anyone use a radius jig?

[mistermikev]

so I've done some looking around at ideas for radius fretboard jig... was planning on taking a shot at it. 

my plan was to mount my router to a 24" board and do a radius cut... then move back an inch (compensating also for other side of blade) and cut another line.  do that twice to make two 12" radi cleats. 

attach together with a 3/4" square in the middle to mount my router on either side of it.  Should be able to make radius blocks, then flip over and radius a fretboard.  if that makes any sense. 

my question is... anyone use this type of jig and comments on how well the idea works?  pitfalls?

I'm guessing your best results will be running the router up and down the wood length-wise and then moving along the radius for another pass?

[ScottR]

I think @Andyjr1515 did something like this a couple of builds back...

SR

[mistermikev]

well... eh-hem...would love your thoughts if you can spare them @Andyjr1515

[Mr Natural]

food for thought-in case you might like a more "really get to know your fingerboard" method. I still use this method-not sure why- a bit more work but I find it relaxing.

skip to 2:55 mark on the video. fwiw- this guy has some really great videos on his youtube site.

 

[mistermikev]

26 minutes ago, Mr Natural said:

food for thought-in case you might like a more "really get to know your fingerboard" method. I still use this method-not sure why- a bit more work but I find it relaxing.

skip to 2:55 mark on the video. fwiw- this guy has some really great videos on his youtube site.

 

Right on, great video.  I'm kind of dead set on the idea of building something because I can't afford aluminum radius blocks in all the radius' I would want!

[Andyjr1515]

4 hours ago, mistermikev said:

well... eh-hem...would love your thoughts if you can spare them @Andyjr1515

I'll drop some details on in the morning

[Andyjr1515]

16 hours ago, mistermikev said:

well... eh-hem...would love your thoughts if you can spare them @Andyjr1515

Hi again

I've been very pleased with the jig I made, although - to be honest - it needs probably a version 2 to iron out the things I've learnt along the way - and in the meantime Carlos at Guitars and Woods in Portugal has brought out a metal one of similar design that I am sorely tempted to buy as an alternative.

Anyway - for what it's worth - this is what I designed and built.  I say I designed - I looked at what other people did (G&W's didn't exist at the time) and took what I thought to be the best bits of each:

As you can see, it's fairly simple:

• Roller-bearing carriage that the router fixes to
• A simple frame with replaceable radiused ends for the carriage to traverse
• The frame itself sits on a flat, melamine-topped board (an old IKEA shelf) that has a couple of binding strips as guides

Originally, I arranged it so I could either fix the radial position and traverse lengthways as an option to routing widthways and then traversing in steps along the length:

 

In use, I found it much easier to do the latter and as such, the above was an unnecessary complication.

General issues in the design (and this I would think applies also to the G&W product):

• The radius you cut is, of course, the radius that the end of the router bit is running at.  The radius cut for the bearings to run on needs to be adjusted accordingly.  In my case, the bit end is 1" lower than the bottom of the carriage bearings - therefore I use an 11" radius template to cut a 10" radius fretboard
• This makes the packing under the fretboard (which, of course needs to be flat, stable and capable of being fixed with double sided tape) to end up at the correct height quite challenging.  If all your fretboards are the same thickness, then this becomes more straightforward by just thicknessing a suitable single supporting beam 
• The further the bit protrudes, the less width of fretboard will the router bit cut.  I originally thought - ahaa!  I can cut any radius just by extending or retracting the router bit.  And yes you can - but the physical width and height of the jig rapidly increases and you end up with a very large rig indeed (witnessed by many of the internet designs)
• Finding the centre-point of the radius and lining up the fretboard EXACTLY to this position is critical for getting the radius even and 'square'
• You have to be careful as you come to the end of the board - it is very easy for the bit to ping off the final edge

Like G&W's comment about their own product - you still need to finish off with a radius block.  But, even so, to do a fretboard now takes me 3/4hr max - and it used to take me days with some woods.  Remind me NEVER to try and hand sand a cocobolo board ever again!

Why would I consider buying the G&W product - I think the set up accuracy can probably be made more accurately than my creaky, wood-screw affair and the two template ends will be smooth and equal - which my plywood ends are not.

However, the packing height issue, the centre-line accuracy, the need for rig set up setting accuracy, the need to finish off with a block, the need to guide it lengthways, etc would be all the same.

Hope this helps!

 

[mistermikev]

I'd give you a 100 thanks if I could.  Answered may of my questions -one being the length of the radius. thank you soo much for the awesome pics.  also... is that snakewood?  you gotta be kidding me!

