Les Paul carved top question

pinefd

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I’m disappointed to not be able to see the pics... :(

Sorry about that Daniel! I just changed the permission level on those photos, so hopefully they show up now. If not, I'll try it again.


Frank
 

pinefd

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Can I also assume from the pics that the recurve is almost non existent under the pickguard?

No, you can assume that what's under the pickguard is pretty much a mirror image of the other side. And on the other side, there is most definitely a recurve.


Frank
 

pinefd

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Sorry I left my writing open to misinterpretation:
I meant to say that I build with the edges flat, and on completion it looks like its got a 'dip' below the level of the binding edge due to the reflections. I did not mean to state any rules regarding real gibsons.
The terminology that seems to get confused is what recurve refers to- yes there is always a concave between the slope and the binding, the question is, does this recurve dip below the level of the binding, and if so, by how much?
In replicas, some exaggerate the concave if it is done with a smaller radius at the bottom of the slope, and in another way it is exaggerated by going down below the bindings level, or both in some cases.
In the photos above the rulers demonstrate a concave, but they are not held level with the back of the guitar or square to the sides to show the level of the bottom of the curve in relation to the binding.

Ok, fair point and questions. Here are some other photos I took, using my '53/'57 conversion (with original top finish) as the example...note that I did use a ruler against the side of the guitar, and another at a 90 degree angle to the side of the guitar, to illustrate the point:

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I hope these answer your questions, and eliminate any doubt that there's actually a dip to the recurve!


Frank
 

cmjohnson

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At some point in time, as a labor saving device, Gibson brought this atrocity into their factory, called a "slack belt sander", which was made for sanding doors flat in a hurry. Gibson has had an employee using this monstrosity to quickly sand out the machining marks left after top profiling. Unfortunately this machine, and the employee(s) running it, have often been responsible for taking a nice LP body with a nice recurve, right off the profiling machine, and erasing most of the recurve in the process of sanding it out. If I ran Gibson the first thing I'd do is order that machine cut into brick sized chunks with an oxygen lance and thrown in the dumpster with glee. It's the destroyer of contours.

I've never bothered with templates. I can see what I want to achieve, and I can power carve and sand my way right to it. Chainsaw disk on angle grinder, 60 grit sanding disk on angle grinder, random orbital sander with grits from 80 to 400, that's what I use. The edge of the ROS allows me to make the recurve as narrow or tight, or deep or shallow, as I want to.

I've done it often enough that I'm able to do a full top carve in about two hours. I suspect that's very fast for non-cnc top carves, generally speaking.

Fear? Never crossed my mind. Just sneak up on your desired carve, going to finer and finer grits as you get close to the end. It's hard to make a major mistake with 400 grit sandpaper.
 

paulmarr

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CMJ - how do you use the angle grinder with flap disc without burning the s**t out of the maple? I started out using this and quickly stopped when i was making a brown mess on the top that was not easy to sand away!
 

ARandall

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At some point in time, as a labor saving device, Gibson brought this atrocity into their factory, called a "slack belt sander", which was made for sanding doors flat in a hurry. Gibson has had an employee using this monstrosity to quickly sand out the machining marks left after top profiling. Unfortunately this machine, and the employee(s) running it, have often been responsible for taking a nice LP body with a nice recurve, right off the profiling machine, and erasing most of the recurve in the process of sanding it out.
To be fair, neither the machine nor its users are really at fault.....the cost cutting since the LP was reintroduced are more responsible for the carve changing its profile. Its only just recently that some of the more complex top carves have returned to the USA line of guitars.
 

nuance97

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And I should add, that the above photos probably accentuate the recurve maybe a little more than it actually is. Here's a top carve done using the above guitar as the template (although the edges aren't finished yet):

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Frank
Did this top ever become a guitar?
 

GreaseBox

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We should discuss the "flatness" of the pickup plane on a '59 now..... :)

j/k

Very good info here!!
 

cmjohnson

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FYI, I don't use a flap sanding disc, I use (1) chainsaw disc (very fast stock removal, don't even TRY to get close to your intended carve shape) , followed by a 60 grit 4" sanding DISC (and a fresh, brand new one made by Norton Abrasives, to be specific) for secondary roughing, and if it burns the wood I'm pushing too hard or moving too slow or it's worn out and time for a new disc) and not a flap sander, and (3) I use a random orbital sander starting with 80 grit.

If the disc does burn the wood a bit, it doesn't matter because trust me, the 80 grit disc on the ROS will take the burn off pretty fast.

Using these tools I can do a top carve in just two hours. For reference, the top carving cycle time for PRS's CNC top carving mills is an hour and it then has to go to hand sanding. So ultimately I can carve a top in (roughly) the same time it takes the PRS factory to do it. But speed is not my goal. Making a nice carved top without wearing out my hands and wrists is my goal. Power tools help a lot!
 

Skyjerk

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This is what I use...

Its called a "holey galahad" and I attach it to my angle grinder. the teeth are carbide and it chews through wood like butter and leaves a surprisingly smooth surface and it definitely doesnt burn anything.

This one is fairly flat with a little curve to it, and I have another that has a much more pronounced radius.

I cut straight in from the edges with this and I dont do any recurve with this tool. This just gets me in the ballpark, then I finish with a random orbital sander with various grits. any recurve happens as a result of the sanding, but I definitely dont try to create it. If you put a recurve in on purpose, then by the time you are finished sanding it will be too pronounced.

sesh12-24mag23.jpg
 

nuance97

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No, not yet, unfortunately. I just haven't had the time to do it. Maybe one of these years, though!
I get it...time is a hard thing to come by sadly
 

pshupe

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For reference, the top carving cycle time for PRS's CNC top carving mills is an hour and it then has to go to hand sanding. So ultimately I can carve a top in (roughly) the same time it takes the PRS factory to do it.

Is this correct? I can do a top carve on my machine in less than an hour and it would take me about 5 mins with 120 grit ROS to take out the machining marks. I've seen large production CNC machines that do 4 tops all at once. I would have thought PRS would have to be faster that what I can do on my machine?

Just found a link from a factory tour that showed a top carve CNC at PRS and it shows about 2 mins of a top carve that probably did at least 20%.

Cheers Peter.
 
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cmjohnson

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Well, I don't doubt that over time they've acquired faster machines to get the job done in less time. I do know that at one time a full body and top carve was about an hour's work.
 

pshupe

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Actually I did see a video that the guy said it took in total 1 hr to do the body. That was a full body front and back with all routes, holes, and top carve. He might have even included the finish sanding. I'm sure the CNC a company like that would use would probably be at least an order of magnitude of 10 - 20x the cost of mine. Does your 2hr carve estimate include all the other routes and holes or just top carve? It's not really comparing apples to apples though as your method is much more of a hand approach using a certain amount of artistic license. CNC is just a machine that follows numeric parameters.

Cheers Peter.
 

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