upgrading to a high quality hand spun cone will be a big improvement.

Cone below is warped and even collapsing. This also affects the neck angle to saddle and alignment of the whole neck and string action. No doubt when I install a new cone everything will be out of whack. 

The maple biscuit bridge has had it and the maple saddle is leaning forward ruining intonation and affecting tone. I'll replace this with an all maple biscuit from National.

Some of the supports are unglued and rolling around inside. This cant be good. It also means the neck stick and body are probably out of whack. It's never easy.

The old electronics bouncing around inside needs to be removed. I'll try to save these parts and the jack in case he still wants to keep them. Lots of rust to remove with steel wool on the rim where the cone rests. I'll wipe those surfaces with WD-40 to get them some protection and slow down the corrosion process.

Okay here's where there are signs of someone mashing the upper bout in slightly then doing a neck reset. Now instead of pushing the top back out and replacing the cone and letting everything be right they left the other cruddy parts in and did a neck reset and this shim. Sometimes it's harder to undo someone elses mess than actually fix the original problem. One reason I shudder when I read "neck reset" on Ebay. I'll have to evaluate the whole alignment with the neck and body after the major parts are replaced. You also have to steam out 3 of the inlay dots and remove phillips screws from that go down through the fretboard and body into the neck stick. Fun HUH?

You can tell by the slick white appearance this truss rod cover and nut are made of nylon. I will probably replace this with bone just because I like bone and want to perfect the action.

Old Grover tuners below have seen better days but with some love and care they will work smoothly again. The washers are rusted together so bad the buttons wont come off. I'll have to completely remove them and soak them in solvent. I wont remove the cool aged look though.

I removed the screw that secures the neck block shim. I pulled the shim out from the inside to show you. The height of this shim controls how deep the neck sits in the so called joint area.

This is the neck stick inside and that block fits right underneath it and the screw comes upward into the stick and the whole thing tightens like a sandwich. You are looking at the neck block and toward the headstock. The reason this Dobro design is so much lighter weight that the National resonators in my opinion is the lack of massive blocks of wood in this upper bout area. It might not be as strong but I thing this way also allows more movement in this upper bout.

I've finally got all my parts in. The biscuit bridge is from National. The Quarterman brand 10-3/8" single cone is from Stewart McDonald supply and Joe from Fishman sent me the active resonator pickup system. This doesn't look like much but it was about 220.00 or more. I also needed some misc screws, bone nut blank and supplies.

I used 0000 grade steel wool to clean and remove all the dirt and rust from the body. I then followed up with a light coat of WD-40 on a rag to stabilize and protect. The body was full of dirt and crap. You have to get all the steel wool shavings out too. The 0000 fine grade steel wool pads will not scratch or harm chrome or nickel finish at all.

I lightly block sanded the frets with 300-400 grade sand paper with a few strokes to level the tops of the frets slightly and remove some of the string wear then followed with a hard buffing with the 0000 steel wool. This removed all the gunk and shined the frets up and they look really smooth afterwards. I would normally only use the steel wool.

I put only a little mineral oil on my fingertip and massage it into the whole fretboard. Only takes a little and wipe off the excess. Fretboard looks almost new and no oil soaks into any cracks or goes under any frets. This is something you rarely need to perform.

 

In this case I don't want to snap off a rusty truss rod when I try to adjust it. So I will let a little of this super fine machine oil soak in over night. This can't hurt anything. I just put few drops in there.

 

Beginning to soak the tuner parts as I remove them from the guitar. This little soak is removing a hard, dry layer of corrosion and what used to be grease. You can't do this right by simply squirting oil into the tuners and getting it all over the guitar.

I want to use some super fine machine oil or lubricant but only about a single drop. I don't want oil running out later. They have white grease in a can that might be better. If this was an ultra high end guitar it would probably have tuners you do not lubricate.

Using a scrap board and small hammer to tap the old nylon nut off.

Nut popped out cleanly and the glue seemed to go with the nut. I got lucky.

I cut a new nut out of a bone blank and fit it into place. I used the old nut as a guide and this one is just a little taller. Once I have the slots and everything perfect I will make it
pretty.



Now before I get too carried away I need to temporarily install all these shim supports and get the neck angle right. I'll slip these in without glue and by sliding them up and down the curve of the back I can tighten and loosen the pressure on the neck stick. This will make more sense in a minute. I have to do some things or the whole system will be out of whack.

I temporarily install the new cone and biscuit bridge and tighten some strings up with a capo holding the strings down on fret 1. Now I have to get the neck angle perfect and the correct action. I want the 6th string and 1st string to measure about 3/32" or more clearance so slide playing and fingerpicking will be easy.

In these next three photos I secured the neck block and glued the shims back in place as well as got the best neck angle I could get and maintain a rock solid neck joint.

Everything is tight and solid. Notice the added shim to the top of these to make them fit.

The little block has been sanded to fit perfectly tight in that gap and the external screw squeezes this joint and pulls the neck down into the neck block area. The fretboard extension is screwed down into the top of that neck stick. Now the sustain of this instrument should be much better and the sound should transfer really well.

PROBLEM - Now comes time to face what I knew would be my first big issue. Getting the cone, biscuit and saddle height to line up with the neck angle to provide perfect action. But first I need to fix the nut and get the guitar tuned up to full tension. So let's do the nut and saddle slots.

First I use my nut files to cut a shallow slot for string 1 and 6 on the outside edges. I'm making the width as far as possible so fingers have plenty of string spacing. I'm staying far enough away from the edges so the strings wont roll off.

Then I file two more slots in the saddle for string 1 and 6. Now the outside strings run perfectly down the fretboard spaced evenly from the edge of the fretboard. The picking hand will now have the maximum amount of room for picking. Now it's time to cut all the other slots in the nut and saddle but I will need to create a simple paper tool. First I grab a blank piece of bone below and mark the width of the two strings on the bone.

