Target top thickness

You can ask questions here about Trevor and Gerard's exciting new book on Luthiery.

Moderators: kiwigeo, Jeremy D

Post Reply
User avatar
Tom West
Myrtle
Posts: 70
Joined: Thu Jun 25, 2009 7:40 am
Location: Nova Scotia Canada

Target top thickness

Post by Tom West » Tue Mar 19, 2013 9:17 am

Trevor: Have struggled through and managed to get Audicity for the resonant freqs. and also a spread sheet for the target top thickness.The thickness came within .002" and that is close enough for me. Now it appears to me that the target thickness may only be for falcate bracing. Do these figures apply to X bracing as well,as long as one aims for the two degree rotation at the bridge.
I must say when I ordered these books I did not anticipate a workout for my 70 year old brain cells. Also new to computers,new to Excel as of a couple of days ago. Just high school and Tech school math a looooooooog time ago. I feel full of piss, wind, and vinigar right now. Thanks for the help.
Tom
P.S. Say hello to my Weim Mandy on the left
The person who has never made a mistake has never made anything....!

User avatar
Trevor Gore
Blackwood
Posts: 1605
Joined: Mon Jun 20, 2011 8:11 pm

Re: Target top thickness

Post by Trevor Gore » Tue Mar 19, 2013 10:15 am

Hi Tom (and Mandy),
Tom West wrote:Do these figures apply to X bracing as well,as long as one aims for the two degree rotation at the bridge.
Yes, they work fine for all the more conventional bracing systems with the conventional distribution of stiffness between the bracing and top. If you put all the stiffness in the bracing and use the top more as a membrane (along the lines of Smallman classicals) you will need to use a different vibrational stiffness factor, f. For X and falcate bracing f=75 works fine. If, in the future, as you develop your own style, you want your tops to be thinner, just reduce the value of f that you use. f= 60 is what I use for conventional classicals, just to give you a feel for how the numbers move.

User avatar
Tom West
Myrtle
Posts: 70
Joined: Thu Jun 25, 2009 7:40 am
Location: Nova Scotia Canada

Re: Target top thickness

Post by Tom West » Tue Mar 19, 2013 10:57 am

Trevor: Thanks for that info. With the spread sheet I have just used your numbers but am starting to feel more comfort with the whole process. Thanks again and take care.
Tom
The person who has never made a mistake has never made anything....!

Post Reply

Who is online

Users browsing this forum: GregHolmberg and 12 guests