What to do about a truss rod that is too long?

[Wasted4440]

I recently bought a 4mm allen double action trussrod, and mistook the 24" that the trussrod actually is for 22". When the allen nut is flush with the heel of the neck, the opposite end block hangs out about a 1/2" over the nut position:

Here it is with the fretboard positioned over it. I plan on making the end of the fretboard taper into the flat, Fender stlye headstock.

I was wondering, would it make sense to cut the brass block so that it ends just after the nut (say 1/16" over), or should I look to make a recess in the end of the neck cavity (hidden under the top of the body) in which the allen nut can recess into. Here's a picture of how much the allen rod hangs out when the opposite end of the trussrod ends about a 1/4" shy of the nut. Thanks!

 

[Hopkins]

Honestly, just save that rod for a different project and get you a different rod that isn't too long. I prefer the rods that Bestbassgear.com and Grizzly sells over those Stewmac rods.

 

[Gilmourisgod]

+1 on the Bestbassgear trussrod, I picked it over the Stewmac because it's shallower and requires a standard 1/4" slot, I think Stewmac oversized the width just to sell you another router bit. Unless it's still possible to extend your neck to 24 frets, I think you are out of luck. The BBG double action rods are cheaper and work just as well.

 

[Gilmourisgod]

One other thought:
Would adding a 1/8" wood cover strip and routing the slot deeper get you enough clearance? Some luthiers do that as standard, though I don't see the advantage.

 

[Smilodon]

You could cut the TR to the correct size, but unless you already have equipment to cut threads it's probably easier and cheaper to just buy a new one with the correct length.

 

[Wasted4440]

Honestly, just save that rod for a different project and get you a different rod that isn't too long. I prefer the rods that Bestbassgear.com and Grizzly sells over those Stewmac rods.

Too bad I was so narrow sighted in buying some of my parts. Since the distance from my nut to the heel of my neck is 23.32" according to my drawing, I was wondering if you know the exact length of the Grizzly trussrods. Grizzly's website says 22 7/8", while Amazon says 23 1/4". 3/8" isn't too much, but I'm a little hesitant of locating one of the end blocks underneath the nut. Thanks for your reply!

 

[Wasted4440]

+1 on the Bestbassgear trussrod, I picked it over the Stewmac because it's shallower and requires a standard 1/4" slot, I think Stewmac oversized the width just to sell you another router bit. Unless it's still possible to extend your neck to 24 frets, I think you are out of luck. The BBG double action rods are cheaper and work just as well.

Looks like you're right. After looking at Bestbassgear and Grizzly rods on Amazon (which I should have done earlier), it seems like 1/4" is a standard size, as well as the rods being a bit shorter. I have a separate question I'd like your opinion on: Since I have to buy a 1/4" bit for routing these trussrods, is it possible to use the shank of the bit sort of as a "bearing" when following templates? I ask because when top-routing my pickups, I see that the semi-circle bits where the height adjustments screws go are slightly skinnier than my 1/2" diameter bearing bit can fit (0.426" according to Seymour Duncan). Would it make more sense to try and router that out, or to use a drill bit to make the correct diameter hole, then rout the pickup cavity? Thanks!

 

[Hopkins]

I believe Grizzly sells a 20" rod

 

[Gilmourisgod]

I wouldn't try to use the shaft of the bit as a bearing, it will heat up and burn the wood at best and break at worst. You should really use a 1/4" spiral upcut bit for the trussrod channel because it's captive on three sides, so the wood chips have no place to go. The spiral bits pull the waste up and out.

 

[Hopkins]

I wouldn't try to use the shaft of the bit as a bearing, it will heat up and burn the wood at best and break at worst. You should really use a 1/4" spiral upcut bit for the trussrod channel because it's captive on three sides, so the wood chips have no place to go. The spiral bits pull the waste up and out.

Ive cut more than a few truss rod slots with a straight bit with no issues at all. Spiral bits are nice, but they aren't necessary and they are expensive

 

[Gilmourisgod]

To each there own, I like spiral, the shearing action gives a cleaner cut.

 

[Hopkins]

To each there own, I like spiral, the shearing action gives a cleaner cut.

Yeah, I like spiral bits better myself, they cut better with less risk of tear out. But your post read as though they are a necessity for cutting a truss rod slot.

