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Series 61 oil drain problem

greasysmitty

Plastic
Joined
Jan 14, 2013
Location
Seattle, WA
I recently moved in a series 61, 16” x 54” machine and am cleaning it up and checking/flushing lubricants.

The change gear piston lube pump was not dispensing oil from any of the bijur lines, so I cleaned all its filter screens, disassembled and inspected. I find that with compressed air to the lube gallery, some flow is there, but the lines are likely gunky and need a solvent flush. This will necessitate draining the change gearbox oil.

Problem is, I can’t seem to empty the whole change gear sump when I open the drain plug at the end of the machine specified in the manual. There is still a residual 3/4” of oil in the gearbox sump, even after tipping up the machine several degrees. What am I missing here... it doesn’t seem like Monarch would be so slipshod as to leave a large collection area that can’t be drained. Do they expect you remove the selection knob cover and suction it out? That can’t be right!

Thanks for help in getting this beautiful beast back in order.
 
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Did you replace or disconnect the metering valves, or you're checking the lines with the valves installed?
Did you confirm that the pump itself actually works?

All oil tubings plugging, although theoretically possible, is very unlikely. But if this is a case, you can use something like WD40 in oil gun to clear the lines. No need to replace the residual oil in the gearbox after this.

Gunked metering valves is the most probable cause of the problem. They cannot be cleaned. Just replace them.
 
Not sure about this machine but the headstock on the 12CK has places that won't drain fully with the plug out. The quick fix is to use a turkey baster to suck up that oil and squirt it over where it will drain.
 
On my Series 60 there is a drain plug under the center of the gear box down into the controls cabinet. Unfortunately they failed to drill a hole in the casting below, so the plug is inaccessible. I took the front plate off and cleaned it out that way.
 
On my Series 60 there is a drain plug under the center of the gear box down into the controls cabinet. Unfortunately they failed to drill a hole in the casting below, so the plug is inaccessible. I took the front plate off and cleaned it out that way.

I wonder how you found this drain plug. Did you remove the gearbox and saw it? There is no drain plugs on the bottom of my Ser.60 gearbox. The only one is in the sump attached to the left end of the gearbox.
 
I wonder how you found this drain plug. Did you remove the gearbox and saw it? There is no drain plugs on the bottom of my Ser.60 gearbox. The only one is in the sump attached to the left end of the gearbox.

When I had the front of the gearbox open I spotted it.
 
Thanks to everyone for the prompt and helpful replies. I was able to get all lube points dripping by replacing all the metering valves, which in my lathe were all size "00". Bijur lists this as 2.5 cc/hr, which if you think about it is a pretty slow drip (on the order of a few drips per minute, which is what I get). I also cleaned up a little while I was there, removing swarf and accumulated sludge so that my new vactra would stay purty. I'm attaching pics for reference. Regarding the undrainable space, I used a syringe as suggested. I can see that there's actually a plug in that area exactly as Michael describes (you can see in pics), but alas they left it inaccessible with the gearbox installed. Probably not worth the effort to add access to it, given that you still need to pull the front cover for a deep clean / inspect anyway. My complements to Michael on his comprehensive documentation of gearbox removal on his series 60... really great and helpful work. Thank you for your effort!

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Another quick tip: I cleaned and inspected my piston pump and found it to be in passable shape, though I didn't rigorously check clearances. But I found that with the system reassembled, I couldn't draw enough vacuum to prime the pump... probably due to wear. The stroke actually quite small, probably 1/4" or so, even though the pump is capable of three times as much. I pulled the pump and manually operated the piston over its full range and had no problem priming it, then once oil is in it stays primed due to the inlet check valve. Leakby of the ISO68 lube may be present, but is minimal compared to the throughput. Also... I LOVE this machine. Monarch people are used to the thoughtful craftsmanship, but it is still a novelty to me. I've restored and refurbed a decent amount of ol' iron from "heavy hobbiest" grade on up to industrial stuff (most toward that side of the spectrum), and I can confidently say it's worth putting some love into this old beauty.

