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Pibrocher

Bench-top Router Radiusing

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Here is the radiusing device that I built. I was using a Dewalt router that had about a 4" by 6" base on it. A note to anyone attempting to do this: You will have to customize the design to fit your router and workbench, the idea is stillt here so read on.

radius4.gifradius1.gif

In these shots you can see the basic layout of the arms. Notice that I essentially created a square around the table to ensure that the arms were the same distance apart at the top and bottom.

The radius to be cut is determined by the distance of the pivot point from the fretboard surface. This distance could be changed to any you desire. Here is where the difficulty of making a compund radius with this setup is aparent. I'm open to suggestions as to how to do it though. B)

radius2.gif

radius3.gif

fretboard-radius.gif

radius5.gif

Its important to keep the router guides parallel to the fretboard. Also pay attention to the direction that the router bit is spinning. Its very easy to chip out the sides of the fretboard if you go too deep too fast and are spinning into the grain. I had a few chip outs on this particular board. Birdseye maple is pretty hard and all kinds of knotty. I was able to hide or sand out most everything though.

radius7.gif

radius6.gif

I found that when i clamped down the ends of the fretboard it bowed slighlty in the middle. The fretboard has to be as close to flat on the table as you can get it. Depending on how thick your blank is you'll have to place something under the fretboard to hold it within reach of the clamps. I ended up using a little tiny dab of hot glue behind the center of the fretboard. Make sure you dont use the hot wood glue though as it may rip a chunk out of the back when you go to remove the fretboard.

After it's radiused I cut the frets into this, the blank was still square which makes it easier to get the frets perpendicular. After that i tapered and shaped the fretboard then mounted it.

As always, make sure all the centers are lined up and square, the fretboard is of course one of the most critical places on your guitar. Take your time and always measure twice. This tool will be very usefull now that it is finished. Hope it helps anyone out there who loves to build jigs, this is a good one! Rock On :D

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Thanks for the pics Pibrocher ! I have a much better idea of how it works now !

As for your questions about compound radii fretboards, I thought the same thing. I don't know if you could use the router to radius certain segments of the fret board, say a 12" radius for the first 6", then change to a 14" for the next 6", then finish off with a 16" for the last 6" or so towards the heel. Then possibly use radius sanding blocks to "blend" from one radius to the next.

I don't know if that would work, but it's the first thought that had when you asked the question.

I made myself a set of four radius sanding blocks using the router method described on the PG tutorial pages. I was thinking that I would try mounting three of these or so to a single board like a brace, end to end, then sanding the entire fret board blank using about 6" strokes back and forth, to create a compound radius. Don't know if that will work, but I was going to try and see.

Also in the other thread where you first posted the pic of your jig, I asked if you do the radius before the fret slotting or after. What is your preference ?

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To give a compound radius would it be possible to lower one end of the pivoting arm, so you would create let's say 10" on one end and 16" on the other?? Or what ever radii you would need.

It doesn't look like you set up would allow it though. It looks like it would bind, but it would be an easy fix.

Just a thought. :D

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Here is the radiusing device that I built. I was using a Dewalt router that had about a 4" by 6" base on it. A note to anyone attempting to do this: You will have to customize the design to fit your router and workbench, the idea is stillt here so read on.

    In these shots you can see the basic layout of the arms.  Notice that I essentially created a square around the table to ensure that the arms were the same distance apart at the top and bottom.

   

The radius to be cut is determined by the distance of the pivot point from the fretboard surface. This distance could be changed to any you desire. Here is where the difficulty of making a compund radius with this setup is aparent. I'm open to suggestions as to how to do it though.  B)

    Its important to keep the router guides parallel to the fretboard. Also pay attention to the direction that the router bit is spinning. Its very easy to chip out the sides of the fretboard if you go too deep too fast and are spinning into the grain. I had a few chip outs on this particular board. Birdseye maple is pretty hard and all kinds of knotty. I was able to hide or sand out most everything though.

