Big Lathe – Little Parts

My wife wanted some metal nose pads for her eye glasses.  I thought I’d try my hand at making some….again.  More one that in a few.  So, relatively big lathe making relatively little parts.  At least it is for me.

To start I bummed a piece of stainless rod from Gill.  We’re not sure what kind it is because he salvaged it from a printer.  It about 0.3″ in diameter.  It seems to turn well though.


I chucked it up and turned it down to about 0.27″.  I was heading for 0.25″ diameter but then considered that a little bigger might be better.  I checked to get the ok and left it larger than I’d planned.


Eye glasses nose pads look roughly like a revolved T.  So, I needed to turn down the piece to create posts that hold the actual pads to the glasses.  I took a measurement from the pads that were in her glasses to figure out how big to make the posts.  Then, I copied the size and reduced the diameter down to 0.07″ by 0.125″ long.


To accurately move the carriage I have a dial indicator that I magnetically attach to the front bed way.  The magnet attachment is nothing fancy though.  It’s a 1/4″-20 bolt and nut tightened onto the mounting lug on the indicator that has a magnet recessed into the head of the bolt.  It works well and will slide if I accidentally move the carriage too far.


I swapped to a lathe bit ground a 45 degrees to chamfer the edge of the post and pad.  Not pictured here, but I swapped to a more pointed bit and put a small grove in the middle of the post to fit into the bumps in the glasses.


Next, I needed to part off the first nose pad.  Before cutting, I trammed the tool post with the dial indicator to make sure the cut off tool was aligned with the cross slide’s axis.  I fed the cross feed in and out while watching the dial indicator.  Then, I rotated the tool post and checked with the indicator again until the movement was less than 0.001″.


With the tool aligned, I moved it up until the side of it touched the end of the pad and zeroed the dial indicator.  Then, I backed out the tool and offset the carriage toward the chuck by 0.175″.  This value is calculated by adding the width of the cut off tool (0.125″) and the thickness of the pad desired (0.05″).   I cut in a little bit and then changed tools to chamfer this side of the nose pad.EP5

Next, I swapped back to the cut off tool and continued removing material until the part broke off.   Then I did it all over again to make the second pad.  Seen below are the parts off the lathe.  The smaller post is the one I want.  They larger one needs to be removed.


As I mentioned before, this is the second set of nose pads I’ve made.  In preparation for these, I bought some Starrett pin vises which made working on the pads much easier once they’d come off the lathe.  I turned to the grinder to remove the post.  I alternated between grinding and dunking the piece in water to make sure I didn’t discolor the steel.


The pad looks pretty smooth in the picture below, but it has grinding marks on it which I need to remove.


To remove the marks, I worked the pad on a 400 grit water stone by hand and then polished it up on the buffer.  I didn’t have the buffer when I made the last set of nose pads and it made a huge difference.  I used it to buff the faces and sides of the pads.


Here are the finished nose pads.  I’ve thrown the ruler and penny in to give you an idea for the size of the nose pads.  EP10

This picture shows the previous pads I’d made compared to the new ones.  The new ones have a pad that is half as thick and a more generous radius on the edge.  They’re probably a little over half the weight of the older ones too.


Anyways, here they are installed on the glasses.  Initial comments were positive!


I thinks is about as small a part as I want to make on my lathe.

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