Every once in a while someone brings in an acoustic instrument that somebody sat on. The latest one was an old 60′s Segova mandolin. Usually a neck breaks on an angle so that there is a decent amount of surface area for the two pieces to mate up with. That makes for a strong repair. Every so often a neck breaks like a pencil so there is almost no surface area to glue too . Most repairmen install splines to increase the strength of the break. To install splines you need to route two long 1/4″ or 1/8″ routes length-wise down the back of the neck, through the crack. Then inlay two 1/4″ pieces of hard wood into the routes. It can be very difficult making a jig that will route those lines straight, especially on a little mandolin neck.
I’ve devised a way to fix a neck without having to do the spline thing. My method is quick to set up and comes out super strong. First I crazy glue the two parts of the neck together. This just holds the two pieces in place while I set it up in the jig. The jig consists of two thick pieces of wood mounted on either side of the neck to act as rails for the router to slide on.
Next I crazy glue a 1/4″ piece of wood to the back of the neck (see pic 1). This acts as a router template. The instrument is clamped to my bench that has a little shelf built into it…great for clamping a guitar face down. Next I mount the router on the rails and route out trenches on either side of the 1/4″ jig that I glued to the back of the neck. I use a top-side roller bit and roll the bit against the 1/4″ jig. My starting and stopping points are arbitrary. I kind of go by feel. I just take out about an inch of neck material on each side (see pic 2).
The next step is to carve 2 pieces of maple or oak inserts to fit into the routed sections. This is the hardest part but not so bad. I just keep taking off little amounts on my belt sander until they fit (see pic 3). I carve the pieces so they sit high out of the neck so I can take of the excess after they are glued in. Next I glue the pieces in with 5 minute epoxy to fill any gaps and carve off the excess using the rounded edge on my belt sander or just with a wood file.
After sanding the area it is ready to be sprayed, in this case I did a black “widows peek” like the old Gibson necks. It looks classic and it hides the work. Now all you have to do is avoid sitting on it and you should be just fine in the future!
The DiPinto Mach IV comes standard with a DiPinto double coil pickup in the bridge(actually two DiPinto single coil pickups wired in series) and one DiPinto single coil in the neck. The double coil has a nice big mid-range tone and is great for overdriving a tube amp or playing hard rock distorted passages. Best of all, there is no hum from this pickup. The neck pickup is a single coil DiPinto pickup and while it offers a great straty twang and lots of highs, it does have the annoying 60 cycle hum that is common to all single coil pickups.
Here is a good quick mod you can do to your Mach IV. By adding another DiPinto single coil to the neck pickup you can create your own noiseless pickup. You will need another DiPinto Single coil pickup (available from us direct for $60). Remove the magnet and wire the new coil in series with the neck pickup. To do this you need to disconnect the ground wire from the back of the neck pickup and insert the new coil into the circuit. So black wire from the neck pickup goes to the red wire of the new coil and black wire of the new coil goes to ground.
The best part about this mod is the new coil should fit perfectly into the original cavity of the Mach IV guitar.
NOTE: when you drop the coil into the route you want to flip it upside-down. This will throw the new pickup into a “reverse wound” position and cause the two coils to hum cancel.
The result is very impressive. of course the tone will change slightly. but I think it’s worth trying if you are like me and can’t stand the buzz!
Modern-retro guitars can be a thing of beauty but don’t just settle for an exact re-issue of an old guitar. Those old 50′s & 60′s guitars were cool looking but are often rife with design flaws. And many companies are just sending old, neat looking guitars to China or Korea and having their factories copy them with all their original problems. For instance problems such as poor string angle, pickups that will not adjust to the proper height, and just downright uncomfortable necks are just a few things that appear on these modern re-issues. It takes a luthier with years of experience to re-design an old old-ball guitar properly in order to make it play right while retaining its original beauty and bizarre charm.
I design my guitars with the player in mind while not compromising the look and sound often found on those wild old 60′s guitars. When searching for a guitar with the perfect look, there is no reason to compromise on quality. DiPinto guitars are designed to deliver. Don’t take my word for it, Google “DiPinto Quality”. The reviews speak for themselves. –Chris DiPinto
I’ve spent the last 15 years of my life doing repairs for local Philly musicians. Many of those repairs were fixing old guitars that were worth less than the repairs needed to make them work. Once in a while a customer would pay far too much to save an old guitar for sentimental reasons but usually they’d balk at the estimated price I’d give them (and I tend to very reasonable with my pricing). So I am constantly trying to devise new ways of fixing a guitar without the long hours usually needed to make it work again. The most common problem on an old acoustic is high action. The usual solutions are to lower the saddle and adjust the neck but when you’ve taken those to the limit your only option at that point is change the neck angle.
