Spring mounting thermistor

[taulpaul]

Hey all,

I opted to use a thermistor from b3 (company that makes the pico hotend). It uses a spring to mount inside the existing thermistor hole. I tapped the hole to allow me to screw it in, but the hole depth is a little shallow. I'm trying to determine if I can use a bit to make that hole a little deeper so the thermistor will stay screwed in. Anyone have any experience about extending the depth of the existing hole on the stock hotend? Is there any other way to mount it so it will stay put? It's already popped out once during calibration.

[img]http://i.imgur.com/PvMEEhu.jpg[/img]

[DanHall]

I think you are going to have a tough time making the existing hole deeper without damaging the threads you have already cut. If it were me, I would drill a new hole in the heater block. Tape off the drill but so you don't go through but get the correct depth. If you're using the spring as a screw it may not matter but if you have a screw in thermistor you're going to want to use a bottoming tap so you get nice threads all the way to the bottom of the hole.

[taulpaul]

Thanks Dan,

I also picked up some pc-fahrenheit epoxy. http://www.pcepoxy.com/our-products/put ... enheit.php

Would this be suitable to keep it in place in the existing hole?

[JFettig]

Take the nozzle out and drill thru to center then tap it and reinstall the nozzle.

[DanHall]

Thanks Dan,

I also picked up some pc-fahrenheit epoxy. http://www.pcepoxy.com/our-products/put ... enheit.php

Would this be suitable to keep it in place in the existing hole?

That stuff is intended for emergency repairs and running at temperature extremes above 176C will shorten the surface life of the repair. (paraphrased from their website) You'll be running hotter than that even with PLA. I also don't like the idea of epoxying a connection that may need to be changed out. It will make later repairs much more challenging.