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CNC and a 1982 MusicMan Bass body repair
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10106&t=29115		 Page 1 of 1
Author:  Mike Kroening [ Fri Sep 17, 2010 4:35 pm ]
Post subject:  CNC and a 1982 MusicMan Bass body repair
OOps I posted this in a previous thread. :) I hijacked my own LMAO!

Thought I would share a repair that just came in. A 1982 music Man bass (Pre Ernie Ball) 2 piece Ash body. Someone tried to install a trem bridge on this (sure ruined the value of this thing). The new owner finally found a string through Music Man bridge. So I now have to fill in the cavity and install the bridge. So here are the pics before I start.
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Needless to say tests cuts will be made in MDF before the body is under the gun. :)

So the plan is to make an insert for the pocket.

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Then pocket the offended area. This process will progress from being undersized by about 0.030" and profiled by 0.005 or less" until a perfect fit is achieved.

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next step the tests cuts then the fixture for this project

MK
Author:  Mike Kroening [ Sat Sep 18, 2010 3:06 pm ]
Post subject:  Re: CNC and a 1982 MusicMan Bass body repair
So here is a quick simple fixture I came up with for this. Since it is a one of.:) Milled about 0.010 off my X block that fits in my T tracks to assure it's parallel. Made a new block with a piece of MDF glued to it. Setup an offset and milled the holes for the Bridge post screws to use to locate the body to the table. After clamping the Body down the fixture will obviously be removed to do the milling.
duh

MK

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Author:  Mike Kroening [ Mon Sep 20, 2010 2:02 pm ]
Post subject:  Re: CNC and a 1982 MusicMan Bass body repair
So I cutout the insert. First had to surface to thickness plus 0.010. Then used an extended length 1/8" mill. Must take care with this one because of the flex. :) Kept the feedrate at about 25 ipm and 0.0625 pass depth. Slowed the router down to 10K. Worked out well.

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Next will be to start the pocket on the body.

MK
Author:  Mike Kroening [ Mon Sep 20, 2010 3:58 pm ]
Post subject:  Re: CNC and a 1982 MusicMan Bass body repair
I decided to redo the plug/patch. I think the radius close to the inserts are just a little closer than I want. Better to be safe. A dry run with the plug/patch in hand shows me it's a closer fit than I prefer. No need to remove anymore material than I really need to. beehive

mk
Author:  Mike Kroening [ Mon Sep 20, 2010 5:15 pm ]
Post subject:  Re: CNC and a 1982 MusicMan Bass body repair
Just another update.
I know this is boring as hell.

So after cutting out the full size insert and a test pocket in Ash. I took a hard look at the tolerance of wood available around the threaded post inserts. I will redo the wood insert as this is an Ash body. There will be some tear out that will account for about 0.015. If it were a maple body I wouldn't hesitate on the cutout. I just don't want the Post insert holes to explode :) I have maybe 0.050, +/- 0.005 available on each side.

So now I have to find about 0.060 for this to work and it's going to be close. gaah

and he wants me to not remove the Posts inserts. idunno It would be so much easier to replace the entire area :)





Mike
Author:  Mike Kroening [ Mon Oct 04, 2010 3:22 pm ]
Post subject:  Re: CNC and a 1982 MusicMan Bass body repair
So Finally done with this. Would've liked to make it a tad bit larger but needed to keep as much material around the post inserts as well as stay hidden under the bridge. Customer doesn't even want it finished. :)

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