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Archtop question
https://luthiersforum.com/forum/viewtopic.php?f=10101&t=54551		 Page 1 of 1
Author:  surveyor [ Thu Nov 18, 2021 12:05 pm ]
Post subject:  Archtop question
I'm building (built) an archtop by Benetto's book and would like to make the ebony tailpiece since I've already finished the guitar and waiting for the lacquer to cure. Looking at his pics of the piece doesn't tell me how thick it should be, just that it's radiused on top to fit the fretboard radius. Any of you archtop builders use this type and would you let me in on the "inside scoop", no pun intended. Thanks, Mike Spector
Author:  surveyor [ Thu Nov 18, 2021 12:07 pm ]
Post subject:  Re: Archtop question
Oops, misspelled "Benedetto", please excuse
Author:  Michaeldc [ Thu Nov 18, 2021 12:12 pm ]
Post subject:  Re: Archtop question
Here are some clues.

https://www.stewmac.com/parts-and-hardw ... tailpiece/

M
Author:  surveyor [ Thu Nov 18, 2021 12:23 pm ]
Post subject:  Re: Archtop question
Wow, Thanks, Just what I was looking for , a plan.
Author:  rlrhett [ Thu Nov 18, 2021 2:39 pm ]
Post subject:  Archtop question
Take that as inspiration, but design your own. The tailpiece, like the headstock, is a place of personalization. Nothing screams, “I made an archtop from the Benedetto book” like copying the exact tailpiece.


Sent from my iPhone using Tapatalk Pro
Author:  Chris Pile [ Thu Nov 18, 2021 4:21 pm ]
Post subject:  Re: Archtop question
Quote:
Take that as inspiration, but design your own. The tailpiece, like the headstock, is a place of personalization. Nothing screams, “I made an archtop from the Benedetto book” like copying the exact tailpiece.


If you're going to start somewhere, there are few better in this world to replicate than Bob.
Author:  Terence Kennedy [ Thu Nov 18, 2021 10:55 pm ]
Post subject:  Re: Archtop question
I used the Benedetto tailpiece on my first two. I think I measured the width off the plans.

I just had the first one that I made about 10-12 years ago and kept, break where the wires exited the end. Be sure that area is sturdy enough. If I still used the design I would probably figure a way to reinforce it. Wonder if Bob had any fail?

If you use a pickup be sure to use some copper tape on the back and file the rubber padding off the retaining loop so the wire touches the output Jack to ground the strings.
Author:  surveyor [ Wed Dec 22, 2021 7:07 pm ]
Post subject:  Re: Archtop question
Well I made the "Benedetto" style tailpiece anyway and it came out pretty darn good. I reinforced the backside with a 0.055" brass plate and added the copper tape and scraped the tailpiece cable for contact since I wanted a pickup. I just strung it up today and it plays great, both plugged in and unplugged. I really like how it turned out but it was so much work, I probably won't build another.

Image
Image
Image
Author:  Chris Pile [ Wed Dec 22, 2021 7:27 pm ]
Post subject:  Re: Archtop question
Looks beautiful, well done!
Author:  surveyor [ Wed Dec 22, 2021 7:53 pm ]
Post subject:  Re: Archtop question
Thanks Chris, now I need to make some knobs for it, since I made everything "wood" on it.
Author:  jfmckenna [ Wed Dec 22, 2021 8:07 pm ]
Post subject:  Re: Archtop question
Awesome! I got Bob's book a couple years ago and some top wood. One of these days I'd love to build one but they just seem so intimidating.
Author:  Terence Kennedy [ Thu Dec 23, 2021 12:26 am ]
Post subject:  Re: Archtop question
I used the Benedetto tailpiece to his specs on my first two. The metal portions telegraphed through as little bumps on the top after about a year on both. I fixed that by sanding them flat and flooding in thin CA and reinforcing the back with a thin overlay. One is probably 10 years old and I have contact with he owner and it is holding OK. The other broke through the exit holes after about 8 years while in the case.

I would agree that some reinforcement would probably be a good idea with that design in the hands of the average luthier like me. Seems to have worked great for Bob. I have gone to a brass end plate and skeleton with an Ebony overlay a lot like the Eastman design or an all metal type.

ImageIMG_3103 by Terence Kennedy, on Flickr

ImageIMG_3223 by Terence Kennedy, on Flickr

I love looking at tailpiece designs. It certainly is an area of great creativity. I wish I was a machinist. A friend that was was head of CNC at a local factory and owed me a favor machined a really cool design as a one off but to produce them was not cost effective for the small number of Archtops I build a year.
Author:  Victor Seal [ Thu Dec 23, 2021 8:26 am ]
Post subject:  Re: Archtop question
Wowzer. I have the plans, the books and the wood for a D'Angelico archtop. I know it will be a real project, but looking at your pics is an inspiration. Beautiful work. Thanks for posting.
Author:  bionta [ Thu Dec 23, 2021 11:18 am ]
Post subject:  Re: Archtop question
Beautiful guitars here!

Terrence, did you make the brass parts in your new tailpiece yourself or do you have a source for it?
Author:  jfrench79 [ Thu Dec 23, 2021 1:41 pm ]
Post subject:  Re: Archtop question
Terence Kennedy wrote:
I used the Benedetto tailpiece to his specs on my first two. The metal portions telegraphed through as little bumps on the top after about a year on both. I fixed that by sanding them flat and flooding in thin CA and reinforcing the back with a thin overlay.


