Hoping for some ideas on how to fix mistake with rim

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blnote

Hoping for some ideas on how to fix mistake with rim

Post by blnote »

I had CAD friend at work print me out a 15' and 25' radius template and made my sanding bars/caul. My issue is with the lining and end/neck blocks. The end block was the same height as the sides and was glued on without it being proud at the top or bottom. The neck block was glued in being proud only on the bottom and flush with the top. Weeks later I glued in the lining after reading the step in Bill Cory's book without taking into cosideration how I had set the blocks, so the lining is 3/16 proud of the rims, top & bottom.

My question is do I just radius/sand it all down until I get into the block which will take off some of the rim height? or do I glue a small piece of mahogany to extend the blocks and bring them level with the lining? I actually already made pieces to do the second option and thought I should ask first. I'm just happy I don't have to see everyone shaking thier heads at this. Really appreciate any thoughts you all may have.
tippie53
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Re: Hoping for some ideas on how to fix mistake with rim

Post by tippie53 »

How short are you ? The back should have a slight taper going from about square to 5 degrees at the neck block, the top will be pretty flat and just a slight angle at the neck area for the fretboard extension . What are you building ? a small body 000 / OM will finish off at about 4 1/8 with top and back and a Dred would be 4 3/4 . I don't think you will have any serious issue just sanding down as long as you are within 1/16 to 1/8.
You can take out the blocks and replace it , glue a piece on . As you can see , it isn't that major.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
kencierp

Re: Hoping for some ideas on how to fix mistake with rim

Post by kencierp »

The insides of the blocks on the back side are considerably taller then the rim edge since the dome of the back increases toward the middle -- I would suggest that you glue an extension on the blocks to make sure your back plate will make good contact and not distort (a common and very ugly mistake). There is no need the worry about the top edge and in fact if you go to my website you can find out how its done at the Martin factory -- flat sanded and then sloped. Anyway here's some info and pics to show what needs to happen.

http://www.kennethmichaelguitars.com/ba ... ouro3.html
Tony_in_NYC
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Joined: Thu Aug 12, 2010 9:11 pm

Re: Hoping for some ideas on how to fix mistake with rim

Post by Tony_in_NYC »

Glue extensions onto the blocks. I did it on a recent guitar that is not yet finished, but it is a common fix. As long as your joint between the original block and the added piece is tight, you will not have any problems. You will simply end up with a deeper bodied guitar which will add some volume to it.
blnote

Re: Hoping for some ideas on how to fix mistake with rim

Post by blnote »

Thanks for the replies, I'm leaning more towards going ahead and extending the blocks. Here's a few pics in case my post wasn't very clear.
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blnote

Re: Hoping for some ideas on how to fix mistake with rim

Post by blnote »

back/neck block. might be hard to see but this is the only place thats a little proud.
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tippie53
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Re: Hoping for some ideas on how to fix mistake with rim

Post by tippie53 »

What are the measurment of the sides at this point ? you may not be fine. Often there is a bit of extra length for this part of the process. A dred with the top and back on should be 4 7/8 at the tail block . I think it is 4 3/16 at the neck but don't hold me to that.
You may just need to sand the kerfing a but more. .
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
blnote

Re: Hoping for some ideas on how to fix mistake with rim

Post by blnote »

Sides are 4 3/4 at the tail block and 3 3/4 at the neck. I might need stronger glasses but they both look pretty dead on at 3/4 mark. This is a D18 kit, I've haven't done any sanding yet. The kerfing is mostly 2/16 proud of the sides give or take a 1/32 here or there. I probably should have got a new block, or set the kerfing flush, or??.
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
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Re: Hoping for some ideas on how to fix mistake with rim

Post by tippie53 »

Looks like things are going to be fine .
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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