Sambo Posted February 19, 2005 Report Share Posted February 19, 2005 Hiya, I've had a warmoth neck with the compound radius for a few months now, and i love the bloody thing. Its from 10-16" radius. Just wondered if there was an easy way to do this? Cant really think how to do it and get it vaugely accurate. Thanks Quote Link to comment Share on other sites More sharing options...
frank falbo Posted February 20, 2005 Report Share Posted February 20, 2005 You should be starting with the board radiused to the "nut radius" in your case a 10". Then you can gradually use flatter and flatter blocks as you go up the board. When you start at the lower frets, be sure to radius from there all the way up. So you'd do a 12" perhaps from the 5th fret, but all the way to the last fret before switching to the 14" radius block. Then you'd do the 14" at, say the 10-12th fret all the way to the last. Then the 16" from the 16th to the last. You can tell when you're done because the radius blocks will only make contact in the middle for starters, and then gradually begin making contact out to the edge. Then you can smooth out any transitions with a narrow, flat block (preferrably a file) running all the way up and down the neck, following the taper of the string pattern. It's not as perfect as a multi-length pendulum, but it'll do just fine. With this method I can be in control of when my radius will start to change. It doesn't have to be exponential. I can leave a 10" radius right up until the 8th fret if I want, and then still transition to a 16" by the 16th fret. Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted February 20, 2005 Report Share Posted February 20, 2005 Good advice from Frank. I tend to find that the compound radius thing almost happens naturally even when using a single radius block (i.e. tends to be slightly flatter at the higher frets), so really it is not that difficult. Use a sharpie marker to draw a line on the very top of the frets when sanding down, that way you'll know when you've gotten the correct radius all along the fret. You can use a pencil in the same way (draw horizontal lines) when you're sanding the fretboard. Quote Link to comment Share on other sites More sharing options...
Sambo Posted February 20, 2005 Author Report Share Posted February 20, 2005 thanks for the advice, never really knew how it was done 'properly' anyway! I'll give it a go on a cheapy fretboard blank and let you know how i go on! Quote Link to comment Share on other sites More sharing options...
tirapop Posted February 21, 2005 Report Share Posted February 21, 2005 I've seen jigs for holding the fretboard over a belt sander. Someone posted a pic on this forum of a router jig. The part holding the fretboard pivots on bolts... you can see the axis and the cone the fretboard sweeps through. Quote Link to comment Share on other sites More sharing options...
Cracked Posted February 21, 2005 Report Share Posted February 21, 2005 I've seen jigs for holding the fretboard over a belt sander. Someone posted a pic on this forum of a router jig. The part holding the fretboard pivots on bolts... you can see the axis and the cone the fretboard sweeps through. ← Was that Myka's jig? http://www.mykaguitars.com/tools/neckcarvejig/default.htm Quote Link to comment Share on other sites More sharing options...
Devon Headen Posted February 21, 2005 Report Share Posted February 21, 2005 I think he's talking about a jig like the new one Grizzly sells. http://www.grizzly.com/products/item.cfm?itemnumber=G0577 lmii sells a kit for building one, too I think. Quote Link to comment Share on other sites More sharing options...
tirapop Posted February 22, 2005 Report Share Posted February 22, 2005 LMI has a picture of a belt sander jig. This is what I can recall about the router jig: the router slid on a track mounted above the fretboard. The fixture holding the fretboard had to moved after each router pass. I think the router could also be fixed to the track and the fretboard could be rotated freely. Quote Link to comment Share on other sites More sharing options...
Setch Posted February 22, 2005 Report Share Posted February 22, 2005 I think you are better off establishing your flat radius first, then introducing the tight radius near the nut and blending it in. Why? Well, to sand a 16" radius into a 10" you remove material from the edges of the board. To do the opposite you have to remove material from the centre of the board - which reduces it's thickness. If you do this on a fretboard already glued to the neck yo'll be effectively reducing your neck angle - and changing your action in the process. If you do the flat radius first you end up with a board which is of constant thickness along it's entire length, and with a little care and planning, one which has sides of equal height along its entire length. I should add that I haven't actually worked with compound radiused boards, or done any myself. The post is based on previous discussions I've seen by experienced builders, and some of my own thoughts. Quote Link to comment Share on other sites More sharing options...
