The tail piece parlour bail

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DarwinStrings
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The tail piece parlour bail

Post by DarwinStrings » Wed Apr 10, 2013 10:33 pm

All boxed up and it looks like this. I have to have a think now I guess and decide what to do next.

Jim
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Life is good when you are amongst the wood.
Jim Schofield

jeffhigh
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Re: The tail piece parlour bail

Post by jeffhigh » Thu Apr 11, 2013 7:38 am

Looks pretty damn good to me Jim
By the time you put a bridge on, sand the top and tune the back you should be pretty close to your target 170HZ wasn't it

One of the things which was really useful to me in the book was Figure 2.4-5 in the design Book.
Realize that everything you do to one component will affect the tuning of all the modes to a greater or lesser degree so approch you targets slowly and give yourself room to move. It's a lot easier to bring frequencies down than move them up.

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DarwinStrings
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Re: The tail piece parlour bail

Post by DarwinStrings » Thu Apr 11, 2013 11:10 am

Cheers Jeff, that is it with the bridge bolted on with two 1/8 bolts. The sound hole is already as small as I can go and still sneak my hand in. I guess for looking at Fig. 2.4-5 i should reduce the back mass. I didn't really have any target I just figured to put it together and see what happens. The braces are 7.5mm high so assume I could reduce them next time if I want to get a lower top. I am not 100% sure what to do other than thin the back which wasn't thickness using the book. My graph does not look as spikey as Trevors but happy so far with the outcome. Any suggestions would be very welcomed.

Jim
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Re: The tail piece parlour bail

Post by jeffhigh » Thu Apr 11, 2013 2:13 pm

Have you used trevors live back bracing? you can scallop the lower bout brace in the centre to drop the back which will also push the top resnonance a bit lower and also the air.
Then you have side mass and thinning the top around the edge, bridge pin weight etc

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DarwinStrings
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Re: The tail piece parlour bail

Post by DarwinStrings » Thu Apr 11, 2013 3:12 pm

I did and yep that's is what I have just been up to. I have stopped at; sound hole is 107.5Hz (at least between notes), top is 184Hz(needs to be moved) and back is 224Hz. I suppose I should just whack it together now and go from there.

Jim
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Re: The tail piece parlour bail

Post by jeffhigh » Thu Apr 11, 2013 3:36 pm

I'd be leaving it there and finishing assembly and lacquer
It is easy to overshoot the target if you get too close too soon
Strings and pins wil make a difference too

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Trevor Gore
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Re: The tail piece parlour bail

Post by Trevor Gore » Thu Apr 11, 2013 3:42 pm

Nice work and nice plots, Jim.

There's not much I can add; Jeff has said it.

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DarwinStrings
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Re: The tail piece parlour bail

Post by DarwinStrings » Thu Apr 11, 2013 4:06 pm

Before I did anything I checked the book again and realised that thinning the back was the wrong direction so I thinned the brace in the end.

Jim
Life is good when you are amongst the wood.
Jim Schofield

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