Anyone familiar with Mosrite vibratos?

[Mark Hammer]

I'm waiting to gain entry to the Mosrite users forum, but thought I'd ask here, in the interim.

I have a clone of the Mosrite Combo. It was their semi-acoustic model, and has one of those cast-aluminum Bigsby-ike vibratos. The holes in the tailpiece, to pull the strings through, are staggered. The B and D string holes are lower than the others. Using the vibrato arm yields the expected pitch drop in the other 4 strings, but the B and D tend to keep their pitch. Reading around, I see mentions of "adjusting tension", but it is starting to seem like it was a primitive way of doing with a palm pedal does, except in this case it's more of a D and B-unbender.

Does anyone have any insight into what the true purpose and performance of those vibratos was?

[Tom Phillips]

Hi Mark,
I don't personally have any insight about the Mosrite vibratos. However, if I wanted to ask the question, I would contact Eugene Moles. Eugene is a master luthier and professional performer who grew up in Bakersfield where Mosrite Guitars were developed and manufactured. His dad, Gene Moles, worked at the Mosrite factory.
Eugene's FB page can be viewed at https://www.facebook.com/eugene.moles .
Cheers,
Tom

[52 Bill]

I think that that staggered spacing on the vibrato was an early attempt to keep the guitar in tune as you raised and lowered the pitch. It would only sorta work with a very specific set of string gauges. Semie Moseley tried to explain it to me at a NAMM show a hundred years ago, but it didn't make any sense to my small brain. Every original vibramute tail piece that I've seen, was fairly crude in construction. The staggered holes almost seemed to be drilled by eyeballing their positions.

[Mark Hammer]

It returns to pitch well enough. The design and the roller bridge seems to take care of that well enough. It's the not going OUT of pitch that is the issue, although I'm wondering if that was the intent.

[Greg_L]

It returns to pitch well enough. The design and the roller bridge seems to take care of that well enough. It's the not going OUT of pitch that is the issue, although I'm wondering if that was the intent.

As the owner of four Mosrites and a Hallmark, and a member of the Mosrite forum, I feel like I can tell you that your observations are correct. The Mosrite vibrato, while being probably the best vintage vibrato out there, does not induce humongous variations in pitch. It's not a Floyd Rose. In my experience you might get a step-and-half pitch bend at best out of the vibrato. It's designed for little country twang and surf wiggles, not dive bombs, and it returns to pitch flawlessly.

The weakness IMO is what you mentioned - the staggered through holes. And where it's a problem is that they can actually break strings at the ball end. It's really weird. It's happened to me and I've read about it happening to others. The high E or B string will break right at the wraps around the ball end if you use the wiggle stick a lot. The solution is tedious but works - flow a little solder around the twist at the ball end of the strings before you put them on.

In your case of not getting enough pitch bend from the vibrato, make sure your bridge is not rocking around when you use the vibrato. That happens sometimes too. The Mosrite roller bridge is a slick design but the way it sits on those skinny adjustment pegs can lend to some movement.

[Mark Hammer]

Still waiting on the administrator of the Mosrite forum to register me.

The roller saddles on the bridge that originally came with the guitar were not all rolling, and all attempts I made to get them to perform their appointed duties were coming up unsuccessful. So I purchased an inexpensive, but serviceable, aftermarket roller bridge., which does not "rock" (at least not very much). It the pitch change was not unevenly distributed in the manner it currently is, I might consider it a product of stiff rollers. But the absence of pitch bend is only for the two strings with the staggered tailpiece holes. Everything else can else be dropped by 3 frets of pitch, but the B and D remain stable. ( Actually the B goes up a few cents, but not more.) I'll need to explore it further, but perhaps the sharper angle between tailpiece and rollers for those two strings, prevents the rollers from doing their job and allowing pitch-drop.