Homemade CHT Bayonet sensor

[Kent Ashton]

For the hardcore builder:  This uses a brass fitting from the hardware store, a small spring, GG-J type thermocouple wire.   You can view the wires at Omega.com but there is lots of cheap wire on ebay.   Search ebay for glass thermocouple wire.  Any type J will do but the glass-covered wire is stouter and will not care about hot exhausts nearby.

 

The spring will push the balled-up sensor up against the cylinder.  Twist the two wire ends together and roll them into a ball with needle-nose pliers.  Silver-solder the ball (lots of tutorials on Youtube).  Wash off flux.  Cut wire to length and fit spring and brass fitting

 

Sparkplug types can also be made.  Start with a copper washer, clean it bright, apply Wite-Out where you don't want the silver solder to flow (called "resist" in the jewelry world").  Twist the T-couple wire a couple of turns and silver-solder to the washer.  For a better-supported device, bend a piece of stainless welding wire and solder it too, wash off the flux.  Below are a couple I made for a bike.  The trick is to avoid excess silver-solder which will interfere with the seal.

 

There are lots of uses for silver-solder skill.  Making primer lines is another one.

 

Time or money, take your choice.  :-)