Introduction
Shown in the above photo are the calibers for which I reload.  Firing and resizing work-hardens the brass and shortens its life causing it to crack at the thinnest parts, the mouth or neck.  To prolong the life of rifle brass it should be annealed.  Annealing is the process of heating the brass to make it softer so it will last longer.  I’ve never tried to anneal my brass in the past, because I don’t shoot that often, but I decided to build my own brass annealer.

There are two primary methods to anneal brass; heat the brass in a flame from a propane torch, or heat the brass with an inductive heater.  Inductive heating uses alternating current through a coil of wire.  The brass case is placed in the center of the coil and heated to a specific temperature for a fixed length of time.  Only about the top 1/3 of the case needs to be annealed.

aled at the factory by the manufacturer.  In the above photo you can clearly see the line where the top of the brass was annealed.  An Internet search brought up a post on the Sniper’s Hide Forum by Tim Sloper on how to build an inductive annealer using parts purchased from Amazon.  I decided to copy his build, but I found the parts cheaper on ebay.  Some had to come from China to get the lower prices, but I don’t mind waiting 2 weeks to get the best price.

Inductive Annealer Parts
Here are the parts I purchased from ebay:

I purchased the version that came with a case because it had longer push-button actuators.  I plan to mount the timer board in a case using standoffs so I needed the longer actuators.

This induction heating module came with an insulated coil of copper tubing.  The diameter of the coil was too large to use with brass cases which is why I’m using the copper wire.  I’ve seen some homemade case annealers on the Internet that pumped water through the copper tubing to keep it cool.

Ten feet of wire was enough to make two coils. 

Because most of the parts came from China, they had to be mounted with metric screws.  The four holes on the bottom of the power supply used M4 screws, and the four standoffs for the inductor used M3 screws.  I purchased a metric fastener set from Amazon that had the screws and washers I needed.

I already had line cords for the power supply, a momentary push-button switch to trigger the timer, and a plastic case which I will explain about later in this article.  I also had plenty of hookup wire and terminal connectors for this project.

I had an AC power socket I purchased from ebay that I used for another project.  I deactivated that project and recycled the AC power socket for this project.  This socket comes with a lighted switch and a fuse.  I can keep the annealer plugged in and just use the switch to turn it on or off.

I needed standoffs to mount the timer in my case and fan controller on the baseboard.  I had purchased a set of M3 nylon standoffs for another project, which worked perfectly for this project.

Cutting Out the Panel
Long ago I had purchased a plastic case from Mouser.com #546-1591XXDSBK that was large enough to house a digital volt meter, the timer, the momentary push button, barrier strip, and AC power socket. 

I laid out the panel using CorelDRAW v12.  The case measured 6” x 3” so I started with a 6” x 3” rectangle.  I carefully measured all the components and laid them out on the rectangle.  Everything you see in red in the above figure will be cut out using my tabletop CNC mill.  The words and up/down symbols I’ll engrave with a 0.040” milling bit also with my CNC mill.  The large space on the left is to accommodate the AC power socket.

I placed exact size photos of the internal components onto the drawing.  There needed to be enough space between the back of the AC power socket and the volt meter for the AC wires and spade connectors connected to the AC power socket.

I exported the layout as a .dwg file which I imported into BobCAD CAM v2.0.  Once imported I created the G-code for my CNC mill.  I centered the lid of the case on the cross-slide table of my CNC mill and used a 3/32 end mill to cut out the holes.  I turned and moved the bit slowly because I didn’t want to melt the plastic and bind or plug the bit.  After all the holes were milled, I used a 0.040” bit to engrave the letters and symbols.  I only engraved 0.010” deep, I didn’t want to go completely through the lid.

After I completed the milling and engraving, I melted a white wax crayon over the letters.  When the wax dried, I scraped off the excess.  I then coated the panel with a mat clear coat to prevent the wax from coming out of the letters.

I installed all the components in the panel and everything fit perfectly.  As they say, “measure twice, cut once”.  I actually measured about five times to ensure everything was correct.  The volt meter came with locking lugs to lock the meter into the panel, but those broke off long ago.  I used some hot glue on the back edges of the meter to hold it in place. 

I wanted to mount the AC power socket at an angle so it would fit on the end of the case.  I created a pattern with CorelDRAW on plain printer paper, then cut out the pattern.  I taped the pattern to the end of the case and used a straight edge to score the plastic around the edges of the center.  Notice how the pattern is tilted 20-degrees so two of the edges would be parallel to the top and bottom of the case.

