How to Adjust Bridge Saddles for a Compound Radius Neck

Video that explains fretboard radius: • Fretboard Radius Expla...
More info about compound radius fretboards: warmoth.com/guitar-neck-fretb...

[@lIIIIIllll]

Assuming that the compound radius is linear then 16"r - 10"r equal 6"r difference over a 19" long fretboard. This gives us 0.315789"r change per inches of length. The distance between the 24F and bridge is 6.5" so multiply that by 0.315789" and you get 2.05" radius change. 16"r + 2.05"r = 18.05" radius at the bridge.

[@ReVeRbx-fe5wr]

How would this work for 21 fret, 22 fret, and 24 fret fretboards? The fretboards are different lengths. If they based it on the length of the fretboard then the compound radius would be slightly different for each one. You can get the compound radius on any style neck. Vintage, Vintage Modern, Modern, 24 fret so I don’t think we have enough information to determine what it is exactly. I used basically the same formula but used the position of the last fret on 22 fret guitar with a 25.5 inch scale length. But this might not be accurate. It is possible that compound radius is milled exactly the same for all of them. If that is true then we still do not know exactly where on the fretboard the 16 inch radius actually is. 21 fret? 22 fret? end of the fretboard? Heck maybe the 16 inch radius is at the 24 fret which would be the theoretical 24th on a 22 fret guitar. It would be nice if Warmoth clarified.

[@lIIIIIllll]

​@@ReVeRbx-fe5wrMy calculation is based off of my 24F guitar, and the 24th fret is exactly at 19". My 22F guitar's last fret is at 18.25", leaving 7.25" between it and the bridge. With the same formula, this now gives me a bridge radius of 18.38" instead of 18.05". I'm not going to lose sleep over a ~1/4" difference.

[@BeantownToBigD]

Beginner here. A luthier described it to me by saying 10"-16" (nut > last fret) = 6" change along 2/3 of string length. So for the remaining 1/3 of string length add 3"...16" + 3" = 19" = starting point for setting saddle height.

[@kuhboom22]

MAYsurement! 🤣. Just gotta poke fun at that again, love your content Aaron!

[@tiki_trash]

That's how my mother says it, and ayggs for breakfast.😊❤

[@warmoth]

It's hilarious how many people bring this up. LOL. Must be a Seattle thing....I don't know how else to say it.

[@ericv7720]

Definitely a Northwest thing. Put the groceries in the baayyg!

[@tiki_trash]

@@ericv7720 It's a Midwest thing and a southern thing. pank-aches anyone?

[@tiki_trash]

@@ericv7720 I say pan-cakes and my mother says pank-aches. I love my Momma!

[@ravenslaves]

One of the things about these videos, and Warmoth in general. Is that this is the kind of knowledge that was once common in your local guitar shops. Where most of the people running and working them, were also guitar techs with a considerable amount of time spent on a very wide assortment of guitars, unknown today, that were all hand built and unique. Now your options are very restricted by the major corporations. Most of those corporate necks are standardized to the point where they're all, by definition, mediocre. And most of that crucial knowledge has mostly been lost as the big box stores and the internet has mostly driven away those smaller shops and the people who actually knew what they were doing through experience. Which is why companies like Warmoth and these videos are valuable and needed today.

[@jonahguitarguy]

I just set the string height at the 12th fret by measuring from the fret to the bottom of the string. That automatically takes care of the radius. Standard or compound makes no difference. The string is a straight line from nut to bridge. I used to to use the radius gauges it's just unnecessary. You really don't even need to know the radius.

[@ReVeRbx-fe5wr]

I do the same. I used to be a professional guitar tech. This is the best approach. I do a .060 to .050 taper. .060 on the low string and .050 on the high string. Sometimes I can get it lower or sometimes I have to raise it depending on how level the frets are or sometimes depending on the radius.

[@eddiejr540]

Same here👍

[@nuthinbutlove]

Same

[@mewgava]

The best way. We can use any fret for adjustment. I prefer to use the last one on fretboard. And note: adjusted string radius is not equal to neck radius.

