The Acoustic Guitar Forum

Go Back   The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Build and Repair

Reply
 
Thread Tools
  #1  
Old 04-05-2020, 08:19 AM
Madpiper13 Madpiper13 is offline
Registered User
 
Join Date: Jan 2011
Posts: 13
Default OM Top & Back Sanding Radius

What sanding radius templates would I need for both the top and back, when building an OM?
Reply With Quote
  #2  
Old 04-05-2020, 02:28 PM
Bruce Sexauer's Avatar
Bruce Sexauer Bruce Sexauer is offline
AGF Sponsor
 
Join Date: Jan 2009
Location: Petaluma, CA, USA
Posts: 7,525
Default

I looked at this post this morning and didn’t understand it, so I’ve waited for others to say something. Looks like I’m not alone.
__________________
Bruce
http://www.sexauerluthier.com/
Reply With Quote
  #3  
Old 04-05-2020, 02:48 PM
Madpiper13 Madpiper13 is offline
Registered User
 
Join Date: Jan 2011
Posts: 13
Default

I would like to use radius discs for sanding the kerfing of both the top and back. The Stewmac instructions suggest using a sanding stick (one degree and 5 degrees). What would that translate into if I was to use a radius disc instead?
Reply With Quote
  #4  
Old 04-05-2020, 02:49 PM
redir redir is offline
Registered User
 
Join Date: Aug 2011
Location: Mountains of Virginia
Posts: 7,657
Default

My guess is that he wants to use radius dishes. I don't use them so I cannot make a suggestion but if you search online or wait for another response here, for radius dishes, then you will find a lot of info.
Reply With Quote
  #5  
Old 04-05-2020, 02:51 PM
redir redir is offline
Registered User
 
Join Date: Aug 2011
Location: Mountains of Virginia
Posts: 7,657
Default

Looks like we replied at the same time. A radius is a radius so if the stick is 5deg then so would the dish be, I would think. Most people it seems measure by foot.

Have a look at these here: http://www.bluescreekguitars.com/sho...roducts_id=202
Reply With Quote
  #6  
Old 04-05-2020, 02:55 PM
Madpiper13 Madpiper13 is offline
Registered User
 
Join Date: Jan 2011
Posts: 13
Default OM Top & Back Sanding Radius

I’m trying to decide which radii to purchase. 1 & 5 degree translate into what radius?
Reply With Quote
  #7  
Old 04-05-2020, 03:15 PM
JonWint JonWint is offline
Registered User
 
Join Date: Mar 2016
Location: 1 hr from Nazareth
Posts: 1,045
Default

Depends what you are building. What are you using for the brace radii? Making braces from scratch or preshaped? Using a kit?

StewMac kit uses 20' back and 28' top radii.

If you're making one guitar skip the sanding discs. Use the kerfed lining sanding stick with wedge.

https://www.stewmac.com/freeinfo/i-W...2.doc.1219.pdf

Last edited by JonWint; 04-05-2020 at 03:22 PM.
Reply With Quote
  #8  
Old 04-05-2020, 03:29 PM
runamuck runamuck is offline
Registered User
 
Join Date: Jul 2006
Posts: 2,276
Default

15' for the back; 28' for the top.
Reply With Quote
  #9  
Old 04-05-2020, 04:03 PM
IndianHillMike's Avatar
IndianHillMike IndianHillMike is offline
AGF Sponsor
 
Join Date: Feb 2012
Location: Montreal, QC
Posts: 546
Default

I think the confusion might lie in that you can't really translate an angle into a radius. If you think about a back brace sanded to a 15' radius, the "angle" of the curve increases as you get farther from center. So, not sure what StewMac is suggesting, but a 15' back and 25' top is what I would do.
__________________
Michael Kennedy Guitars
michaelkennedyguitars.com
facebook
instagram
Reply With Quote
  #10  
Old 04-05-2020, 04:14 PM
Madpiper13 Madpiper13 is offline
Registered User
 
Join Date: Jan 2011
Posts: 13
Default

Thanks for the replies, that was what I was after. I plan on building a couple, so I will look to pick up the appropriate sanding disks. I believe these will do a more uniform job than the stick outlined in the instructions.
Reply With Quote
  #11  
Old 04-05-2020, 04:49 PM
charles Tauber charles Tauber is offline
Registered User
 
Join Date: Feb 2011
Posts: 8,381
Default

Quote:
Originally Posted by Madpiper13 View Post
Thanks for the replies, that was what I was after. I plan on building a couple, so I will look to pick up the appropriate sanding disks. I believe these will do a more uniform job than the stick outlined in the instructions.
I haven't looked at stewmac's instructions, but for more than three decades I've used a stick with a curve (radius) in it. I've never used sanding disks.

The first thing to understand is what is the contour of your tops and backs. A sanding disk will give you a spherical shape. I use a cylindrical shape for tops. Others start out with a spherical shape and then alter it, particularly in the upper bout. Sanding disks can make sense - and be easier - if what you are making conforms to that.

My point is simply that it isn't a given that sanding disks do a more uniform or better job in all circumstances.
Reply With Quote
  #12  
Old 04-05-2020, 06:30 PM
Madpiper13 Madpiper13 is offline
Registered User
 
Join Date: Jan 2011
Posts: 13
Default

Charles,

Could you tell me more about why someone would alter the upper bout? To what benefit?
Reply With Quote
  #13  
Old 04-05-2020, 06:39 PM
charles Tauber charles Tauber is offline
Registered User
 
Join Date: Feb 2011
Posts: 8,381
Default

To achieve the desired neck angle.
Reply With Quote
Reply

  The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Build and Repair

Thread Tools





All times are GMT -6. The time now is 06:51 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ©2000 - 2022, The Acoustic Guitar Forum
vB Ad Management by =RedTyger=