I used my Dremel tool with a cutoff disk to cut out the square hole following the scored lines.  Because the tool spins so quickly it has a tendency to melt the plastic.  I used a fine file to clean up the edges and remove the melted plastic.  With the AC power socket in place, I marked where to drill the mounting holes.  I used a 3/32 drill bit to drill the mounting holes, then used sheet metal screws to mount the socket.  The socket fit perfectly; it is flush with the bottom and does not interfere with the lid.  The reason I used the case was so I could mount the AC power socket and be able to leave it plugged in.

Winding the Coil

Tim’s post says to wind the coil no larger than 20mm in diameter.  I wound the copper wire 10 turns around a piece of 3/4” PVC pipe.  This came out to 20mm in diameter.  After I wound the coil, I took a flat blade screwdriver to separate the individual loops.  Reading Tim’s post his annealer is set up for .223 cases so his coil is 15mm – 16mm in diameter.  The larger the coil the more time it takes to heat the case.

I trimmed the ends of the coil and bent one side so it would fit in the inductor connectors.  The copper wire was too thin to fit under the screws so I removed the plastic insulator from two butt connectors and soldered them onto the wire ends.  The photo above doesn’t look straight because of the angle of the camera when I took the picture.  I later discovered the leads were too long!  I shortened the leads, removed the insulators from two #6 ring connectors, spread the connector apart and soldered them to the leads.  Now I could screw the leads directly onto the standoffs on the inductor board.

Connections

I created a schematic of the connections I would need.  The only things not shown here are the 24v fans.  I’ll mount them in front of the two heatsinks on the inductor board and the coil to keep them cool.

I have a box of electronic components and parts.  In there I have two packages of rubber grommets I purchased long ago from Radio Shack.  Radio Shack no longer sells these, but sets are available on Amazon and ebay. 

I drilled two 3/8 holes on the left side of the case for AC out and +24/GND in, and one 3/8 hole on the right side for the timer output.  I installed 3/8 grommets into the holes which will protect the wires from becoming frayed on the bare edge of the plastic holes.  In the above photo you can see the AC line cord coming out of the case.

For some reason I have many spare AC line cords.  One I will use to plug into an AC wall socket and the other end I’ll plug into the AC power socket in the case.  I took another AC line cord and cut off the ends to expose the wires.  On one end I crimped female spade connectors, which I connected to the AC power socket.  The other end I crimped U connectors which I connected to the power supply.

I mounted a terminal block inside the case to connect the internal wiring.  The heavy black cable on the left is a line cord that carries AC from the AC power socket to the power supply.  Notice how much space I had to leave to accommodate the connectors on the back of the AC power socket.  The red and black wires on the left are +24 and -24 coming from the power supply to the terminal strip.  Although its hard to see, the meter and the timer are connected to the terminal strip.  The red and black wires coming out of the right of the case go from the timer to the inductor board to turn it on.

Rather than running separate wires from the switch to the terminal strips on the timer board, I soldered wires directly to the contact points on the back of the timer board.  I connected +24 to the switch, then from the switch to the positive trigger input.  I connect a wire directly from ground to the negative trigger input.  Everything fits in the case.

Layout
As mentioned before, I decided to duplicate Tim’s layout with two changes.  The plastic case as mentioned before, and 24-volt fans to cool the inductor board heat sinks and coil.  The 40mm fans I will wire directly to the power supply, the 120mm fan to a fan controller

Building a Stand
I took some scrap wood I had in the garage and built a stand for the annealer.  I cut a 24” 2x4 in half making two pieces 12-inches long.  These are the legs for the stand.  I cut a piece of 1/4-inch hardboard into a 10” x 20” baseboard.  I laid the 2x4’s on their edge and screwed the hardboard onto the 2x4’s.

I drilled holes and mounted all the components onto the stand with the appropriate metric screws and washers.  I screwed the plastic case onto the stand by drilling holes through the bottom of the case into the hardboard, then used #10 x 1/2 wood screws to hold it down.  I drilled a 3/8 hole in the stand to feed the AC line cord, and a corresponding 3/8 hole in the leg below the power supply.  I fed the AC line from the case through the two holes and connected the leads to the power supply.  I connected the +24 and -24volt wires to the output of the power supply.  I did not connect the inductor board.

Testing and Adjustments
I found that the leads for the coil were too long; the coil was almost over the edge of the stand.  I shortened the location of the vertical bend and cut the leads accordingly.  I soldered two ring connectors to each lead and connected them to the inductor board as mentioned before.

I left the inductor board disconnected until I figured out how to program the timer.  Once I had the timer programmed, I connected the annealer board.  I initially set the timer to 8 minutes (480 seconds) which was way too long!  I tested the annealer with a .30-06 case and discovered that I only needed 23 seconds before the top of the case just started to turn red.  The above photo shows my first annealed case.

