Friday, December 20, 2013

Sherline Mill - X Axis Oiler

Just like all Sherline mill owners I have had a hard time oiling the X axis but when I saw the X axis oiler option for new machines from Sherline it got me thinking about how I could do a retrofit on my two mills.

I am always looking for "no cost" upgrades like my Y axis Extension so this is what I came up with.

Using (for the 1st time) my 1/8" tube bender I created a perfect little work around.

I made the aluminum one as a test but didn't have enough soft tubing to make the finish versions. So I switched to copper tube, the copper had to be annealed 1st.
The room above the spindle is very slim so I crushed the tube about half way. I made the little hold downs and the flaring tool too.

Ultimately the fill end of the tube has to be above the exit end as a result the tube remains full of oil in between oilings, I drop a small steel nail into the top to keep dirt & chips out and use a magnet to pull it out.

It's easily removable if it gets in the way but it is below the top of the ways so I don't think there will be any issues.

I think it makes a perfect no cost upgrade, I'll report on any issues as they come up later. 

Saturday, December 7, 2013

Sherline Lathe - Back lash adjusters

Wishing to add backlash adjustment to my manual lathe I noticed Sherline's new offering of what is essentially the CNC Z axis lock modified to fit the lathe. I understand that backlash in normal lathe work is almost a non-issue but having the gibs tight but not too tight is the goal. Also for cut-off work you would hate to have a wondering X.

I thought that I would buy the 3/8 - 20 LH tap instead of buying the parts and found one only at The Little Machine Shop.

Not caring for the simplistic design from Sherline I thought I would try something of my own.

P/N 4417Z CNC: Lathe Lead-screw Backlash Adjuster Upgrade, $35.00

Each time I make an addition to the Sherline machines I take great pains to digitize whatever part of the machine needs to be designed to or around and this was no exception.

I came up with this, the motion for tightening the lock lever is CC in this view.

I got a good millings out of 1/8" 6061 - T6 for the adjuster arm and 1/2" thick brass for the lever.

Had to make a little fixture for the lever so I could hold it during milling. 

For the adjuster I leave .010" at the bottom and have to cut and trim afterwards.

I also added the standard star-wheel for the Y axis too.

To get the lever in the adjustment range required for this to work I had to slowly mill the saddle nut down until the lever ended up in the lower right quadrant. This is where machine repair patience is learned; mill, assemble, disassemble, mill, assemble, disassemble, mill, assemble, disassemble, mill, assemble. 

After all that I got the Y axis down to a good feeling .003" backlash but I could only get the X axis down to .008" before it felt too tight? Maybe after some wearing-in I can settle into a better number.
NEXT DAY: I rediscovered the Sherline detail regarding the hand wheel position; the hand wheel can and should be tight up against the mounting, in the case of my X axis it had become very loose about 0.008" loose. After tightening it I discovered that I have essentially 0 backlash with my new system.

I know; it was about 8 hrs work when I could have just bought the thing for $35 but... now I have the LH tap, and more experience on the mill, plus more confidence in tear down.