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Cutting purfling channels
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=12128		 Page 1 of 1
Author:  Colby Horton [ Mon May 21, 2007 12:58 am ]
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I have been thinking about getting a binding cutting machine like LMI sells. The kind it seems like most people are using now. My question is would I have to cut the purfling channels before the binding channels. It seems like if you were to cut the binding channel first the bearing might fall off into the binding channel when cutting the purfling channel. If you do have to cut the purfling channel first is it difficult to get the width of cut set perfectly without having the binding channel already cut?
Author:  Mike Mahar [ Mon May 21, 2007 1:21 am ]
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I cut the purfling channel first for exactly the reason you state. I think some of the other rebating bits have a long shaft so you could do it either way but mine is short enough to make me nervous.

If the bearing isn't going to slip into the binding channel, it probably doesn't matter which way you do it. There is one concern with cutting the purfling channel first and that is that the ring that rides on the top of the guitar might drop into the burfling channel and make your binding channel too deep. My ring is wide enough that that is not a problem.
Author:  Pwoolson [ Mon May 21, 2007 1:46 am ]
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The bit that LMI sells (maybe others too but I don't have experience with them) has a longer shaft so the bearing sits "lower" in the cut. It allows you do to the bindings first then the purfling. But keep in mind that you are only about .125" on the side so it wouldn't take much to pop into the chanel and really screw everything up. As a safety measure I do the purfling chanels first.
Author:  Michael Dale Payne [ Mon May 21, 2007 2:43 am ]
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I have used John Halls version of the "Ribbecke" binding machine and depending on your bit and bearing set you will need to cut the purfling ledge first. This rig works great as does the Williams/Fleshman (sp) set up.

My issue with the "Ribbecke" rig is that it will not allow clearance of the neck block area when cutting some cutaways. The Williams/Fleshman does not have this issue. but the only way to get one now is to build it. but it is not hard.


Now days I use neither. instead I use this hand held system from luthierstools.com. I really like it because it uses 2 bearing. one at the lower edge and one near the cutter to maintain a good square cut. With it you can cut the binding ledge first if you wish.



I find it much more versatile than the Ribbecke rig that LMI sells
Author:  Colby Horton [ Mon May 21, 2007 5:43 am ]
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Thanks for the help guys!

Michael,
Is that hand held machine as accurate as the LMI machine? What are the down sides to that thing?
A LMI jig may not work well for me because I do build cutaways.
Author:  Michael Dale Payne [ Mon May 21, 2007 6:21 am ]
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Every bit as long as you control it properly. If you keep both bearings on the side at all time without causing the sides to deflect in; then in relationship to the sides is more accurate than the Ribbecke as the Ribbecke indexes only by one bearing on the side and holds a vertical plane based on the fixtures tower. This requires that you index in the body's sides to be true parallel to the tower to be as accurate as my hand held when proper contact is maintained.

That is what I like about the hand held with two bearing system. set the depth and width of the cut and go. Channels are parallel to the sides every time.

I works on the same principle as the one at guitar Jigs but you move the router instead of the guitar
Author:  Sylvan [ Mon May 21, 2007 8:50 am ]
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I was one of the first to actually test the LMI-Ribecke jig when Tom first
developed it. I liked it. It worked very well and I used it from about
1990-2005. The only downside was that you never felt like you were really
in control. It was scary but it worked. Then I built a Williams/Fleischmann jig
intending only to compare the differences. However, the Williams Jig worked
so much better and allowed much better control of the process. I tell my
students that you can rout the purfling and binding edges blindfolded, it is
that easy! Needless to say, it is the only binding jig I recommend to
students.
Author:  Dominic [ Mon May 21, 2007 11:55 am ]
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Hey, I recently got the Stew Mac binding jig with the cutter. I was going to make my own but time was an issue. I find it great to use. It is very simple. Its small base means you can get the guitar in to the cutter at many angles. The cutter has a sleave which moves the bearing down so it does not drop into the binding channel when you cut the purfling channel.
Dom
Author:  KenH [ Mon May 21, 2007 12:57 pm ]
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I would love to see this Williams jig in action.... anybody care to make a short movie of it?
Author:  Colby Horton [ Tue May 22, 2007 9:03 am ]
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I can't pull up a site for luthierstools.com. Can someone give me the web address where this handheld jig can be purchased?
I'm still trying to decide what method I'll go with.
Author:  Dominic [ Wed May 23, 2007 1:05 pm ]
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Hesh, looks like nice wood you used for the arms. One of the things I like about the SM jig is that you can set the stop on the carrage so if the guitar moves away from the cutter the router does not drop down too far. You only need it set to the lowest point on the side you are cutting.
One a Williams jig like yours can you do this? It would seem a good safety feature as well and prevent the cutter blades falling down on your hand if you slip(ouch).
Dom
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