Make a Guitar Amplifier Motherboard Out of Phenolic




Introduction: Make a Guitar Amplifier Motherboard Out of Phenolic

First of all, I made this at TechShop Detroit. All of the tools used can be found in the shop, which is pretty awesome. The link for techshop is here:

I am building a guitar amplifier from a kit, and the motherboard was made of cheesy cardboard.  I decided to make mine out of phenolic. This is one of my favorite materials to work with because is is easy to machine, and it looks beautiful. In this instructable, I will run through the steps for laying out the new motherboard and drilling/cutting it out. The phenolic I am using was salvaged from an old transformer. (Recycling... Yay!)

Tools needed:
Transfer punches
Ball-peen Hammer
drill bits
Phenolic Sheet
Hand Clamps
hand Scribe
drill press
Belt Sander

Step 1: Mark With a Scribe

The first thing I did was mark the edges of the template using a scribe.

Step 2: Check the Hole Size

The next thing I did was determine the size of the holes I needed using a caliper. I checked the size of the bit I was using against the template.

Step 3: Mark the Holes With a Transfer Punch

After clamping the template to the phenolic, I began to mark where my holes will be. Transfer punches come in many different sizes (they can be seen in the foreground of this picture.) They allow a person to transfer a mark to the new material in the exact center of the template holes. The also aid in making precise holes with a drill because it gives a drill bit a place to register. This prevents the bit from "walking" on the surface of the material.

Using a ball-peen hammer and light blows, I tap the transfer punch, making a mark on my new piece.

Step 4: Off to the Drill Press

After having all of my new marks made, Its time to make the holes with the drill-press. I simply line up the bit with my marks made with the transfer punch, and drill through the phenolic.

Step 5: Cut It Out on the BandSaw

After drilling all the new holes, its time to take the piece to the bandsaw to cut out the final shape.

I used a push-stick to help move the piece through the blade.

Safety first.

Step 6: Clean It Up on the Belt Sander

The bandsaw tends to leave a fairly rough surface, so I just cleaned it up with a touch on the belt sander.

Step 7: Thats It!

Tune in to my next post where I show how to create brass eyelets to insert into the holes.

The Next Instructable can be found here:

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    2 Discussions


    5 years ago on Introduction

    sweet.... but remember creepage.... the current CAN and sometimes WILL creep across the board in high voltage applications such as vacuum tube amps... thats one of the reasons Fender choose the fiber board (basically cardboard)

    Nice how to. Please be advised that phenolic is a carcinogen and use of a respirator is highly advised during forming operations (to include sanding).