Now that I am using the enlarger I have noticed a loud metal-on-metal squeal when lowering the head. Time to open up the column and have another look inside (I had it apart once but did not see anything unnusual).

Even with it open I could not pinpoint the squeal. So, the plan was to lubricate all moving parts and see if that makes it better.

The vertical screw was moist with oil, so I left that for last (mistake...)

There are a number of ball bearings that act as wheels and center the head apparatus on the 8" round column. Each ball bearing unit has a metal-to-metal contact with the column. Each bearing also has a little felt piece to hold lubrication. The bearings along the bottom of the apparatus have the felt piece mounted on the underneath side. A little hard to oil with a gravity oiler. I decided to use a spray oil that is made for things like motorcycle chains. It is thick and will stick on an underneath surface, but it also penetrates well. It does not evaporate easily, also.

I am not recommending this brand, just documenting what I did. I used Tri-flow. I sprayed all the ball bearings, making sure the felt got soaked also.

It still had the horrible grinding, so I sprayed the lube in the little copper tube that leads to the vertical screw. This solved the problem. It also incresed the speed that the head goes up and down. This little copper tube lines up with a hole in the side of the column panel when the head is all the way down. Therefore, you can supply the lubrication to the vertical screw without having to take things apart. This is covered in the supplement sheet to the owner's manual. (Free pdf for the asking...)