Small (hopefully) Problem

[Ilikes2shred]

This is my first post, so hi! I've been exploring this website for about 4 months and have decided to make my first guitar. It will be a seven-string neck-through. Due to not being able to find much other good wood in my area, I started out building the neck with what is basically a perfectly planed oak 2 by 4, 48 inches long (flat sawn). After taking it home, I found that it had very slight bow, extremely hard to see without a light from behind it. I selected to cut the side that would make it have a back-bow. I made the side cuts, and had no noticeable changes in the bow of the wood. I made the back cut and headstock cut, and rounded the neck, and checked again for bow. Now, the neck bows back a hair over 1/8 (5/32)..... My fingerboard, frets, truss rod, and some other stuff should be coming soon, and I don't know how to correct this bow. I'm new to this (this is my first guitar), so I don't know if this is a lot of bow or not.

Here's a pic.

Do I need to correct this and if so, how?

I figure that the bow may be due to the grain being a little wavy, but it's wavy along the front, not the side..

I'm sorry if this has been answered somewhere else before, but I tried the search function and couldn't find much.

Thanks!

[wohzah]

Your bow is probably due to moisture, you probably bought the wood and it was shipped and since we are just exiciting cold winter months the moisture percentage dropped very quickly and warped the wood. The best way (I would think) to correct this is to steam the wood in a steam box httpdirections for steam box

and then clamping or weighting the wood to something flat. Also maksure that wood has already been properly dried (ie kiln dried or sufficient air drying time). If you do need to dry it still, make sure it is flat. A quick google search will find you everything you will need to know about drying wood (or a trip to the library.

[fryovanni]

How dry was the wood? How long did it aclimate in your shop prior to use? Do you monitor or control your humidity in your shop? How long ago was the neck ruff profiled?

1/8" bow in 1" thick wood makes me think either the wood was not dry, and or the wood has a very odd grain in some area.

Here are a few recent topics-

link

link

link

Rich

[MiKro]

Send it to me I'll use it in my smoker on my next cookout, It will add some nice flavor to the ribs.

Just kidding!!

It sounds like it was not dry enough, As Rich asked what were the circumstances of purchase location, humidity from that location to yours, the moisture content of the wood if known, and time to acclimate in your environment? Most wood in my shop sits at least 6 months if it is kiln dried, and most likely 1 to 2 years, unless I really know my source. Otherwise all bets are off on changes once starting the milling process or shaping. Even then some pieces still exhibit stress moves due to removal of wood through the milling process.

MK

[Ilikes2shred]

How dry was the wood? How long did it aclimate in your shop prior to use? Do you monitor or control your humidity in your shop? How long ago was the neck ruff profiled?

Well, i remember the lumberyard I bought it from said it was kiln dried, and it was nicely planed and sanded, so I assumed that it was thoroughly dried..... I don't have a shop, just a basement with two workbenches, and no way to control humidity. (this is my first guitar i'm building, and I don't want to invest too much before I know that I can actually make one.)

The neck was ruff profiled about 2-3 weeks ago, and it started to bow after that.

It sounds like it was not dry enough, As Rich asked what were the circumstances of purchase location, humidity from that location to yours, the moisture content of the wood if known, and time to acclimate in your environment?

The place I bought it from is pretty near to me (10 miles?) and seemed to have about the same climate, but I didn't measure the humidity or anything... And I kinda jumped right into it; I only let it sit for about 2 weeks.

What I'm thinking is that the neck bows because of humidity changes-- Here in Pennsylvania, the weather has went from about 20 to 60 to 30 to 60 to 30 to 70 degrees f in the time that i was building this guitar.

So, do I have to completely build a new neck (laminated this time!), or could I really just steam bend it? How long do I have to let it dry after steam bending? Or could I just glue it to my truss rod and fretboard, so the truss rod keeps it straight? (the neck can easily be bend out of that bow. I barely even have to push...)

[killemall8]

i think a major part of the problem started when you chose oak for a neck.

[Ilikes2shred]

Yes, I think so too... but at the lumberyard near me, it was the best that they had, and at that point, I didn't want to order online because I wanted to know exactly what I was getting... I guess I didn't know what I was getting anyway. Next time I plan on choosing anything but oak.

Edited April 18, 2008 by Ilikes2shred

[guitar2005]

When shaping a neck, the wood moving a little can be normal.

You should have started with a completely flat piece though. 1/8" of bow is huge for a guitar neck. Maybe its a good thing that the neck bowed so early in the process?

If it were my piece, I would chuck it and use a different piece of wood. If it bows that much during shaping, you never know how it will react under string tension and seasonal changes.

[Ilikes2shred]

If it were my piece, I would chuck it and use a different piece of wood. If it bows that much during shaping, you never know how it will react under string tension and seasonal changes.

That's what I was afraid of. Are you sure that there is no way to salvage it?

Anyway, how do I prevent this from happening again?

[fryovanni]

If it were my piece, I would chuck it and use a different piece of wood. If it bows that much during shaping, you never know how it will react under string tension and seasonal changes.