[@momcilopucar8749]

If you buy Gibson you don't have to worry about bridge radius, it's already set by manufacturer. You Just have to adjust strings hight at bridge posts that has about adjuster 1/2"diameter little wheels. You could also buy a Duzenberg type tremolo that seats on top of tail piece. Gibson's bridge system is a mich simpler to set-up then strat.♥️🕊️🌍👌👍

[@andresilva8444]

I happen to be one of the fellows who asked Warmoth that question. The customer rep at the time told me just to use the 16" radius at the bridge as there shouldn't be much difference. Now, as a mathematician I wasn't happy with that answer and did the calculations myself. Turns out is was something like 17" and a bit (or minus a bit) It was a long time ago, my memory is quite vague. At the end of the day, no-one makes a 17" radius gauge so I had to go by feel. String by string. Tuning, adjusting, measuring, repeat. Quite Zen, actually.

[@Peaceful_Romancer]

Harley Benton makes a set with a 17" radius gauge.

[@andresilva8444]

@@Peaceful_Romancer good to know. Back then it was only Stewmac, via a paper catalog following an advert in a magazine. 🤣😂

[@somebodyelseuk]

You don't need a radius gauge. If you set each string to the same height above a chosen fret, they will follow the radius for the entire length of the neck, as long as the nut is cut properly. As a 'mathematician, you should have known that.

[@jimmpanik3402]

Pro tip: Whatever the measured radius is at the 12th fret will be doubled at the bridge for compound radiused fretboards. Then you can get it "exact" for those that are that deep into the details.

[@PamaPamapop]

Thanks for doing this, it’s the only video I could find for compound radius fretboards

[@Floodland-bn3ol]

I just had a Warmoth compound radius neck installed on my Strat. It's really great.

[@TommySG1]

Your videos are awesome Aaron, when I first started buying your unfinished bodies and necks I learned a ton from them man 🤙 Keep them coming!

[@WindsurfMaui]

OK great information. I have to pull out my guitars and check and see how off I am on my compound radius necks. Thanks Aaron.

[@ReVeRbx-fe5wr]

And for a compound radius of 9.5 inches at the nut and 14 inches at the 22nd fret on a 25.5-inch scale length guitar, the radius at the saddles on the bridge would be approximately 15.56 inches.

[@softwareengineer8711]

I am and here's a neat trick to set perfect radius at bridge: just set equal action under the strings on your last fret, your bridge saddles radious will automatically match perfectly with your compound radious.

[@harmonicseries6582]

Cool yes, the paralel conical planes calculate it for you

[@harmonicseries6582]

@@nopinionocomntthe difference is negligible, try this method then measure to see for yourself

[@dannytaylor3201]

Great to see a YT video where I wasn't doing it wrong!

[@A.J.99]

The proper bridge saddles radius can be calculated this way: RBridge=(R24th fret-Rnut)/3+R24th fret. For example, saddle radius for 12-16" 24-fret fingerboard supposed to be about: (16-12)/3+16=17,33

[@RoyBelmont]

I actually was just about to attempt this, was curious to the real way to do it

[@ReVeRbx-fe5wr]

For a compound radius of 12 inches at the nut and 16 inches at the 22nd fret on a 25.5-inch scale length guitar, the radius at the saddles on the bridge would be approximately 17.39 inches.

[@JohnDoe9764]

Thank you! That are exactely the measurements of my main guitar :)

[@somebodyelseuk]

LMAO.... sorry Aaron, I always chuckle about how guitarists overthink this. All you need is a steel rule and an allen key, regardless of radius - no radius gauge required. You're basically setting six individual strings to a height above their corresponding frets. Pick A fret and set the strings to a height. They will ALWAYS follow the radius precisely (as long as the nut is cut properly and the relief is correct) for the entire length of the neck. FWIW. I'm a qualified chemist and metallurgist, so the engineering/physics stuff is also part of my wheel-house.

[@alsmith7316]

While this is true for the most part. If you are like me and set the first string lower than the last string, you would need to make adjustments to your depth as you go. This makes it easier, especially for those that are "vision impared". If I did not already have the gauges for checking the radius on the fretboard I would just measure each string. Either way works well. When using the gauges I do not put it below the strings and pull up. That makes it a difficult task. I just rest the gauge on the top, much easier.

