Trussrod Replacement

[stewblack]

1 hour ago, 3below said:

Some measurements every cm along the the neck and channel for the first 7 frets or so would really help establish the profile and what room is available.

doing this now:

Channel = 9.5mm deepens to nearly 10mm at 7th fret

Edited May 16, 2020 by stewblack

[3below]

Keep going with the measurements, need the neck thickness in the same way so we can get to the wood thickness under the channel.  if we get lucky a two way rod inserted at a strategic position with wood strengthening may still work.  The simpler the solution the better (as long as the solution is valid).

Edited May 16, 2020 by 3below

[stewblack]

Trying to work through the questions posted above, but am here with the bass so keep 'em coming 

[stewblack]

1cm from paint = 14.5mm

2cm = 14 and so on in cm increments 

13.5mm 

13mm

12.5mm 

12.5mm 

12.5mm

in fact 12.5mm all the way to fret 7

 

[3below]

@stewblack, thanks for the measurements, summarising as far as fret 5 (22cm approx)  if I have understood correctly:

position /cm	neck   depth/mm	channel depth/mm	wood     thickness/mm
0	14.5	9.5	5.0
1	14.0	9.5	4.5
2	13.5	9.5	4.0
3	13.0	9.5	3.5
4	12.5	9.5	3.0
5	12.5	9.5	3.0
6	12.5	9.5	3.0
7	12.5	9.5	3.0
8	12.5	9.5	3.0
9	12.5	9.5	3.0
10	12.5	10.0	2.5
11	12.5	10.0	2.5
12	12.5	10.0	2.5
13	12.5	10.0	2.5
14	12.5	10.0	2.5
15	12.5	10.0	2.5
16	12.5	10.0	2.5
17	12.5	10.0	2.5
18	12.5	10.0	2.5
19	12.5	10.0	2.5
20	12.5	10.0	2.5
21	12.5	10.0	2.5
22	12.5	10.0	2.5

My take would be that you have sufficient depth for a two way rod (9.5mm).  You will need to bring the adjuster nut as far towards the headstock as far possible - allowing for allen key insertion and truss rod cover clearance.  I would aim to get the 'bearing' end of the two way rod into the 4 ~ 4.5mm zone.  Look for a rod with a 'short' adjuster length.

The bearing point is the threaded block in the diagram.  What do my esteemed colleagues think now that we have the neck profile established?

@stewblack you have kept your beard in much better trim than mine, I am going for the ZZ top version

 

 

 

[stewblack]

Ha! Beard envy.

No @3below I think you have those columns mixed up. The neck is 14.5mm dropping to 12.5mm, the depth of the channel fairly consistent at 9. 5 the 5mm is the width of the channel. 

Otherwise the channel would be deeper than the wood in which it sits! 

Edited May 16, 2020 by stewblack

[Pea Turgh]

This thread, and all the contributors, are awesome 👍🏻

[stewblack]

Just now, Pea Turgh said:

This thread, and all the contributors, are awesome 👍🏻

Not all. I'm here too remember 

🤯

[3below]

11 minutes ago, stewblack said:

Ha! Beard envy.

No @3below I think you have those columns mixed up. The neck is 14.5mm dropping to 12.5mm, the depth of the channel fairly consistent at 9. 5 the 5mm is the width of the channel. 

Otherwise the channel would be deeper than the wood in which it sits! 

I thought I had done the same sum as you above, i.e. at start of fretboard (my 0 cm) the neck is 14.5 mm deep, channel is 9.5 mm deep giving 5 mm wood thickness under the channel.  My second row, neck thickness drops to 14 mm, channel depth 9.5 mm  giving 4.5mm wood thickness.   Is this correct?

[stewblack]

Just now, 3below said:

I thought I had done the same sum as you above, i.e. at start of fretboard (my 0 cm) the neck is 14.5 mm deep, channel is 9.5 mm deep giving 5 mm wood thickness under the channel.  My second row, neck thickness drops to 14 mm, channel depth 9.5 mm  giving 4.5mm wood thickness.   Is this correct?

Ignore me, sorry. The doctor warned me that one of the symptoms of my condition is confusion and foggy thinking. I think we both just witnessed this. 

[Jabba_the_gut]

I'm not sure if it got mentioned earlier but a typical two way truss rod is 6mm wide with a 7mm diameter nut. As the channel width is 5mm then this would need to be widened as well if a two way truss rod was to be fitted. For me, that would need some form of jig making to enable a router to cut this as it would need straight edge to use as a guide. 

[stewblack]

I understand about the jig, I have built such things when using a circular saw in a previous life. And I'm not afraid to use a router. I would make several dummy runs on scrap wood first. But I can't afford to buy one and can't imagine it getting much use hear after. 

Although this job has got me thinking about a build one day. 

[3below]

There may be a non-router way out of this.  Am going out for some time - to look at a truss rod I have in my possession.  Lockdown, brings out the simple pleasures in life 😎

 

[Jabba_the_gut]

2 minutes ago, stewblack said:

I understand about the jig, I have built such things when using a circular saw in a previous life. And I'm not afraid to use a router. I would make several dummy runs on scrap wood first. But I can't afford to buy one and can't imagine it getting much use hear after. 

Although this job has got me thinking about a build one day. 

Does this effectively push this down the route of replacing the truss rod with a like for like item? I'm not sure of another method of making a neat and accurate slot without using a router. I'd be concerned that doing it by hand could weaken the crack in the neck further.