That's what I was afraid of. Are you sure that there is no way to salvage it?

Anyway, how do I prevent this from happening again?

I suspect that is more movement than you would have got from small humidity changes if the wood was well aclimated to begin with. You are either dealing with some stored tension that caused some movement(you mentioned a bit of odd grain), and or the wood was still drying, or it is possible the wood was dried too agressively and it had some case hardening(trapping core moisture, which was able to dry rapidly after a bit of surfacing. As for Oak, it has only a slightly higher tangential shrinkage rate then hard Maple and the radial is about the same. It has been used for necks with success (although personally I don't care for it as a neck wood)

So how do you prevent this.

1. choose your wood well. Straight Grain, no defects or odd grain, choose wood that has low volumetric shrinkage and most importantly wood that has low dimensional change at moisture levels between 6-14%(in service moisture contents), also choosing a wood that has closer radial to tangential shrinkage ratios helps, Quartersawn wood will generally move less with changes in moisture(this is a plus), not to say it is absolutely required. Quality neck wood is critical, body wood not so much. There are plenty of guys who have winged it or used odd grained wood for necks and fretboards. Personally, I think that is not very wise, and if it worked out ok for them it was partially dumb luck, possibly problematic down the road, and certainly building in stress that did not need to be there. Quality cuts of wood are available, you just have to look.

2. Buy your wood well dried, kiln dried is usually ok. You need to allow that wood time to aclimate to your shop. The longer the better. If you need to use wood very quickly, you should buy very well dried neck blanks from a reputable dealer, preferably located in a similar climate to yours. Buy several neck blanks worth of wood in advance and allow them to aclimate so they are ready to use when your ready for your next project.

3. Ruff carving as you did is not a bad way to go(saved you from a problem when you had done more work). The idea behind ruff carving is to allow you to make minor changes if it tweaks a little. Allow a little extra material to remain during the ruff carve step. Allow the blank a week or two to see if it moves. True it up and cut closer to final dimension.

4. If you want you can use a glue that does not introduce a lot of moisture when attaching your fretboard. This can be a plus. Titebond has worked fine for me in the past, and is not particularly problematic, but epoxy will reduce moisture introduced.

[Ilikes2shred]

Straight Grain, no defects or odd grain, choose wood that has low volumetric shrinkage and most importantly wood that has low dimensional change at moisture levels between 6-14%(in service moisture contents), also choosing a wood that has closer radial to tangential shrinkage ratios helps

Thanks for the long post. It's just what I needed.

Could anyone give me some examples of these woods that are like this ^^^^^^

or a link would be good.

btw, I just got my fretboard and some other stuff a few hours ago.

[killemall8]

well not just one species of wood is going to be good. and some wood that is normally good can have horrible grain or defects. it is specificly about how the wood is cut and dried. there can be some really good clear wood, but it can be a solid board of horrible runout. its not something you can just go, oh, quarted maple is always good and will always be suitable for necks. you have to physicly inspect the wood and know what to look for.

[fryovanni]

well not just one species of wood is going to be good. and some wood that is normally good can have horrible grain or defects. it is specificly about how the wood is cut and dried. there can be some really good clear wood, but it can be a solid board of horrible runout. its not something you can just go, oh, quarted maple is always good and will always be suitable for necks. you have to physicly inspect the wood and know what to look for.

I agree 100%.

The degree of face grain runnout is going to modify the strength of the wood, even if it appears perfectly quartered and straight grained. One up side to most of the woods we use for necks is that they exceed the strength requirement significantly, so it would take a fair bit of runout to cause a structural issue(meaning leading to failure). Of course it is great if you can select wood that has the best orientation you can. One thing I have consistently found splitting wood to detect grain orientation, is that medullary rays appear the best when a wood is split with the grain. Different woods have larger or smaller medullary rays. Hard Maple for instance has very large easy to spot rays. A piece of well quartered, straight, clear hard maple that has very strong medullary rays. Is likely going to be a fine cut. Some woods like Mahogany have interlocked grain (it actually twists and interlocks), so runnout is less of an issue.

Go download The Wood Handbook (put together by the Dept. of Agriculture)- link

It is the best book around for information on many subjects dealing with wood, and woodworking topics. Best of all it is free to download

Rich

[Ilikes2shred]

Alright. Well, I downloaded the book, which is very informative, and I went to check out some wood today. I went to a place called Rockler, and they assured me that their wood was kiln dried to 6%. Their prices were decent, so I went ahead and got enough wood for 2 guitars.

guitar 1:

5 piece Maple/mahogany/M/m/M neck

paduak/poplar body

Guitar2:

5 piece maple/walnut/m/w/m neck

paduak/poplar body

Hopefully this wont turn out like the last...

I plan to hang the oak neck on the wall as a reminder that I should pick better wood.

[Ilikes2shred]

I wasn't sure if I should start a new thread for this but...

In gluing together the neck laminates, do you glue them all at once, or just 1 at a time?