Official Luthiers Forum!

Hi guys,

Just bound the back of #1, using ivoroid binding which is about 1/4" tall by .060 thick. Its nice and tight around the bottom of the ledge, and I have about 1/32" or so proud along the back edge to scrape down (for a total height of 7/32")

My question is, there is about a 6" area, around the neck block, where it sits a little proud of the sides.. not sure how much, but its more than the rest. Once I scrape this down flush, is there a guideline to how much of its thickness I can scrape away before its considered too thin? Or is it mainly an aesthetic thing - if i don't notice it, don't worry about it kinda deal?

I mention it because it is substantially prouder of the surface than the rest, but I don't *think* up to half the thickness or anything like that.

If I decide its unsightly, can I just rout it off? again, its ivoroid, and I used the duco stuff to glue it on. I can post a pic if that helps.

thanks!

Adam

_________________
"Everyone wants to BE something, but nobody wants to BECOME something" - William Cumpiano

Pretty much. As long as it sits tight in it's channel (no gaps), then you're good.

My 2 cents...

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

It'll be fine as long as there are no gaps.

The question you need to answer though is "how did it end up like this?" so that you don't do it again. Did your router bearing leave the side of the guitar when you routed that bit? Did you take a small piece of the binding and run it all the way around the channel after routing and prior to binding to test the fit? If not, then maybe that's what you need to do next time, maybe?

Good luck! Don't forget, we like pictures.

Cheers,
Dave F.

_________________
Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

Sounds like the sides are not completely flat in the area. You have to be extra picky about the sides being totally flat or things like this happen. If it were me, and for a customer, no way would it pass. If it's just a learning thing then it's up to you (well of course it's up to you regardless) if you can live with it. If you want to learn even further then yes you can rout it off and start again.

_________________
John Mayes
http://www.mayesluthier.com

All good advice and suggestions. I'll scrape it and see how it looks, but more than likely I will go ahead and rout it off and try again.. it really shouldn't take that long, and it will always bug me if I don't.

I guess if i scrape it down and its barely noticeable, i'll not worry about it, but more than likely I will (if nothing else, this will force me to check more carefully next time).

I did take a small piece of binding and check it all the way around, but now that I see "close enough" isn't, I'll have a better idea of what i am looking for next time.

Thanks all!!

i will post pics when i get into it, i am sure someone will benefit from this

_________________
"Everyone wants to BE something, but nobody wants to BECOME something" - William Cumpiano

Adam,

I would guess that this is along the back edge. If it is, the angle between the sides and the back in that area is off perpendicular more than any other part of a flat-top (non-archtop, that is), and would be more likely to have this problem due to how the depth of the cut is regulated on your binding cutting setup. If the shoe or pad that rides on the back to control depth contacts the back very close to the centerline of the bit, this problem is minimized, though it doesn't go away completely.

I check, and dress with a file as needed.

As to whether it's too thin, I vote for aesthetic. Go with what looks right.

Pat

_________________
formerly known around here as burbank
_________________

http://www.patfosterguitars.com

Hi Pat,

yeah, its along the back edge, just about a 6 inch length centered over the neck block. Without measuring, i would guess it to be perhaps 2 fingernail thicknesses proud of the surface there. The rest looks OK.

We'll see how it goes, but i am leaning towards routing off and dressing with a file as you mentioned. Guess I was mostly worried about whether the plastic would harm my router bit (by burning and sticking to it??)

adam

_________________
"Everyone wants to BE something, but nobody wants to BECOME something" - William Cumpiano

Another thought - I've had troubles with the binding ending up pretty thin once everything was scraped flush. At first it was the issues of the geometry of the back and the router not being parallel with the sides, but instead, perpendicular with the back,which doesn't work with the taper of hte back...

Now I think the issue is that I didn't sufficiently smooth and sand the sides, prior to routing the bindings. If they're not entirely flat (which can happen when bending with a pipe), if you wait until the bindings are installed to scrape them perfectly flush, you'll lose too much binding thickness when scraping them.

For me the moral of the story is, scrape them (or sand them) very flat prior to routing and installing the bindings. Thanks.

What I think may be happening is as noted above. You lost perpendicularity . What was your method of routing? In most beginners this is not an uncommon thing to happen , and why we use a binding jig . What will happen is that the binding when flushed to the back and sides will have the appearance of thinning out. In most cases to less than half of the binding thickness and it is noticeable. The top won't matter as much as the top is relatively square to the sides , but the back will not only have a decisive radius , it also has an angle that throws the geometry way off when using a square based router.
Let us know your methodology and we can go from there

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Ok.

As far as the sides being flat, I did go all the way around with a straight ruler and scraped/sanded flat as I went around. I think that its more along the lines of not being square.

I used a laminate router with a very small base, and the Stewmac binding bit with the appropriate bearing.

I am thinking now how bout this - since the height is right, I can get a 1" piece of the binding, and use the self-stick 3m 80 grit to the back of it (but leave smooth on the bottom) and just use that (instead of files) to work around the channel in that area (accounting for the thickness of the paper of course)?

_________________
"Everyone wants to BE something, but nobody wants to BECOME something" - William Cumpiano

Your sides have to be square because I've done just what your doing. I scrapped the binding to thin, it looks horrible, always buy the best you can afford and go to guitar stores and look at how the guitars are built and build yours as good.
I would, if it were me route the plastic stuff off and put wood on because wood looks soooooooooooooooooo much better, there should not be any plastic on a really nice guitar. I know Martin and other have plastic binding on theirs, but you can tell its plastic and you know when you are looking at wood! Pay attention to what you are doing, if you feel like you are getting a little bored doing something, then do something else. I do this all the time after I have been working on something for a couple of days I want to get a new perspective so I work on another part for the guitar. It helps tremendously. I've just been building nine years, not so long but I experiment a lot.
cheers

Your methodology is wrong for the back. You made the assumption that the binding bit will make your rout perfect . In reality your base is tilting and the cutter looses alignment. This then sets the channel at the upper bouts to a slight angle. This is why the binding machines were developed. Look close at the back and you will see a radius ,and then this is also at an angle. The apex of the upper bouts are where the point of where the angle displacement happens.
Take a small square say 2 inch by 2 inch you can trot this around the back and watch what happens as you turn the corner at the upper bouts ,you can see the square open at the back mating surface. This gives the appearance of thin binding when in reality you have wedged binding.
This is one of those things that are part of the learning curve. Observation is 90% of learning.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thanks for the reply - I did just that, went ahead and pulled it off and started over. I think it will look much better. I think my next guitar will use wood binding, however this is for a friend, and he wants the ivoroid.

I found actually that I can use a sharp scraper with a square corner to square and deepen the ledges in the areas it needs, and it binding fits and looks so much neater and crisper. However, I am committed to taking it back off again if I still don't like it after scraping flush... if you're gonna do it, do it right, huh?

Thanks to everyone for continuing to remind me of that.

adam

_________________
"Everyone wants to BE something, but nobody wants to BECOME something" - William Cumpiano

Update, went ahead and sprung for the parts to build a tru-channel jig, spent part of yesterday putting it together and building a carrier board, and... man what a difference that makes. so the big lesson here for me was, if its reversible, and you have any inkling whatsoever that its going to bother you if you don't do it over.. GO AHEAD AND DO IT OVER!

Thanks again for all the suggestions and help!

adam

_________________
"Everyone wants to BE something, but nobody wants to BECOME something" - William Cumpiano