Hi Terence. I'm having a hard time understanding what you mean here. Did the brass adjusters on the tailpiece fastener telegraph through to the front of the ebony tailpiece?
Author:  Terence Kennedy [ Thu Dec 23, 2021 5:59 pm ]
Post subject:  Re: Archtop question
jfrench79 wrote:
Terence Kennedy wrote:
I used the Benedetto tailpiece to his specs on my first two. The metal portions telegraphed through as little bumps on the top after about a year on both. I fixed that by sanding them flat and flooding in thin CA and reinforcing the back with a thin overlay.


Hi Terence. I'm having a hard time understanding what you mean here. Did the brass adjusters on the tailpiece fastener telegraph through to the front of the ebony tailpiece?


Yes, they tended to tilt with the tension and caused bumps on the top of the tailpiece.
Author:  Terence Kennedy [ Thu Dec 23, 2021 6:26 pm ]
Post subject:  Re: Archtop question
bionta wrote:
Beautiful guitars here!

Terrence, did you make the brass parts in your new tailpiece yourself or do you have a source for it?


I used sheet brass, I think around .062. Made a cardboard template to get the design right, and then a wood one. Cut to width with a metal cutting blade on the table saw and double stick taped it to the wood template and cut close to the edge with a metal cutting blade on the band saw. I was able to sand the brass to the final shape on the RoboSander and spindle and belt sander. Pretty stone age in the eyes of a machinist but it worked. The Irwin step bit was great for drilling the holes in the end plate before bending I heated the brass in a vise with a torch to bend it.

The string holder is just rectangular brass box stock. I drilled the holes with my bridge pin hole jig and the slots with a router jig and and a Dremel with he StewMac base. The string bar and plate are brazed together with a small hand torch.

The Ebony cover is routed to accept the skeleton so it sits flush and held in with epoxy and short screws .

I have made five so far the oldest being about five years old and they have held together to this point. My biggest concern is failure at the bend or the brazed joint.

Here are some of the parts and templates.

ImageIMG_1646 by Terence Kennedy, on Flickr

ImageIMG_3102 by Terence Kennedy, on Flickr
Author:  bionta [ Thu Dec 23, 2021 8:36 pm ]
Post subject:  Re: Archtop question
Terence Kennedy wrote:
bionta wrote:
Beautiful guitars here!

Terrence, did you make the brass parts in your new tailpiece yourself or do you have a source for it?


I used sheet brass, I think around .062. Made a cardboard template to get the design right, and then a wood one. Cut to width with a metal cutting blade on the table saw and double stick taped it to the wood template and cut close to the edge with a metal cutting blade on the band saw. I was able to sand the brass to the final shape on the RoboSander and spindle and belt sander. Pretty stone age in the eyes of a machinist but it worked. The Irwin step bit was great for drilling the holes in the end plate before bending I heated the brass in a vise with a torch to bend it.

The string holder is just rectangular brass box stock. I drilled the holes with my bridge pin hole jig and the slots with a router jig and and a Dremel with he StewMac base. The string bar and plate are brazed together with a small hand torch.

The Ebony cover is routed to accept the skeleton so it sits flush and held in with epoxy and short screws .

I have made five so far the oldest being about five years old and they have held together to this point. My biggest concern is failure at the bend or the brazed joint.

Here are some of the parts and templates.

ImageIMG_1646 by Terence Kennedy, on Flickr

ImageIMG_3102 by Terence Kennedy, on Flickr

Stone Age is just my speed. Thanks! I’m going to cogitate on this and eventually try something similar.
Author:  Terence Kennedy [ Fri Dec 24, 2021 12:13 pm ]
Post subject:  Re: Archtop question
Just an aside but I considered trying a router table and conventional template bit to flush cut to the template but decided that was a really bad idea.

John Hall, if you see this, as a machinist, do you have any thoughts for shaping brass sheet stock to a template?

Thanks!
Author:  Barry Daniels [ Fri Dec 24, 2021 12:56 pm ]
Post subject:  Re: Archtop question
I'm not John but I worked for a period of time in a machine shop turning brass and stainless parts on a lathe. Brass cuts very easily due to the lead content in the alloy. A router would probably work fairly well with the following caveats. Generally speaking, woodworking tools turn faster than metal tools. You don't need or really want a tool rotating at 10k rpm to machine brass. It will overheat the part and shower you with hot metal chips. You may also get chattering which can make parts slip. Another issue is the angle of the cutter. Wood likes a positive rake whereas a 90 degree rake is better for materials like brass, aluminum or plastic. But you can find router bits for plastic that have a 90 degree rake.

So I guess what I am saying is that a router table may work and it would be worth a bit of experimentation, but be prepared for issues. And keep in mind that the brass contains lead so take a few precautions.
Author:  Alan Carruth [ Fri Dec 24, 2021 2:23 pm ]
Post subject:  Re: Archtop question
I worked in a machine shop running drill presses for six months before I went into the Navy. One of the first things I learned was that when drilling brass you need to use a scraping cut. I normal twist drill will try to advance itself into the work faster than it can produce shavings, with results that can be disastrous. When setting up a job with brass the first thing we did was to 'break back' the edges on a grinder, putting on a small flat parallel to the axis of the bit. These cut well dry, and tend to produce small conical chips that are very sharp. I went home with socks full of them regularly. On one occasion I was finishing 7/8" holes in a brass plate that had to be exactly sized for a press fit, using a reamer on slow speed. I could not break back the edges on the reamer, and it grabbed. It tore the jig (at least 5# of stainless steel) out of my hand, whirled it around a few times, and threw it across the shop when the bit broke off. The only injury was the cut on my hand, and nothing else was broken. Even a 1/4 " bit can grab if you don't break it back. These days, when I drill brass, I use a diamond stone to make a very small flat, and that's all it takes.
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