    I found that when i clamped down the ends of the fretboard it bowed slighlty in the middle. The fretboard has to be as close to flat on the table as you can get it.  Depending on how thick your blank is you'll have to place something under the fretboard to hold it within reach of the clamps. I ended up using a little tiny dab of hot glue behind the center of the fretboard. Make sure you dont use the hot wood glue though as it may rip a chunk out of the back when you go to remove the fretboard.

   

After it's radiused I cut the frets into this, the blank was still square which makes it easier to get the frets perpendicular. After that i tapered and shaped the fretboard then mounted it.

   

As always, make sure all the centers are lined up and square, the fretboard is of course one of the most critical places on your guitar. Take your time and always measure twice. This tool will be very usefull now that it is finished. Hope it helps anyone out there who loves to build jigs, this is a good one! Rock On :D

I'm building a jig similar to yours(nice job by the way), and with my design it should be possable to cut a compound radius without any additional blending afterwards. Basically, the router is mounted on parrallel steel rails. Each rail has a bearing on the end which rides on a steel track 90 deg. from the fretboard. The track at the one end will have a 12" radius, and the track on the other end will have a 10" radius. So the radius in the middle of the board should be, of course, 11". I will be taking pictures along the way, and will be posting either my successes, or failures along the way. Even if I fail, it might spark an idea in someone elses mind at least. :D:D

Edited by Guitarfrenzy

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i would think the compound thing would work just fine as long as you had a way for your router rails to pivot at each end but only on one axis.. if the pivoting lets the router twist at all you would be out of luck..

Nice design. The pivot really wouldn't be that hard i wouldn't think. nice (but loud) way to quickly radius a board.

I should add this is in reference to being able to shortent he radius up on one side.. having the pivot point 12" away from the board on one side and say 16" from the board on the other.. From the top down, you sould have pivoting on the Y axis on each end of the arm, then your rails would pivot on the Z axis at the top of each arm allowing the different radii without hindering the movement of the rails. Never tried this but in my head it seems like it would work just fine :D

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INSPIRATIONAL...given me all kinds of ideas...love stuff like this

Makes you wonder what else you could carve up with variations on this idea

One thing though...all the pics crash my connection, but I get the idea

Well done...take it further

pete :D

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I see now that by adding pivot points to the top of the arms you would be able to make a compound radius. I would love to see pictures of someones design here. I wonder if some sort of spring-tension would be required to inusre that both arms still swing as close to in unison as you can get them.

Seems to me that if the rails are no long parallell to the fretboard then the radius will lose its perpendicular-ness to the fretboard. The shorter arm is gonna tend to move the rails more drastically at one end then the other. Pivoting would allow the rails to swing independently but what does the this do to the radius itself besides make it compoud?

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I see now that by adding pivot points to the top of the arms you would be able to make a compound radius. I would love to see pictures of someones design here. I wonder if some sort of spring-tension would be required to inusre that both arms still swing as close to in unison as you can get them.

Seems to me that if the rails are no long parallell to the fretboard then the radius will lose its perpendicular-ness to the fretboard. The shorter arm is gonna tend to move the rails more drastically at one end then the other. Pivoting would allow the rails to swing independently but what does the this do to the radius itself besides make it compoud?

There are plans for a similar jig at MIMF. One of them does in fact use springs.. Actually, theirs the router just goes back and forth on a fixed rail.. the fretboard swings underneath on a pivot.. although that seems more dangerous to me.

Rethinking it, the pivot would only work if the rails were allow to twist some. With wood that would be pretty hard to do. There are tons of variations of this at MIMF.. go goin, it's free, and take a look in the archive under fretboard radiusing. All kinds of things in there.

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There's also a common one shown in Koch's book and elsewhere where the router's on a base with curved sides that roll over parallel steel pipes...won't do compound though. There's also pic's in there of one at martin's factory where the board is swung back and forth on a very similar jig to this, but inverted, over a giant belt sander...this can do compund stuff just by having the radius of one end bigger than the other.

