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PostPosted: Fri Nov 17, 2017 9:28 am 
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Joined: Sun Mar 06, 2011 12:04 am
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First name: Chris
Last Name: Pile
City: Wichita
State: Kansas
Country: Good old US of A
That would work. Drive on!

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Stop saying "How stupid can you get?" Too many people are taking it as a challenge!


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PostPosted: Fri Nov 17, 2017 11:37 am 
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Koa
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Location: United States
Just take it slow and cut only about 1/8" deep passes. Do you have a template to control the cut or are you free-handing it?


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PostPosted: Fri Nov 17, 2017 11:49 am 
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Walnut
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Joined: Wed Nov 08, 2017 10:29 am
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First name: Lee
Last Name: Glenn
Focus: Repair
Status: Amateur
Barry Daniels wrote:
Just take it slow and cut only about 1/8" deep passes. Do you have a template to control the cut or are you free-handing it?


I'm going to make a pattern screwing 4 pieces of wood together to leave a slot the correct width and length. I just grabbed a 1/2" pattern bit.


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PostPosted: Fri Nov 17, 2017 11:52 am 
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Koa
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Good plan.


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PostPosted: Fri Nov 17, 2017 11:55 am 
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Walnut
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Joined: Wed Nov 08, 2017 10:29 am
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First name: Lee
Last Name: Glenn
Focus: Repair
Status: Amateur
Any recommendation on the specific grade of Titebond? Lowe's has a bunch of different ones. I've always used the yellow wood glue but don't know if there is a preferred grade for this application.


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PostPosted: Fri Nov 17, 2017 1:31 pm 
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Koa
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Joined: Fri Aug 19, 2005 4:02 am
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Location: United States
If you use Titebond, ONLY use the Original version. Titebond II and III have creep issues. I would probably use West Systems epoxy on a repair like this, especially if you can't get super tight joints.


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PostPosted: Fri Nov 17, 2017 4:15 pm 
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Koa
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Joined: Thu Nov 04, 2010 1:46 pm
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First name: Freeman
Last Name: Keller
Focus: Build
Status: Amateur
Good advice above, Lee. A 1/2 bit would be fine, get the kind with the follower bearing on top (shaft end). I would consider just clamping three pieces of 1/2 wood to the top of the guitar - make sure you have straight sides and put one on each side of the channel and one across the end. Make sure that they are big enough that your clamps won't get in the way. You can also use double stick tape on the back but I tend to trust clamps more. Put a bunch of blue tape on the top to try to avoid screwing up the finish.

The three pieces will have square corners but your follower bearing will just span it and make the radiused corner. You can either drill out some of the waste wood with a Forstner bit (maybe 3/4) or just make several passes with the router. Start shallow with the bearing riding on the pieces of wood, lower the bit and make another pass, do it again. At some point you will transition from following the pattern to the walls of the channel - just keep going until you are at the correct depth. Make sure the bottom is as smooth as possible - thats one of the gluing surfaces.


You will likely rout into that cavity on the back - if you go slow there shouldn't be any chipping. I would not try to plunge into the cut, rather enter it from the control cavity end.

Make your inserts a hair oversize and sand/plane to fit. Make those little radiused corners - you could pull the bearing off the router bit and use that as a template to draw around. I will be 1/2" diameter.

Titebond Original is the glue to use or as Barry suggests, a slow setting epoxy which will fill voids, but if your piece fits well Titebond will do fine. Clamp down against the bottom of the cavity, clean up glue squeeze out, open a nice cold adult beverage and post the pictures. We'll be waiting...


