Archtop Tailpiece issue

[Allen]

Do you have some photo's you could post of your design Dave?

[Dave Stewart]

Allen, it's basically Benedetto's design right out of his book. This is an older shot showing the various jigs I use to make it, as well as a couple of prototypes. For those interested, the jigs are 1) tap the (pattern-sanded) blank for tailgut hole location 2) holds blank vertically while drilling 3) holds blank belly up for adjuster slot (collar) routing (which you can just see in the prototype) & 4) sequences for plunge routing button holes, then slots for strings. Prepare the underside, glue the pivot, radius/chamfer the top and done.

[Nick]

I build mine similar to Dave's (Welcome to the forum Dave, I love your archtops So your input here will be an excellent addition, for anybody that isn't familiar with Dave's beautiful work check out one piece of it here &/or his website!) & Bob's design.
When I read your problem Alan I was initially puzzled as to how or why this joint would give way, there should be no side loading at all on this little block as the adjusters are usually recessed into the tailpiece block itself. So any load on the fulcrum should be downwards toward the top.But then I saw your picture of the doweled mark 3 version and saw why you were having problems effecting a satisfactory joint, you are putting all the string loading onto that block. The tailpiece material should be thick enough that you can let the adjusters right into it (I think mine when fully 'home' sit flush with the underside of the tailpiece with a small thickness left between the adjuster & the top face of it). I don't let the fulcrum block into the tailpiece either, I glue it straight onto the underside (after a wipe with naptha or Acetone of both surfaces). If everthing is 'loading up' properly the force should be downwards on this block so in effect the glue is only there to locate the fulcrum when it has no load on it.
Anywho, if nothing else this piece has added to your learning curve & pool of knowledge so it gave it's life for a good cause .

[ozziebluesman]

Thanks Dave and Nick for your input.

Dave: Do you have any pictures you could post of your finished tailpiece especially the fulcrum end? A side, front and top elevation would be great is possible.

Nick: Do you have some pictures you can post of your archie tailpiece please?

I still haven't got my head around where I'm going wrong.

Cheers

Alan

[Nick]

I'll try and dig some out for you Alan, sure I had some somewhere. Otherwise I'll 'borrow' one from one of mine and grab a few pics of it.

[Dave Stewart]

Thanks Nick. Alan, strangely I don't have much in the way of pics of completed tailpieces. Here are some prototypes & works in process that may help, as well a as pic of postioning a pivot for CA glueing. (Or you could try the "raised saddle" route as Dominic showed above). I hollow the underside a bit to promote a lighter look. Adjusters are not visible from the side. I'm also trying the "center spine" look shown on a current build (typically I just radius & chamfer), which if a violin tailpiece would be called the "English style". Check out the "pictures" & "instructions" for Stewmac's Benedetto archtop tailpiece.

Tailpc pivot attach.jpg (92.49 KiB) Viewed 6445 times

[ozziebluesman]

Dave:

I see where I've gone wrong now. Half my 3 mm holes where going thorough the block so no longer it would not hold. My tailpiece compared to yours design was not thick enough at the area where the fulcrum block was glued on either. I see now where the tail gut is positioned in the tailpiece itself which will solve my problem. Thank you so much for your pics and information. I do believe I should be successful with the next designer tailpiece.

Cheers

Alan

[Dave Stewart]

You're welcome Alan...glad I could help.
BTW, you may find you have to go to 5/32" holes to get enough tailgut clearance...I did.