IMG_3415.jpg
 
Thanks to everyone for the prompt and helpful replies. I was able to get all lube points dripping by replacing all the metering valves, which in my lathe were all size "00". Bijur lists this as 2.5 cc/hr, which if you think about it is a pretty slow drip (on the order of a few drips per minute, which is what I get). I also cleaned up a little while I was there, removing swarf and accumulated sludge so that my new vactra would stay purty. I'm attaching pics for reference. Regarding the undrainable space, I used a syringe as suggested. I can see that there's actually a plug in that area exactly as Michael describes (you can see in pics), but alas they left it inaccessible with the gearbox installed. Probably not worth the effort to add access to it, given that you still need to pull the front cover for a deep clean / inspect anyway. My complements to Michael on his comprehensive documentation of gearbox removal on his series 60... really great and helpful work. Thank you for your effort!

View attachment 258743View attachment 258744View attachment 258745View attachment 258746


Adding access to that unusable plug via cutting a hole in the base casting is definitely not advisable just in case anyone else contemplates that. The base casting has a reservoir cast on top of the electrical components area that catches drips and such from the gearboxes and directs it out through the two holes under the clutch lever and into the chip pan. Cutting a whole in that reservoir would need to be done with the gearbox removed so you could tap the hole for a pipe plug in order to avoid oil dripping into the electrical controls area of the machine. Nice machine by the way and kudos for being so meticulous cleaning everything.

Jared
 
Yup, that was my thought... they intended the leakage to end up in the chip pan. Adding another plug just seemed like a pointless hassle.

Adding access to that unusable plug via cutting a hole in the base casting is definitely not advisable just in case anyone else contemplates that. The base casting has a reservoir cast on top of the electrical components area that catches drips and such from the gearboxes and directs it out through the two holes under the clutch lever and into the chip pan. Cutting a whole in that reservoir would need to be done with the gearbox removed so you could tap the hole for a pipe plug in order to avoid oil dripping into the electrical controls area of the machine. Nice machine by the way and kudos for being so meticulous cleaning everything.

Jared
 
Yup, that was my thought... they intended the leakage to end up in the chip pan. Adding another plug just seemed like a pointless hassle.

I just re-read what I posted and it didn't really come across how I meant it too. Adding access to that drain plug is a fine idea. It's just that doing so properly would be quite a time investment. Using a syringe as you did and others suggested is just as effective and a whole lot easier. I never really considered adding access to mine when I had it apart. I plan to change the oil regularly so hopefully it doesn't end up getting nasty again over time.
 
Another quick tip: I cleaned and inspected my piston pump and found it to be in passable shape, though I didn't rigorously check clearances. But I found that with the system reassembled, I couldn't draw enough vacuum to prime the pump... probably due to wear.

It makes sense to replace the filter felt at the bottom of the pump. I used synthetic filter felt bought from McMaster-Carr. As far as I can see, the current product # is 6376T7 (mine was 51625K17, but the new one sounds the same: 100 micron, 0.11" thick, white polyester felt).

Enjoy the lathe: it is, indeed, great.
 
I dunno whether to start a new thread on this or just keep dragging one on, but...

First, a question: can anyone post a pic of the details on the oiler on their compound? Mine just has an open hole with a brass insert, which was filled with swarf and pisses me off mightily. There is a small steel floating piece left inside that must have held the original cover captive, but I have no guess how it was meant to work. This is for the oiler for the compound handwheel, lead screw, gears, etc.

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Also: I pulled the lead screw and feed rods from my machine this weekend, and with the copious info on this forum I'd describe it as an easy task. Specific shoutout to the late Harry Bloom / Beckley23 and his kick ass, selfless screeds. I've got the apron dropped about two inches and hanging from two cap screws, ready to heft off with a buddy when I get a chance. This is all in service of cleaning and inspecting, probably at least replacing the carriage metering valves, etc. Here are a few pics in case they might help others. One thing I noticed in Harry's thread was that he cursed himself for marring up his lead screw with a pair of channel locks; there's really no need for this boorish behavior when god hath provided us the chain wrench, or barring that the strap wrench. Easily grabs the shaft securely with no damage! You'll also find a swing type spanner wrench incredibly helpful to get the spanner nut off the lead screw; I was able to remove it without even pulling the gearshift cover, only the top cover from the change gear box.

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