PM-728vt design change request. Potential oil line failure.

[sunrise305]

Are these oilers installed by PM or the factory?

 

[rwm]

Mine is the PM DRO. Very satisfactory.
R

 

[rwm]

Can someone comment on whether their line to the Z stays primed with oil?
Thanks
Robert

 

[sunrise305]

Mine does not seem to interfere:

View attachment 378919


The line that goes up to the Z axis does not stay primed. It leaks down and fills with air. Anyone else? Is this a valve issue? I thought about adding a check valve on the outflow port.

Robert

Edit: Adder- it appears that your 3 way connector is mounted backwards. Can you flip it?
R

A one-way valve added to the Z line should solve this problem.

 

[addertooth]

When I use the pump, the Z-Axis is the last to "burp". They are off a common feed, so the Z line drains down (due to gravity), and continues to flow down the the X and Y axis after pumping. As several people have mentioned, a one-way ball valve on the Z axis line will fix this. Those "check valves" cost about ten bucks on eBay.

 

[rwm]

Mine are on separate ports from the pump (unless they are linked internally.) I will look for a check valve. What is the tubing size designation???
Robert

 

[addertooth]

I mis-spoke. Mine has two lines. One for lubricating the Z axis, the second line is for everything else. I see no clear indication the Z axis line has a check valve, and I bet internally the two connections go to the same place.

 

[rwm]

The fitting out of my oiler appears to be M10. The oil lines measure 5/32 OD = 4mm.
I found brass check valves here:

Fitting Metric M10 M10x1 Male X Compression 4mm OD Tube Check Valve One Way | eBay

Check Valve Fitting One Way Direction from M10 Male to Tube (see the arrow on the listed picture). We also provide the Check Valve with the opposite direction.

www.ebay.com

I also ordered a M10 90 deg elbow. I will replace the elbow on the oiler and then add the check valve coming off the elbow. Pretty simple fix if it works. I will keep y'all posted.
Robert

 

[rwm]

I have some news on this. I received my new fittings today and took apart the old line to install them. To my surprise, there is a check valve installed in the factory elbow! Assuming this may be defective, I went ahead and changed the elbow and installed a new inline check valve as shown above. I will monitor this for a week and report back.

Robert

 

[rwm]

Reporting back- my Z axis lines are now filled with air again : ( I must assume that these check valves are not "checking" and that the oil is draining back into the reservoir. I am not sure how to proceed?
Robert