[@RudeRecording]

I would think that the important spec would be the string to fret clearance at the last fret before the pickups/bridge. I now have 5 Warmoth necks 4 of which have 10 -16" radius necks and that is how I adjust them.

[@nickmizell1141]

Thank you!!

[@azbluesdog]

I have a Tele bridge with 3 traditional barrel saddles. I always had trouble dialing them in with the stock 9.5" radius neck. I'll be installing a new compound-radius neck from Warmoth this weekend, so I appreciate everyone's comments!

[@Dbj5555555]

Thanks.

[@ContemporaryFingerstyleGuitar]

Awesome content, Aaron! I was thinking about this issue, so your insights are timely! What are folks' best practices for adjusting the height of the individual saddles? Is it best to use shims to raise up the saddle(s) and therefore flatten out the whole bridge? And if so, do folks recommend adjusting the overall height of the bridge to compensate for the elevated saddles? Thanks much!

[@myopicautisticmetal9035]

I keep my radius gauges on a key ring, love them! Stewmac has a demo on how to use them.

[@donald-parker]

I think the most important message is that this gives you a starting point. But depending on the strings you use, your playing style and the feel you like, you may wish to change things. There is no "right" vs "wrong". If it sounds good and feels good (to you), it is good. I've always said that you should do your own set ups, because no one else can dial in the perfect feel for you. A "pro set up" will just restore factory specs (if you are lucky) which should be playable for anyone but optimal for no one.

[@GearBoxTy]

I have the Stew-Mac under the string radius gauge set. My issue with them is their steel color is so close to string color that there is little contrast to see how the strings are sitting. My favorite local guitar tech has some radius gauges that are colored and so much easier to see where the string is hitting or missing...that's why he's the pro.

[@soyborne.bornmadeandundone1342]

I need to get those lil tools haha. I'm always just winging it with my saddle height. Mess with it for a hour until it feels meh, good enough haha.

[@Carlito_Sway]

Thanks for this great video! Learning a lot as always, both from Aaron and from the mathematically inclined in the comments! I have two questions: 1) Am I just going crazy or did Warmoth formerly offer a 10-22" compound radius neck? 2) To confirm the presence of a compound radius on a client guitar (or one of my own) should I just use the "card"-style radius gauges to measure the neck radius at the nut and the terminal fret?

[@gradis13]

im a novice and i just used to put the 16 inches radius gauge and the end of the fretboard and adjust the saddles from that point.

[@matthewmckinney5387]

I have a Korean squire strat body from the early 90s, im trying to get a new neck and was wondering if the strat replacement necks you guys sell will fit that body, id hate to spend 400 plus and it not fit my body properly. Asking because im not sure if the korean and American measurements are compatible

[@bc454irocz89]

10-14 compound is my favorite radius or just a straight 12 will do

[@stug5041]

I usually measure once to get the action in the ballpark, and do all my fine adjustments from there based on playing feel. My buddies will ask me what height I set my action on this or that guitar and I’m always like - I don’t know, whatever feels right for this guitar 😅

[@bbilman056]

easiest thing would be to measure the radius at the end of the fretboard using a 16" gauge. I'm assuming the nut slots are radiused at 10"

[@LooseOrangeJuice]

A trick to using those radius gauges is to tie a bit of string through the center of that hole and pull the string gently upwards. That allows for more steady and repeatable results ime. As opposed to trying to hold the thing directly steady and evenly without turn it or pushing into a string too hard. For me, this was a game changer for using those types of gauges.

[@alsmith7316]

I just rest the gauge on the top of the strings after setting the outside string heights. No chance to stretch the strings this way, much less frustration.

[@LooseOrangeJuice]

@@alsmith7316 You don't want to set the radius from the top of the strings though. You want to set the radius from the underside of the strings. Doing so from the top is going to lead to issues because the strings all have different diameters. What I does it set the high and low E string heights and then raise the rest of the strings a ways up. Then I put the radius gauge under the strings and pull it gently so that it rests against the two outer strings. Then I carefully lower the rest of the strings down until they make contact with the gauge. So, basically what you do but from the bottom.

