I'm revisiting a topic that has come up here many times: flood coolant on an FP2. I was using water soluble cutting oil a few weeks ago for a slitting saw on steel, and again last week as I was working on some mild steel parts that will be welded up to make a bracket for an inside grinding attachment.
![]()
At some point I felt coolant dripping where it is not supposed to go: it was leaking in between the vertical table and the horizontal table and dripping on my hand when I reached for the Z-axis handwheel. So after I was done I decided to pull off the vertical table to have a look. I was worried about trapped coolant between the tables, because my experience with this coolant is that if it is on surfaces exposed to air, then all is well. The water evaporates, leaves a thin oil film behind, and no damage (corrosion) ensures. But I feared trapped coolant, which I thought would lead to rust.
It turns out that my concerns were unfounded. Here is the vertical table. You can see the path that the coolant was following down:
![]()
Here is the same table after five minutes scrubbing with WD40:
![]()
Here is the horizontal table before:
![]()
and after scrubbing:
![]()
So the bottom line is that the coolant didn't do any damage here: my fears were unfounded.
During reassembly, I put a thick stripe of grease at the top of the interface where the horizontal and vertical tables meet. This should seal it well enough to prevent coolant ingress in the future.
PS: an interesting find was this:
![]()
It's a broken M12 T-bolt, one of the 8 that was holding the horizontal table onto the vertical table -- you can see it in the second photo above. I must have overtorqued it. Fortunately it did not damage the vertical table. Curiously the bolt is sheared on the threads, and also broken on the head. I suspect that it first sheared at the threads, then the tension rocketed the remaining part of the bolt into the T-slot with enough force to crack the head against the inside of the T slot.
I am using coolant more frequently these days when working on steel, because I have a lot of HSS tooling and it works better with coolant. A steady stream doesn't make a mess, because the HSS speeds are slow enough that it doesn't fling coolant everywhere. At the end of the day I do have to spend 15 minutes taking the vise apart and cleaning the table off, but it's worth it IMO. I've got Z-bellows in place, one of those protective hanging skirts to keep coolant out of the Y-axis ram, and the Z wipers are in good shape, so I don't think coolant is getting anywhere else that it's not supposed to be.
At some point I felt coolant dripping where it is not supposed to go: it was leaking in between the vertical table and the horizontal table and dripping on my hand when I reached for the Z-axis handwheel. So after I was done I decided to pull off the vertical table to have a look. I was worried about trapped coolant between the tables, because my experience with this coolant is that if it is on surfaces exposed to air, then all is well. The water evaporates, leaves a thin oil film behind, and no damage (corrosion) ensures. But I feared trapped coolant, which I thought would lead to rust.
It turns out that my concerns were unfounded. Here is the vertical table. You can see the path that the coolant was following down:
Here is the same table after five minutes scrubbing with WD40:
Here is the horizontal table before:
and after scrubbing:
So the bottom line is that the coolant didn't do any damage here: my fears were unfounded.
During reassembly, I put a thick stripe of grease at the top of the interface where the horizontal and vertical tables meet. This should seal it well enough to prevent coolant ingress in the future.
PS: an interesting find was this:
It's a broken M12 T-bolt, one of the 8 that was holding the horizontal table onto the vertical table -- you can see it in the second photo above. I must have overtorqued it. Fortunately it did not damage the vertical table. Curiously the bolt is sheared on the threads, and also broken on the head. I suspect that it first sheared at the threads, then the tension rocketed the remaining part of the bolt into the T-slot with enough force to crack the head against the inside of the T slot.
I am using coolant more frequently these days when working on steel, because I have a lot of HSS tooling and it works better with coolant. A steady stream doesn't make a mess, because the HSS speeds are slow enough that it doesn't fling coolant everywhere. At the end of the day I do have to spend 15 minutes taking the vise apart and cleaning the table off, but it's worth it IMO. I've got Z-bellows in place, one of those protective hanging skirts to keep coolant out of the Y-axis ram, and the Z wipers are in good shape, so I don't think coolant is getting anywhere else that it's not supposed to be.