Porter 300 CM with grease in the bearings

[John Hovard]

Hello,
I just ventured into vintage machinery with a purchase of a Porter 300 CM jointer from a military base. Built in 1952 and looks to be complete and in good shape. Someone decide to replace the oil bath and oil fittings with grease. The outboard bearing appears to be original with M 306 K FAFNIR stamped on bearing. So the conclusion is that the bearing wasn't replaced and the grease is a mistake. So I'm converting back to the oil. The questions is how to flush out any grease in the inboard bearing next to the motor. I'm considering using mineral spirits. Any suggestions? Should I do the same with the outboard bearing? I'm not looking forward to breaking down the head to remove the grease.
In addition I need to disassemble the infeed table and mechanism. Everything is extremely stiff and stuck. Any advice on that process? Dos and Don'ts?
Thanks in advance for any suggestions.
John

[David Kumm]

Obviously the Porter worked a long time with grease but they were originally an oil bath lubrication system. The large 63xx bearings were precision and in oil could run at a much higher rpm than the 3600 delivered from the direct drive. Probably why grease didn't hurt anything. I'm not convinced the bearing is original. My Porter and others had a higher precision mm306 ( back is probably 6308 ). In Fafnir language m306 is an ABEC 3 6306 phenolic cage bearing. The mm306 is more like an ABEC 7.

If the grease is still good, flush out what you can, mineral spirits or kerosene will work. Then I'd add light oil and run the jointer, take off the end bell and clean the grease oil mixture. I'd still remove enough of the motor and bearing housing to make sure the bearing was clean and not crusty stuff was there. Just trying to dilute the grease and run it out the overflow is not really effective. You want to see both bearings and you do NOT want to run them, even for a few seconds, dry. 6306 and 6308 ABEC7 precision bearings can be found on Ebay if you study nomenclature ( every bearing manufacturer is different ) and know what to look for. I'd guess 100-150 each for the Fafnir, RHP or SKF equivelant. 300-500 new in a bearing store. P4= ABEC7 and you will see RHP uses that. If you swap, pm me and I will look for bearings and send you a link. Dave

[John Hovard]

David,
Thanks for the response and information,
In my attempt to flush the inboard bearing with mineral spirits I discovered the mineral spirits leaking out and onto the spindle/cutterhead. It appears that the seal has failed.
Before i do anything else I need to replace that seal, can you give me any advice on this? Is it a packing material? or is the seal part of the bearing? Do I replace the bearing with one that doesn't need oil? i hope I have descended into a rabbit hole.
John

[David Kumm]

I see you posted over at owwm.org and Jeff is a great resource. I've not had my inboard ( motor end ) bearing out but all other seals on my Porters were paper. excess oil will bleed into the head and exit so as to not allow over filling. Bearings with too high an oil level will run hot. Is there a drain plug on the motor end? I don't remember. You will need to remove the motor housing and stator to access the bearing. You can then see if grease or oil has gotton into the motor. It probably has 50 lbs of saw dust and grease caked in it anyway.

Porter was one of the best jointers ever made and well worth the effort. If the tables haven't been reworked, you should be able to see straight lines on the surface as they were cold planed rather than Blanchard ground, and still within a few thou across the width and 8' length. Much tighter spec than new jointer tables. Dave

[John Hovard]

Well, this is a much bigger deal than I thought, the end result will satisfying. In the process of inspecting the bearings we discovered the leads coming out of the stator need replacing. The insulation is crumbling off revealing exposed wires. Likely ran hot. So we will need to have it rewound/re-wired, if anyone has suggestions on where to send it please PM me with the info. The other curious issue is the inboard bearing is labeled McGill 308, I assume not original. I have decided to give up on the oil bath bearings and put in new self aligning sealed bearings, any recommendations would be appreciated.
The most pressing issue is removing the cutter head. The stator is removed exposing the spindle and cutterhead but I just can't get it to slide out of the outboard bearing. Any suggestions would be appreciated.
John Hovard

[Andrew Hughes]

Can you screw a bolt into the end of the shaft? Or a short length of all thread? If so use it to your advantage to get the front bearing moving out of the housing. leverage wise
Thats how I did the bearing on my direct drive jointer.Its a Oliver but pretty much the same predicament.
Good luck and you have a nice machine.
Porter 300 would be the only jointer that could hold a candle to my Oliver.

[David Kumm]

I've not had mine out but if there is nothing to lock the shaft in position, a brass or aluminum drift pounded on the outboard end should push the shaft towards the stator end. I hope you rethink the bearing swap. Sealed or shielded standard stamped cage bearings will run fine for a hobby machine as the 6306 and 6308 have an rpm limit of 5300 vs 20000+ for the ones you are removing. With the machine designed all ready for oil, all you need is to cut some gaskets. You don't need or want self aligning bearings there as Porter took pride in machining their castings for an accurate alignment with deep groove bearings. There should have been a bolt and mechanism under the outboard end to level the head to the machine. Everything is very precise and designed to run 24/7 when using the precision oil bearings. oliver made a great jointer ( I have one too ) but did not use the quality bearings or adjustable head that made Porter so special. Dave

[Bill Dufour]

I would replace with modern bearing using modern grease. Seal and lubrication technology has much improved in 75 years so a sealed bearing will be fine as long as rpm is under 4500 rpm or so.
Bill

[Martin Wasner]

I would replace with modern bearing using modern grease. Seal and lubrication technology has much improved in 75 years so a sealed bearing will be fine as long as rpm is under 4500 rpm or so.
Bill

I'd listen to Dave. Old equipment is his thing and he's a wealth of information on the subject.

[Darcy Warner]

Any motor shop can re-lead a motor, easy an not very expensive. I have it done all the time.

I would retain the oil bath set up. The bearings that are in it may be fine once you pull apart and clean them.

[David Kumm]

One thing to keep in mind is that although a standard sealed bearing will handle the rpm, it provides less than half the load rating of a precision bearing. Not relevant in many applications but important when spinning a 5" spindle under radial load. Dave

[John Hovard]

My motor shop indicates that the black resin material is difficult to remove, even if he tried just to open up the area where the leads exit it will damage the magnetic wire and will unlikely result in a satisfactory repair. I have decide to rewind the motor.
This reminds me about the guy who bought a classic wood sailboat for some day sailing. It only need minor TLC but the boat was a classic. He found something else he quickly was restoring it to past glory.
Not sure about the bearings, am now leaning back to the original high precision oil bearings. I'm just troubled about my ability to seal them.
Have decided to repaint the rascal.
John

[John Hovard]

oops, typo meant to say "unsatisfactory repair"

[David Kumm]

pm'd you. Dave