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Ken LeVan - Posted - 01/05/2020: 13:43:29
Rudy-rod how-to.
I did a thread about this once before, but all the images were unlinked by Photobucket because I refused to pay their ransom, Anyway, no problem, because I have refined the way I do this several iterations since then, so many of those images are obsolete, and you will see that these pictures are not all of the same banjo, nor are several of the components, particularly the nuts and bolts.
SO, for those who are not familiar with them, a “rudy rod” looks like a dowel stick, but isn’t.
The problem with dowel sticks is that they are notoriously non - adjustable, and very difficult to install, even more difficult to reset. Many vintage banjos were designed to have 1/2” bridges and as the trend towards higher ones came about, lots of people want to put a higher bridge on an older banjo. It is very difficult to change the bridge height on a dowel stick banjo without resetting the angle of the dowel because it’s essentially part of the neck - changing the angle is an exacting and tough job requiring steaming the dowel out, that I don’t like to do and, in fact, don’t do any more.
ERRATA: Above, in the diagram above, which I made several years ago, I said that "the dowel stick facilitates the transmission of vibrations from the pot to the neck". We now know that just the opposite is true—the vibrations go from the strings to the neck via the peghead, thence to the pot.
This is true whether you use a dowel stick, coordinator rods or a Rudy-rod.
Then you have coordinator rods, and I’ll admit that this system kind of offends me for some existential reason I don’t fully understand. One of the sales points of the new “coordinator rod” system when it was introduced by Gibson was that it eliminated the “perch-pole (an older name for the dowel stick). A more shaky claim they made later was that it could be used to adjust the action (yikes). Co-Rods, when used to change the string action, can “egg” the rim, which is dangerous and in the wrong hands have caused delamination breaks in some old pre-war rims, but I guess the thought of easily adjusting the action is too hard to resist, both when Gibson introduced it and today. They have become a kind of norm ever since—part of the grammar of bluegrass banjos much the same way as the dowel stick has become part of the grammar of openback banjos. There is really no good way to change the heel angle without shimming or re-cutting the heel. “no free lunch”, as they say.
Around 1960 Vega abandoned the dowel stick system they had been using for at least 70 years and introduced a double rod system similar to the Gibson system, except with two aluminum rods, one of very large diameter, hearkening back to the dowel stick it was replacing. The rims for these were 7-ply hard maple with cross grain lamination, which allowed holes to be drilled and tapped so that 1/4-20 set screws could be threaded through the rim and used to adjust the neck angle side-to-side and up and down. The two rods were used to loosen and tighten the neck as the set screws were adjusted. Complicated and reviled by many people who thought the neck had to have full contact against the pot. I have an original one of these banjos and have made a semi-reproduction of the system on a longneck for a folk performer, and trust me, it works, but is complicated, and requires a special rim that can have threaded holes.
Enter the “Rudy rod” —a hybrid system consisting of a hollow wooden dowel with a threaded metal tension rod inside - it’s very simple and works by means of tightening the tension rod - i.e. putting it in tension, which puts the wooden dowel into compression and makes an absolutely solid connection of the neck to the pot, more so than dowel sticks or coordinator rods.
I still isn’t “adjustable” in the true sense, BUT, it allows conventional adjustments—shimming or re-cutting, to be done much more easily, in a small fraction of the time that it would take with dowels or co-rods, both of which make it difficult to work on the heel without obstacles being in the way. I probably remove and re-install the neck an average of 5 times to adjust the heel during the setup of a banjo I have made, and this is easy with the Rudy rod, but would be a nightmare if I had to work around a dowel stick or bolts coming out of the neck. This may be the reason why we read about so many banjos need to have the neck angles readjusted.
This system depends on having an anchor in the heel that the rod screws into allowing more tension to be applied than with lag screws, which pull out of end grain. A Rudy-rod couldn’t be tightened as much if the tension rod was screwed into the end grain of the heel like they do with co-rods, and you read about them pulling out all the time, so you start with an anchor, which can be steel, aluminum, or brass—I usually use aluminum, but brass, shown below is easier to thread:
The rod itself is a hollow wooden rod about 3/4“ square. I make them by laminating them in the same stripe pattern as the neck on the banjo so they become a visual extension of the neck.
