Double Bass Double bass machines

[JohnWT]

The machines on my Chinese bass rattled every time I played a C on the E string. They had a lot of backlash and in general seemed sub standard so I bought a new set of Reubner machines. I had to cut into the timber surrounding the existing holes because the position of the cylindrical metal pegs was a bit different on the Reubners but I got to where they moved freely and fitted the new machines.
The result was machines that felt much nicer to use and made tuning easier but that pesky rattle was still there. I've tightened everything I could find to tighten and even took out the flat spring that lies under the cog wheel that attaches to the outside of the D string peg (which is the area where the rattle seems to originate) and bent it to give it more tension but that rattle persists.
My line of thought now is that perhaps the plate on the G and D side is not quite rigid enough and I was considering gluing a couple of small brass strips on as braces.
Any positive suggestions would be gratefully received.

 

[Gilmourisgod]

No solutions to offer, but you might have better luck posting this on the Double Bass part of the forum. Ive seen very few (none?) posts on DB repair in Luthiers Corner, though I know there are a handful of Pros who do work on them. The only one I can think of offhand would be @Bruce Johnson

 

[Matt Liebenau]

You might have better luck on the double bass side. This is bass guitars. I’m sure the mods can move it.

Having said that, I can tell you that on electric basses and guitars I have seen more then one rattle that seemed to be coming from one area that was from someplace else on the instrument and the sound was just transferring to another spot so check everything before you get too crazy with what, I’m guessing, are expensive tuning machines.

 

[Stewie]

My upright had a rattle. I pulled the peg out as far as it could be and played the note. The rattle was gone. The peg was maybe 15 inches longer than I needed , so I cut off 10 inches with a hack saw. Rattle was gone. It would take you about 5 minutes to check if this is the problem. Good luck!

 

[Mikich]

Have you tried putting a rubber band around the pegs (or stems not sure of the term)? Your guess seems logical. I would get someone to stand on a stool and feel around and listen while I try to replicate the rattle.

 

[DoubleMIDI]

When I had a rattle in the pegbox it was always a screw holding the toothwheel that was loose.
Try with a second person touching anything with n and around the pegbox to identify where the rattle comes from. If you cannot find it it might be somewhere else like the inner endpin.

 

[BobDeRosa]

My upright had a rattle. I pulled the peg out as far as it could be and played the note. The rattle was gone. The peg was maybe 15 inches longer than I needed , so I cut off 10 inches with a hack saw. Rattle was gone. It would take you about 5 minutes to check if this is the problem. Good luck!

I think you mean the end pin rather than the peg?

 

[JohnWT]

Thanks for the comments.
I have checked everything involved for tightness. I agree that it can be difficult to know exactly where a rattle is coming from but this one is loud and obvious.
Thanks too to whoever moved my question to a more appropriate forum.
Yes, they are good quality machines but I think that I haven't fitted them well enough.
I can see that the surface of the wood falls away slightly, where it's beginning to taper towards the top of the head, under the top of the plate that holds the machines. My idea now is this;
first apply gaffer tape around the edges of the bass plate that supports the machines in the area concerned,
then remove the plate with machines and sand all the finish off the timber underneath,
then build up the surface where the head starts to fall away with plastic wood filler.
When that's completely dry I'll plane the whole surface that supports the machines with a very sharp block plane no more than is necessary to get it flat, fit the machines, run around the edges of the supporting plate with a knife and then tear the gaffa tape off.