Thanks, I will look into it. Do you know if there is a way to replace it without tearing apart the saddle?
This same sort of sight glass is on my Jet lathe headstock, and I tried to pull it out with an ice pick, mistake, it broke the edge flange off.
The rubber gaskets were still pliable, so I used a bit of RTV silicone for automotive gasket making. This has never leaked. I did have to clean the oil from the machined casting area. I used engine starting fluid from a spray can to wash the oil off.
I looked at the McMaster site, and those are all threaded sight glasses. Only could see one that was a brass bodied press fit sight glass. The ones on my lathe just press into the molded rubber seal. The seal is placed on the plastic sight, and then pushed into the machined hole. Clearly for very low pressure head use only.
To remove your sight glass, I think you need to pull the lead screw, then drop the gear box from the apron, to access the inside, where there should be enough room to reach with your fingers and push the sight glass out.
OK, I did a quick internet search using "lathe sight glass parts" and got this first link:
https://www.ereplacementparts.com/oil-sight-glass-p-448659.htmlSee if your enco model is findable, but I'm guessing they are mostly the same sight glasses used on these imports.