Replacing The Gearbox Gasket

First thing you want to take a look at when you get your lathe is the gasket underneath the top lid of the gearbox.  The lid is held in place with the 8 Allen-key screws.  Remove these screws and carefully pry the lid up.  There's a groove cut in the metal on 3 sides around the top of the gearbox.  As oil splashes around the gearbox, it splashes up onto the lid and drips into this groove.  The groove is channeled towards the headstock and directs the oil to the front headstock bearing.  In many cases, the gasket, a cheap "cardboard" one,  has spread out and blocked the groove so that oil can't get to the front bearing.  It also blocks the oil that you squirt into the oil hole on top of the headstock.  And pretty soon you have instant front-headstock-bearing failure! 

When you remove the lid, inspect the gasket to make sure it hasn't crowded over and onto the groove,  blocking the flow of oil, particularly towards the headstock and into the hole leading into the bearing.  If the gasket has crowded over the groove, you need to make a new gasket.

Which is also another reason for making sure that your metal lathe is properly levelled.  With the lid off and the gasket removed, drizzle some oil into the groove.  Make sure it flows towards and into the bearing hole.  

It's easy enough to make a new gasket. The gasket material is Victor Renz JV127-31527 with an SKU number of 25975-32915-3. It measures about 1mm in thickness. (Comes in other thicknesses but the 1mm thickness will do the job.) Readily available at your local NAPA AutoPro store just around the corner from you.  If you don't know where, just ask your local garage (I did).   

Making the new gasket is relatively easy with a box-cutter (utility knife), a straight edge, and a drill.  Use the lid as a pattern to cut the outside edge of the gasket.  Measure the width between the outer edge of the gearbox and the outer edge of the oil channel.  Mark the dimensions on the gasket material and cut out the centre rectangle. 

When drilling the holes for the gasket, use the 8 holes in the lid to select the proper size drill.  For drilling the holes, it helps if you have a drill press.  Place the lid on top of the gasket and place the whole setup on top of a scrap piece of plywood on your drill table.  Using the lid as a guide, drill the holes.

Voila!  New replacement gasket.

Before you replace the lid, brush some oil on the gears so that they are well lubricated from the get-go.  Replace the lid and turn on the lathe.  Remember that sound.  In the future, if that sound changes, you know it's time to inspect the lubrication of the gearbox.