First off, that you for your time.

I have a Chinese Grizzly lathe 12x36” that’s leaked since I got it and it’s been irritating me and I decided to tackle it so my floor isn’t an oil slick.

One of the leaks I found is the sight glass to the headstock.  I snugged it up on the viton backing washer.  It still leaked, I drained the oil and cleaned the metal fines out again and permatexed the sight glass in figuring I’d fix that once and for all.  I washed out the gear box with kerosene to get the rest of the metal dust out and found that the sight glass continues to leak......right around the glass and the glass gasket.   I pulled it, cleaned up and set it on a dry paper towel face down and filled the cup with K1.  It in a few minutes wetted the paper towel.  

The cheap sight glass appears the same as an Uxcell.

https://www.amazon.com/dp/B0B8CSNZRZ?tag=arfcom00-20

further looking at its twin on the front gear box it’s sight glass is also weeping at the bezel.  It loses so little oil I never had to top that one off.  Only the headstock oil leaks down over a few weeks.

They appear to be typical cheap Chinese crap.  


Are there good and bad sight glass makers? I need to replace the M20x1.5 threaded in sight glasses.  

20+ years ago my Dad bought a Chinese metal working lathe from HF that leaked like crazy. He was only a hobbyist so didn’t care.
It was a 6 foot long table top type lathe. He mounted it in a long plastic bin to catch the leaks.
Cool part was he tapped some hose fittings into the head stock and mounted some oil reservoirs to keep the level where it should be all the time.
I wish I had kept that lathe when he passed but logistically was impossible.

I'd just order one of the right size from McMaster Carr, or MSC and be done with it.  Our shop occasionally has to replace sight glasses on various machines, and we have yet to experience a leak at the glass itself with new replacements.  Only when an improper job was done to repair one, which we could not obtain quickly enough, would leak at the glass itself.

You have a lathe, make a body of your own and purchase a piece of glass to install.  Seal the new body with something like Yamabond, it's resistant to oils/fuels and doesn't ever harden so it's easy to remove.

Ha!  I never even thought of that.   I don’t know why, the first lathe project I did was levelling feet for the lathe.

I did think of just taking oil safe permatex to the junction of the glass and the metal.

Meh, I just ordered some brass ones with a more robust bezel on them.  9.95 for 2.   And a micro plane grater for the kitchen.

Since both OEM ones leak, one way faster than the other, I assume they were manufacturing defects.

Wife loves that thing.  Uses it to put a swipe or two of fresh cinnamon in her coffee.