Large Thumbwheels?

[po56okie]

Yes, I've seen photos of Bill Monroes well worn F5 and have often wondered why no one nowadays makes a bridge with the large thumbscrews like Bill's mando. It looks cool ! I mean, it just seems like it would be easier to adjust height as you would have more of a radius to turn, plus it looks so retro.

[billhay4]

Mine has very small, hexagonal wheels and a wrench to turn them. Make adjusting very easy, even with strings at tension.
Bill

[George R. Lane]

Mine has very small, hexagonal wheels and a wrench to turn them. Make adjusting very easy, even with strings at tension.
Bill

Would that be a Weber?

[HonketyHank]

I have heard that the large thumbwheels were replaced because it was thought that their mass was damping vibrations that should be transmitted to the soundboard. Smaller thumbwheels have less mass, ergo ...

I have also heard that it is quite debatable as to whether or not the small difference in mass makes a detectable difference.

Finally I have heard that big thumbwheels look old fashioned and clunky while little bitty thumbwheels look modern and sleek.

Me, I would like to trade some little bitty wheels for big clunky ones and try them out for myself.

[MikeEdgerton]

Bill's mandolin went through many repairs over the years with some oddball parts entering the mix. At one time it also had (at least on one side) Handel F-4 tuners. A while back David Harvy made a copy of Bills mandolin and did use the big wheels. If you like them you can probably buy guitar wheels at Stewmac and put them on your bridge. The original bridges on the Loar signed mandolins had small wheels.

[MikeEdgerton]

I have heard that the large thumbwheels were replaced because it was thought that their mass was damping vibrations that should be transmitted to the soundboard. ...

I doubt the man got that granular.

[Jeff Mando]

I doubt the man got that granular.

Agreed. If Monroe wanted "more sound" he would just play harder..............

[Soupy1957]

Agreed. If Monroe wanted "more sound" he would just play harder..............

and lean into the mic more!!

[pops1]

The larger thumbwheels were thinner than the smaller ones so there was less threads on the screws to hold the tension. At least from the ones I have seen over the years.

[Tavy]

The size of thumbwheels supplied with new bridges seem to be all over the place recently - some are so small they're un-turnable, but others have been really quite large. For those that want to experiment look for M3 "thumb nuts" on ebay.

[HoGo]

The size of thumbwheels supplied with new bridges seem to be all over the place recently - some are so small they're un-turnable, but others have been really quite large. For those that want to experiment look for M3 "thumb nuts" on ebay.

US made bridges use 1/8" thread, not metric.

[Ivan Kelsall]

George - I think that billhay4's mandolin must be a Weber. There was a thread on here quite a while back in which Verne Brekke joined in. I mentioned that the hex. on the Weber bridge was too shallow & too soft (brass). The small wrench is hard steel & one false slip could round off the soft brass hex.corners - Verne Brekke agreed with my idea that a steel thumbwheel/hex. might have been better. Having thought about it since then & realising that some folks do like to raise the bridge height without slackening off the strings,that maybe we could do away with the knurled thumbwheel altogether, & simply have a steel hex. which if deep enough (top to bottom) could be turned using the steel wrench without damaging it. Certainly it could be offered as an option ?.

Personally,i prefer the idea of stainless steel thumbwheels instead of brass which soon tarnishes. For a mandolin with Gold hardware,the hexes could also be Gold plated = they won't tarnish,but the effect of a steel wrench on them might not be too good. However, i do prefer to loosen the strings to make raising/lowering the bridge as easy as possible anyway,
Ivan

[Hendrik Ahrend]

US made bridges use 1/8" thread, not metric.

The Montana Gibsons used M3 threads; US-made? Don't know.

[Phil Goodson]

I think the large wheels look a little bit like 24" alloy wheels on an old Buick. YMMV

[MarkELynch]

The Montana Gibsons used M3 threads; US-made? Don't know.

I just measured an original Gibson adjustable bridge. The thread size, as others have said, is (US) number 5 by 40 threads per inch. This appears on the US National Coarse Thread series table as 5 (1/8) - 40.

Not sure why a Montana Gibson bridge would be metric M3 x 0.5.
This would be slightly smaller in diameter (0.118” versus 0.125) And have a finer thread (50.8 versus 40 per inch).

Also, the material in the original is not steel or brass, it is nickel silver like some of the other hardware such as the pickguard support wire.

Great discussion, I love this minutiae.

Mark

[pops1]

The finer thread would be a plus as more threads to support the force.

[Paul Hird]

I find it hard to believe anyone would have to turn the bridge wheel so hard that it would slip, stripping the corner off the bridge wheel. When adjusting the bridge on my Weber up or down, it is such a delicate maneuver I would have to work hard to have the wrench slip and strip any corners. Just sayin.

[Dave Martin]

My Breedlove -- Oregon made -- uses a .050 allen wrench to adjust. As noted above, with the wrench supplying some torque advantage (lever and a place to stand) it make fine tuning the action under string tension very do-able.

[CarlM]

The finer thread would be a plus as more threads to support the force.

Finer threads are also shallower so generally this is not true. With an extremely thin nut finer threads may give a benefit but usually the benefit is finer adjustment not more load carrying.

[billhay4]

Would that be a Weber?

No. A Jacobson.
Bill

[Hendrik Ahrend]

Not sure why a Montana Gibson bridge would be metric M3 x 0.5.
This would be slightly smaller in diameter (0.118” versus 0.125) And have a finer thread (50.8 versus 40 per inch).

I remember 20 years ago, when I measured the bridge on my F5. The whole bridge was smaller, lighter than original Loar bridges, and the threads were 3 mm ø brass.

[Ivan Kelsall]

From Paul Hird - "I find it hard to believe anyone would have to turn the bridge wheel so hard that it would slip,..".

Hi Paul - When i tried it,i wasn't turning the hex. hard. Under full string pressure,the hex was 'hard to turn'. The wrench slipped off the hex. & rounded a couple of the corners off. IMHO - if that can happen,there's something wrong with the design 'as it is',& Verne Brekke agreed. A steel hex. wouldn't have been damaged so easily,
Ivan

[fatt-dad]

I'm a bigger fan of the hex nuts and the use of wrench.

I mean it's like almost never I fuss over the action. Get it right and play!

f-d

[pops1]

I carry a couple tools to lever the saddle slightly to turn the wheels under tension. Depending on summer or winter the bridge is lower or taller I will have to use different tools, but it is simple and seems to work well. When my hands were stronger I would spend a lot of time getting the fit of the saddle to the wheels and could lift the saddle under tension with just my fingers, can't lift it anymore, but sometimes on a good day I can lower with just my fingers. I have thought many times of changing the wheel to a nut, just haven't felt the need yet.

[Steevarino]

Well, since so many Café folks have used our bridges, I'll chime in here and let you know that the thread size we have used on Cumberland Acoustic bridges is indeed #5-40. About 20 years ago, Charlie Derrington handed me three bridges off of true Loar era mandolins. He asked me if I could make them just like that, they would start using them on their current line of Gibson mandolins. The thread size on those bridges was indeed #5-40, so that's what I went with.

About materials and plating, our thumb wheels are brass. They are then plated either nickel, gold, or occasionally silver. Also, staying with original specifications, they are .09" thick and 3/8" diameter.

Those who have veered from both the thread size and the spacing between the posts haven't done mandolin players any favors. I can't tell you how many requests I have had for "just the saddle". A fair request, because that's the part that usually needs replacing, and fitting a new bridge base isn't required if you can just replace the saddle. Problem is, if the thread size or hole spacing is different, we cannot replace just the saddle.