Hand-Carving Threads (to Connect a Mirka CEROS to a Festool 27mm Hose)

To see how I installed the CEROS transformer on my Festool CT26 dust extractor, click here.

This article shows how to layout and carve threads in a rubber hose end-piece.  However, the same techniques can be used to carve male threads in wood or another material.

The Mirka CEROS (Compact Electric Random Orbit Sander) has a dust extraction port with internal threads that screw directly onto the end of a Festool 27mm hose to prevent it from dislodging accidentally.  However, that means the tapered rubber connector on the end of the hose needs to be removed.  This is not a difficult procedure but it is not something I want to do every time I switch between the sander and another tool.

I know of four solutions to avoid having to install or remove the connector when using it with the CEROS:

1. Jam the connector in and hope it stays;
2. Buy another hose and dedicate it to the CEROS;
3. Make an adapter using a short length of 27mm hose and some fittings; or
4. Cut threads on the connector.

Tired of fighting to get it to stay connected with just a press-fit, I decided to carve threads on the adapter to secure it into the port.  I used two carving tools, a rule (double square) and black electrical tape.

Next, I used a V-shaped carving gouge (#12 sweep, 2mm wide) along the edges of the tape to transfer the layout lines through to the connector.  Then I peeled off the tape so I could better see the V-cuts.

Following the V-cuts, I used a veining tool (#11 sweep, 3mm wide) to cut the threads.

Finally, I tried to thread the connector into the port.  When simply press fit, there was 7/8″ of exposed connector between the first shoulder and port.

Once threaded in fully, only 1/2″ of the connector was exposed between the first shoulder and port.  The threads mated very well and there was no chance of the hose disconnecting accidentally.  And I was able to still use the hose with other tools without a problem.