I have seen variations where the router is fixed to the jig, and the jig moves on a set of fixed pvc pipes(or other) - this is what I was planning but you've got me 99% convinced it is not the way to go.  So now I am thinking to build the bearings version like yours... but to make the radius part flip-able.  I'm fixated on flip-able because it would allow me to build caul, sanding block, and scale up to do the top/back of guitar. 

my plan was to use aluminum fastened via bolts (for track rails) so that I could adjust the base height and conquer the issue of radius length/proximity (for the most part).  could work for either version.

I'm sorry, w/o a drawing I doubt very much of this would make sense to anyone other than me... just thinking out loud here.

 

[Andyjr1515]

On 21 July 2018 at 2:35 PM, mistermikev said:

I'd give you a 100 thanks if I could.  Answered may of my questions -one being the length of the radius. thank you soo much for the awesome pics.  also... is that snakewood?  you gotta be kidding me!

I have seen variations where the router is fixed to the jig, and the jig moves on a set of fixed pvc pipes(or other) - this is what I was planning but you've got me 99% convinced it is not the way to go.  So now I am thinking to build the bearings version like yours... but to make the radius part flip-able.  I'm fixated on flip-able because it would allow me to build caul, sanding block, and scale up to do the top/back of guitar. 

my plan was to use aluminum fastened via bolts (for track rails) so that I could adjust the base height and conquer the issue of radius length/proximity (for the most part).  could work for either version.

I'm sorry, w/o a drawing I doubt very much of this would make sense to anyone other than me... just thinking out loud here.

 

Let us all know how you get on.  If it works OK, I'll gleefully and shamelessly steal your ideas for my Mark 2  

[mistermikev]

hehe... that would be a real honor.  I've got to think it through at least a thousand more times before I make a move but... will do.

[MiKro]

.

[mistermikev]

thank you sir.  that is a very thorough pictorial on that jig and def some good ideas there. 

it's really similar to the scheltema jig.  this vid is another variation on the scheltema... being used to profile that back of the neck but I assume it could be also used for the fretboard radius perhaps w some modification.

 

[ZekeB]

I don't know if this helps but this is what I made for my compound radius jig. 

[mistermikev]

compound radius... naw... not tackling that one!  std radius is complicated enough for this simpleton!  Thanks for posting tho, looking at it - I admit - I have no idea how that works!

[mistermikev]

so... given that it's regularly over 110 degrees here... have been doing anything but finishing my templates in the garage so... spent a little thought on this the other day:

 

cross section of what would be a flip-able 30" radius jig for radiusing the front/back of a guitar.  the blue squares are the rails from my router sled jig and are mounted on carriage bolts that can move up/down.  yellow are cleats that would connect two radiused rails.

this jig has a 'rate of change' of .8" from center to edge on a 14" body.  ie a 2" body blank would result in a 1/2" radiused body.  I think that is too much but am unsure what would be a 'typical' radius for a guitar face/back.... anyone have advice on this?

[ScottR]

My current build has a 1" top with quarter inch edges, so the rate of change in that (top) is .75". Of course the radius is compound depending on what part of the body you are looking at, but at least that would give you a visual of what you are considering.

Obviously, I don't think .8" is too much.

SR

[mistermikev]

1 hour ago, ScottR said:

My current build has a 1" top with quarter inch edges, so the rate of change in that (top) is .75". Of course the radius is compound depending on what part of the body you are looking at, but at least that would give you a visual of what you are considering.

Obviously, I don't think .8" is too much.

SR

right on - what sort of style body is that?  just curious. 

thank you for the confirmation.  in my case... I'm going to radius the top and back - this is for an eventual spector-like build.  My material is 2" to start with... so leaving me with a 1/2" body - well I'm not sure that's going to be right.  I suppose I could leave a flatter middle section... and technically the piece I would be working with would be just under 13" wide, so my change would be less than .8 either way but... I think I might redo this drawing and shoot for a 40-45" radius.

when I worked as a solid surface fab guy, I had to do a taco bell counter that had a 16' radius.  I screwed two 9' boards together and screwed that into the floor... cleared out a bunch of floorspace... mounted my router and cut the pattern out of sheets of mdf.  I had to create it in 2 pieces so we could load them into a truck and glue em up on site.  don't know why I'm telling you this... just a good memory I guess... was so proud of that counter!

anyone have a guestimate what the typical spector radius is?

