[tpmx57]

I have a series II cnc and have a question about the oiling system.
I have check my pump and it does run as long as the spindle is running but i never see the plunger drop to execute an oiling cycle.
I pull the plunger on the outside up and let it oil this way.
How do you tell if internally ths oiler is working?

[NorthBranch]

I have a series 2 r2e3 '84 with the same situation. Plunger up but little oil on the ways. Alex

[Caprirs]

Those pumps have a little motor inside with a cam that lifts the plunger, then drops it. There should be a tag on top that states the interval between strokes. On yours it's likely about 30 minutes. The pump should be "on" constantly, always getting power. Every 30 minutes the plunger will gradually rise, then drop. You can get pumps with intervals ranging from a few minutes to an hour or more. Although some pumps can have the interval adjusted, most cannot, they are fixed.

The amount of oil per stroke is determined by adjusting the thru-rod usually between 3-6 cc per stroke.

At each oiling point (ways, quill, ballnuts, etc.) there is a meter unit like this to control the amount of oil dispensed at that point. When the plunger drops, pressure rises in the hydraulic lines because all the meter units are initially closed. At each meter unit, the oil is dispensed and then the little valve closes again to keep the hydraulic line pressurized.

Add up the volume of all the meter units on the machine to determine how much oil is required per plunger stroke to supply all points with an adequate amount. If you adjust the pump plunger's volume too low, some point on the machine will be starved of oil. Over time, that area will rust or wear prematurely.

[9 1/2]

Caprirs, thanks for the excellent info on this unit. I've always wondered how it works as I too have a Bijur on my mill, as well as most of the units at school.

Owen

[Dennis Storzek]

I have a couple manual Bijur lube pumps on manual machines, and the electric timed pump on a BOSS mill, and all have been trouble free. However, I’m also responsible for an injection molding press with a Bijur system on the clamp toggle that must have 30 lube points, and cycles once every machine cycle, so this system sees more cycles in a day than one on a mill sees in a year. Here are some of the things I’ve found to look for:

The pumps have a strainer / filter on the inlet side, which should be down in the oil at the bottom of the reservoir. If this filter is clogged, the unit won’t pump oil. There should be some way to unbolt the pump and pull it straight up out of the reservoir (sorry I can’t be more specific, but Bijur makes about twenty different pumps). The bottom of the filter should unscrew. Disassemble and clean. May as well dump the oil in the reservoir and clean it too.

Put the pump back in the reservoir and add some clean oil, but leave the line to the fittings disconnected. Run the motor to a point where the pump is off the cam, and try the hand pump. A spurt of oil souild come out the outlet with each stroke. Put some clean paper under the outlet and put power on the motor; it should eventually time to a pump cycle and pump a spurt of oil.

These are a closed pressure system, that distribte a very small volume of oil. One leaky fitting and all the oil exits there, without opening the meter units. Check the system for broken lines or leaky fittings.

Likewise, if there was a leak, then it is likely all the oil has drained back out of the tubing. At the volume these pumps put out, it takes a long time to expel air in the lines. One needs to break each line at the connection to the meter unit and pump repeatedly until oil comes out. This can take a lot of pumping.

If the meter units haven’t opened in a while, they tend to fill up with crud that the moving surfaces pack into the lube port. You’ll need to unscrew the meter unit and dig around in the port to see what comes out. Use brass wire as a probe so you don’t score any bearing surfaces. If it’s bad, you may have to pull the table, saddle, and knee to clean them.

I’ve never had much luck cleaning and testing meter units; this far into the job, I just replace them. Order some new compression collars. The Bijur collars have a shape that permanently crimps into the tubing. You can normally break a joint and make it again without problems, but if you have to cut the end off the tube, the old ring won’t seal on new tube. Sometimes the tube has seen so much motion that it won’t seal and leaks at the nut (admittedly, this is a bigger problem on the molding machine than on a mill, but it is possible). In this case, the end of the tube needs to be trimmed back and a new compression collar will be required.

Good luck,

Dennis

[MrBoss8]

There is also a pressure gauge in the same enclosure as the pump, and it has a red pressure verification pointer, you turn it lightly CCW to reset it, then it shows the pressure obtained since the last resetting of the pointer. This just verifies if the pump is pressurizing the system and to what pressure.