New Cocobolo Jumbo

Guitars by Grant Goltz of Hackensack, MN
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whitespruce
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Re: New Cocobolo Jumbo

Post by whitespruce » Mon Jan 25, 2010 10:35 pm

Well, the weather was too crappy to go anywhere to buy new batteries for the camera, so I used the old trick of heating up the batteries with a hair dryer and managed to coax out a few more shots ;)

OK, what I want for the top purflings is 3 lines, starting at the binding going inward, red/holly/black. Now handling this many separate veneer lines while instaling the binding can be a pain in the pa-toot, I know, I have done it. Gluing up that many lines and then trying to bend the whole thing is also a pain.

So I thought, why not glue up a veneer sandwich, tape it to the side bending form and let it dry. Then saw already bent purflings off the edge :D

So I cut two strips of each color (a set for the cutaway and non-cutaway sides), glued and stacked them and bent them around the side forms. Taped heavily and let them dry for an overnight. Here is one on the form and one taken off
Image

And here is a closeup
Image

One thing that is a must-do with this is after you have the glued veneer stacked up, spritz both faces with water and wipe it over the surface...keeps the outer layers of veneer from curling.

Now there are a few slight irregularities in these, but I intentionally glued them with plain wood glue. That way they will wet up a bit when being glued on with the bindings, and the bindings will form a gluing caul to even them out.

G

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burge guitar shop
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Re: New Cocobolo Jumbo

Post by burge guitar shop » Tue May 11, 2010 4:32 pm

Well Grant Guess Who Is watching you.
Man that is going to be a fine looking guitar, Hurry up and post some more pictures of it.
I just had two more steroids shot put in each shoulder yeaterday, so I'm down for a week before I can do anything.
Doc says if this don't work he will have to put in a new shoulder joint in each shoulder.
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Re: New Cocobolo Jumbo

Post by Dennis Leahy » Wed Dec 26, 2012 9:11 pm

whitespruce wrote:OK, here is the skinny on the back bracing.

On my last 3 guitars, I have been using a double "X" back bracing laminated out of layers of strips. The strips are 3/16" wide by 5/32" thick.

Next, I will go over it with a specially ground router bit to taper the sides of the braces.
Image
I ground this bit down from an old Craftsman bit, and cut the pilot to a shallow depth so it just rides on the bottom layer strip.

Here it is after routing:
Image
This is just the first step in shaping the cross section of the braces. It is rough at this point, but a lot of wood has been removed.

...
G
Where did you find that bit? I don't want a bearing, just a "rub nub" (like the really cheap plastic laminate bits use), right?

This is the closest I can find, and I'm trying to figure out how to get a rub nub on the end without a screw sticking down.
http://www.amazon.com/Freud-40-100-15-D ... B00004T7I9" onclick="window.open(this.href);return false;

Dennis
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whitespruce
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Re: New Cocobolo Jumbo

Post by whitespruce » Wed Dec 26, 2012 9:22 pm

Dennis Leahy wrote:
whitespruce wrote:OK, here is the skinny on the back bracing.

On my last 3 guitars, I have been using a double "X" back bracing laminated out of layers of strips. The strips are 3/16" wide by 5/32" thick.

Next, I will go over it with a specially ground router bit to taper the sides of the braces.
Image
I ground this bit down from an old Craftsman bit, and cut the pilot to a shallow depth so it just rides on the bottom layer strip.

Here it is after routing:
Image
This is just the first step in shaping the cross section of the braces. It is rough at this point, but a lot of wood has been removed.

...
G
Where did you find that bit? I don't want a bearing, just a "rub nub" (like the really cheap plastic laminate bits use), right?

This is the closest I can find, and I'm trying to figure out how to get a rub nub on the end without a screw sticking down.
http://www.amazon.com/Freud-40-100-15-D ... B00004T7I9" onclick="window.open(this.href);return false;

Dennis
Dennis, If you want this one, you can have it. I don't use it any more, I just use my mini planes and a carving chisel and do it all by hand.

Let me know and I will mail it over.

G

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Re: New Cocobolo Jumbo

Post by Dennis Leahy » Thu Dec 27, 2012 12:23 am

I have been looking around, and I don't think anyone makes that bit any more. All the chamfer bits (11.5°, 15°), and solid surface bits have bearings.

I don't have any of the cute brass planes like you made (hmmmmm... Harbor Freight sells a 3-pice set of them for cheap. I wonder if those and better steel for the blade would be worth the trouble...)

I can make some angled sanding blocks, starting at 60 grit, and that would probably go pretty quickly. Let me try that first, and if it seems to be taking forever, I'll take you up on your generous offer. :~)

Thank you!

Dennis
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Re: New Cocobolo Jumbo

Post by whitespruce » Thu Dec 27, 2012 2:42 am

Dennis Leahy wrote:I have been looking around, and I don't think anyone makes that bit any more. All the chamfer bits (11.5°, 15°), and solid surface bits have bearings.

I don't have any of the cute brass planes like you made (hmmmmm... Harbor Freight sells a 3-pice set of them for cheap. I wonder if those and better steel for the blade would be worth the trouble...)

I can make some angled sanding blocks, starting at 60 grit, and that would probably go pretty quickly. Let me try that first, and if it seems to be taking forever, I'll take you up on your generous offer. :~)

Thank you!

Dennis
Dennis, I ground this bit from another shape.

Yes, do the sanding blocks, but start with something around 36 grit, 60 grit will take you all day. I use 36 grit for the first pass on radiusing fingerboards. Also, if you use this method, you can taper the brace height first and that makes the sanding go faster. With the router bit you have to leave everything full height for starters.

G

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Re: New Cocobolo Jumbo

Post by Dennis Leahy » Thu Dec 27, 2012 2:49 am

I'll go 40 grit. I don't think I can even find 36 grit, locally, other than on some belts.

What are you doing up at this time of the morning? Hey, What am I doing up? Time for some sleep here...

Dennis
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Re: New Cocobolo Jumbo

Post by Jim » Thu Dec 27, 2012 8:35 am

Dennis Leahy wrote:
I don't have any of the cute brass planes like you made (hmmmmm... Harbor Freight sells a 3-pice set of them for cheap. I wonder if those and better steel for the blade would be worth the trouble...)

Dennis
Dennis,
The Harbor Freight mini-planes don't need a better blade for brace work. I find them easy to use, even better than an expensive, hand-made mini plane I bought a few years ago.
Jim
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