Neck problem with early model 4004L bass

anonymous · Post by **anonymous** » Thu Feb 27, 2003 5:22 pm

I recently bought a 4004L, s/n 76-7092, that looked to be almost unused. It had obviously sat in it's case most of the time since being made in '93. I noticed that the neck had too much relief, so I tightened up the truss rods. I was able to straighten out the neck from the 12th fret to the nut, but there is still too much bow in the neck from the 12th fret to the 20th fret. If I crank down any further on the truss rods, I will have a backbow condition up near the nut and fret rattle will occur. As a result, the action is too high in the upper neck from about the 9th to 20th frets. There is slightly more relief on the E-string side than on the G-string side, which is no bad thing for controlling E-string rattle.

The bass is playable as is, so I am not up in arms about it yet. One thing I should note is that it came from the Denver area where the air is very dry. Almost all the screws were loose in the wood body when I got it due to wood shrinkage. One truss rod nut was completely loose. The tuning keys were shifting around, and I could turn the mounting nuts with my fingers. The volume and tone pots were loose and needed tightening. The rear cover plate screws were loose. The input jack mounting screws were loose, as were the logoplate screws. In other words, this bass got a GOOD drying out in Denver. I am going to let it rehydrate a bit in our humid Texas spring weather to see if it causes the neck to move around. Then I would be interested in taking out that excess bow in the neck down around the heel area.

I wanted a new Cheyenne or Laredo bass, but they were impossible to find and the delivery time would be in the summer, at the earliest, if I ordered one. I got a good deal on this one and can afford to mess with the neck a bit. I heard that maple responds to bending and heat very well and will tend to stay where you put it after it cools down, so I am game for trying that. I think the strings were left in full tension on this bass with the truss rod getting little or no attention as the neck shrunk down due to the dry air in Denver, leading to a permanent bow in the neck near the heel.

admin · Post by **admin** » Sun Apr 13, 2003 10:19 am

Philco: Any change in the neck of your 4004L after letting it adjust to the new climate?

philco · Post by **philco** » Mon Apr 28, 2003 7:21 pm

I was able to ease up a bit on the truss rod without increasing the bow around the 12th fret by any noticeable amount. This gave less tendency to buzz on the first several frets as it eliminated any backbow near the nut. The action is OK if you want a high action for slap bass or as a practice bass to strengthen your fingers. I hear that the only way to really strengthen your fingers is to set a practice guitar really high and play it. Your fingers will thus have it easy in a live playing situation. Finger strengthening devices do not quite work your fingers the same way as moving up and down a fretboard. I will play it this way for now and strengthen my fingers. The humidity is just now getting up to 50% at my place. It normally climbs to 60%+ later in the spring. I suspect it will take at least a year to normalize from the Denver area, because it is really dry there and the instrument probably sat there at least 8 years not being used much. The curve is a simple bend, and not an "S" bend unless you really crank down on the truss rods. I will make a jig later and use heat lamps to try to shape the neck to my exact requirements. There seems to be no twisting, which is far worse than a simple bend. The beauty of maple is that it is heat bendable and then holds its shape after cooling. That is a major reason I want an all maple bass neck unless it has synthetic reinforcements. John Entwistle said he smashed at least a dozen basses due to persistent neck problems, even one of his Buzzard graphite basses. Both my basses came from extreme climates and had the same neck problem. I think it has to do with sudden cooling of the strings before the internal truss rod can cool down and provide counter pull. The weakest part of a neck is near the heel end as the leverage is greatest there. Bending can be a problem even if carried in its case to a gig. One winter in northern Minnesota or Alaska will make a believer out of you. I would say detune in a very cold climate before ever taking your bass to a gig in a cold car. Also try to preheat the car, but you know that can take a half hour or more of idling and really wastes gas. A Canadian must know these things as well as I do.

admin · Post by **admin** » Thu May 01, 2003 10:55 am

Philco: Ah yes, the hidden costs of keeping your guitar and yourself comfortable throughout a relentless winter. Your are quite right, the temperature extremes are considerable and cause significant changes to the neck and the finish unless watched very carefully.

A -40C temperature and a strong wind lower the instrument's temperature and change its climate within the case drastically, only to see a rapid rise in temperature and humidity when it comes out of the case at the gig. I have seen pristine finishes become crackled within an hour.

Glad to hear things are starting to look somewhat more postitive with regard to the neck.

tbass66 · Post by **tbass66** » Sat May 10, 2003 3:48 am

I have a 3001 bass that has to much bow in the neck..the rod nuts were bent back into the wood of the neck..got the rods out and they look like this ~ so i got the rods out of another 3001 i own and put a bend in them like this ( so i will see how that works..was wondering how this heat treatment works on a neck? how do i go about doing this? any links online that explain this method? i would really like to get this bass playing well because its a nice sounding bass and looks sharp also with its red finish.

johnhall · Post by **johnhall** » Sat May 10, 2003 7:44 am

If the ends of the rods were bent over near the base of the threads, it's a sure sign that someone tried to adjust them with something other than a nutdriver, i.e. a socket set. It also means they didn't follow the published procedure of pushing the neck to where you want it and only then snugging up the nuts to hold it in place. Just tightening the rods like crazy first bends the rods over and then pops the fingerboard off.

Curving the rods before insertion is a perfectly valid procedure to assist the overall pressure to straighten the neck.

tbass66 · Post by **tbass66** » Sun May 11, 2003 4:18 am

Thanks John, i'm going to give it a go today..i'll let everyone know the results.

admin · Post by **admin** » Sun May 11, 2003 10:26 am

It would seem that the nutdriver and socket set tools are the bane of the truss rod. I hate using any tools that have high mechanical advantage ratings as it is so easy to go too far. Hand tightening seems to work best in making most guitar adjustments.

philco · Post by **philco** » Sun May 11, 2003 6:24 pm

I read where one guy bends the neck in a jig. Then he uses heat lamps to slowly heat up the wood. Not so much that it ruins the finish. Maple is bent to shape in other industries by steam heat as it is bent in a jig. You can apply more bend after an initial bend is applied. Works best when the wood is still green. Since a neck is seasoned and finished, your bending angle is reduced, but that's OK. You're just getting the neck back to straight, or "unbending" it. You use heat lamps to apply the heat, use a thermometer to monitor the heat (you don't need more than steam temperature), and let it set overnight to heat the wood all the way through (wood is a good insulator and heats up slowly). You let it cool down for a day then remove the jig. If you need more straigntening, just do it again. Don't get in a hurry and overdo anything. You'll have to make your own jig out of wood and clamps. Don't remember where I read this, but I did check out the part about maple being excellent for shaping with steam heat.

I'm letting my neck rehydrate after 9 years in Denver. The wood had shrank so much that everything was loose when I received it. I checked the tuning after setting without playing for a week, and it had climbed a bit, which means the neck is rehydrating. It seems to be helping some. It could be that the fretboard shrank more than the neck and pulled the bend into the neck. It showed no damage from having the truss rod overtightened. In fact, one truss rod had a loose and rattling nut. The proplem was probably caused by constant string tension as the neck shrank and the truss rods loosened. The bass showed evidence of almost never being played. The finish is almost new in appearance. Absolutely no fret wear.

After one year, the neck should be settled down from its move from Denver. Would somebody in a damp climate like to give it a home for a year to help it rehydrate the wood?

Just kidding.

tbass66 · Post by **tbass66** » Thu May 15, 2003 1:27 am

Thanks for the info Philip, i reinstalled the truss rods following the method mentioned on this forum but still have to much bow in the neck for my taste so i might try reinstalling them one more time. If this fails the heat treatment will be my next move.