Sambo Posted February 22, 2005 Author Report Share Posted February 22, 2005 (edited) That LMI pic has given me a few ideas. I cant remember who's the router jig was, but thats a damned good idea too. I thinks im gonna have a go at building on over easter Addition: Just a thought, couldnt the router jig be modified with a sanding disc in the router? Hmmm... just a thought. Anyone ever done anything like this? Edited February 22, 2005 by Sambo Quote Link to comment Share on other sites More sharing options...
Guitarfrenzy Posted February 22, 2005 Report Share Posted February 22, 2005 It's not hard to do a compound radius just using a 16" Fret/Fingerboard Leveler that Stew Mac sells. Basically to do a compound radius you'd sand the fretboard lengthwise as if your following the way the strings run. Instead of keeping the leveler parallel at all times to the center of the neck when sanding, you'd angle the leveler so that it would follow the shape of the neck. Kinda hard to explain, but maybe I can draw a picture to better explain later. I've been thinking about buying the Grizzly sander also though, because it would make it much faster and more accurate. Quote Link to comment Share on other sites More sharing options...
Maiden69 Posted February 22, 2005 Report Share Posted February 22, 2005 Setch got it right, If you do the 10 first you will remove material from the center to do the 16 and this will give you an uneven fretboard. I have been practicing on MDF to see the best way and the 16-14-12-10 seems like the best bet so far. Matt, that jig is so easy to make, that if you made your neck jig, this thing you can pull out in while sleeping. the only thing is that it will be hard to pull the compound on it, I have been playiing with some drawings but all I get is a straight radius, by adjusting one end at 10 and the other at 16 you will have to fight the piece to make it swing right to the compound it will want to follow the tighter radius instead. Quote Link to comment Share on other sites More sharing options...
jnewman Posted February 23, 2005 Report Share Posted February 23, 2005 (edited) Setch got it right, If you do the 10 first you will remove material from the center to do the 16 and this will give you an uneven fretboard. I have been practicing on MDF to see the best way and the 16-14-12-10 seems like the best bet so far. Matt, that jig is so easy to make, that if you made your neck jig, this thing you can pull out in while sleeping. the only thing is that it will be hard to pull the compound on it, I have been playiing with some drawings but all I get is a straight radius, by adjusting one end at 10 and the other at 16 you will have to fight the piece to make it swing right to the compound it will want to follow the tighter radius instead. ← I believe that if you're going to try to make a jig like that and use it to make compound fretboards, you're going to have to use a sort of ball-and-socket or gimble hinge (that permits rotation on two axes) at the top of one of the arms and a single-axis rotation hinge (like a bolt through both pieces) at the top of the other arm so that, for example, if you wanted a 10"-16" compound fretboard you would: Make one arm 16" long from the hinge to the desired surface of your fretboard and make the other arm 10" long from the hinge to the desired surface of your fretboard, then move the short arm's mounting bracket down the frame until the fretboard is perfectly horizontal. You then back off the knobs at the top a little bit so that you can push the fretboard down onto the sander, and as you swing it back and forth, the long arm would swing straight and the short arm would swing in a slight curve in which it moved towards the long arm as you pushed it away from the center. You wouldn't have to fight it at all, and it would do perfectly even compound fretboards. If people are interested, I can draw up a blueprint of what I'm talking about and find parts numbers of the kind of hinge I'm talking about. Edited February 23, 2005 by jnewman Quote Link to comment Share on other sites More sharing options...
Devon Headen Posted February 23, 2005 Report Share Posted February 23, 2005 I think that'd be great. I've been looking at a router jig for radiusing, but the idea of using a router on a piece that small makes me nervous. I've been meaning to get an edge sander anyway. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted February 23, 2005 Report Share Posted February 23, 2005 Setch & Maiden, It sounds like you guys have a pretty good grasp on compound radius. I have never really tried one and have a question. I am thinking about the fret height ( I am picturing a straight neck little or no relief). If you start with a 16" radius on the entire board. Then you use a 10" radius on the upper neck taking care not to remove much from the peak of the 16" radius. Wouldn't the lower frets be higher than the upper neck frets with the smaller radius (progressively getting worse as you move off center of the board) and possibly fret out? I have never studied this so forgive me if this is a stupid question. I guess I had thought you would have to drop the height in the center on the larger radius on the lower half of the board to compensate for the steaper radius at the upper part of the neck. Basically Start w/ 10" entire board/ then go to the 16" on the lower section and only take it down from the middle of the board until you match the fret height at the fret edges. That way your fret height would drop as you go away from the nut, but fret edges remain constant throuout the length of the board. ????? I dunno ????? Confused and curious, Rich Quote Link to comment Share on other sites More sharing options...
