Official Floyd Rose Routing Guides Contradict Themselves - Which is Correct

[North55Tones]

I'm working to build a couple of new 6-string guitar with a 26.25" scale length, one is to be a Christmas gift. I've purchased a couple of Floyd Rose Special trems, and I'm have a very hard time determining the dimensions for the route, the location of the mounting posts and the size to drill for the mounting posts. Floyd Rose claims on their website that the Floyd Rose Original (FRO) route will work for the Specials (they claim identical dimensions for both trems); however, if you look at the routing guides, there are some issues.

1. Neither the metric or inch versions of the guide for the Special gives the location of the intonation/scale line relative to the saddles.
2. Stud post hole dimensions vary from 9.5 - 10.5 mm, depending on where you find them. The studs I have measure 10.00 mm outside of the knurling/splines on two different caliper gauges.
3. The metric and inch versions of the guide for the Special have different dimensions when converted to a common system of measurement (this is not simple rounding error).
4. The inch version of the routing guide for the FRO is very, very different from the metric version of the routing guide for the FRO (which appears to match the metric version of the guide for the Special).
5. The actual dimensional drawings for the Special show quite different dimensions than for the Original (even though they claim that they're the same dimension, just different materials in their advertising copy).
6. The actual dimension (measured from the Special which I purchased) seem to match the drawing of the FRO better than the drawing of the Special on the Floyd Rose website.

Setting aside that this seems like a serious issue in engineering quality control on the part of Floyd Rose, I could really use some help understanding what the ground truth is. I'm manufacturing these two bodies using CNC, it's not practical for me to measure things back to the nut on the neck, or use other build to fit type techniques. I don't have (or want) router templates.

Has anyone else noticed the discrepancies above? Does anyone have a work around, or can anyone confirm that the ProjectGuitar (or perhaps another openly published e.g. the one at electricharold.com) template works to route a recessed Floyd Rose Special?

I'm running out of time to get these bodies machined and painted before Christmas. I really hope someone can help. A CAD model of a known good pocket (front and back) for a Floyd Rose Special would be an enormous help, if anybody has one that they're willing to share.

[curtisa]

12 hours ago, North55Tones said:

Neither the metric or inch versions of the guide for the Special gives the location of the intonation/scale line relative to the saddles.

Because the saddles are movable. The best they could give you will be a rough guide as to where the intonation point should begin from. If you're after an absolute value, I'd set the scale length point 12mm back from the leading edge of the bridge plate, which is what the OFR measures on a guitar I put together some years back.

 

12 hours ago, North55Tones said:

Stud post hole dimensions vary from 9.5 - 10.5 mm, depending on where you find them. The studs I have measure 10.00 mm outside of the knurling/splines on two different caliper gauges.

The FR Special routing templates from the FR website (metric and imperial) seem to agree with each other - R5mm = R0.1969" = 10mm dia. If in doubt can you drill a test hole in a scrap bit of timber a see if your studs will press in OK?

 

12 hours ago, North55Tones said:

The metric and inch versions of the guide for the Special have different dimensions when converted to a common system of measurement (this is not simple rounding error).

Again, I can't see any discrepancy between the two versions of the FR Special routing template drawings. I didn't check every dimension shown, but the 4 or 5 I picked at random seemed to align spot on (values specified in inches multiplied by 25.4 gave me millimetres).

 

12 hours ago, North55Tones said:

The actual dimensional drawings for the Special show quite different dimensions than for the Original (even though they claim that they're the same dimension, just different materials in their advertising copy).

The actual dimension (measured from the Special which I purchased) seem to match the drawing of the FRO better than the drawing of the Special on the Floyd Rose website.

I was under the impression that the Special and Original were more a case of 'identical enough for one to drop into the pocket of the other', so that a guitar fitted with the Special may be upgraded at a later date without having to have major surgery to fit it. I might have that wrong though. In any case, are the discrepancies you're seeing enough to prevent your example fitting in the route specified in the Special drawings? 

 

12 hours ago, North55Tones said:

Setting aside that this seems like a serious issue in engineering quality control on the part of Floyd Rose, I could really use some help understanding what the ground truth is. I'm manufacturing these two bodies using CNC, it's not practical for me to measure things back to the nut on the neck, or use other build to fit type techniques. I don't have (or want) router templates.

If you're doing this on CNC, can you mill a test route in some scrap timber to see if your design will accept the bridge before committing to the proper bodies?

This may also be of interest to you:

At the bottom of the page are some PDF drawings of the templates I used to make that article. I can confirm the dimensions provided work, although you may want to tweak some of the shapes and clearances if appearances are mission-critical to you. I can take a photo of the guitar that was made using those templates, but the light isn't so good here at the moment.

[North55Tones]

Thanks a lot, Curtisa for your detailed reply! I agree that I could manufacture a test sample, but I was hoping to start from a known good reference. It's unusual that such a large brand as FR would not have more consistent documentation. To clarify my point about drawings being contradictory here are two links from the FR website:

Original_Floyd_Rose_Route.pdf (shopify.com) (This are the inch drawings, accessed by the link on the FRO item page).