[@alsmith7316]

@@LooseOrangeJuice I had not thought of that. However, I have found it easier to put it on the top. I am not aligning the strings perfectly with the radius anyway. I set the low E lower than the high E, so it is a bit off anyhow. Not looking for perfection, just consistency from guitar to guitar. It is as much a comfort thing for the strumming hand as it is a string height across the fretboard IMO.

[@caipira6622]

I would love to hear the sound of this guitar 🙂

[@Elektronijaenis]

Apart from teh feel only, wouldn't it be just fine to adjust by the string height on the high frets? I mean the goal of the adjustment is even string height between the strings on the fretboard anyway. (Yes, that is a bit of a simplification as you mostly want the low strings a bit higher, but you get the point an can adjust for that too.)

[@goder18]

Can't find on Warmoth site what does compound radius numbers represent? Most producers said it is measurement at the 1st (or nut) and 12th fret

[@warmoth]

This video explains it all: kzbin.info/www/bejne/sIHRhnt4mZ5nrqssi=Y0feDvWiYxYtiiaK

[@goder18]

@warmoth I watched through 3 times and there is no precise answer, just pointing at the nut and neck heel :)). Does it mean 1st and last fret? No matter how many frets?

[@warmoth]

Yes, that is correct.

[@srinip]

What if you adjusted the saddle heights based on the action at the 12th fret (or even the 21st or 22nd fret, for that matter) instead of using a radius gauge? Wouldn't that automatically compensate for the flattening curve?

[@warmoth]

Yep, it sure would. By doing what you describe the radius at the bridge would essentially "set itself". This video was more to explain the concept of the compound fretboard, which some people have a hard time grasping.

[@srinip]

@@warmoth Thanks so much! In fact, I think an added benefit of doing it this way is the you can get a "radius" that "fits" the correct compound radius setting, but it doesn't have to be parallel. What I mean by that is that the first string's height can be made just a tad lower than the 6th string (which needs more room to vibrate anyway), so the radius curve of the strings is just slightly skewed. Obviously that skew needs to be very, very subtle!

[@KainzMusic]

But all you did here was check the radius at the bridge..?

[@RandomTuber782]

Or just uses 16 inch radius gauge at the last fret. But I like the with the top commentor said even better. Just measure string height at the 12th.

[@ghost_java35]

Is that one of the 7/8 strat bodies?

[@warmoth]

Nope. Just a regular Strat replacement body.

[@bradleejaymz]

All feel for me, baby! Sometimes I FEEL like I get it right...sometimes I don't 😝...but I do need a set of radius gauges.

[@geraldponce8336]

Was curious about this. Kind of figured it is just math. 10-16 divided by x distance + y distance times 10-16 divided by x distance. Plan on pressing frets on a 10-16 radius. So I got cauls 10 thru 16 and make the appropriate jumps in caul radius sizes. Or just hammer it in and let the fretboard be the stop. The one that has me wondering is how to fret level a compound radius? I'm guessing just have to fan the sanding beam out as the neck widens. Very intuitive approach. Where as a straight radius. You want to keep the beam very perpendicular to the center line of the fret board or you will inadvertently end up with a slight compound radius. Where as a compound radius you definitely want to fan the sanding beam out with conical shape of the neck. Like a slice of a road side cone. What we end up doesn't really matter. As long as flows. Been studying this one guitar repair guy. He actually uses a flat sanding beam with a piece of leather glued on the bottom. It makes sense to me. Because a fretboard is typically radius where as a sanding beam is flat. Why not have something that contours to fretboard a little bit rather than something that is flat on a round surface. Feel like a compound radius requires a very intuitive approach like that. Just go with the flow and follow the natural contours of the neck.

[@geraldponce8336]

Had a few beers so don't hold me to that math formula. Think it is more x distance divided by 16 minus 10 times y distance. Fret cauls 10-16 or hammer em on. And a sanding beam with a piece of leather glued on the bottom following the fan of the neck. that should get me there. Pretty good

[@Floodland-bn3ol]

Is that a Candian accent: may-sure for measure?

