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Weird compound radius on a larrivee
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=51209		 Page 1 of 1
Author:  Pmaj7 [ Fri Nov 09, 2018 2:13 pm ]
Post subject:  Weird compound radius on a larrivee
I was doing a level and setup on a twenty-year-old larrivee and measured the radius at about 16" to the 3rd 20" to the 12th and then nearly flat to the sound hole. I thought for sure it had had a refret and somebody sanded the board beforehand, but the customer told me he bought it new.

All I could find on the internet was larrivee uses a 16-20" radius. I've seen one of their old machines, and it does not look like there is much room for adjustment.

New username, same ole Pat Macaluso!
Author:  meddlingfool [ Fri Nov 09, 2018 4:37 pm ]
Post subject:  Re: Weird compound radius on a larrivee
The tongue of the FB was usually untouched on the profiler.

The goal was to have a little horseshoe pattern left of unsanded wood. The railer would hit the edges of the board all down the length on each side, but due to the curved radius, the centre of the board would be untouched. Then feather the transition with some 180 on a cork block. So yeah, to have the area right next to the soundhole be flat is totally normal.
Author:  Pmaj7 [ Fri Nov 09, 2018 6:41 pm ]
Post subject:  Re: Weird compound radius on a larrivee
Well that explains it! So it's actually a 16"-flat. With that process, I assum they were hammering the frets in? Anyway, I was able to get the action lower than normal on that one.

New username, same ole Pat Macaluso!
Author:  meddlingfool [ Fri Nov 09, 2018 8:15 pm ]
Post subject:  Re: Weird compound radius on a larrivee
the compound radius goes all the way to the body join, then it turns to fallaway. Yep, hammered frets.
Author:  meddlingfool [ Fri Nov 09, 2018 8:16 pm ]
Post subject:  Re: Weird compound radius on a larrivee
If I remember, I'll post a pic next time I'm at that step as I use one of their old machines...
Author:  Michaeldc [ Fri Nov 09, 2018 8:42 pm ]
Post subject:  Re: Weird compound radius on a larrivee
meddlingfool wrote:
If I remember, I'll post a pic next time I'm at that step as I use one of their old machines...


Pretty sweet having the authority on the forum!

Thanks!
Author:  meddlingfool [ Sat Nov 10, 2018 12:09 am ]
Post subject:  Re: Weird compound radius on a larrivee
It was 18 years in the trenches of real life application, I value it more now than I did at some points...
Author:  Pmaj7 [ Thu Nov 15, 2018 1:59 pm ]
Post subject:  Re: Weird compound radius on a larrivee
meddlingfool wrote:
It was 18 years in the trenches of real life application, I value it more now than I did at some points...
Ed, what action did you send them out with?

New username, same ole Pat Macaluso!
Author:  Bryan Bear [ Thu Nov 15, 2018 2:12 pm ]
Post subject:  Re: Weird compound radius on a larrivee
meddlingfool wrote:
the compound radius goes all the way to the body join, then it turns to fallaway. Yep, hammered frets.


Interesting, I plane in my compound radius then grind in the fallaway on the fret tops when leveling. I'm mildly annoyed at the extra time to take so much off those frets. It never occurred to me that I could plane in the fallaway. I'm gong to try to do that. I'm not 100 percent sure I can get consistent shavings with the heel of the plane riding on a slightly elevated surface.
Author:  meddlingfool [ Thu Nov 15, 2018 4:22 pm ]
Post subject:  Re: Weird compound radius on a larrivee
.090 bass, .070 treble, with as little relief as you can get away with. This seems to be a good generic beginning setup that pleases most people out of the gate.
Author:  meddlingfool [ Thu Nov 15, 2018 4:23 pm ]
Post subject:  Re: Weird compound radius on a larrivee
I'm not 100 percent sure I can get consistent shavings with the heel of the plane riding on a slightly elevated surface.

Hard block + 100 grit...
Author:  meddlingfool [ Tue Nov 27, 2018 5:58 pm ]
Post subject:  Re: Weird compound radius on a larrivee
Here’s the machine...Image
Image
Machine has a negative ~16-20” compound radius which gets transferred as a positive to the FB

Neck is attached with the flat, untouched FB. Make witness lines...
Image

Place on machine...Image

Image
Image
Check and course correct as you go...

Image
Image
Feather the edges of the last little u-shaped area and Roberto is your Uncle.

This can also sort out any anomalies in shape at the body join and deviations in the joint between the fb and neck. I use a 2 way rod and snug it backwards before profiling.

Joyous results.

Image
Image

The machine most definitely requires a ‘knack’, without which a great deal of sadness can happen real quick...:)

Not that I’d know!


Sent from my iPhone using Tapatalk
Author:  Pmaj7 [ Wed Nov 28, 2018 12:15 am ]
Post subject:  Re: Weird compound radius on a larrivee
Thar she sits! Thanks for sharing Ed. Do you sand any Fall Away in before or after? Or just go totally straight?

New username, same ole Pat Macaluso!
Author:  meddlingfool [ Wed Nov 28, 2018 12:41 am ]
Post subject:  Re: Weird compound radius on a larrivee
The third picture from bottom with the u shape shows the fallaway, where the straight plane of the machine template doesn't actually touch the FB.

I guess technically the fallaway is built into my geometry.
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