Double Bass Is the gap between the frog and the underslide normal’

[taksnficll]

I recently got a rehair done and the bow came back with the frog far off the stick on the screw side.

I gradually turned the eyelet about 1 and 1/12 turns and looks like this:


Is this normal? I also tried turning the eyelet another half turn but the screw got too tight.

Just one last thing. Is it normal for the screw to not be flush with the stick as well? There’s a little bump where they meet and the screw seems to point upwards. Thanks everyone.

 

[T_Bone_TL]

It's not normal. Sign of sloppy work by the rehairer, IMHO. If the fit was correct when you sent it in, there's no good reason they should have loosened it.

Double Bass Post in thread ''Play' between frog and stick of new bow?'

Sep 6, 2018

Ooops!
I may have misunderstood your problem. If there is a gap between the top edge of the Frog, and the Stick, you may need to (take the Screw all the way out, to access the eyelet screw) to try turning the eyelet screw 1/2 turn INTO the Frog. This will bring the top edge of the frog closer to the stick. If there is still a gap, you can try another 1/2 turn of the eyelet screw, until the gap is close to "gone". You'll need to be sure that the Screw threads are not binding when reassembling the bow - DON'T FORCE IT. If so, you'll need Pro Help.
Or, take it to a luthier for adjustment...

• T_Bone_TL

• 

If your button-to-stick interface was not out of whack before the rehair, I'd be asking the rehairer exactly what the <bleep> they did to my bow. There's absolutely no reason that should change that isn't abuse, IMHO.

 

[Stuart.C]

Take the frog off the stick
and turn the eye where the screw goes through a half turn in
Should tighten it up

 

[taksnficll]

Take the frog off the stick
and turn the eye where the screw goes through a half turn in
Should tighten it up

I already did and this is the furthest it can go. If I do another half turn, the screw well be very hard to turn when I adjust bow tension. I feel like if I keep it that way it's going to strip the threads off of the eyelet.

 

[jj.833]

I think my main bow probably has a little gap there too. I never really checked, but I kind of thought it's pretty normal. I'm not sure it it is a good idea to tighten the eyelet though. If you press the eyelet too low, that would only force the screw tip to move more off axis, right?
Bow rehairer once told me that new hairs are made as tight as possible, so they would last long enough, as the hair naturally gets slowly stretched. New hair needs just few screw turns to get the right bowing stiffness, old hair needs more screw turns. Perhaps the frog moves in a slightly different path than you were used to, and all the little clearances just add up?

 

[turf3]

Well, you've got a fairly crude mechanism that requires the frog to slide on the stick, but the only adjustment of the clearance is by half-turns of the little screw in there. If you want it to slide, there WILL be a clearance. If you get the little screw too tight, not only will you be straining everything every time you tighten and loosen the hair, you'll also be adding tension to that wee screw that it's not intended to take.

As for alignment of the screw to the main stick, that's basically going to be what it is. I'd check to make sure the screw is collinear to the "handle" (what is the right name for the part you grasp and turn?) It might be that the screw is bent, or that its fixing in the handle is misaligned. If it's bent, of course you straighten it, but if it's not collinear, there's probably nothing to do.

 

[Stuart.C]

I already did and this is the furthest it can go. If I do another half turn, the screw well be very hard to turn when I adjust bow tension. I feel like if I keep it that way it's going to strip the threads off of the eyelet.

Oh interesting, maybe some wax lubricant that was there got cleaned off.

You could try rubbing the screw and the contact areas on a candle and see if that makes it tight and smooth.

I'd ask whoever did the rehair if they had to adjust anything.

 

[T_Bone_TL]

(what is the right name for the part you grasp and turn?)

When not lumped all together with the attached parts as "the screw" or "the adjuster" the more specific to that part name is commonly "The Button", AFAIK.

i.e. IVP calls this: BASS Bow Screw with Eyelet 3 part button, French

but mostly the button is just sold as part of the screw/adjuster and not referred to separately in most "anatomy of a bow" type guides. It is a separate part, as you can seen in the link that they sell screw and eyelet sets with no button as well.

 

[MikeCanada]

There are a whole bunch of different problems, reasons, solutions, wear, time, wood, etc. happening at that end of the bow, so let's look at a few.

It sounds like the eyelet (the brass/bronze part in the frog that the screw goes through to connect the frog to the stick) was loose, and you tightened it as far down as you could before it started to bind. That's the right thing to do, and can/should have been checked during the rehair. They sometimes start to wear, get a bit loose, the stick shrinks and the wood wears inside the holes. If everything is properly aligned that shouldn't be a problem, but if the hole in the back of the stick isn't centered and in line with the smaller hole at the front, a gap can open up here.

The octagon (or some other 8 sided shape with different angles) of the stick and the frog both have to be perfectly the same where they fit together and the silver underslide acts as a bearing surface on two mating planes, but often they aren't cut perfectly the same, the stick is slightly smaller, or maybe the line wiggles a bit, isn't perfectly flat, leans a bit, etc. If it's handmade, on a bass bow that's a lot you've got to get perfect to make all the gaps go away. If this isn't a perfect fit, it also can get really full of "gunk" from rosin, your hands, whatever the rehairer lubricated the screw with, metal dust from the eyelet slowly wearing out because the gap usually means things aren't quite right, etc.

Should the button and the stick be in line with each other? Yes. Are they always? No. Some makers are drilling those holes by hand and cutting the octagon by hand and don't get either of those things perfect, some do it at various stages during the process, and everything might be aligned earlier, and then not later, and sometimes, they just aren't perfect. If you take the screw out and look at the end of the stick, is the hole in the middle? There should be a nipple at the end of the stick too, which may or may not be centered as well, and a part of the solution or problem.

All of it can be corrected. If it wasn't like that before the rehair, then it should be made right, but if the holes weren't drilled in the right place to begin with, unless the rehairer started messing around with those, the bow could have any of the above issues or a combination of them that end up with it being not quite right back there, but especially on German frogs where the contact between the frog and the stick is so long, it's pretty common for a small gap to happen. Sometimes you just need to turn the eyelet, sometimes it needs bushings, sometimes it's a whole thing.

 

[turf3]

There's also the option to get it as tight as you can without binding and then just use it.

 

[Mark Gollihur]

Is it lifted up on the other side of the frog, too, or is it pretty flush?

I'm no bowmaker, and this might just sound counter to "common sense," but my hypothesis is that the gap may have opened up because the internal brass nut is too tight to the frog, not too loose. Since you basically have that adjustable brass nut bottomed out, that makes me think this could be the issue.

The screw part of the button/adjuster goes through a hole which opens up into the channel for the frog nut to slide laterally, to allow for hair adjustment. But the hole at the button end is only just large enough for the screw to pass through cleanly without a lot of play. If the brass nut on the top of the frog is too low - but you're still able to thread the screw through it, the screw post could be forced into state of constant downward pressure which causes it to be "pinched," or "binding" on the top edge and/or bottom edge of that hole. See the red arrow in my crude illustration for the "pinch points" I mean. The pic on the left is when it's set too low - on the right, the screw passes more cleanly through in parallel with its channel.

So, counter-intuitively, RAISING the height of that nut would allow the screw to pass cleanly through the hole and channel, without binding or having lateral downward pressure put on it, and would thereby operate properly - and should let the frog sit more evenly on the stick, and allow for smoother loosening and tightening, since it's in a properly balanced alignment.

Being overtightened and out of "square" would also explain the upward "cant" to the button, for the same reasons.

Food for thought!