FR_Original_Routing_Diagrams_MM_Packet.pdf (shopify.com) (These are the metric drawings, accessed by the link on the FRO item page). Note that the link on the Special item page is identical to these.

Since the metric routing diagram for the FRO and Special are identical, it follows that the inch versions should be too. So, I should have asked: Which of the two inch versions is correct?

The inch version on the FRO item page does give a location for the intonation line, they recommend placing the leading edge of the trem plate cavity about 19mm short of the scale line of the guitar (closer to the nut). Neither the metric or inch drawings on the Special item page provide that detail. This detail is helpful, but it's hard to trust given that both drawings show a different space between the leading edge of the cavity and stud centers (6.35 mm vs 7.62 mm).

Finally: Thanks a lot for your article and routing templates, they've been the best advice I've found so far. My plan (if I didn't get any feedback from the community) has been to base the dimensions of the route off of those templates and manufacture a test piece. Did you use either of the FR guides when developing the templates, if so, which one?

[curtisa]

9 hours ago, North55Tones said:

Since the metric routing diagram for the FRO and Special are identical, it follows that the inch versions should be too. So, I should have asked: Which of the two inch versions is correct?

I think they'll both work. One might give you a route with a slightly smaller border around the tremolo outline compared to the other, but I suspect there's nothing wrong with either of them. Don't forget that the cavity only has to allow enough clearance for all the bits to move freely. Assuming you go for form over function (ie, you don't make the cavity so small that it's...well, broken), how much clearance is entirely a matter of subjectivity. If it were me I'd go with the Special routes, only because the two versions agree with each other, and the rear section is marginally longer than the OFR one you've linked to (might be handy to allow for a little more intonation adjustment on the lower strings, where the string clamping screw will stick out further). But y'now - measure twice, cut once and all that...

 

9 hours ago, North55Tones said:

The inch version on the FRO item page does give a location for the intonation line,

It's handy, but it's also a bit dangerous - it's not an intonation line as such, but more a relative offset from the nut (notice how the offset changes based on scale length - your nominated scale length is different again, so is there an easy way to extrapolate those values to your requirements?). It's also an offset that describes the position of the cavity rather than the bridge, which means it's been positioned based on someones opinion of what route clearance around the leading edge of the bridge looks 'right'. It would've made more sense to show the offset relative to some feature on the bridge itself. I'd ignore it and position the bridge relative to what your guitar needs in order for it to intonate correctly, that being the scale length based on the point where the strings leave the saddles when positioned in the most forward practical position on the baseplate. In my case with an OFR it's about 16mm from the leading edge of the baseplate (ignore my previous recommendation of 12mm - it was dark, I had a drink, it was late...).

 

9 hours ago, North55Tones said:

Did you use either of the FR guides when developing the templates, if so, which one?

Pretty sure it was the metric one, but I can't remember if the drawing they have now was the same drawing I used back then. Again, my choices in making those diagrams was more about the appearance of the finished routes (well...plus I had a limited number of router bit sizes to choose from and couldn't be bothered trying to work out measurements to two decimal places by eye...)

FWIW, here's some photos of the guitar that was made using that exact set of templates in the article. Excuse the dust:

If I were to make the templates again I'd probably bring the top edge of the cavity 1mm or so closer to the leading edge of the baseplate to make the outline a bit more uniform (see first pic), and the back of the recess where the string lock screws need to clear when pulling up on the bar a couple of mm longer (second pic). The low-E clamp screw does clear everything, but I wouldn't want it to go back much further.

[henrim]

In the end Floyd Rose cavities are rather loose fitting and you can suit them to your needs. About only number you need to take literaly is stud spacing. Depths maybe too. Others you can adjust to your liking. The original drawings are directly converted from imperial, so it looks intimidating with far too fine measurements like 71,12 mm, 20,96 mm etc. If you think metric like me it's better to redraw to metric instead of directly converting dimensions. I have done it for myself with relative dimensions, as a guide for a manual milling machine. It's unfortunately not a useful drawing in your case (measurements are compensated for different bit sizes etc). 

If you have the FR tremolo in hand check the measurements from there. For intonation @curtisa has given you good pointers to get the in place. 

[North55Tones]

Thanks Henrim. Curtisa, the photos are helpful, I appreciate you taking the time to post them.

13 hours ago, curtisa said:

It's handy, but it's also a bit dangerous - it's not an intonation line as such, but more a relative offset from the nut (notice how the offset changes based on scale length - your nominated scale length is different again, so is there an easy way to extrapolate those values to your requirements?).

