North55Tones

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.

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.

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.

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

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?

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