New Oilite Bushings.....Drill Holes?

[Spokerider]

Got some new oilite bushings for the 101.07301 lathe. They do not have any oil holes in them.
Should I drill small holes to line up with the oiler cups? Would this direct passage of oil to spindle be of benefit, offering *better* lubrication vs oil seeping through bushings?

Thank you.

 

[Brnoczech]

I replaced the oilite bushings on the countershaft on my myford lathe. The ones in the lathe when I purchased it (used) had holes drilled, and even through he bushings and shaft appeared to be in good shape the oil cups drained regularly and a lot of oil escaped out the side of the bushing. The oilite bushings I ordered from Myford did not come with any drilled holes and I installed them without drilling them. I did some research and my understanding after a lot of reading is that because the oilite bearings are oil impregnated you don't need to add oil through a hole to the insternal surface of the bearing. Apparently just having the oil from the cup available to the outside of the bushing allows some oil to be absorbed into the bearing (very slowly). On another note I read that trying to machine the bearings will cause the microscopic pores in the bearing to "smear" such that oil cannot be absorbed or released as intended. Without drilled holes the bearings on my lathe seem to work OK. Any oil they absorb through the cup is pretty miniscule in amount. Should also mention that the Myford shaft does not have the spiral groves that are normally associated with distribution of oil that is fed from a cup to the inside of the bearing.

 

[Tozguy]

From my limited experience, porous bushings come soaked with oil and do not require holes or grooves to be added.
Brno has summed it up nicely.

 

[Spokerider]

Thank you Brno.
The ?original? bearings in my Craftsman don't have holes in them either.....but the little oil cup [ on the right side ] seems to drain pretty darn quickly with the left side cup draining much slower. That oil is going "somewhere", be it out between the bearing and the bearing retaining cap, or, it's seeping through the oilite bearing very quickly......or a combo of both.

How much oil / at what rate, should be absorbed by oilite bearings? If you're filling the little oil cup and the level is not going down over xx period of run time, how much oil is actually getting to the spindle? That be my main concern with installing new bearings.

 

[wa5cab]

Spokerider,

Answer to your first question is no, you don't need to drill holes in the new bushings. Answer to your last two questions is I donlt know. I've never seen any published data on that. Just keep the cups full.

 

[matthewsx]

The oiling system on most older lathes is a "total loss" system. That means you keep adding oil until it comes out somewhere and if it's not leaking then you should check the oil fills. Kinda like my British cars were

Cheers,

John

 

[Brnoczech]

I would say that if your current bushings do not have a hole in them and that one of the cups is draining quickly then perhaps the external fit of the bushing is on the loose side (or maybe it's getting out of the cup fitting). If you are losing a lot of oil from the cup then I would think a close examination might reveal where it is coming out. My only experience is with the Myford and very little oil now goes out of the cups. I think the pores in the oilite are pretty microscopic and probably little oil is absorbed from the cup. If the pores were large enough for oil to flow through the bushing easily then these types of bushings when installed without cups would likely dry out/wear out pretty quickly. I would go without the hole myself.

 

[Spokerider]

I would say that if your current bushings do not have a hole in them and that one of the cups is draining quickly then perhaps the external fit of the bushing is on the loose side (or maybe it's getting out of the cup fitting). If you are losing a lot of oil from the cup then I would think a close examination might reveal where it is coming out. My only experience is with the Myford and very little oil now goes out of the cups. I think the pores in the oilite are pretty microscopic and probably little oil is absorbed from the cup. If the pores were large enough for oil to flow through the bushing easily then these types of bushings when installed without cups would likely dry out/wear out pretty quickly. I would go without the hole myself.

Thanks Brno.
That's kinda my thinking too. Too much oil, other than being messy, can't hurt. Now too little oil...…….

BTW, the spindle oil cups on this little 6" craftsman are tiny...like 5/16 in diameter and 1/4" tall. Not much "capacity" to them at all.
I think I'm going with small oil holes in the bushings. Spindle oil is cheap enough.