Slipping machine head question

[spaceheater5000]

Hi guys -

I've been having some problems with the A string tuner on my upright. The string goes out of tune fairly easily, and the main problem seems to stem from some "play" or slipping by the machine head/tuner.

It helps a little when I tighten the master screw on the outside casing of the machine head unit, though it pretty quickly goes out again. I'm having to tune the A string every few songs during a gig, which is a big drag.

Do I need to replace the tuner or is there something else I could do?

[Jsn]

What kind of bass? What kind of tuners?

[Jake deVilliers]

What kind of string? Tuning up or down? How high the moon?

[spaceheater5000]

I don't know the brand of upright - it's used. It's a Czech laminate bass - kind of a cheapy, but sounds okay.

The tuners are just standard upright tuners - again, no brand name listed. Not much help, I know.

As for tuning up or down, the 1/4" of play exists just flat of the A. The tuner sometimes doesn't "grab" the string until it's one or two cents sharp of the A, which is difficult to deal with. It usually grabs just flat, however. Is this clear?

[spaceheater5000]

p.s.

as for "How high the moon?"

The average distance from the moon to the Earth is 238,857 miles (384,392 kilometers).

[Jake deVilliers]

Originally Posted by spaceheater5000

p.s.

as for "How high the moon?"

The average distance from the moon to the Earth is 238,857 miles (384,392 kilometers).

Excellent! You're going to fit in well.

You could try using a 2B or softer pencil in the string slot of the nut to help smooth things along, but I find that most string instruments need a little help equalizing the tension on both sides of the nut.

On guitars, mandolins and double basses I find it worthwhile to pull the string up to pitch on the peg side of the nut. Just a firm tweak of the string to make sure its settled keeps me in tune longer. It works for me.. .....

[robobass]

I saw a problem like this on an EUB which had slab bass tuners. The end of the peg had a flat section where it fit into the gear, but had gotten rounded, so was slipping. If you remove the end screw and take off the gear, you might be able to see if this is what is happening. I fixed the problem by drilling a small hole radially into the gear (between two teeth) through the peg, and pinned it with a #6 finishing nail. If you've got a neighbor with a drill press, you might be able to do this yourself. If the slot in the nut is too tight, you want to fix that as well. It might have caused the problem. But, fixing the nut alone probably won't correct it.

[RCWilliams]

if the problem is slippage between the gear and the peg, a simple solution is toremove the screw and drill a small hole on the joint line between peg and ring gear, so half the hole is in each part, then insert a matching diameter pin and reinstall the screw. the screw should cover the pin, and the pin should act as a key (much like a key in a motor shaft and pulley.

[spaceheater5000]

Thanks for the insight, guys. I'll check it out and see what I can figure out. I'm not particularly mechanically inclined, so I may have to just take it to the shop anyway, but I really appreciate your input!