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PostPosted: Fri Nov 17, 2017 5:38 pm 
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Koa
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I am going to extrapolate and make the guess you have a 1/4" shank 1/2" pattern bit (bearing on top)...take your time with this and work carefully to the pattern edge...1/4" shanks will deflect a tad when bogged down...when I'm doing things similar to this I most always use a drill bit of some sort to hog out most of the material, in this case a forstner bit would be preferred as you are trying to create a totally flat bottom...point being a spade bit with a long center pilot will leave said pilot hole after routing, a forstner bit's pilot tip is very small and one just makes sure not to go too deep and leaving that indentation...

as far as your pattern goes, what I do is to make a "master" pattern out of 1/4" plywood using a table saw (and yes, there will be over cut slots left over), then screw that to a thicker piece of plywood to use a pattern bit to make a working pattern. every now and again if I need thickness to allow me to limit my depth (the pattern bits I use are 1" long, so if I need only 3/8" depth of route I need to have a pattern about 1" thick) I'll leave the 1/4" pattern attached to the additional 3/4" piece of plywood...if I'm making a pattern I plan to use repeatedly over time I'll make all parts from the master and then save the master to make new patterns as needed over time (you see being human I, now and again, make a mistake (like letting the router tip a bit and eating into the pattern, or having excess chatter from using a 1/4" shank, etc) and damage the pattern, so it's great to have a master saved up to remake it all

yeah, use TB original, the others suck except for using TIII for binding purfling before bending it (the heat of bending actually hardens the TIII and because of TIII's characteristics makes it the purrfect glue for such work)


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PostPosted: Sat Nov 18, 2017 1:12 pm 
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Walnut
Walnut

Joined: Wed Nov 08, 2017 10:29 am
Posts: 12
First name: Lee
Last Name: Glenn
Focus: Repair
Status: Amateur
So here we go....

I started by taking measurements to help locate the post holes after the new piece is in. I know I can figure it out from the scale length and the intonation adjustment on the bridge gives me some leeway, but wanted to measure everything just in case. I used a small hammer to tap the broken piece back into the original location first.
Attachment:
image001sm20.jpg

Attachment:
image003sm20.jpg

Next I pulled the post inserts, which I was able to do by screwing the posts in and just pulling with my fingers. Not exactly well secured.
Attachment:
image004sm20.jpg

From tapping the piece back into place and pulling the inserts out the putty, or whatever the previous "person" (I'm not sure who to blame for this but I suspect it was the owner, not someone who actually works on instruments. I surely don't want to use the word luthier.) used for the repair started falling out. I scraped a bit more and discovered more damage and "repair" work. There was no actual wood on the neck side of the bass post, only putty.
Attachment:
image005sm20.jpg

There was a screw added that I assume was meant to stabilize the piece!
Attachment:
image017sm20.jpg

I hard already started to back the screw out in that pic. It was screwed all the way down.

I could then see that the entire piece was broken loose, even from the floor of the pickup cavity:
Attachment:
image012sm20.jpg

I then wiggled the piece a little and it came out easily!
Attachment:
image016sm20.jpg

So far I was able to remove the majority of the wood with my fingers!

Next step is to laminate the maple piece that Freeman sent me into one ~1"x1"x6" piece.
Then I'm going to make my guide and learn how to use the router by using the guide to make a practice route(s) on some scrap wood before trying it on the actual guitar body.

More pics as I go.

Thanks again for all the guidance and materials!


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PostPosted: Fri Nov 24, 2017 1:05 am 
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Walnut
Walnut

Joined: Wed Nov 08, 2017 10:29 am
Posts: 12
First name: Lee
Last Name: Glenn
Focus: Repair
Status: Amateur
I kind of tweaked my back and fell behind on this project. I did manage to:

... laminate the maple pieces:
Attachment:
image002sm20.jpg


... make a template from a piece of 1/2" plywood and do a test route on a piece for scrap:
Attachment:
image012sm20.jpg


Happy with that, I routed the guitar body:
Attachment:
image009sm20.jpg


Since, as I described in my previous post, I was able to remove most of the wood by hand I was able route out the rest in two passes:
Attachment:
image016sm20.jpg


Next step is making the new piece out of the laminated maple pieces.


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