Now using this simple template I line up the bone blank on the lines and mark all six. Now I can go back to the guitar and cut the slots with perfect spacing.

DOWNLOAD THIS STRING SPACING TEMPLATE FOR PRINTING

Transferring the spacing pattern back down on the saddle. No need to buy any fancy tools from Stewmac ;) Learned this trick from watching luthier Ralph Luttrell.

Repeat the process with the nut slots. Just making starter depths for now. I'll perfect it shortly.

The string spacing is finally fully utilizing this nice nut width of 1-7/8". Notice the 1st string is smaller and more likely to roll off the edge so I left it just far enough from the edge. The string 6 bass string is going to see a lot of blues thumb rollovers so I stayed close to the  edge but not so close that it will roll off the end of that fret on the bass side. I have the nut seated very tightly against the end of the fretboard and I'm not afraid to glue it in either.  I'll make it pretty later.

Notice how the strings follow the fretboard perfectly now and dont close in as they go toward the bridge. This is something I love to correct. Now you're getting what you paid for.

WARNING: YOU MUST ADJUST THE TRUSS ROD NOW so the rest of the setup
will turn out perfect. I go for only about .007 - .010 gap in standard tuning.

Now I am cutting each nut slot deeper to an almost finished depth. I want to be able to press fret3 like this. It makes the string force down on fret #2 and then barely clear over fret #1 without touching it on the way to the nut. Now if the nut slot is too high there will be a noticeable gap above fret #1. When I press and release my index finger in this photo I  will see each string bouncing up and down off fret #1. I keep lowering the nut slot for each string until they just barely clear fret one. Now this doesn't always mean you are finished but it's a nice place to stop until you can ultra refine the slots. It makes the guitar easier to play and prevents notes on fret one from pulling the guitar out of tune as much while playing. The down side to getting them too low is you begin to buzz. So wait until the entire guitar is almost competely perfect then possibly lower these more as a final step. Or even a week or two later after the whole setup settles. This is worth trying to explain.

 

Below:  The action at the 12th fret is nice for most acoustics but still not really high enough and my biscuit bridge and saddle are at their maximum height. Something drastic and tricky needs to be done to raise the action. I cannot move this neck angle any more. It's perfect. The height of the cone/bridge/saddle and neck angle are almost in alignment and I have a trick up my sleeve. I do not want to make this neck angle any less shallow.

I don't want a taller saddle but if I glue a maple shim on the bottom of the biscuit I can add the 1/16" or so of height at the saddle to raise the action about 1/32" at the 12th fret. You usually need about double at the saddle to raise the action half that amount at fret 12. I've recorded the guitar and listened closely and I don't believe this will hurt the tone at all.

Here's the modification in progress before I begin sanding the bottom down.

Sanding it on a flat surface on a sheet of sandpaper and I want it flat.

After fully assembling the guitar about 5 more times I determined all the parts line up and action is perfect. Now time to full assemble. I'm putting a little glue on the cone so the bridge doesn't rotate or move off center. It will have a pickup underneath and I want the whole assembly to be very tight. The tight bond glue also hardens kinda brittle which is good for transferring tone and I know the little voids under there will be filled. Can't hurt. The little biscuit looks brand new again after a shot of black spray paint. You wouldn't even notice it's been thickened.

Had to install the pickup using the screw and plastic collar supplied. I tightened until it began to grab then tightened another 1/8 of a turn just to snug it. I pointed the exiting wire carefully to the butt end or bridge of the guitar. I was very careful not to pull or bend on that wire. That little donut on the end of the wire is the entire Fishman resonator pickup. It's just that simple!

I used extra stickie ties to secure the wires from flapping around inside. I installed the end pin preamp into the supplied jack panel too. This was a breeze. I just feel sorry for the next poor bastard that has to open this up just to replace a 9 volt battery once a year. I hope I'm not that poor bastard.

Stuck the 9volt pack closer to the upper bout where less bass vibration goes on.

I used every trick in the book to remove a ton of rusted out and stripped screws. I had to tap and refit all these holes with better new screws. I also used slot heads to have a more vintage look. This took a lot of work and slowed me way down.

I found out the hard way this must not be the stock Dobro cover plate. A good clue is the fact it's chrome plated and the body is nickel plated. After some persuading I managed to get the strings and saddle to sit at the perfect height. Making all the parts align is one thing but then getting them to appear in this window perfectly is an art form. I had my work cut out but with some patience this thing probably plays better than it ever did. Even new.

 

Started to ride up and buy a cap for this old volume control hole. Decided a lucky 1930s wheat back penny would be just as good and bring my friend some good luck on stage and on the road. Won't buy you much of anything else.

Well after much more labor than this web page reveals I was able to refine the action on the nut and saddle. Remove all rattles and vibrations throughout the guitar and give this instrument a new lease on life. This one plays better than my new National which is my next project which will be much easier. I was pretty skeptical about how great this Dobro could be but it has a mean little growl and a tone all it's own. It's much lighter than the ole Nationals and a smaller feel and neck profile. One thing for certain. When Mudcat comes over to pick it up next week he's going to flip. I left medium strings 13-56 on it because I'm hoping to show him that with proper setup you dont have to go quite as heavy to get a fat slide sound.

The pickup system sounds good through my LR Baggs Para-DI but sounded a little too bright for my tastes through the Ultrasound DI. Really surprised me how different the tone was. I also got a really good sound testing it through a PA. I was getting a dead string 5 but tapering off the saddle slot on the rear side fixed that tone issue. The tuning machines tune like butter now and the action is delightful at about 3/32" give or take on the low and high E fret 12.

HEAR THE FINISHED DOBRO