I'll check out the other forum for some more ideas.

p

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There's also a common one shown in Koch's book and elsewhere where the router's on a base with curved sides that roll over parallel steel pipes...won't do compound though. There's also pic's in there of one at martin's factory where the board is swung back and forth on a very similar jig to this, but inverted, over a giant belt sander...this can do compund stuff just by having the radius of one end bigger than the other.

I'll check out the other forum for some more ideas.

p

I saw the first one you mentioned.. easiest to build by far.. the pendelum over the belt sander is the best. You can buy it premade from grizzly for 899 :D (sander not included)

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I have a question.

Do you do your inlays before or after you radius?

Would the router ruin your inlay?

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Sweet! I like it as a relatively simple solution to a problem. To me, that's some elegant engineering. :D

Soulchaser: I know it probably wasn't intentional, since you're new to the forum; however, there are quick and easy ways to have replied without "quoting" all those photos back at us.

Option 1: Near the "reply" button, there's a "quote" button. Press it once to turn off auto-quote for your reply.

Option 2: Just press "add reply" because you weren't responding to anything specific in that one post anyhow, so a generic reply to the thread would have worked fine.

Option 3: Manually edit the post. When the text-entry box pops up, just manually delete the {img}blahblahblah.jpg{/img} tags (with square brackets in place of the curly brackets for the real thing) before submitting.

Cheers! Great work, Pib

Greg

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Nice design! Looks like it works great.

But I gotta say...in the time it would take me to build that thing, I could radius 10 boards with a belt sander and radius block.

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Cool design! I've seen several swing-arm types like this around the net, including several that do compound radius boards. Pivot length is different on each end, probably needs a bit of 'play' to accomodate the swing, but it seems to work well for lots of people. I may build one for myself some day, but for now I just don't have the space for it, sadly.

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I was looking through another guitar forum and found this gadget for radiusing from CT Holden Luthery

I thought it may be of some interest

It does standard and compound radiusing - a bit pricy though

Just wondering if anyone has seen it before and if so, would like to give any feedback

P1010028.jpg

A few more pics

http://www.cthluthiery.com/WebForm14.aspx

http://www.cthluthiery.com/WebForm11.aspx

http://www.cthluthiery.com/WebForm13.aspx

http://www.cthluthiery.com/WebForm18.aspx

dayvo :D

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I was looking through another guitar forum and found this gadget for radiusing from CT Holden Luthery

I thought it may be of some interest

It does standard and compound radiusing - a bit pricy though

Just wondering if anyone has seen it before and if so, would like to give any feedback

P1010028.jpg

A few more pics

http://www.cthluthiery.com/WebForm14.aspx

http://www.cthluthiery.com/WebForm11.aspx

http://www.cthluthiery.com/WebForm13.aspx

http://www.cthluthiery.com/WebForm18.aspx

dayvo :D

Yeah, Craig's setup is pretty nifty (posted that URL here not that long ago), and I'd very much like one (I could build one, I suppose, but he did all the work, and fair's fair and all that). I know a couple of people who have them, and swear by them. Solid, dependable, accurate, fast. It's mostly the compound radiussing I'm interested in; jigging up for a simple radius really isn't all that difficult, and this is a nice 'tabletop' tool for compound radiussing (the other variations I've seen require tall swing-arm setups, and I'm short on space). Shipping, however, would run me almost as much as the jig itself, so.... :D

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That's great isn't it...I love seeing things like that....

I wonder if something similar could be adapted to "radius" (shape) the back of the neck too...

Better yet...how about acurate fret sawing...oh well...just a thought...

I imagine that there is an axle through the bottom of the box so that the two ends swing together...do you think that's the way it works?

thanks for that Dayvo... pete :D

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That's great isn't it...I love seeing things like that....

I wonder if something similar could be adapted to "radius" (shape) the back of the neck too...

Better yet...how about acurate fret sawing...oh well...just a thought...

I imagine that there is an axle through the bottom of the box so that the two ends swing together...do you think that's the way it works?

thanks for that Dayvo... pete :D

I don't think there's an axle, because if I've got it right, the swing needs to be different on each end for it to do compound radii properly. But I'm not sure.

