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I am just starting to build a copy of an 1830 Panormo built by Louis Panormo in England. It is a 25" scale fan braced nylon 6 string

I have all the parts prepped including joining the top and back.

In looking through my reference photos I just noticed Panormo's tops are joined with the wide growth rings at the joint and the narrow rings at the outside of the guitar. I have a few photos of other years of his guitars and they all look the same way. My top is joined the opposite so I will have to fix that.

I am not well versed in gut strung vintage instruments other than the Panormo so I am wondering if this is normal practice and if so what is the reason behind this?


If someone whants pictures of this I will be happy to post them.


Thanks for the help,

Bob

Normal practice varies by builder, as I'm sure you know. Panormo's bracing has the center fans very straight (i.e. same orientation as soundboard grain). The outer fans are quite skewed to about 30°. Straighter fans are stronger in resisting string pull, while skewed fans are weaker. Maybe old Louis was compensating for this by orienting the finer grain, which is presumably stronger, towards the edges.
Good luck with the pin bridge. The string holes just barely miss the fans in the original.

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Ring spacing has nothing to do with strength or stiffness of the top.

Normal practice these days is to join top halves on the 'bark' edge. This can facilitate getting better-quartered wood, which has higher cross grain stiffness, in the center of the top. Normally growth slows down as the tree gets bigger, so the ring lines tend to be closer together in the center of the top. However, trees can also develop more twist in their growth as they get larger, which produces more run out at the center join. This reduces the long-grain stiffness, and causes problems with bridge gluing. With a top like that a 'heart match', putting the bark side toward the outside of the top, can be beneficial. It's possible that's what Panormo was doing in the tops you've seen.

The only Panormo I've ever worked on had a one-piece top.

Thanks for the response guys,



Yea, I see a number of them that he literally cut through the edges of the fan braces. I have this all drawn up in CAD and will use a paper template to locate the holes correctly.




I would have thought the tighter the spacing of growth rings the stiffer the wood would be, like little I beams.



Perhaps that is what I am seeing here. I have never seen a Panormo in person so I can only go by pictures and what has been written about (not a lot)

Thanks again for the help,

Bob

The picture is very illustrative. Even though the wider grain is in the center the latewood lines are quite thick. It appears to me this would yield stiffer wood than the edges, where the latewood is finer.

_________________
Stay with the happy people.
--Reynolds Large

The more I look at it, the more that sems to be a one-piece top. Note the 'knot shadow' behind the bridge between the B and E strings, which is not mirrored in the other side. Of course, it's hard to be sure with a picture.

RusRob wrote:
"I would have thought the tighter the spacing of growth rings the stiffer the wood would be, like little I beams."

TRein wrote:
" It appears to me this would yield stiffer wood than the edges, where the latewood is finer."

It's not a matter of how many lines there are per inch, but of the proportion of hard late wood and softer earlywood. 50 lines per inch or 5 would end up the same if the latewood lines are always just 1/3 as wide as the earlywood. Usually with tighter grain spacing the latewood proportion goes up; the wood gets stiffer but its also denser, and the density rises faster. You can make it a little thinner, but for a given stiffness it weighs more. That makes the top harder to drive: it's less 'responsive' at low levels, but can often be 'pushed' harder without the sound 'breaking up'. I'm not sure the heavier top actually puts out more sound at that point, but it can sound better.

I often see relatively thicker late wood lines from very large trees, and closer to the bottom. I suspect that's the tree adapting to the static load. One local wood supplier to the music trade pointed out to me that you can often find less latewood, and wider ring spacing, higher up in the tree. He used to label each piece of wood with a code that indicated which cant (drum) it came from, and which quadrant of the tree. If you found a piece you liked it was relatively easy to find another from the same part of that tree, or a comparable tree.

I recall reading that some early guitar makers would join their tops but cut the tops based off of one side, so the join line was off to the trebel side of the guitar. I wonder if that is what Panormo did?



Thank you for that explanation Alan, I can see how that would make sense of what I am seeing in his tops.




Yea I think that Alan pretty much explained the "why"

Thanks for replying


Thanks again guys for the help in explaining this,

Cheers,
Bob

Ok, I just found this PDF I had saved a while back.


All credits go to RM Mottola at Lutherie Information Website

https://www.liutaiomottola.com/

In writing about the Panormo



And that would explain this small detail drawing I saved that shows asymmetrical bracing (I thought it was a mistake).

So for anyone interested I hope it helps someone that wants to build a copy of a Panormo.

Cheers,
Bob

Regarding traditional carved-top instruments, it seems like the bark sides would be joined since splitting the wood creates wedges with the bark side being wider. This would yield a shape easier to carve a raised area in the center. I reckon this may not apply to flat-top instruments.

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dzsmith:
That's the usual way, alright. If you get the wedges from the right size of tree the annual ring lines will end up very close to perpendicular to the surface all the way across the top, which gives the highest cross stiffness and greatest stability.

Yes. I've only looked at the insides of a few "in the Spanish style" Panormo guitars, but James Westbrook's dissertation has quite a few photos. From all of this, it appeared symmetrical fans were used for all one piece tops. In the cases where an extension to the width of the top plate was added, the most common approach appears to be to move the outer fan brace so it "cleats" the seam. In at least one case an additional fan brace was added, going from the tail end of the outer braces and angled off toward the waist, again, cleating the seam in the top plate. The latter of course could have been the result of a later repair.

BTW, the drawing from Davide Serracini is excellent. And also BTW, James Westbrook's dissertation in now available as a book: Guitar Making in Nineteenth-Century London: Louis Panormo and his Contemporaries. Very expensive, but definitive.

_________________
R.M. Mottola
LiutaioMottola.com

Author of the books Building the Steel String Acoustic Guitar, Practical Design of the Acoustic Guitar and Similar Instruments, and Mottola's Cyclopedic Dictionary of Lutherie Terms.

I don't check in here very often. If you need to contact me the best bet is via email through the contact page on my site.

@rmmottola
Thanks for commenting here. I had no idea how Panormo set up his tops until I found your site.

I have been planning this build for almost 2 years now, I had a bit of a setback and fractured my back which took me out of commission
for about a year. In that time I have been collecting as much info on the Panormo so I could draw my own plans which I am just finishing up now.

My plans for this guitar is to build it as accurately as I can to the 1930 high end that Panormo made. My intent is to create this as an aged
instrument as if it were just found in a closet.

I am planning on documenting the process here so I will be starting a new thread on it pretty soon.

Thanks again for stopping by and sharing

Cheers
Bob