jnewman Posted February 23, 2005 Report Share Posted February 23, 2005 I believe that if you're going to try to make a jig like that and use it to make compound fretboards, you're going to have to use a sort of ball-and-socket or gimble hinge (that permits rotation on two axes) at the top of one of the arms and a single-axis rotation hinge (like a bolt through both pieces) at the top of the other arm so that, for example, if you wanted a 10"-16" compound fretboard you would: Make one arm 16" long from the hinge to the desired surface of your fretboard and make the other arm 10" long from the hinge to the desired surface of your fretboard, then move the short arm's mounting bracket down the frame until the fretboard is perfectly horizontal. You then back off the knobs at the top a little bit so that you can push the fretboard down onto the sander, and as you swing it back and forth, the long arm would swing straight and the short arm would swing in a slight curve in which it moved towards the long arm as you pushed it away from the center. ← Right. I was thinking about this and drew some stuff up, and this is wrong - in several ways. What you actually need is the places where the arms are fixed to the board the fretboard goes on to be able to rotate about the axis of the arm (sorry for the complicated wording - I'll draw something) and a way for the joint between one arm and the main board to slide along the board about an inch. All of this can be accomplished with nothing more than nuts, bolts, and washers - I'll put up a drawing tomorrow. Why it works: Properly built, the fretboard's surface will always be tangent to the circle scribed by the path of each arm. What this means, is no matter how you move the two arms around, the fretboard's always at the same angle all along its length as compared to the surface of the sander. However, the point on the smaller circle with the same angle as any given point on the larger circle is closer to the centerline than said point on the larger circle. This being the case, the fretboard's surface begins to angle away from flat more quickly on the side with the shorter arm. Perfect. The length of the arm at each end corresponds to the radius of the fretboard at each end. One radius tapers linearly to the other. One problem with this, however, is that the fretboard needs to twist a little bit for this to happen - which is why the board the fretboard is attached to needs to have a rotating attachment (i.e. a bolt, a nut, a few washers, and not too tight. This generates another probelm as well - when the fretboard twists a bit, the fretboard is slightly off of the angle of the line between the centers of the two circles. If you have something 18" long, it'll only connect two lines 18" apart if it's perpindicular to them - if you twist it, it's not long enough. As a result, there needs to a groove at one end of the main board of the jig so that the distance between the actual points of connection can become longer as the fretboard twists, while maintaining an equal distance on the axis of the machine itself. Sorry, I know this is hard to understand. I'll draw it out to post later. Quote Link to comment Share on other sites More sharing options...
Maiden69 Posted February 23, 2005 Report Share Posted February 23, 2005 You see the whole thing behind this is that the nut and the bridge has to be the same radius as the fret board, the nut will be 10 and the bridge I found that likes to be just a tad more than the fretboard end, and about 17-18, this will make for the lowest action possible. the strings will follow the taper of the neck perfectly, but you have to taper the neck propertly, don't just use a 10 and a 16 block, if you don't have a jig, you have to use a lot of blocks, (well 4 to be exact)10-12-14-16. if you only do 10 and 16 you will have some fret buzz at the center of the neck were you started with the 16 block. if you do a taper propertly and you look down the fretboard it will look like it's twisted but it's not. I couldn't understand this much until I got my neck from warmoth and studied it for a while, this thing is so nice. I know they kinda make minor flaws and don't have the carbon fiber reinforcements that Carvin uses, but they are darn good necks, and after playing this compound neck, I think there is not going back. Quote Link to comment Share on other sites More sharing options...
