Ebony wheels, can't wrap my head around this..

[Cody Sisk]

I've installed countless sets of metal bridge wheels but these ebony wheels I ordered have me scratching my head. The wheel and the shaft are not one molded piece. The wheel freely threads onto the shaft but will come off. Do I need to glue it in place before installing? Is it supposed to be two separate pieces?

My other dilemma is the length of the shafts. They are 65mm long. I don't think the Despiau bridges I use will work. The arching won't support a shaft that long. Do I cut it to size? If so, do I cut on the threaded portion or smooth portion?

Do I thread into the foot or into the bridge? or neither? It looks like I could glue the smooth portion into the foot and have a hole big enough to house the threads in the bridge, making the wheel itself do the heavy lifting..


flickr

Thanks in advance for your advise.

[Brent Nussey]

I don't know which direction is better, threads up or down, but for now lets say threads down. So you would drill a hole in the leg the size of the unthreaded part. Then you cut off the feet. Install the unthreaded portion in the leg, probably using glue to hold it in place. Then you drill out the feet with a hole big enough that the threaded portion can easily slide in and out. Now thread on the wheel. The wheel, on the threads, sits on the feet and elevates the bridge when you turn the wheels. Essentially like an archtop guitar bridge.






I am somewhat suspicious of the stability and reliability of this kind of adjuster, on a gut level. Especially the wheel being ebony... No experience, though, aside from having been shown a few.

EDIT: Sorry, yes this is exactly what you're talking about in your third paragraph.... Anyway, I've seen these kind of adjusters before, and that seems to be how it's done.

[Jake deVilliers]

Cody, I install adjusters threads down unless specifically asked to do it the other way.

When you screw the threads down into the foot they'll bind up and then the 'wheel' will be free to raise and lower the upper part of the bridge.

That being said, I think you need a bridge blank with more vertical legs in order to keep those chubby pegs inside the wood!

[forester]

i love wood but...that is a low/no tension adjuster.

[Schoolhouse]

I glue the wheel and shaft together with a jig to ensure squareness and treat them just like aluminum adjusters. They usually have a 10mm thread, an 8.5 mm drill is needed for the tap. Often, I pin the wheel to the shaft with a brass piano center pin. This also serves as a reference for turning up or down. One can trim the top of the smooth shaft to bottom out in the hole in the top of the bridge. This will allow better sound transfer then a too deep hole. If you want to shorten the thread, you can easily do it with wood. Usually, we use straighter legged bridge blanks with the wooden adjusters in order to have enough "meat" in the legs. In any case the tapped holes MUST be parallel to each other.