Here you see there is no mystery as to how they are made, and the hole down the center is “laminated in”.
I usually turn them because I like that better than the square stick and I am really not trying to make them look like a dowel stick.
Here are some ideas for shapes, including the regular old rectangular one:
When I make a rudy rod, I install a washer plate in the rim and put a second bolt below the dowel, which allows a tighter connection, prevents rotation, and facilitates adjustment. Here is a close-up. The washer goes over the scarf joint inside the rim and holes are drilled through the rim using the washer as a template—similar holes are drilled on the other side of the rim, 180 degrees.
You need that washer on one side of the rim and a nylon or similar washer on the end of the stick to allow it to be wedged in
The wedge fit is an “easy” snug one—don’t force it in so that it scuffs the inside of the rim. Just line it up with the holes:
Here’s a picture of the parts I make for a standard set-up:
The bottom bolt can be made in various ways and drilled and threaded on the back end to accept a lower push-pull rod.
Here is how the whole thing is installed:
You start off with the anchor in the heel, and the standard Rudy rod. The end of the tension rod can either be the tailpiece lug or tighten against an L bracket.
The bottom bolt is installed and both the bolt and tension rod tightened with a 7/16” wrench. At this point you are good to go unless you want to install the optional bottom rod.
The optional bottom push-pull rod, which is overkill for an openback banjo with a properly constructed rim, threads into the bottom bolt and goes through the rim. It can push or pull depending on how you adjust it
If it is to be used, it is installed through a second hole in the rim, and tightened into the bottom bolt with a special wrench.
The pull bolt is installed on the outside of the pot, the push bolt, along with a nylon washer is inside. Holding the rod with a wrench, the bolts can be manipulated to push or pull. You can “ tune” the rod, for those who are interested in that technique.
As I said earlier, this is overkill for openback banjos with properly made rims, but I did it on two 14” 6-string ones and am doing this on the bluegrass ones I am currently making, since the bottom rod is a familiar idea to many bluegrass players, and is enhanced by the Rudy Rod, which is a superior neck mounting method on its own.
I’ll add that I think this might be appropriate for thin rimmed 12” pots as well—any time you think that extra rigidity is more important than weight or simplicity. Just don’t use it to adjust the action—it’s meant to stabilize the rim, not to distort it.
Edited by - Ken LeVan on 01/05/2020 14:25:39
awildman - Posted - 01/05/2020: 15:36:21
How snug does the wooden sheath sit around the metal tension rod?
Ken LeVan - Posted - 01/05/2020: 17:49:31
quote:
Originally posted by awildman
How snug does the wooden sheath sit around the metal tension rod?
Just enough so the rod doesn't bind. It can be fairly loose.
Ken LeVan - Posted - 01/06/2020: 05:42:44
quote:
Originally posted by awildmanKen, if you were to omit the lower rod, would you advise lowering the Rudy Rod to the center of the heel?
No, The rod is already in the center:
The bottom bolt is to prevent rotation, to pull the bottom of the heel down tightly against the pot and make it easier to add shims or reshape the heel. I can tell you that when the main center rod is tightened against the pot, the bottom of the heel will still come tighter when tightening the bottom bolt. I find this to be even more important with 12" pots.
80Percent - Posted - 01/06/2020: 09:08:14
Here's my mod to an Ome Wizzard. I very much prefer the asthetics of a dowel located in the middle of the rim. To move the dowel inward, I screwed the neck to the pot with 2 screws, then covered the screw heads with a brass washer. The dowel now is moved inward to the middle of the rim. It's attached to the neck with with one lag screw through the washer. At the tailpiece end a new hole and screw locates the rod in the middle of the rim.
Edited by - 80Percent on 01/06/2020 09:09:17
