Official Luthiers Forum!
http://www-.luthiersforum.com/forum/

Perfling channel accident.. Section too wide.
http://www-.luthiersforum.com/forum/viewtopic.php?f=10101&t=45848		 Page 1 of 2
Author:  G.Cummins [ Sat Jun 06, 2015 9:24 am ]
Post subject:  Perfling channel accident.. Section too wide.
Hi All.

Second time using the Stew-Mac true channel binding jig .Every thing was going great until the little screw that holds the bearing to the cutter decides to fall out taking the bearing with it and now I'm left with this....
Attachment:
DSCF5039.JPG

Attachment:
DSCF5040.JPG


I know I snugged the screw up tight, cant for the life of me understand how it happened.

It is below the horn of the cutaway. My first though was to change the perfling design to fit this width but the gap is 8mm from the inside of the side so goes beyond the depth of the kerfing, also the bearings in the kit dont allow that sort of width of cut.

Any one out there have a similar experience?

I would prefer not to trash the top if possible. If anyone has some creative design advice for me to workaround this it would be greatly received.

I now know why Robbie O'Brien in his video says about high pucker factor when routing channels.

Cheers.
Glenn.
Author:  DennisK [ Sat Jun 06, 2015 10:03 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Ouch! That's quite a wound. At least it's thick enough that the router didn't go all the way through.

If the offcut from the cutaway area is long enough, you should be able to get a piece with perfectly matching grain and splice it in like this:
Attachment:
DSCF5039.JPG


Score with a knife along the grain, and then rout away the rest of it at the same depth. Lucky the router didn't go past that dark grain line, since it should help to conceal the seam.

The little bit of diagonal line just above the waist may be tricky though. Could score and then rout, freehand rout (but be careful if using a small bit, since the difference in hardness between light and dark grain lines makes the router jumpy), or carefully chisel by hand.
Author:  G.Cummins [ Sat Jun 06, 2015 10:46 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Thank you for the advice Dennis, I would never have thought of that.

Unfortunately the offcut I have is not long enough to fill the area. Arrgh!
Author:  Ken Lewis [ Sat Jun 06, 2015 10:52 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
What Dennis suggests exactly, then reroute for a wider purfling scheme to cover the endgrain.
With good planning for regluing and clamping, the segment can be redone for an invisable fix.
If it were mine though I would retop but repair seems a viable option.

No offcuts long enough, even from the waist area?
Author:  G.Cummins [ Sat Jun 06, 2015 11:30 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Hi Ken. I have an offcut that is long enough but the grain is wider and it wouldn't match. If I couldn't make it as invisible as possible I would retop as suggested. Its annoying as the piece that matches the grain perfectly is about half an inch to short.

Cheers.
Author:  Jim Watts [ Sat Jun 06, 2015 2:55 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
I bet if you take an off cut out of the waist area it'd work pretty well as there are no real continuous grain lines as they're broken up by the waist. I think in this situation if you had a good color match it'd be hard to tell.
I once had a bearing fall off too, it really sucks.
Good luck.
Author:  Haans [ Sat Jun 06, 2015 4:45 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Gee, that's tough, Glenn. Do you have any other tops, or did you just order one top? Do you have any bracewood? Lot's of times you might find something suitable on bracewood.
I do use purfling that is extra wide and regularily exceed 8mm, but it would not match your style of rosette. Since you have a double BWBWB, you might consider using it on the rim, and using the short piece of spruce you have. You could put say 1/8" or 3/16" crossgrain Wenge or what ever that is between the BWBWB strips and try to see if you can make it work that way. You could also try wide binding. I usually use .090" instead of the more popular .060". You may just be able to squeak by. Make up a couple of short sections or purflings and binding and see if you can make it work.
Please Keep us posted and do try that before trashing a top...That's a lot of work tossed out the door.
When doing routing like that I always use a pliers and crank adjusting screws tight.
Author:  Terence Kennedy [ Sat Jun 06, 2015 6:05 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
I had that happen last year. Upper bout bass side. The phone rang as I was changing bearings for the purfling and I forgot to tighten the screw.

It was smaller than yours but I reshaped it by making a router guide for the shape I wanted the defect to be and taped it to the top and routed the edges of the defect to a regular shape and installed an off cut from the same area cut to match.