 

[mapleglo]

I've used the standard straight 1/4" bit to cut truss rod slots on a few occasions with good results. I suppose I should buy a spiral bit, but router bits can be expensive, and I've only built a couple of necks, so it's not a priority for me.

 

[PDX Mathias]

I'm not certain that it would make enough difference, but you can shorten (and lengthen) the distance between the two brass blocks by rolling both rods together in the same direction. If you can shorten it enough, you can then just cut off the excess threaded rod (with something like a Dremel) on the non-adjusting side.
Or maybe you can undo the end blocks altogether, shorten the rods a tad, and reassemble? I can't test that out, since all my StewMac truss rods are currently embedded in necks.
You can probably also cut a little of the end of the adjustment nut, it may not need to be quite so long.
The StewMac rods really are quite nice, the two downsides are that you need their special sized bit (and once you have it, you want to justify that expense by buying more of their rods), and that the slot required is quite deep.

About using the shaft of a router bit as a bearing, people do that all the time. You just have to make sure that you choose a good material for your template - no plastic, nothing easily burnt, nothing terribly resinous.
The more proper way to get a small corner radius with a router bit is to get a guide bushing for your router baseplate (not terribly expensive), and make the pickup template bigger.

 

[HaMMerHeD]

I have switched to using a carbide upcut spiral bit for tr slots, and I like it a lot better than the old straight bit. It's a cheap carbide one from Craftsman/Sears. I think it was $17. It's a nicer cutting action and doesn't seem to want to get away from me as easily as the straight bit did.

As for the original question: Buy a shorter truss rod. You can shorten the bbg/grizzly models really easily by chopping and re-welding the end, but threaded rods like stewmac/lmi are more difficult. Easier to buy a shorter rod.

I've switched from bbg/grizzly rods to Allparts, because they are moderately cheaper and available in different lengths. I like the 25" model best for standard scale bass necks.

 

[PDX Mathias]

As for the original question: Buy a shorter truss rod. You can shorten the bbg/grizzly models really easily by chopping and re-welding the end, but threaded rods like stewmac/lmi are more difficult. Easier to buy a shorter rod.

I like it how welding is categorized as really easy!
Personally, if I was in the OP's place I'd really try to make the truss rod i have work for me, simply because I hate to pay $12 in shipping for a $16 part, and wait for a week.

 

[HaMMerHeD]

Well, I mean it is...pretty easy. It's a tiny little weld, so if you have the tools (or access to the tools), it takes about a minute.

 

[Hopkins]

The more proper way to get a small corner radius with a router bit is to get a guide bushing for your router baseplate (not terribly expensive), and make the pickup template bigger.

I use an Ammana 3/16" x 1/2" x 1/4" shank flush trim bit and don't have to worry about making an over sized template to use the collar.
[Invalid or Expired Link Removed]

I like it how welding is categorized as really easy!
Personally, if I was in the OP's place I'd really try to make the truss rod i have work for me, simply because I hate to pay $12 in shipping for a $16 part, and wait for a week.

To make that rod work, he would have to buy a standard and reverse thread die, cut the rod down and rethread it. It would probably cost more than just buying a rod that will already work with a standard sized router bit.

 

[Gilmourisgod]

I used the 1/4" spiral bit on the trussrod channel, gave a perfect cut, but ended up using a straight 1/8" bit for the graphite stiffener channels, and it left a "snowdrift" of sawdust that got packed into the channel like it was glued! I had to scrape it out with a chisel. It was a cheap little bit I got at a used tool store (still new in the package), so it serves me right. It seems like every time I cheap out on a tool, I regret it eventually. I bought a roundover bit at Harbor Freight, and the blades shattered the second time I used it, luckily I didn't get punctured, and was wearing a face mask. The Grizzly prices look pretty good, but I've never bought anything from them. I try to buy the best quality I can, one bit at a time as I need them to spread the pain. I'd buy a whole bit set if I could afford it. Expensive little obsession I've developed here.

 

[HaMMerHeD]

I have a few router bits from Grizzly:

3/4" roundover bit
3/8" round nose bit
1/4" round nose bit
1/4" straight cut bit

They're all the green bits, rather than the more expensive purple ones. They all work well. I also had a 1/8" straight cut bit and it broke the first time I used it. I replaced it with a solid carbide Freud, and it's worked fine the half-dozen times I've used it.