Bought a Rockwell 21-120 Mill

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

Moderators: Harold_V, GlennW

JPar
Posts: 8
Joined: Fri Nov 27, 2015 10:54 pm
Location: Mayoville, MN

Re: Bought a Rockwell 21-120 Mill

Postby JPar » Fri Oct 06, 2017 2:22 pm

The horizontal spindle hasn't been used in years, so I'm thinking it might be a good idea to drain and flush out the spindle oil reservoir, and also the back-gear box. If possible, I'd like to do it without disassembling everything. I would like to hear from anyone who has tried this, and whether or not you were successful.

Thanks,
John

spro
Posts: 6687
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Bought a Rockwell 21-120 Mill

Postby spro » Sat Oct 07, 2017 4:00 pm

The gearbox and the spindle bearings are two different things. The information that I have, says that the gear box is filled with 7 FL. oz of EP-140 gear grease. The spindle roller bearings use CAT # 24-812 spindle oil ( having a viscosity of 58-60 SAYBOLT at 100* F ). The bearings have outside oil
seals to prevent the grease. In oiling the spindle, there is a breather screw which must be removed and THAT is very important for it to be flushed.

spro
Posts: 6687
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Bought a Rockwell 21-120 Mill

Postby spro » Sat Oct 07, 2017 4:09 pm

From what I read, the spindle is oiled near the bottom of the casting and that can't happen unless there is a breather atop. There is some sight glass for the level. This is from PM-450-02-651-0001 dated IM-7-15-68 .

JPar
Posts: 8
Joined: Fri Nov 27, 2015 10:54 pm
Location: Mayoville, MN

Re: Bought a Rockwell 21-120 Mill

Postby JPar » Sun Oct 08, 2017 4:28 pm

I discovered that the back gear box has a drain plug. That will make draining & flushing the it a lot easier; no worries there.

The spindle reservoir is a different story. The only usable access is via the filler hole. There is a breather hole as spro suggests, but it's small, about the size of a 10-32 machine screw. The screw is missing. That might explain why the oil is so dark, almost black. Definitely needs to be drained & replaced!

spro
Posts: 6687
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Bought a Rockwell 21-120 Mill

Postby spro » Mon Oct 09, 2017 7:04 pm

It is a great machine. Rockwell engineering knew what they were doing in those times. Everything was balanced together.
Then again, some weren't.

JPar
Posts: 8
Joined: Fri Nov 27, 2015 10:54 pm
Location: Mayoville, MN

Re: Bought a Rockwell 21-120 Mill

Postby JPar » Sat Oct 14, 2017 10:24 pm

Can someone who owns one of these mills please explain how to lube the bevel gears that are inside the knee? I followed the instructions in the manual I have, but when I pull back the shield to expose the hole, all I can see is the cross slide feed screw. What am I doing wrong?

choprboy
Posts: 167
Joined: Sat Oct 29, 2011 11:23 pm

Re: Bought a Rockwell 21-120 Mill

Postby choprboy » Sat Oct 14, 2017 11:22 pm

Crank the saddle all the way to the front stop, which drags both cover plates to the front. Reverse and crank the saddle to the rear, dragging the top cover plate, and stop when the second cover plate starts to move (about half way back). Push the top cover plate to the rear (under the saddle) with your fingers to expose the hole. If you need to, you can then crank the saddle back another 1/4~1/2" and push the top cover plate again to get a little bit more opening.
Image
Image

You can do the same in reverse to expose the hole from the rear. In both case, you can clearly see the crossfeed screw, but the beveled gear is very difficult to see. Probably best is from the front right corner, get down low and peer in, you can just see it under the screw. I just squirt some way oil on the screw and run the table back and forth a few times, it dribbles off the saddle nut and down onto the bevel gears.
Image

JPar
Posts: 8
Joined: Fri Nov 27, 2015 10:54 pm
Location: Mayoville, MN

Re: Bought a Rockwell 21-120 Mill

Postby JPar » Sun Oct 15, 2017 3:09 pm

Choprboy, thanks for the pictures and description! By exposing the hole to the rear, and using a small flashlight, I was able to access the gears well enough to see and oil them. They looked like they hadn't seen oil in quite some time.
John


Return to “Milling Machines”

Who is online

Users browsing this forum: No registered users and 6 guests