[@gingataff]

Or you could use a 16" gauge at the end of the fretboard

[@bobstrickland4223]

Now that's clever. If it's a 10-16 compound radius, then the space at the end of the fretboard is enough to slip in the gauge.

[@ReVeRbx-fe5wr]

So, for a compound radius of 10 inches at the nut and 16 inches at the 22nd fret on a 25.5-inch scale length guitar, the radius at the saddles on the bridge would be approximately 18.085 inches.

[@bobstrickland4223]

That is the number I have been searching for. It's amazing that Warmoth makes tons of necks with this compound radius but doesn't supply this number - even their spokesman guesses at it. If the formula is not too complex, could you provide it for us?

[@ReVeRbx-fe5wr]

@@bobstrickland4223 Radius @ saddle = Radius @ nut + (Radius @ last fret - Radius @ nut) divided by last fret position in inches multiplied by scale length.

[@ReVeRbx-fe5wr]

@@bobstrickland4223 Im solely basing this information on the assumption that the last fret has the end of the compound radius on the fretboard. It’s quite interesting actually because Warmoth offers 21, 22, and 24 fret necks. Would the compound radius be the same for all of them? Then the last fret wouldn’t be the same radius on each one. I wonder what the last fret is on a 24 fret neck. Maybe the compound radius on warmoth neck extends to the 24th fret whether there is 24 frets or not. We have to determine where the 16 in radius is on a Warmoth compound neck

[@FiddeBL]

I was looking at this a few days ago, so I set up the formula to compare various compound radius necks. So for whom it may concern: 10-16 compound -> gives 18.3 at the bridge 9.5-14 -> 15.8 7.25-10 -> 11.1 10-13 -> 14.2 Assuming that the larger radius is measured at the 22nd fret, regardless of scale length.

[@T-MAN6969]

What was the formula that you used for computations? Just curious and want to learn……thanks!!!

[@harmonicseries6582]

That's not needed, setting action to be the same for all strings makes the strings cone parallel to fretboard cone, so continuation of the string cone which is the saddles will be the desired radius that is continuation of the compound radius.

[@FiddeBL]

P*(R-r)/(p-P)+R Where P is the position (or distance) of the large radius relative to the bridge, p is position of the smaller radius (at the nut), R is large radius, r is small radius. Since this doesn’t care about scale length, you can call the distance between nut and bridge (which is the same thing as p) to be equal to 1. So p = 1 always P= 0.281 when measured at 22nd fret, assuming equal temperament between semitones (P=0.25 when measured at fret 24) Example for 10-16 compound measured at 22nd: 0.281*(16-10)/(1-0.281)+16 = 0.281*6/0.719+16 = ~18.3 Hope this helps!

[@somebodyelseuk]

Or you could just set the height of the strings above a fret and save a lot of unnecessary fannying around.

[@T-MAN6969]

@@FiddeBL Thanks!!!!! Always great to learn something new!!!!

[@diegomendivil7101]

At the end of the day it is up to taste. But to me it seems more reasonable to set the nut to the first nut radius and the saddles to the radius of one of the last frets of the board. Why the need to make the saddles flatter than any part of the fretboard?

[@somebodyelseuk]

...because if you set them to the last fret radius, the strings in the middle of the board will be very slightly higher. The easiest, and most accurate way, is to just pick a fret, eg 12th, and set your strings the same distance above it. Assuming the nut has been cut properly, the strings will be exactly the right radius for the entire length of the neck.

[@fisiosaiter]

After having two compound radius guitar I sincerely think that this was an unnecessary improvement. To the point that I prefer regular radius guitars.

[@johnnycab8986]

On individual adjustable saddles like on a strat, you can set the strings parrallel (or at equal height across the strings IE .014" at the 1st and 0.20" at the 21st fret for all strings if that's what you wanted) the entire length. You'd have to use feeler gauges (or something like the Stewmac nut file dial indicator gauge tool) at the 1st and last fret. This would be more accurate than using radius gauges.

[@ReVeRbx-fe5wr]

String height gauge works perfect and they are cheap

[@andresilva8444]

Or, it you're handy with design software, design the fretboard with the known measurements then extend it to the bridge and it will tell you the radius.

