Mill knee leadscrew bearings

[striker]

As I've made a new, longer leadscrew for the knee of my Chester 626, I thought maybe I'll put new bearings on the top.
Currently there's 2 6004 bearings back to back.
They're open and full of swarf.
I've checked a few exploded drawings online, and the grizzly 6x26 has a 6004 (single row deep groove) and a thrust bearing too.
So, should I fit 2 x 6004 or one and a thrust bearing? I will fit 2rs shielded bearings to keep the swarf out, either way. If I use the thrust, then it should be protected from falling swarf from the 2rs bearing above.

 

[m_c]

For that application, I'd expect at least the lower bearing to be some form of thrust bearing.

Personally, I'd see if there was a suitably sized angular contact bearing (7xxx series IIRC) that would fit the lower side, and fit a 6004-2RS to the top to keep swarf from dropping through.