It is unacceptable because that part will be of dissimilar metal, causing an error. Be sure to extend with a thermocouple wire or a compensating lead wire.
Care should be also taken to connect the thermocouple or compensating lead wire.
It is unacceptable to connect by soldering or with a copper Y-terminal like a regular electronic circuit, etc. because that part will be of dissimilar metal.
Basically, connect by spot-welding or with a joint part made of thermocouple.