[@ReVeRbx-fe5wr]

This is hard to determine exactly because I don’t know where the compound radius ends exactly on the fretboard. Is it the end of the fretboard or the last fret. Like when they say 10 to 16 in radius, we know 10 in radius starts at the nut but 16 is where? end of the fretboard or last fret? I imagine its end of the fretboard. If it was last fret, then the compound radius would be different for 21 fret, 22 fret, or 24 fret. If its end of the fretboard, it would be different for 21 fret, 22 fret, or 24 fret. We know where it starts because its at the nut, but then again maybe it starts a little before the nut where the fret board extends onto the headstock by little bit. 😂 Sorry, I need some more information to calculate this accurately. I calculated based on compound radius starting at the nut and ending on the last fret of 22 fret guitar with 25.5 scale length.

[@PeterWasted]

I'm sorry but I disagree with the whole concept of using radius gauges for this. Set the action to whatever you like at twelfth fret and the radius is taken care of. Radius at bridge is only relevant where individual heights can't be adjusted. These have limited radius choices anyway. Assuming a compound radius of 10" to 16" That is a change of 5" over 21 or 22 frets. The 24th fret is three quarters of the scale length and is close enough to the 21st or 22nd fret. So we add half the difference. 16" plus 2.5" gives 18.5". For 9.5" to 14" we get 16.25" and for 12" to 16" we get 18". Bridges are not available with these radii. If there's a choice at all. go with a tighter radius as that makes the E strings closer to the fretboard. Remember also that tune-o-matic bridge saddles are meant to have a slot filed into them.

[@LMerchant01]

Not a single adjustment made.

[@joehodge6695]

You didn't show anyone how to set the radius , you just showed people how to "accept" the flaw in floyd rose saddles that cause that stupid "hump" on the two middle strings. Now why don't make a real video showing how to shim those other saddles to match the middle ones ans then lower the bridge slightly.

[@warmoth]

This video was not about the Floyd Rose at all. It was to explain the *concept*. There are hundreds of different bridges out there, all with different ways to adjust the saddle height. Should I do a video for each one? Or...how about you do bridges that start with A-K, and I'll take L-Z?

[@alsmith7316]

Everyone uses these gauges incorrectly, IMO. The reason they allow for going under the strings is to measure the fretboard radius. If you want to adjust the saddles, just get the outside ones where you want them, and then rest the gauge " ON TOP" of the strings. Much easier to just hold the gauge on the top, then having to pull up on the gauge and often pulling to hard and stretching the strings etc. I think I have even Stew Mac do it this way and it makes zero sense to me.

[@boogieman00001]

Measuring on top of the strings ignores the fact that all the strings are different diameters. The low E has roughly 5 times the diameter of the high e. This will skew the results if measuring from the top of the string. What matters is the distance between the top of the frets and the bottom of the string. Using the gauge under the strings is the "correct" way. In reality, no special gauge is needed at all. Use the frets themselves instead. Set the open string height equal for each string above the last fret. Add a tiny bit of extra clearance for the bass strings if needed and you're done. Works for any guitar with any fretboard radius, compound or straight.

[@alsmith7316]

@@boogieman00001 Yes, this is true and a point that I omitted. However, I do not go even across the Low E and High E, so the strings do not exactly match the radius to begin with. I just find this to be the easiest and most consistent way to go about it. I always used to go under the strings, but it was a struggle not to pull up to hard and I switched to the doing it on the top. Much easier and have been happy with the results.

[@alsmith7316]

@@boogieman00001 I never said I was MEASURING from the top. I simply set the low E, HIgh E to where I want them, and then use the tops of the strings to get all of the others set. The difference between setting the other strings from the bottom to the top using these gauges is minimal. The ease of setting them across the tops is not minimal. Again, I am already offset as my Low E and High E are not set to the same height, so no matter what I am not following the fretboard radius.

[@momcilopucar8749]

Buy a Gibson then you don't have to worry about set-up as with Stratocaster. Bridge radius is already set up you just adjust bridge hight. No needs strings individual set up at bridge as its on start.