How to install an independent probe for Cropster

This article shows you how to install an independent probe.

These instructions are based on the compression fitting provided by Cropster Inc which is designed for probes we provide, whether 1/8" diameter or 3/16" diameter.

You can order the compression fitting and probe from Cropster. 

    Please take into account that your roasting machine has rotating paddles inside, and make sure your probe location will not interfere with their movement. It is also important to take into account the direction in which your barrel turns.

    You will usually place the probe on the same side as your current probe but not too close. You do not want beans trapped between the two.

    Tools needed

    • Drill with sufficient torque
    • 11/32" Drill bit (.85cm), for use with steel
    • 1/8" (3,18mm) tap size with 27 threads per inch. The tap is used to create the threading for the compression fitting which has NPT of 1/8"


    Once you have selected a good location to place the probe you may begin the work.

    Step 1

    Drill bits have a tendency to wander when you first start drilling. To prevent this, measure and mark where you want the hole and then use a center punch and hammer to create a small dimple. This gives the tip of your drill bit a place to ride in as you begin to drill.

    Step 2

    Drill the hole.

    Hint: You may want to set something in the cooling tray to catch dust and minimize clean up.

    Step 3

    Create the threading with the tap. Use a hand tool such as a wrench or socket wrench to turn the tap. Turn slowly in order to create nice clean threads.

    Step 4

    Screw in the compression fitting until snug.

    Step 5

    Place the probe in the compression fitting. You decide how much of the probe you want entering into the machine. Once placed, tighten down the outside hexagonal screw until the probe cannot move.

    Make sure that the paddles in the drum do not interfere.