This isn't clear. What exactly is the first "5v"? The sensor VCC pin?
Same for the second "5v". Is that the 5V output pin of the Arduino?
This datasheet says to use 3.3V for the sensor VCC. The signal levels are also directly related to that.
The Arduino UNO is a 5V device, so you'll need some signal level shifter.
For a type K thermocouple you should use the MAX31855K version.
Also, don't skip the capacitor between VCC and GND.
Try to get just one of the sensors to work reliably, then you can add the second.