4+2 Ratio Electric Locking Machine Heads Mini Contemporary Button (PRL-8421, Select Finish)
4+2 Ratio Electric Locking Machine Heads Mini Contemporary Button (PRL-8421, Select Finish)
PRL-8421-C0
702725245376
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RATIO® patented gear technology
RATIO® - Calibrated Machine Heads incorporate different string gauges into the tuning equation.
From Low E to High E 39:1, 24:1, 20:1, 35:1, 20:1, 12:1.
We balanced the gear ratios to each string simplifying the tuning process.
With RATIO®, a half-turn is a semi-tone!
Every string reacts the same to any tuning adjustment. Predictable, precise tuning, on every string.
The PRL-8421 is a right-handed set of Locking RATIO® Calibrated Machine Heads for a Music Man, or other 4 x 2 style headstock.
It has a mini contemporary button.
It has a two-pin casing that can be used as is, or with our Patented InvisoMatch Mounting Plates [opens in new tab].
4 different sets of InvisoMatch mounting plates in brushed aluminum are included to make installation on most guitars fast and accurate by using your existing screw mounting holes.
Gear ratio: unique for each string position - one turn-one tone
Peg holes diameter required: 13/32" (10mm)
String post diameter: 0.236" (6mm)
String post length to string hole: 0.910” (23mm)
Weight per single machine head: 0.083lbs (38g)
Weight per set: 0.496lbs (225g)
String diameter up to 72 gauge
Includes 6 machine heads, mounting screws and bushings
Includes complimentary 4 sets of aluminum mounting plates
Invisomatch Mounting Plates
InvisoMatch Mounting Plates for RATIO Tuned Machine Heads are the easiest approach to installing Ratio Tuned Machine Heads on your guitar.
Simply select the installation plate design that matches the screw/pin hole location of your factory installed machine heads.
You’ll be up and running within minutes, perfectly installed and aligned. Stay classy you axe master.
For stunning accuracy and response... upgrade to Ratio Machine Heads with it's patented Multi-Geared Tuning Technology.
The new standard in tuning.
NO DRILLING, PERFECT ALIGNMENT, FAST INSTALLATION
With InvisoMatch mounting plates you will reduce the time to install RATIO machine heads to well under 15 minutes.
The alignment of the machine heads is perfect, no holes to drill or fill, ideal for vintage instruments.
Four sets of brushed aluminum InvisoMatch mounting plates come free with every set of Ratio Tuners.
Premium finishes including chrome, nickel, black and gold are available for order.
“After reading some reviews and seeing the ads, I decided to try a set of Graph Tech’s ratio tuners on my American standard Strat. The tuners arrived and I was very pleased with the quality and finish. Installing the tuners was a breeze using the included InvisoMatch plates — no need to drill any holes in my beloved Strat and the performance of these tuners is outstanding!"
"Tuning becomes incredibly easy and holds tune even when using the tremolo bar. I would highly recommend these as a great upgrade to any guitar and will be telling my customers what a great addition they would be for very stable and easy tuning.
Thanks, Graph Tech for a great product.!
Jay Langan / Magdon Music / guitar sales/ guitar tech
Click a picture to open a PDF file with the dimensions.
- DODanail O.Verified BuyerReviewing3+3 Ratio Acoustic Guitar Machine Heads (PRN-2411, 2421, Select Finish and Button Style)I recommend this productRated 5 out of 5 stars1 month agoQuality Acoustic Guitar Machine Heads!
I was looking for a replacement machine heads for one of my acoustic guitars and these happened to be a perfect fit. Build quality is top notch and they turn smoothly. Installation was easy and although I purchased the matching black Invisomatch plates I end up not using them. Overall a fantastic upgrade.
- MLMark L.Verified BuyerReviewing3+3 Ratio Acoustic Locking Guitar Machine Heads (PRL-8411, PRL-8441, Select Finish and Button Style)I recommend this productRated 5 out of 5 stars1 month agoratio tuners
nice looking tuners of good quality and ratio makes tuning a breeze
- SMSamuel M.Verified BuyerReviewing6-In-Line Ratio Lefty Electric Locking Machine Heads (PRL-8721-L, PRL-8731-L, Select Finish and Button Style)I recommend this productRated 5 out of 5 stars1 month ago👍
Perfect drop in fit for my Chapman ML1 stormburst
- RDRock D.Verified BuyerReviewing6-In-Line Ratio Electric Locking Machine Heads (PRL-8721, 8731, Select Finish and Button Style)I recommend this productRated 5 out of 5 stars1 month agoBest locking machine heads I've used
Much more precise than average tuners
- SHSteven H.Verified BuyerReviewing5 String 3+2 Bass Ratio Y-Style Button (PRB-5320, Select Finish)I recommend this productRated 5 out of 5 stars2 months agoPerfect!
These work exactly as advertised, and are a great replacement/upgrade from stock. Note: some of the tuners may come from the factory tightened a little aggressively - definitely try loosening a bit if you notice one or more aren't turning as easily as they should :)