4mm Allen Nut Hot Rod Truss Rod

  • 96 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.

Read more

12-1/4" overall length

Item # 2550
In stock, ready to ship!


6 or more $13.74
12 or more $12.95

14-1/4" overall length

Item # 2551
In stock, ready to ship!


6 or more $13.91
12 or more $13.11

18" overall length

Item # 2552
In stock, ready to ship!


6 or more $14.78
12 or more $13.93

24" overall length

Item # 2553
In stock, ready to ship!


6 or more $18.26
12 or more $17.21
Quantity Discount Prices apply when you buy multiples of the same item number.
Total: $0.00
Quantity: 20


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

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.

Product Instructions

Hot Rod Adjustable Truss Rods

Installation and adjustment instructions for Hot Rod Adjustable Truss Rod.

    • Item #
    • Weight
    • 2550
    • 0.197
    • 2551
    • 0.232
    • 2552
    • 0.296
    • 2553
    • 0.385

Ratings & Reviews

4mm Allen Nut Hot Rod Truss Rod

  • Based on 96 Reviews
Displaying 4 of 10 1 2 3 4 5 6 7 8 9 10
Write a review

Very nice truss rod

By sofislele from Athens, Greece
(Customer's Reviews) Saturday, December 29, 2012

Double action rods was always my favorite. My suggestion is that the brass collars should be replaced with a stronger material. Time will show it's strength.

Powerful rod

By Colt W. Knight from South Charleston, WV 25309
(Customer's Reviews) Thursday, November 29, 2012

I have found if I bed both brass ends with epoxy, the rods work/sound better.

Total adjustability

By Will Hirsch from Arcata, CA
(Customer's Reviews) Wednesday, October 24, 2012

I've been using this rod in all my guitars and they've worked great. I even was able to pull a neck back into position that had spent days floating around in it's case two years ago in the flood that hit the Nashville lockup where lots of touring musicians stored their instruments. I do think owners need to be advised not to try and straighten a neck just by turning the nut. Clamps are your best bet and just use the neck rod to hold things in position once you've got things where you want them. I'm afraid an uninformed owner might strip threads otherwise.

Great choice

By Mark Davis from Canada
(Customer's Reviews) Thursday, October 04, 2012

i am working to build a 7 strings LesPaul shaped guitar,For the Truss rod,I stopped my choice on 4mm which corresponded to my expectations, the build quality is excellent and the rod is adjusted to perfection, thanks StewMac.Mark Davis

True to its own design.

By Pharnton Smith from Douglas, WY
(Customer's Reviews) Saturday, September 29, 2012

This is not my first choice for truss rods. It's very deep, taking away more wood than neccessary, and the use of soft brass makes me nervous. Also because of the round top profile there is very little metal in contact with the fretboard. Still, it is a good execution of a design that does make a lot of sense.

truss rod

By bluesplayerx from ca
(Customer's Reviews) Thursday, September 13, 2012

well built and works fine

Hot rod

By Dean W Richardson from Kirkland, Washington
(Customer's Reviews) Sunday, September 09, 2012

Had never used this type before, was impressed with how well it works.

very nice truss rod

By mike ryman from erwin tn
(Customer's Reviews) Friday, August 17, 2012

I bought this double action truss rod for my first guitar build. I was very scared of installing a truss rod in general because of the whole cutting a deep slot in the neck and sanding through idea. It just terrified me. I wanted to make sure the rod could help adjust for a bow in either direction an i had never built a guitar. I was extremely pleased as well as surprised with the quality of the rod, and the ease in which it went in. I bought the special router bit made for the install and it went perfectly. Thank you stewmac!

so far so good

By JDCguitars from Hawaii
(Customer's Reviews) Wednesday, June 20, 2012

I bought this hotrod for the sole purpose of flipping it upside down and making it a headstock adjust on Strat and Tele style necks. so far so good

Wow this thing adjust amazing!

By Pestvic from Sparks NV
(Customer's Reviews) Tuesday, June 19, 2012

Take your time and make sure thing thing gets installed nice and snug and tight. Don't install this loose or it will rattle. I like to put some silicone or hot glue right before I install it so that it snugs itself in and doesn't rattle. I make sure mine fits perfectly, when you get it in just right the smallest little adjustments will change the neck big time. No more half turns or full turns to set the neck. Small quarter or less turns will make the adjustment you need. I will always use these truss rods in my builds.

Displaying 4 of 10
1 2 3 4 5 6 7 8 9 10

Shown on page 72 of our latest catalog.
  • Hot Rod® is a registered trademark of Stewart-MacDonald Manufacturing Company, Inc.