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Home : Truss rods : Adjustable truss rods : 4mm Allen Nut Hot Rod Truss Rod

4mm Allen Nut Hot Rod Truss Rod

Read 93 Reviews   |   Write a Review

A smaller 4mm (5/32") Allen nut for most instruments. Smooth two-way action corrects upbow and backbow, giving complete control over the neck.

See details below

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4mm Allen Nut Hot Rod Truss Rod
Item# Description In stock Price Quantity
2550 12-1/4" overall length Yes
6 or more $13.64  
12 or more $12.38  

2551 14-1/4" overall length Yes
6 or more $13.91  
12 or more $12.67  

2552 18" overall length Yes
6 or more $14.84  
12 or more $13.60  

2553 24" overall length Yes
6 or more $18.96  
12 or more $17.74  

Quantity prices apply to multiples of the same item number Selected currency  


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Easy to install. The Hot Rod® fits in a straight channel. For proper operation, this truss rod must be installed so that the active rod (the rod with the adjustment nut) is below the passive rod. A wooden filler stick is not required.

Smooth 2-way action with superior strength for stubborn necks.
Our Hot Rod neck adjustment system features twin rods in threaded brass collars. The stainless steel active rod turns for smooth neck alignment, with 2-way action to correct upbow and backbow.

The Hot Rod requires an access cavity for the adjustment nut, and a straight 7/32"-wide x 7/16"-deep slot (measured from the bottom of the fretboard) for installation.

Pick the Hot Rod Truss Rod size you'll need:
(overall length includes the nut)

Resonator guitar
Acoustic guitar with 12th fret at the body
Acoustic guitar with 14th fret at the body
Electric guitar

We've designed the Router Bit for Hot Rod Truss Rods especially for routing your neck to fit our truss rods.

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 Ratings and reviews
4mm Allen Nut Hot Rod Truss Rod
4mm Allen Nut Hot Rod Truss Rod
4.5 out of 5 stars
Based on 93 ratings Write a Review
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Displaying 81 – 90 < 1  ...  8  9  10 >
4 1-19-2011
Thank you stewmac

A truly affordable product. Good size and adjust ability. Will certainly use again.

Michael Grannis  Phoenix, Az Read my reviews (4)
Customer supplied image for review
5 1-17-2011
allen head truss rod

i really like this truss rod and use it extensively in all my banjos. it's the ease of installing which i like. For the truss slot i know a router bit is suggested but what i do is use 3 circular saw blades on the table saw and make only one clean pass down the center of the neck. then i just drop the rod in and fill the rest of the truss rod channel. it is a nice fit and the allen head ensures no slippage when adjusting the rod. i want quality in my instruments and this rod is the one i prefer.

D.M.Holzer Banjos  West Fargo, N.D.
Customer supplied image for review
4 12-13-2010
Not bad overall, but can be better with some mods

I've installed this Hot Rod in carbon fiber bass neck 4 string, phenolic fretboard. Strength 8/10, I wasn't able to do more than 1/3 of a turn in each direction starting from 0 for each direction, but it was enough to fine tune this neck. I would probably do more with finer threading or in wood.

As this is a truss rod and is not meant to be adjusted everyday, more welcome would be a "slow" instead of "fast" tuning, in terms of turns and they depend of the threading on the rod. So finer is better choice for this instead of current one.

finer threading = more turns = more accurate tunning = less force to adjust
(just what's needed for rigid necks + better used strength of the rod)

Other than that, the rod is susceptible to temperature (shrinkage) and because of it's length the results are pretty noticeable (this is effective in more drastic temp change). So no matter how stable neck you have it will react because of the rod, therefore better alloy for this use is more than welcome.

Final thoughts, good truss rod but definitely better alloy and finer threading in next production (whether it is for wooden or non wooden necks).


Maylo  Kumanovo, Macedonia Read my reviews (2)
5 12-12-2010
14-1/4" truss rod

After trying out a few brands of other truss rods, I've used this type on all of my guitars. Excellent stuff!

DhaenensGuitars  Aarschot, Belgium, Europe Read my reviews (10)
3 11-23-2010
not really happy ....

Sorry but I find the nut anchorage to the bar not enough resistant.
Others truss double action rod are more resistant in that zone

Utopia Custom Shop  Alessandria -Italy Read my reviews (5)
5 10-26-2010
Hot Rod truss

Well made, easy install and perfect fit using the Stew Mac truss rod router bit. I have used 6 now with very good results.

R Guess  North Florida Read my reviews (16)
4 9-30-2010

I have built 8 electrics with these and I find them convenient to install since they use just a flat bottom channel.
I had one shear at the adjuster once, which made me livid, but I was able to save the neck and replace the truss rod without removing the fretboard. Always lubricate the threads and test it before installing. Proceed with caution while adjusting any truss rod.
On Fender style necks, with the adjuster oriented just under the fret board, the tightening/loosening direction is opposite to conventional so watch out for that!!
Finally, I'm glad there is now metric adjuster sizes!!

James B.  Ontario Canada Read my reviews (3)
Customer supplied image for review
5 9-16-2010
4mm Allen Nut Hot Rod

It works realy well no rattle in the neck.Also theres no need for a large truss rod cover

Andrew t Bruton  st Catharines Ontario Canada Read my reviews (3)
Customer supplied image for review
1 9-03-2010
HotRod installation for Fender headstock adjustment

Just received the 4mm allen nut Hot Rod, and butchered a nice piece of wood trying to install it with adjustment at head stock end. CAN'T BE DONE ON A FENDER GUITAR but StewMac doesn't mention that anywhere. It can only be installed as a heel end adjuster) The 7/16 slot depth puts the adjuster too low into the head stock to allow access. If you want a heel end adjuster, buy the Fender style model, and don't mess around with an oddball 4mm adjustment.

Strat41  San Dimas, CA Read my reviews (2)
5 8-13-2010
4mm Allen Nut Hot Rod

I love these hot rod truss rods. They are incredibly easy to install and use. The dual action has come in handy on a kit guitar I built. I use them on my electrics and acoustics.

slingerland guitars  fairfax, va Read my reviews (4)
Customer supplied image for review
Displaying 81 – 90 < 1  ...  8  9  10 > /\ Top of Reviews

Shown on page 72 of our latest catalog.

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