I also discovered that the coil gets very hot.  I put the 24-volt 120mm fan I purchased from Amazon.com behind the coil to cool it down.  I programmed the timer so that when triggered, there is a 45-second delay before turning on the inductor to help cool the coil, then the inductor stays on for 23-seconds.

Installing the Fans

The inductor board heatsinks were raised above the board so I couldn’t mount the 40mm fans directly on the board.  I glued 5 craft sticks together with wood glue, then glued the makeshift stand to the board.  I attached the fans to the raised stand with hot-glue and added an extra drop of glue to the bottom ends of each fan.  In the above photo you can clearly see the craft sticks and drops of hot-glue on each end of the fans.

The 40mm fans came with connectors which I removed and added 5-inches of wire to each lead.  I soldered the ends of the fan leads to the extensions, then protected the solder connection with heat-shrink.  I crimped U-connectors to the other ends of the extensions.  I attached the U-connectors to the appropriate connectors on the power supply.  Now the fans come on when I turn on the AC.

I mounted the 120mm fan behind the coil.  I drilled holes in the baseboard and fixed the fan with tie wraps.  I used nylon 3mm standoffs to mount the fan controller to the baseboard.  I cut the wires so they would reach the output of the fan controller.

I wanted the 120mm fan to come on only when the timer was off so it would cool the coil.  I didn’t want to cool the coil when annealing a case.  I connected the black fan wire to power supply -24v and the red fan wire to the normally closed relay contact.  I connected +24v from the power supply to the relay common contact.

The way this is wired, as soon as I turn on AC, the 120mm fan comes on.  When the relay is energized power is removed from the fan and the fan shuts off during the annealing process.  When the annealing is finished after 23-seconds, the fan comes on to cool the coil.

I discovered that when the timer is off, both of the timer outputs are at +24-volts.  I connected the negative timer output to the DC- input of the fan controller.  I connected positive timer output to both the fan controller DC+ and trigger in as shown in the above figure.  When the timer is off, both the positive and negative inputs to the fan controller are +24v so the relay is de-energized which allows +24v to be routed to the 120mm fan.  When the timer is on, the negative output of the timer goes low, the trigger stays at +24v allowing the relay to turn on and removing +24v from the fan.  When the timer shuts off, the cooling fan comes on to cool the coil.  I was afraid the fan would blow over the case inside the coil, but the case didn’t move.

Height Adjuster

Because I planned to anneal different lengths of cases I wanted a means to adjust the height of the case inside the coil.  I purchased two packages of 45 large craft sticks from Walmart.  I drilled a 1/4-inch hole in the end of each stick, drilled a 1/4-inch hole in the baseboard, then glued 16 craft sticks together to form a base.  I added another 16 craft sticks on top and secured them to the base with a 1/4-inch screw and a nut.  I now have a platform that I can adjust the height by swinging out a number of sticks.  After the case is annealed, I swing the entire platform out so the case can drop through a hole to an aluminum pan.  I swing the platform back under the coil for the next case.  I swung 4 sticks on top of the base for the correct height for .30-06 cases.  I took a black marker and marked the edge of that stick and labelled it .30-06.

My Annealing Process
Here is the process I follow:

1.    Adjust the craft stick platform for the appropriate height.

2.    Swing the platform under the coil.

3.    Place a piece of 3/4-inch PVC in the coil.  This helps to center the case.

4.    Drop a case into the PVC pipe so it sets on the platform.

5.    Remove the PVC pipe.

6.    Press the Start button on the timer.

7.    After the inductor shuts off, place the PVC pipe over the annealed case.

8.    Swing out the platform so the case drops through the hole into a metal tray.

9.    Repeat steps 2-8 for each case.

Once I got into a rhythm I annealed 60 .30-06 cases fairly quickly.  It was actually a fun process!

Summary

The above photo shows my completed annealer.  So, what did this cost me?  At the time of this article this is what I paid:

If you wanted to purchase the other parts I already had, you would need to purchase:

This was a fun and cost-effective project to build.  Using the inductive annealer I wouldn’t have to continually purchase propane.  You can build your own annealer for under $200, and even less if you copy Tim’s annealer and you don’t use a case or fans.  I used the case because I wanted to include a voltmeter and AC power socket.  Hopefully this will give me many years of service.

Addendum April 2025
I was reading through Tim's post and he mentions that he needs 3.6-seconds to anneal a case.  The diameter of the coil directly affects the annealing time.  I rewound the coil around a 5/8" brass rod so the diemater came out to be 17mm.  It now takes my anneler 7.8-seconds to anneal a .30-06 case.  Like Tim mentions in his post, tenths of a second matter with the smaller diameter coil.