Building a Solid Pine Wood, Finger Jointed Guitar Amplifier Cabinet.




Introduction: Building a Solid Pine Wood, Finger Jointed Guitar Amplifier Cabinet.

About: Journeyman electrician, Musician, woodworker, and Inventor.

Building a solid pine wood, finger jointed guitar amplifier for my Fender pro Jr.
Done the same way Leo Fender did back in 1946.
There is Nothing like the Warm sound of a pine wood cabinet!

Fender is a licensed trademark for FMIC Not to be affiliated with ampRiser or

Step 1: Measuring the Four Sections to Be Cut

The Fender pro jr. cabinet measures 14 1/2" H x 15 1/4" W x 8 3/4" D
I wanted the wood grain to match throughout the cabinet,
After purchasing a piece of select pine wood 1" thick 10" wide and 8' in length,
I carefully marked the 4 sections to be cut at 14.5" then 15.25" then 14.5" then 15.25"
Measure Twice CUT Once! Make sure to always were proper safety glasses and
read and understand the proper use of your power tools!
I used my radial arm saw to cut the sections.

Step 2: Numbering the Cut Sections

After the sections are cut I number them so that they will go together in the proper order.

Step 3: Dry Fit the Sections

After the sections are cut and numbered in order
for proper assembly.
I dry fit them to see how the cabinet will look,
notice how the wood grain matches and follows
throughout the cabinet.

Step 4: Cutting the Finger Joints

After the 4 sections are cut and numbered 1-4
I set up sections 1 and 3 in my finger joint jig
to be cut with my router.
1" stock is actually 3/4" thick, so I set the depth of cut at 3/4"
sections 1 and 3 start the cutting at an open finger on the jig
sections 2 and 4 start the cutting at the finger of the jig,
that way they are of set and will go together properly.
*Remember to ALWAYS wear safety glasses*

Step 5: Dry Fit the Cut Sections

Once again I dry fit the cut sections to check for proper fit.

(finger jointing a cabinet can be complicated and requires
special tools and skills, so if you want you could skip
these steps and simply assemble the cabinet with out them?)

Step 6: Applying the Glue

After dry fitting the sections I carefully apply quality wood glue
to all the surfaces of the cut finger joints.
I usually apply 3 or more coats of glue
allowing them to set up and soak into the wood for a couple of minutes.

Step 7: Start to Assemble

I usually apply glue to the bottom of the two sides
and both sides of the bottom section, then set up corner clamps,
apply glue to the top of the sides and top section,
allowing to set up a few minutes before complete assembling.

Step 8: Assemble and Clamp

After completely gluing and assembling,
I clamp the cabinet at every possible angle.
I start by applying only enough pressure to hold the cabinet together,
and slowly tighten over a few minutes.
This allows the glue to react and set properly.

Step 9: Remove the Clamps and Sand

After allowing the glued and clamped cabinet
at least 24 hours to set, I remove the clamps,
and give the cabinet a basic overall sanding.

Step 10: Cutting the Angled Front

After the cabinet has been lightly sanded,
I set up my guide on the table saw at about 3 deg.
so that I can cut the angled front of the cabinet.
The cabinet was made square 14.5 x 15.25 x 10"
so that I could finger joint the cabinet easier.
the cabinet actually has an angled front.
the TOP measures 8.75" and tappers down to 9.5"

(This procedure is NOT easy)
*Always wear your safety glasses*

Step 11: Finishing the Angled Cut

The sides of the cabinet are cut to the 3 deg. angle
and the Top and Bottom are cut straight.

This cut is hard to do perfectly,
so when I am done I will have to sand the

Step 12: Adding the Speaker Baffle Trim

After the cabinet has been sanded,
I cut two pieces of 3/8" thick x 1" W x 12 3/4" L
with a 3 deg. bevel on the sides.
These are glued and clamped to the inside
of the front of the cabinet.
These sections will be used to accept the speaker baffle.

Step 13: Measuring and Marking for the Amplifier Chassis

Measure and mark the section to be cut out for the amplifier chassis.