Guitarfrenzy Posted February 23, 2005 Report Share Posted February 23, 2005 Here is a drawing I did trying to illustrate how you can use a leveler to get a compound radius neck. Quote Link to comment Share on other sites More sharing options...
daveq Posted February 23, 2005 Report Share Posted February 23, 2005 This is the type of router jig that I built a while ago. The pic isn't all that great but you can see that it's not the same old 16" tall on one end and 10" on the other type of design. GAL Jig (Mike Nealon's jig). Unfortunately, the GAL issue (#66) has the wrong angles/measurements in it's description. It wasn't too hard to figure out the correct math for it though. It took about 1 day to build. To do a board with it, it takes about 15 minutes. There is some sanding required so whether it is really that much of a help could be debatable. For the real tough stuff like ebony, I think it can be a time saver though. I've done about 4 fretboards with it. I can't say if it's any better than other jigs I have seen but it does seem to use the proper geometry. I've seen other jigs that seem to rely on the joints giving a bit to accomplish the task. It's very difficult to explain without pics. I'd give it a try with sanding by hand first though if you only plan to do a couple of boards. The stewmac bars are ideal for this stuff. I built my jig expecting to do a whole bunch over my lifetime. Quote Link to comment Share on other sites More sharing options...
jnewman Posted February 23, 2005 Report Share Posted February 23, 2005 This is the type of router jig that I built a while ago. The pic isn't all that great but you can see that it's not the same old 16" tall on one end and 10" on the other type of design. GAL Jig (Mike Nealon's jig). I've done about 4 fretboards with it. I can't say if it's any better than other jigs I have seen but it does seem to use the proper geometry. I've seen other jigs that seem to rely on the joints giving a bit to accomplish the task. It's very difficult to explain without pics. ← Can you explain how that jig works? I can't really see what it does from that picture, and I'd like to see all the options before I bother with building something. The sort I was talking about is for use with one of the big stationary belt sanders, and the use of rotating joints on the main board that holds the fretboard, as well as the use of a groove that allows one of those joints to slide along the axis of the board. When this happens, you get an uneven pendulum setup that actually doesn't rely on the joints having any give at all - with the rotating joint at one end of the board and the rotating/sliding joint at the other end, the setup is completely articulated for the set of motions it needs to make - you could machine the whole thing out of steel and use something like a ball-bearing lazy susan rotating joint and a ball bearing slider and it'd still work fine. If you build it properly with adjustible length arms on fittings that are themselves adjustible for height, you can get any constant radius or any compound radius perfectly tapered from one radius to another. You do still have to build the arms so that you can slide them towards their centers of rotation about a little bit (the jig linked at the beginning of the thread does this with rods with threaded knobs at the end so that you can adjust the amount of movement youget) so that you can slide the arms up, push the fittings down until the fretboard touches the sander, and still have the little bit of extra distance that lets you sand the entire fretboard down a little bit for a completely even radiusing job. Quote Link to comment Share on other sites More sharing options...
dingfelder Posted January 8, 2007 Report Share Posted January 8, 2007 Here is a drawing I did trying to illustrate how you can use a leveler to get a compound radius neck. I am enjoying this discussion but the image you posted seems to be broken. Is it available anywhere? Quote Link to comment Share on other sites More sharing options...
pmarlin Posted January 8, 2007 Report Share Posted January 8, 2007 its not broken it just isnt available anymore because this thread is about 2 years old Quote Link to comment Share on other sites More sharing options...
cherokee6 Posted January 8, 2007 Report Share Posted January 8, 2007 Check luthier's cool tools. I just ordered the plans for that jig. It looks pretty good from what I've read about it and the designer just threw in drawings for the more common electrics: 7.7, 9.5 10, etc. He's a real nice guy and will probably help you with any questions about the jig. It may save you some of the time and issues faced with building the jig Mike Nealon built from the plans in the GAL issue. This jig can do compounds pretty easily from what I've been told. You can make it longer to accomodate longer fretboards. It's just a suggestion. (there is a thread on it by Mattia; it's fairly recent) Being a novice builder, it'll probably be summer before I get to it! Good luck in your endeavor. Quote Link to comment Share on other sites More sharing options...
The royal consort Posted January 8, 2007 Report Share Posted January 8, 2007 I think this... http://buildyourguitar.com/resources/tips/radblock.htm Could very easily be used for a compound radius if your Maths is up to it Quote Link to comment Share on other sites More sharing options...
westhemann Posted January 8, 2007 Report Share Posted January 8, 2007 you can't use that for compound radius i think...it looks like a straight radius board if i am not mistken at first glance.those work by rubbing the block up and down the fretboard and doing that will screw up the compund . Quote Link to comment Share on other sites More sharing options...
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