He's also got a slotting setup if you care, check the website.

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I think that this is a nice set up that can be easily copied or improved, and one that we get a lot of questions, so I'm pinning it. Now let's wait for one of you CAD savy guys and post a nice rendering!

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I think that this is a nice set up that can be easily copied or improved, and one that we get a lot of questions, so I'm pinning it. Now let's wait for one of you CAD savy guys and post a nice rendering!

It is patent-pending, though. Keep that in mind. Craig's a stand-up guy, by all accounts, and what little contact I've had with him on various forums has been very nice.

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That's great isn't it...I love seeing things like that....

I wonder if something similar could be adapted to "radius" (shape) the back of the neck too...

Better yet...how about acurate fret sawing...oh well...just a thought...

I imagine that there is an axle through the bottom of the box so that the two ends swing together...do you think that's the way it works?

thanks for that Dayvo... pete :D

I don't think there's an axle, because if I've got it right, the swing needs to be different on each end for it to do compound radii properly. But I'm not sure.

He's also got a slotting setup if you care, check the website.

Having a good look at all the pictures, to me the copper piping seems to be joined with a shaft going through the bottom of the box so that when it is moved left to right the vertical copper arms move in unison

The steel rails holding the router base can move up and down as a whole unit, as the end arms that hold them slide up and down the vertical copper pipes

Now Im presuming that when say a 10'' and a 16'' radius guide are put either end and the guides are both dead level at top centre, as the the router base rails are moved left to right will the base and rails can drop slightly more on the sides at the 10'' end (remember the rails and end arms move as one unit straight up and down on the copper piping) so that it will shave off a slightly tighter curve on the 10'' end and a slightly flatter curve on the 16'' end, giving you a compound radius

Does this make sense? Have I got this right?

dayvo :D

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That's great isn't it...I love seeing things like that....

I wonder if something similar could be adapted to "radius" (shape) the back of the neck too...

Better yet...how about acurate fret sawing...oh well...just a thought...

I imagine that there is an axle through the bottom of the box so that the two ends swing together...do you think that's the way it works?

thanks for that Dayvo... pete :D

I don't think there's an axle, because if I've got it right, the swing needs to be different on each end for it to do compound radii properly. But I'm not sure.

He's also got a slotting setup if you care, check the website.

Having a good look at all the pictures, to me the copper piping seems to be joined with a shaft going through the bottom of the box so that when it is moved left to right the vertical copper arms move in unison

The steel rails holding the router base can move up and down as a whole unit, as the end arms that hold them slide up and down the vertical copper pipes

Now Im presuming that when say a 10'' and a 16'' radius guide are put either end and the guides are both dead level at top centre, as the the router base rails are moved left to right will the base and rails can drop slightly more on the sides at the 10'' end (remember the rails and end arms move as one unit straight up and down on the copper piping) so that it will shave off a slightly tighter curve on the 10'' end and a slightly flatter curve on the 16'' end, giving you a compound radius

Does this make sense? Have I got this right?

dayvo :D

Hmm....yeah, good point. And yes, I believe you do. When I make a compound radius board, I want to make sure the edges of the fingerboard are the same height; don't much care if the boards thinner in the middle at the end of the body than it is at the nut. I think that happens here, though, if you pick the right two radii (what want, I mean), since how high or low the router bit sits is defined by the two sets of guides, and the spacing between the bars that ride the guides is fixed (so will be lower for a tighter radius when the router's centered on the neck; bit lower at the end with the tighter radius).

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Very nice design he has there, but like others have said, pretty expensive. There's good information in the mimf library that shows multiple ways to radius a fingerboard. You have to log in first though if I'm not mistaken.

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Lots of good ideas here. Has anybody tried the router jig shown in the Guild of American Luthiers Publication?

AMERICAN LUTHERIE # 66 (Summer 2001)?

Picture: http://www.luth.org/backissues/66jig.jpg

Publication Abstract: http://www.luth.org/backissues/66.htm

Please reply with feedback.

Edited by BrianOC

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