I like the idea of a straight edge along a grain line.

I did a burst with a pretty dark edge and it was pretty much invisible although at just the right light angle you could just see the margin. I was the only one that could see it.

Image
Author:  G.Cummins [ Sun Jun 07, 2015 4:54 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
I'll give the repair a try and report back. Lovely looking burst by the way Terence.

Thank you all for the excellent advice.

Glenn.
Author:  Clay S. [ Sun Jun 07, 2015 6:52 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
"Score with a knife along the grain, and then rout away the rest of it at the same depth"

This same thought had occurred to me, but upon reflection, It might be easier to remove that section entirely and replace it with a full depth piece.
Another way repair it would be to continue the "mistake" around to the neck area and add a perfle that matches the design of the rosette. It would be a little unusual looking, but so many of the tops these days are, with scoops, and bevels, and what not.
Author:  Goat Rock Ukulele [ Mon Jun 08, 2015 12:08 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Make a nice looking wood let in pick guard from some nice contrasting wood and cover that mess and then some.
Author:  G.Cummins [ Mon Jun 08, 2015 3:32 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Well this is what I ended up with. It was the best scrap piece match that was big enough (only had this one Adirondack top).

Attachment:
DSCF5050.JPG

Attachment:
DSCF5053.JPG


Overall I'm happy with the way it turned out. It obviously doesn't match the opposite side but I think with the break in symmetry with the cutaway it is somehow better than I thought. Now I've got to decide whether or not to keep it. The guitar is not a commission but I would like to start selling what I make even at cost just to keep the hobby going.

Thanks once again for all the advice I never would have thought I could do it.

Cheers.
Glenn.
Author:  Clay S. [ Mon Jun 08, 2015 3:36 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Looks good!
Author:  SteveSmith [ Mon Jun 08, 2015 3:53 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
That looks good. Nice work.
Author:  Alex Kleon [ Mon Jun 08, 2015 3:56 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Thats a nice fix, Glenn. It isn't finished, and it already has some history!

Alex
Author:  Ken Lewis [ Mon Jun 08, 2015 4:04 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Nice save, even though we know the grain is a little different the eye isn't drawn in so to speak.
Having the lines in the right place is important. After finish it wont even be noticable to another builder. Glad it worked out.

Ken
Author:  Glen H [ Mon Jun 08, 2015 7:23 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Incredible save there! If it really bugs you, burst it.
Author:  Terence Kennedy [ Mon Jun 08, 2015 7:44 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Nice job!!
Author:  Doug Balzer [ Mon Jun 08, 2015 8:02 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Nice work. If I didn't know you had fixed it I doubt I would ever notice.
Author:  Mike OMelia [ Mon Jun 08, 2015 9:02 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Wow. Good save. I will admit when I first saw the accident, my heart sank for you. But u sure did recover!!!!!
Author:  Bobc [ Tue Jun 09, 2015 5:57 pm ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Great job. It looks terrific. No burst necessary.
Author:  G.Cummins [ Wed Jun 10, 2015 7:04 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Thanks for all the encouragement and kind words.
Author:  Haans [ Wed Jun 10, 2015 10:54 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Good save!
Author:  ScooberJake [ Wed Jun 10, 2015 11:44 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
Looks great! To document this fix for the future, can you elaborate a little on what you ended up going with? Is the patch full depth?
Author:  G.Cummins [ Thu Jun 11, 2015 7:09 am ]
Post subject:  Re: Perfling channel accident.. Section too wide.
I did what Dennis advised.

Scored with a marking knife along the grain line that would remove the accident but no more, also the grain line I chose terminated on a part I knew would be covered by the perfling channel. Then routed to the depth of the perfling line which was just over 1mm up to the scored line, as I was routing freehand I left a small gap and finished off with a chisel. I headed Dennis' warning about the different hardness with the grain lines so used the biggest router bit I could in the Dremel.

Cut the patch from an offcut trying best to keep the dark grain line on the edge to be glued. Then fettled the join until it matched with no gaps. This took the most time as the scored line need some work to make it straight. I used a chisel ran on its side like a scraper to straighten out any variances. We're only talking very small variances but they were enough to keep the join apart. I treated it as when joining tops with the aim of no visible seem line.

Big thanks to Dennis for the idea/advice.
Page 1 of 2 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/