The usual way of changing the neck angle is to completely remove the neck and re-set it. The problem with that approach is, the neck rarely comes off completely without a fight. It is very common to steam the neck off but this is also time consuming and just not an affordable approach to fixing and old $100-$200 guitar.
Old acoustic guitar necks are glued in with a dove-tail joint but they are never fitted very tightly. There is always room below the joint. I’ve been fairly successful at “shimming” the neck on an acoustic guitar much the way you shim the neck of a bolt-on style guitar. For this example, I’ll use an old Harmony Monterrey.
The first step is to remove the fret where the neck meets the body. If there is no fret right above the meeting place, choose the one closer to the nut. The next step is to saw though the fretboard with a fret saw at that spot, down to the neck wood, in this case mahogany (see pic 1). Now you need to remove the fret board that is glued to the body. You can try heating it up with an iron. Once the wood has become hot, you need to pry off the fret board with a metal spatula. I use one sold through Stu Mac. Once the board is off you have a clear view of the dovetail. My next step is to cut out wedge shaped pieces of wood and lightly hammer them into the space below the bottom of the dove-tail joint (see pic 2). This will tilt the neck away from the body and increase the neck angle, which is what you need for lower action.
At this point take a straight edge and lay it on the board so that it also rests on the bridge saddle. This will give you an idea of how low the action will be. once you are happy with the new angle trim the shims to the level of the dove-tail (pic 3). Strip all the old glue off and re-glue the fret board on. I like to lay the original fret in place to allow for it to be hammered back in later. I clamp the board using a radius block (also a Stu Mac product) for even pressure (pic 4). Once the glue is dry, hammer or glue the original fret back in and string it up. If you did it right the action should be much better. You can now fine tune the action at the saddle.
The drawback to using this method is that you make a gap at the heel of the neck which can be seen when you look down at the guitar when in playing position (pic 5). I fill this gap on both sides of the heel with either wood filler or latex wall grout and touch up the color with wood staining markers. You may also notice that the action, while low up to the body gets higher over the body. This can be fixed by making a wedge shaped shim that fits under the fret board before you glue it on. But remember, this repair is design to be quick and cheap and since most people don’t play above the 12-14Th fret, I skip this part.
The result is far from picture perfect, but that’s not the point. This repair allows you to enjoy an old guitar that would otherwise be a wall hanger for a lot less time and money spent. One could always spend more time on cosmetics but once again the price will start to sky-rocket.
- Pic 1
If you’ve ever strung up a Fender P or J bass you probably noticed that you need to snip the strings down before you load them into the tuning peg; that is if you happen to have a wire clipper. If not, you are stuck winding excess string for a good 1/2 hr. For those of you with no wire cutters, that extra labor may have been tedious but you avoided a major problem by winding all that string: open A string Buzz. Those of us who clipped our string learned pretty quick that the A string does not have enough string angle behind the nut with only a few wraps around the post, causing an awful buzz when plucking the A string open. This can be remedied by remembering NOT TO CLIP THE A STRING before loading into the tuner. Usually, by the time it is ready to change the strings, this fact is long forgotten and you end up in the same boat again with the horrible buzz.
Now vintage Fender basses are not so much of a problem because the shaft of the tuning machine has no flange to it and the string can be forced down the shaft with very little winding, and sufficient string angle can be achieved even if you clipped it too short. However, newer Fender basses including Mexican made instrument, have tuning shafts with flanges. Don’t ask me why they changed this. The original design worked fine. All i can think is that they thought it looked nicer. Well, this nice looking flange forces the A string up the shaft unless you wind the entire A string onto it.
I personally got sick of throwing out new A strings and came up with a remedy. I milled the shaft of the A tuner to defeat the bottom part of the flange. I don’t own a milling machine or a lathe so i utilized my drill press. First I removed the shaft from the tuner and removed the back screw that holds the gear to the shaft. Then I found a longer screw that fit the threads of that same hole (about 1/2″ longer). I cut of the head of this new screw so there was about 1/2″ of threading sticking out. I loaded that into my drill press chuck. This allowed me to spin the tuner shaft in my drill press while I held a metal file to the side of the shaft. I held the file steadily in the area that needed to be reduce; basically a half an inch of the area below the flange (see pic 1). It took a long time but the results were worth it. When I installed the shaft back into the tuner and strung up the bass, the A string had just as much angle as the strings with the string tree…and I didn’t have to throw out a perfectly good A string or add another string tree the head stock. Plus after it was strung up, my repair was hidden by the string wrapping (see pic 2)!
Hope you’ve enjoyed my guitar nerd tech tip, there’s more where that came from!