[ScottR]

6 minutes ago, mistermikev said:

right on - what sort of style body is that?  just curious. 

 

It's a Les Paul outline....this one:

You've seen it.

As I said, it is not a constant radius, but rather a compound radius. The point being that much change in thickness from center to edge is not a problem in looks. A half inch thick edge on the belly cut side is quite comfy. Take into account how much room you need in the control cavity before radiusing the back that much on that side though.

SR

[mistermikev]

25 minutes ago, ScottR said:

 

It's a Les Paul outline....this one:

You've seen it.

As I said, it is not a constant radius, but rather a compound radius. The point being that much change in thickness from center to edge is not a problem in looks. A half inch thick edge on the belly cut side is quite comfy. Take into account how much room you need in the control cavity before radiusing the back that much on that side though.

SR

ok, right on - I actually thought you hand chiseled that out - based on your neck chiseling... "the great oz curtain is being revealed!"

I'm pretty sure my belly could fill out at least a 45" radius!  good point on the control cavity.  I think I want to leave approx 1.25" of body.  well... back to the drawing board as they say!

 

edit... perhaps I need to angle my wings for that build... that might be an answer... I wonder how spector does it because it looks like the body is about 1.75 at the edge... just thinking out loud.

Edited August 6, 2018 by mistermikev

[ScottR]

4 minutes ago, mistermikev said:

ok, right on - I actually thought you hand chiseled that out - based on your neck chiseling... "the great oz curtain is being revealed!"

I did hand carve that and then sanded it smooth.

I was just tossing it out as an example of what that much change in size could look like. No radius templates were harmed in that build. ....or used.

SR

[mistermikev]

ok, back to thinking "dang, dude carved that whole thing by hand!"

 

so... one thing I need to consider is how to manage the radius but miss the neck/fretboard on a neck thru guitar...I suppose I'd just have to be careful in that area.

[mistermikev]

share your wisdom?  some questions if I may?  Can anyone tell me approx what would be the maximum you could bend and glue down a 1/4" top without making releif cuts in it, and without steaming?  is this "crazy talk"? 

in the below drawing I'm planning out a 60" radius planing jig.  the drop on either edge would be a hair less than .325 on a typical strat body (pictured in gold'ish below).  so both sides figured in the bend would be a .75"ish change over 12.15" body.

Ultimately I'd like to be able to put a radius on the front/back of a strat body and then glue down a top over it.

any all thoughts would be most appreciated.

 

[Andyjr1515]

On 8/6/2018 at 5:25 PM, mistermikev said:

ok, back to thinking "dang, dude carved that whole thing by hand!"

 

so... one thing I need to consider is how to manage the radius but miss the neck/fretboard on a neck thru guitar...I suppose I'd just have to be careful in that area.

I missed this post.  Do I gather that you are thinking of radiusing the fretboard after gluing it?  And, if so, can I strongly suggest that you don't. 

I'm not sure even how that could be done jig wise if you are planning to use a router ( other than a fairly high spec and large cnc).  You could do it with a hand sanding block but immensely problematic to replicate the kind of router jig principles above.

 Any reason why you couldn't just radius it in a jig then glue it on?

[mistermikev]

2 hours ago, Andyjr1515 said:

I missed this post.  Do I gather that you are thinking of radiusing the fretboard after gluing it?  And, if so, can I strongly suggest that you don't. 

I'm not sure even how that could be done jig wise if you are planning to use a router ( other than a fairly high spec and large cnc).  You could do it with a hand sanding block but immensely problematic to replicate the kind of router jig principles above.

 Any reason why you couldn't just radius it in a jig then glue it on?

Sorry, kind of jumping back and forth between radius for the fretboard and radius for the body. 

if you mean the comment: "...consider is how to manage the radius but miss the neck/fretboard on a neck thru guitar" -I was talking about radiusing the body and missing the fretboard/neck when I radius the horns. 

afa radius a fretboard attached to the neck... no need to do that here.

[Andyjr1515]

2 minutes ago, mistermikev said:

Sorry, kind of jumping back and forth between radius for the fretboard and radius for the body. 

if you mean the comment: "...consider is how to manage the radius but miss the neck/fretboard on a neck thru guitar" -I was talking about radiusing the body and missing the fretboard/neck when I radius the horns. 

afa radius a fretboard attached to the neck... no need to do that here.

Ah - OK.  I'd misread the post 

And, in terms of suggestions re the actual issue you are referring to - absolutely no idea