[3below]

30 minutes ago, Jabba_the_gut said:

Does this effectively push this down the route of replacing the truss rod with a like for like item? I'm not sure of another method of making a neat and accurate slot without using a router. I'd be concerned that doing it by hand could weaken the crack in the neck further.

+1

Having just contemplated a truss rod I can see how I would (might?) do it by hand using a plough plane, jig and considerable skill (above my pay grade and needs more practice than I do on the bass).  I would also be highly concerned about 'breaking out' the skunk stripe / crack and making matters worse. 

Now got thinking hat on some more.  Hand tool method, slow but do-able (I think).  Remember you only have to remove 1 mm width most of the way.  Flat file, handle removed, non-toothed side down, slide along the channel.  Eventually the rod will fit in the middle section.  Adjuster end could be opened out with regular or round file.  Heel end of neck, open out the slot using a chisel if needed.  The heel end rather depends on the actual rod, the one I am physically looking at has a blob of weld proud of the 6mm, when I use it I will have to chisel out an inset to accommodate.

In view of the thinness / state of the skunk stripe I would probably round the ends of my file over using a stone / diamond plate so that they do not catch the wood.  Another tactic could be 3/4mm wood block, glue 80 grit (or less) sandpaper on, slide in the channel. 

 

Going back to a single action rod, I wonder if there will be (was) sufficient curvature available. @Andyjr1515 touched upon this earlier and should be able to advise.

Edited May 16, 2020 by 3below

[stewblack]

The careful use of a file and or sanding block is fine (assuming I could take evenly from either side and not deepen the channel by mistak) I have the necessary tools and patience.

[stewblack]

I think my input now is limited until the elders meet and decide between them the best course of action. I'll then get on with whatever the consensus is.

Can just I say if I follow anyone's advice and up with a broken neck I hold no one but myself in any way responsible. It's my choice to follow the advice, no gun to my head.

[songofthewind]

Bruce Johnson on Talkbass has a thread on milling out a skunk stripe on a Stingray (I think) to replace a snapped truss rod. He used a giant vintage milling machine and nerves of steel. I don’t think Stew, or indeed any of us, would manage this task.

What a great thread! Stew, I’ve got a feeling you’re going to make this happen!

[Maude]

2 hours ago, Pea Turgh said:

This thread, and all the contributors, are awesome 👍🏻

Basschat at its best.

Some threads can get heated when folks don't agree but deep down I think we're all here with a common interest and a willingness to help others if we can. 

Warm hugs all 'round. 

Now enough of that malarkey and back to manly wood carving. 

🙂

[Andyjr1515]

4 hours ago, stewblack said:

16.5mm at the paint line

slot here 9.5mm deep 

So for the elimination of doubt...are you saying that directly underneath the slot at that point there is 7mm of wood before you hit fresh air?

4 hours ago, stewblack said:

I removed nothing from the underside.

And so the original rod was also acting on this same thickness of wood.

Well, given the above, if this was my bass, and as long as I made sure the trussrod was positioned correctly at the nut end (and 'correctly' means in relation to that thicker area of the neck, which will put the rod just a touch further forward than normal), I would be keeping it simple and putting a modern two-way truss rod in. 

Anyone disagree?

[Reggaebass]

I’m following this with interest, Theres some really great advice here , @stewblack whatever you decide to do, if you need a router to do the work, I’ll post one to you  with the cutters , and return it whenever you want 👍

[3below]

19 minutes ago, Andyjr1515 said:

So for the elimination of doubt...are you saying that directly underneath the slot at that point there is 7mm of wood before you hit fresh air?

And so the original rod was also acting on this same thickness of wood.

Well, given the above, if this was my bass, and as long as I made sure the trussrod was positioned correctly at the nut end (and 'correctly' means in relation to that thicker area of the neck, which will put the rod just a touch further forward than normal), I would be keeping it simple and putting a modern two-way truss rod in. 

Anyone disagree?

This is exactly what I would do as well. In my table of results I had missed the earlier post with the at the paint line measurement.  

[stewblack]

39 minutes ago, Reggaebass said:

I’m following this with interest, Theres some really great advice here , @stewblack whatever you decide to do, if you need a router to do the work, I’ll post one to you  with the cutters , and return it whenever you want 👍

That is uncommon civil of you. Thank you very much.

 

53 minutes ago, Andyjr1515 said:

So for the elimination of doubt...are you saying that directly underneath the slot at that point there is 7mm of wood before you hit fresh air?

Let me eliminate that doubt by double checking

Double Checked 7mm.

Edited May 16, 2020 by stewblack

[Simon.]

Whether Stew goes ahead with this or not, whether it works or not, this has to go down as one of my all time favourite Basschat threads!

The sharing of ideas, the willingness to help out, the support, camaraderie and Stew's willingness to give it a go, are all just awesome. Exactly what BC has come to mean to me.

Now, I have to go as apparently I have something in my eye... 👀

 

Edited May 16, 2020 by Simon.

[stewblack]

@Simon. is spot on with his praise of the selflessness of Basschatters.

The knowledge you people share so freely must have been very hard won over a long time. To just give it away is beautiful. I would never in a million years attempt this just from watching a youtube video, but with my hand so firmly held I haven't felt the slightest apprehension at any time. A wonderful experience already no matter how things go from here.

Thank you all, and a special mention to @songofthewind who first told me to get a grip and do it, then @Maude who picked me up when i thought I couldn't do it and set me back on the path, @Reggaebass for offerring tools, and of course the Elders Of The Build, Des Meilleurs Ouvriers de Basschat , those who's sandals I am not fit to tie. Thank you all.

Edited May 16, 2020 by stewblack