The recommendation which FRO gives for locating the leading edge of the route (and one can work out where that places the posts) relative to the scale line only changes by 0.76mm for a scale length change of 19mm, with no other information, linear extrapolation would be the only option for estimating a better offset. I'd hope that there's enough adjustability to just go with the value for 25.5" scales. It seems your 12mm value is pretty close to what Dan Erlewine recommends in his book (about 1/2" for a 25.5" scale), It's strange to me that so many (including FR) reference the leading edge of the cavity and not the centerline of the posts. The posts make a lot more sense as a datum.

My biggest concern is that I plan to machine two bodies, at the same time. So, if I get it wrong for one, then I get it wrong for both.

[curtisa]

8 hours ago, North55Tones said:

The posts make a lot more sense as a datum.

Correct, and this was the hardest thing for me to establish when I did my templates. It would have been so much easier if FR had derived all their measurements from this point.

All we really need to know is where the saddle take-off point is when it's in it's most forward practical position (NB: 'practical' - don't forget that it's possible to adjust the saddles on a FR so that the legs overhang the baseplate, which will introduce new issues of their own). This is the point where scale length exists; the saddles only go backwards from here. Then just provide us with a measurement from this point to where the trem posts need to be drilled. After all, if you get this wrong then it doesn't matter how much clearance you provide for the trem to sit in, the guitar will never play in tune. 

 

8 hours ago, North55Tones said:

My biggest concern is that I plan to machine two bodies, at the same time. So, if I get it wrong for one, then I get it wrong for both.

All the more reason to try your nominated route on scrap, then. You have a few different, but hopefully usable templates to choose from - pick one and take it for a spin. Massage the results until you're happy to commit the required cuts to your working bodies.

[North55Tones]

I'm convinced that I need to build a test piece with a provision to install a neck so I can confirm that I can intonate a 26.25" scale length neck - I'll likely just use dimensional lumber from the hardware store for the dummy body, so I'll have a 2x6 guitar to play with for a couple of days. I know this seems like the obvious solution, but it bothers me that FR doesn't provide the input that builders need to use their products and I don't think it's unreasonable to expect that they provide this information which they must have after roughly 40 years in business.

Our modern attitude that all information is highly valuable intellectual property, or a potential liability may be why they withhold this valuable information. Large companies can afford to take on the cost of prototyping and archiving this sort of knowledge, but private builders, small boutique builders and others who aren't mass producing a product assume a lot of risk (or expense to prototype) because FR isn't providing details which they must have available to them after so many years in business.

[curtisa]

6 hours ago, North55Tones said:

Our modern attitude that all information is highly valuable intellectual property, or a potential liability may be why they withhold this valuable information.

I don't think it's anything quite that sinister on FRs part. I think it's just a case of their datasheets are a bit weak in terms of the info they convey. We're actually pretty lucky they offer trem cavity routing plans at all - good luck getting the same info out of Gotoh for their GE1996T locking bridge.

As a builder you're more likely to purchase one of FR's trems because you specifically want their product in your guitar, rather than because their dimensional drawings are (not) awesome. Once you have it in your hands there's nothing stopping you making your own measurements to fill in the gaps. Annoying, yes, but by no means a showstopper.

[North55Tones]

I was able to reach FR Marketing by phone today, and they were very helpful (so my cynicism was misplaced). The feedback I received is that the inch drawings provided on the FR Original Series item page are probably the best drawings to use. They were prepared by Floyd himself in the past few years. The person on the phone advised me that for a 25.5" guitar the post centers should be at 25.125". It's nice to know which of the different drawings is considered to be the most accurate by FR. I modeled both routes (FR Original - Inch and @curtisas), they are pretty similar.

[curtisa]

40 minutes ago, North55Tones said:

a 25.5" guitar the post centers should be at 25.125"

0.375" offset seems a little light on (I'm eyeballing using a plastic ruler, but mine measures more like 0.5" offset), but if you're happy and they're happy, run with their advice. I'd only be a little concerned that at 0.375" offset you're going to need to pull the saddles back further to achieve correct intonation, and that the low-E string clamp screw may end up overhanging the back of the trem route.  Scratch that. 25.125" is further away from the nut than mine is at 25", which means there's a chance the legs of the high-E and B string saddles will overhang the leading edge of the baseplate after intonation has been adjusted. Might be inconsequential, but make sure the forward-most edge of the route has a bit of clearance to allow the saddle legs to swing freely without fouling on the body between the trem and bridge pickup.

[North55Tones]

2 minutes ago, curtisa said:

0.375" offset seems a little light on (I'm eyeballing using a plastic ruler, but mine measures more like 0.5" offset), but if you're happy and they're happy, run with their advice. I'd only be a little concerned that at 0.375" offset you're going to need to pull the saddles back further to achieve correct intonation, and that the low-E string clamp screw may end up overhanging the back of the trem route. 

I'm definitely going to test this on a mock up of the guitar. I have a 26.25 scale length neck which I could use, or maybe I'll make a plank with a movable nut to test a few different scale lengths...and report back on the distance from the nut to the post center.