How to make a Milwaukee Train Horn

Disclaimer: We highly recommend purchasing one of our ready-to-use Train Horns directly from BossHorn. These horns are professionally assembled, tested, and fully operational right out of the box — simply attach your Milwaukee M18 battery, and it’s ready to blast instantly. However, if you enjoy hands-on projects and want to build your own Train Horn from scratch, this guide will show you exactly how to do it using our Milwaukee Train Horn DIY Kit.

If you’ve ever wanted to build your own Milwaukee Train Horn, the good news is — it’s totally possible. Using a real Milwaukee M18 impact driver and a Milwaukee Train Horn DIY Kit from BossHorn, you can create a powerful, professional-quality horn that looks like a Milwaukee tool but sounds like a real train. It’s a fun weekend project that takes a few hours and basic mechanical skills.

What You’ll Need

• Milwaukee M18 impact driver or drill — You can use a new or old one, as long as the housing is in good condition.
• Milwaukee Train Horn DIY Kit — Available from BossHorn. It includes the compressor, trumpets, tubing, control board, and remote module.
• Milwaukee M18 18V battery — OEM or compatible aftermarket battery.
• Basic tools — Screwdrivers, pliers, wrenches, wire cutters, and a grinder or Dremel for adjustments.
• Optional materials — Rubber padding, sealant, or foam to help secure the compressor inside the housing.

Step 1: Prepare Your Milwaukee Drill or Driver

Start by cleaning and inspecting your Milwaukee tool body. You’ll be installing the compressor and air system into this housing. Remove the front bit holder and any attachments you don’t need. The drill’s body will serve as the frame that holds all the new horn components together.

Step 2: Mount the Compressor

The Do-It-Yourself Kit does not include mounting brackets, so you’ll need to secure the compressor yourself. To make it fit properly, ensure the compressor sits tightly against the drill body. If necessary, use a grinder or Dremel tool to slightly modify the inner housing so the compressor fits firmly inside. Alternatively, you can use rubber spacers, sealant, or dense padding to hold it securely in place and reduce vibration.

The key is to make the compressor fit snugly and stay stable inside the tool body — it should not move or rattle when handled. A firm, sealed fit also helps maximize sound output and prevent air loss.

Step 3: Connect the Air Tubing

Once the compressor is fitted securely, connect the air tubing from the compressor outlet to the trumpets. Tighten the fittings carefully — even a small air leak can noticeably reduce loudness. Check the alignment and make sure the air lines are clear and unrestricted.

Step 4: Wire the Electronics

Next, install the control board and remote receiver module. These components let you activate the horn with either the Milwaukee trigger or the included wireless remote. The wiring is simple and uses plug-and-play connectors — no soldering required. Follow the included wiring diagram to connect the power terminals correctly.

Once wired, the system will respond both to the tool trigger and to the wireless remote. The remote has a range of up to 160 ft (and up to 2000 ft if you’re using the long-range model).

Step 5: Attach the Trumpets

Connect the metal trumpets to the compressor output. Depending on your chosen model, your DIY Kit may include dual, quad, or Extreme Series trumpets. Arrange them so they’re evenly spaced and pointing in the same direction for the best projection. The trumpets are powder-coated and built to last, giving your homemade horn a professional, factory-built look.

Step 6: Test and Tune

Insert your Milwaukee M18 battery and give the horn a short test blast. You should hear that powerful, deep train sound right away. If the sound is weak, check your air connections or battery charge. You can also adjust the volume level — most horns have three sound settings: Low, Medium, and High.

Step 7: Safety and Battery Tips

• Always wear hearing protection. The horn produces up to 150 dB, which can cause immediate hearing damage at close range.
• Use outdoors only — never indoors or in enclosed spaces.
• Disconnect the battery if you won’t be using the horn for more than 5 hours to prevent standby drain.
• The horn features auto shutoff protection — it powers off the remote receiver after 3 hours to protect your battery.

Step 8: Finishing Touches

Once everything is working, clean up the wiring, double-check all connections, and make sure the compressor and trumpets are stable and properly sealed. The result should look neat, well-fitted, and solid — a professional-looking Milwaukee Train Horn ready to roar.

Build Time

Most people complete the project in around 2 hours, depending on their experience. It’s a fun project that’s both practical and satisfying — especially when you hear that first blast.

Alternative Option

If you’re not confident in your ability to modify the drill housing or just don’t want to spend several hours building, you can always buy a ready-to-use Milwaukee Train Horn directly from BossHorn. These pre-assembled models are professionally built, tested, and ready to use straight out of the box. Simply insert your Milwaukee M18 battery, and it’s ready to blast instantly — no tools or setup required.

Final Thoughts

Building your own Milwaukee Train Horn is a fun, rewarding way to customize your own piece of sound power. You’ll need a little creativity and patience — especially when fitting the compressor — but the end result is worth it. With the BossHorn DIY Kit, you can create something that looks like a Milwaukee power tool but sounds like a freight train. And if you prefer to skip the build, BossHorn’s ready-made models are the perfect alternative for instant, plug-and-play performance.