Bowlback mando tuners...

[Mike Kolb]

My better half recently started learning the mandolin and she has a decent import F-model to use, but I thought I'd restore an old bowlback I've had knocking-around for her birthday in April.  

So now the search is on for a decent set of those old inset tuners, as the current ones are just barely usable, having been "fixed" a few times over the many years and they're probably not overly trustworthy. 

From what I've seen these tuners are old, to be sure, but not terribly rare ...as it seems as though there were thousand of these type of bowlbacks made during the "mando craze" back in the day.

I've scoured the likely sources to no avail so if anyone has any leads or ideas, I'd appreciate hearing about 'em.  Many thanks.

[Robbie Collins]

Any possibility you could remove the tuners from the cover plate then install something like Grover 309s, and then reinstall the cover plate?

[Mike Kolb]

I may end-up doing just what you suggest. The existing current tuners probably have some life in them, but they're on a respirator. Maybe I'll install what's there, continue looking-for replacements and...failing that... go with something like the Grover 309's as you suggest.

If everything fails, one thought was to cut & trim mahogany inserts to fill-out the two existing slots, then just start from scratch with a fresh set of modern tuners... but as "old-style"-looking as possible.  

By the way, thank you, Robbie, for responding to my post.  I always feel badly when anyone's post is "orphaned" without any answer or comment... (let-alone one of my own) so your involvement is appreciated :)

[Roger Häggström]

If I knew a way I would have answered, but finding new matching tuners is borderline impossible. You may find a similar bowl back you can rob for tuners in better shape. You can have one off tuners made but it will not be for cheap!

Repairing the ones you have, fill the holes in the head with wood and put new tuners on or hide new tuners inside the old shell as suggested is probably it.

[Robbie Collins]

You're welcome. My suggestion was obvious and a 2nd best solution. I best love projects that require thinking outside the box. I bet I've read every one of Frank's articles on frets.com three times because of his ingenious solutions and his willingness to go the extra mile to get it right.

[Ned Knepp]

Mike,

How long are the posts and what's the distance between them, center to center. While you are at it, how thick is the wood around the posts?

I'll have to go look, but I'm pretty sure I still  have a set of old tuners that might fit with some adaption. If I remember correctly, they have roughly the same curvature an the button shafts as your's seem to have and the buttons were even "white".  My recollection is that they are in pretty good condition too.

 The tuners were not mounted on the cover plates like yours appear to be and would probably require some very short screws to fasten them in place. The posts are very short, like maybe 1/2 inch so there wouldn't have been much wood for a screw go into. They're also odd because the top of the mounting plate is square, like you would expect but the bottom end is rounded. 

 I think I have the cover plates as well but can't say that I know where those are now because I keep my old tuners together and don't keep "stuff" like that with them. They are probably out there, in a box somewhere.  I'll see if I can find them too. 

[Mike Kolb]

Hi Ned...

  Let's see, just back from the shop with some measurements so let's see if I can convey this correctly!

  The posts are .980" center-to-center;  they are each 1.130" in total height; there's .450" of post that extends beyond the peghead face when installed.

  The peghead itself is .650" overall height; the cut-outs for the tuner strips are .350" deep, leaving .300" of wood.

  The tuner strips are not firmly mounted to the plate, they're loose and being only held in-place when the covers are screwed down to the peghead from the rear.

 There's three screws per cover, and the two end screws are 4.100" apart. The cutout itself in the wood is 3.925" in length and (as mentioned above) .350" deep.

  So that's what I've got here.... If what you have knocking-around someplace is anything close, let's talk.

  All that said (-and whether we can make something work or not-)  I surely do appreciate the interest!

[Ned Knepp]

Mike,

 I found the head easy enough but still can't find the cover plate.  I don't have my calipers here but I used a machinist ruler for the following measurements; 

The overall length of the back plate is 4 3/16 inches.

The post heights is only 17/32 of an inch overall with the taper to the string hole starting only 7/32 from the back plate which basically setting the thickness of the face of the head at about that thickness too. 

The diameter of the string post is approx. 7/32 inches

Center to center the post are spaced at 58/64 which I think converts to about .90625 inches.

The button shafts are longer on the ends (outside) and measure 3/4 inches from the inside edge of the button to the center of the gear.  The two inner (inside) button shafts are 5/8 inches to the center of the gear.

When I first looked at your measurements I was worried that these were just too different but now I'm wondering if you can use them with your string shafts and redrill the holes in the head.

 Anyway, I'll see if I can get a halfway decent picture to post tomorrow so you can see what I'm talking about. They are actually in very good condition, steel worm gears on brass gears and not a lot of wear on either. They turn just fine without too much slop in the gears. The buttons are typical yellowed "white" ivoride but in good shape and there isn't any indication that any of the shafts have been bent.

One thing that concerns me besides the differences in specs is how these might have been mounted. I'm wondering now if these were mounted in sockets that were cut in the face of the head with a steel plate over them instead of being mounted from the back like you are needing. They still may work, if you can use/find longer string shafts but I'm not sure how you would mount them securely on your head since these appear to have been screwed down.  

[Mike Kolb]

Thanks for the attention to detail and the efforts, Ned, although I think we're "close but no cigar".  Everything sounds just different enough (especially the post-spacing) that it seems to be a different horse.

I'd really hate to re-tool the holes in the peghead, although it may come to that someday.  Hmmmm. 

So the plan for now will be to run what I've got and hope everything holds!  In the meantime, I'll keep my ear to the ground for a set of tuners that (fingers crossed) will drop-in.  

And if that means purchasing another bowlback to scavenge for parts, so be it.  Ebay and reverb.com have "notify me" options so maybe that's the next move and filter-through the bowlbacks that come up.

Again, I thank you for your diligence and offer.   But hey, we tried!  

[Ned Knepp]

I think you're right Mike, these are pretty nice for as old as they are but you would probably need to rework almost everything about the head to make them work.

.