fiona749•3d agoProlific Poster

Spent a whole shift chasing a weird finish on a 4140 part

I was running a simple facing op on a lathe, and the finish looked like garbage, all torn and fuzzy. Checked the insert, speeds, feeds, everything. Finally, after like five hours, I noticed the coolant mix was way too weak. Topped it up with concentrate and the next part came out smooth as glass. How do you guys keep your coolant concentration right without a refractometer?

3 comments

3 Comments

wyattramirez3d ago

Classic coolant ghost hunt. Bet you checked the phase of the moon before you finally looked at the mix. I just taste it. If it burns a little, you're good. If it tastes like sad water, time to add more goop. Not the safest method, but the shop taste buds haven't failed me yet.

vera293d ago

My buddy Dave did that exact thing last winter. He swore his coolant was fine because it had a "nice spicy kick" to it. Took his truck up the mountain and it started overheating on the way back down. Turns out his spicy kick was just weak, sad water with a dash of rust. Had to get it towed. I stick to the test strips now.

william_craig73d ago

Man, that reminds me of my uncle who used to test his battery acid the same way... said if it made his tongue go numb it was still strong.