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Necks
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10102&t=14468		 Page 1 of 1
Author:  Monty [ Sat Nov 10, 2007 1:51 pm ]
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When carving a new neck for a guitar, does the wood swell?


 


Thanks for any help.
Author:  joelThompson [ Sat Nov 10, 2007 2:21 pm ]
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Swell ?

In what way, get bigger?

wood being wood it does move and of course when you string up, a neck
that you carved streight will bend upwards.

This is why we have truss rods (one of the reasons anyway).

But if you mean swell as get bigger i have never noticed but as you are
taking wood off it shouldent realy matter.

Joel.
Author:  Monty [ Sat Nov 10, 2007 3:01 pm ]
Post subject: 
Thanks for that, sorry, i meant to add bleed, the question was does it swell or bleed. When you take the wood off, sometimes wood can bleed, or cause small swellings or lumps. I know this can be true of some unseasoned woods, but what about seasoned woods. is this possible if the wood has retained some sap.
Author:  TommyC [ Sat Nov 10, 2007 3:49 pm ]
Post subject: 
I don't think that most neck woods have sap pockets if that is what you
mean.
Author:  Rick Turner [ Sat Nov 10, 2007 3:51 pm ]
Post subject: 
I am a strong believer in carving necks close to final size before gluing on the fingerboard with a non-water based glue.

If you're carving wood that is going through noticeable changes or is bleeding sap or anything like that, you're working with the wrong wood.   For necks you need the most stable wood you can get and/or age yourself.
Author:  Monty [ Sat Nov 10, 2007 8:21 pm ]
Post subject: 

OK i am just asking these questions as i am an amateur. I have heard various things said from other amateurs who claim to know a thing or 2 about building guitars, so i am just trying to clarify a few things on neck building. Ok final question, What happends to a neck, after the back has been freshly carved?


 


Thanks for all your help guys, i have put a few kits together and now i want to move on a step, and learn more about building a guitar, this site i have been reading for some time, and has been most helpful in the past with tips. You guys are the best. Thankyou.
Author:  bob J [ Sun Nov 11, 2007 12:06 am ]
Post subject: 
Sorry Monty,
I son't understand the meaning of your last question.
Author:  bob J [ Sun Nov 11, 2007 12:09 am ]
Post subject: 
PS less esperienced builders (like me) have the same trouble. It takes some time to learn the correct luthier veranacular-that greatly aids communication-comes with time
Author:  Mattia Valente [ Sun Nov 11, 2007 3:41 am ]
Post subject: 
Since I saw Rick mention the pre-shaping, I've started making necks by pre-carving, then re-levelling, then gluing the fretboard. I was surprised by how much movement there was in even very well cured (quartered, drying cut close to size for 5 years at least) mahogany. OK, so it was less than a mm across the length of the fingerboard gluing surface, but that's something that's corrected quickly and easily in mahogany, less so on an ebony board.

I still finish-carve the neck after the board's on, of course, and level before fretting, but it's minimized what needed to be done for the last three guitar necks.
Author:  Parser [ Sun Nov 11, 2007 3:51 am ]
Post subject: 
Yep, necks move after hogging them out. As for water based glues - you can change the moisture content of the wood by about 1% by simply wiping water over it (as you would to make the grain pop). Some woods such as mahogany are very stable and others will want to move around more.

I think that the wood moves after cutting due to a couple of different causes. One is that the wood in the center may be wetter than the wood outside...and exposing this core will cause some additional drying and thus some movement. The other cause is probably due to stress release...grain is very rarely perfectly straight and by cutting out certain pieces of wood you are destabilizing the part.

Even so, if you have the wood where it is experiencing temperature and/or humidity changes then it will move around due to that as well.

As has already been said...it is pretty smart to re-level your fingerboard glue up surface before gluing it on. It also probably doesn't hurt to sand the neck after it has been built.

Author:  Alan Carruth [ Sun Nov 11, 2007 2:34 pm ]
Post subject: 
There is built-in stress even in very straight grained and well quartered wood. Some pieces have more than others, and it does seem to be slowly releived over time as the wood goes through moisture cycling. In extreme cases the built in stress at the base of large hardwood tress can be sufficient to crush the cell walls on a microscopic level, according to one study I have. This stress manifests itself in a number of ways, and movement as the wood is carved or sawn is one.
Author:  Rick Turner [ Sun Nov 11, 2007 3:22 pm ]
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This is one of the reasons to resaw billets of wood as close to working dimensions as soon as possible. At one point I had some large...8" thick by about 12" wide billets of walnut on hand for a good six years before I cut them.   It was wood that just fell into my lap, and I didn't have my resaw yet.   When I finally cut into them, the center was nearly as wet as freshly cut logs.

This is also a great argument for laminating necks out of stress relieved thinner stock. For acoustic necks we now generally laminate with two pieces of 5/4 flip grain matched with some build-up of center laminates.   

I am a great believer in not simply keeping wood at one humidity level.   I think that if you allow wood to cycle up and down for a while, the changes and stresses work themselves out.   Then bring the wood in under climate control for several months before building something with it.
Author:  Rick Turner [ Sun Nov 11, 2007 3:28 pm ]
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Oh, one more tale...

Dave Wendler told me that when he worked for Peavey doing wood purchasing, the bean counters gave him all kinds of grief for wanting to purchase maple for necks and keep it in inventory for six months.   Said bean counters had all read up on JIT...Just In Time...inventory control whereby you don't even put the parts that come in the door on the shelf...they come in and get used.   That was a highly orchestrated thing in the Japanese ship yards in the 1950s and '60s...   Dave finally convinced management that they were losing more money in warranty work than they were gaining in fast inventory turns.   

The point is that as you keep wood in your shop, it should become more and more valuable as it becomes more stable.   Sure there's a point of diminishing returns, but the maximum value point is probably at least six months and perhaps several (many?) years down the pike. I think that good wood should probably increase in value by a good 10% a year for at least 10 years in our business.   So don't under-price any nice stuff you've had for a while...
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