Step 14: Cutting the Amp Chassis Section Out

After carefully measuring and marking,
I cut the section out using a scroll saw.


measure Twice CUT Once!!!

Step 15: Rounding Over the Edges

After cutting out the section for the amp chassis,
I carefully round over the edges with my router table.
I used a 3/4" round over bit.


Step 16: Finish Rounding Over

I round over all the edges to the cabinet.


Step 17: Final Sanding

After rounding over all the edges,
I give the cabinet a final sanding.
The cabinet is finally starting to take shape!

Step 18: Fitting the Amp Chassis

Next I will measure and mark the holes for the amplifier

*My NEXT Instructable I will show the making of the speaker baffle
covering the cabinet with TOLEX and installing the amp and speaker*

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    Question 3 years ago on Step 1

    Hi. I am having trouble finding wood over 8" in width. Do you know how one might get girthy wood?


    Tip 3 years ago on Step 18

    A quicker way to construct this is to produce a cut file on a computer and get the wood sheet CNC cut. Then it's a simple matter of gluing it together.


    3 years ago

    Go to stodoys if you'd like to know how to build it. Good solutions for everyone I think


    4 years ago

    I appreciate you for sharing this. I plan on making my own custom cabinet for a swanky custom amp. I'm going to load it with a chassis and reverb tank from Award Session (Blues Baby 45). You gave me some great ideas. Thanks!


    6 years ago

    butt joints with bracing all around will do just as well

    real simple too. and don't even need a buncha clamps, just glue and NAIL (mesa does it that way, and they've got the beefiest cab builds of the big brands)

    bracing butt joints is simple:

    > 1 2 2 2 2
    1 3 <
    1 ^

    1, 2 - side boards
    3 - brace board
    ^,<,> - nails with directional vector

    glue & nail the brace FIRST, and to board #1 (offset) for a good butt joint with two planes of attachment & double the glue-up surface

    important: use a "true" board for bracing... poplar dowels are crap to be avoided. maple can be nice but is crazy hard, difficult to nail, can break improperly/unpiloted screws, and weighs a ton. ALDER is your friend

    if you can't find 1x1 (real 0.75x0.75") alder, go with 2x1 (1.5x0.75") and this pattern:

    1 3 <
    1 3 <
    >1 2 2 2 2


    Reply 5 years ago

    I plan on doing it this way, with butt joints. The only issue I see is the nails need to be placed so that when the route (round over) is done the bit does not hit the nails.


    Reply 6 years ago


    1 2222
    1 3


    6 years ago on Introduction

    This is great! I'm just about to get started building a cab for a valve amp I made and this instructable is very helpful. Thanks for posting, and great job on some really neat jointing :)


    6 years ago

    from one guitarist to another....I tip my hat to you.
    excellent craftmanship!


    7 years ago on Introduction

    Question....and if I missed it somewhere in the instructable I apologize. But what's up with the bottom cabinet in the heading picture up there? Looks like a piece of wood obstructing the speaker grille on bottom. Is that the case?


    7 years ago

    Right now I have a danelectro honytone amp that I am going to make a wooden cabinet for. Your instructable used a thickness of 1". For a mini amp would I have to dial back the thickness?


    10 years ago on Step 3

    Where did you find the routing template and how much was is? Thanks chad


    Reply 10 years ago on Step 3

    Sorry for the delay, havent been here in a while?

    I bought the Box Joint Router Template and Jig at...

    4 about $40.00?


    12 years ago on Introduction

    This is very nice, and complete enough for someone to follow and duplicate.

    One minor point: it looks like you uploaded all your photos at the beginning (certainly much easier :-). Unfortunately, that has the side effect of also attaching all of those pictures to your introduction. You may want to remove the "in process" pictures from that step (it won't affect where they are in the rest of the I'ble), leaving only the beautiful finish product.

    If you're not familiar with the (slightly weird) markup I'bles uses, you could replace your all caps with either italics, putting two apostrophes before and after the text, like this:
            &apos&aposlike this&apos&apos
    or with bold face, using three apostrophes, like this:
            &apos&apos&aposlike this&apos&apos&apos