Oilite bronze bearing acceptable wear

[Freenet]

Working on my Boxford S200 I found some wear on the Oilite bronze bearing supporting the small spur gear side (the axle with the v-belt pulley).
Wear measured to ~0.1mm (~4thou). Now the questions I have:

- is this wear excessive? the axle is 19.05mm, so is 0.1mm relative to a 19mm bore
- what clearance would be adequate for such a bearing? I mean as new.
- I to not have "Oilite" sintered bronze available, I am thinking to plain bronze and a 0.02mm clearance, should it be ok?

 

[RaisedByWolves]

I would want that fit new to be .0015- .002ish, so no, the wear is not excessive at all.

Bronze is going to eat your shaft in this application, buy olite.

 

[benmychree]

Regular bearing bronze should not be a problem with wear, that is what it is made for, after all, I refer to our sae 660 bearing bronze, or equivalent.

 

[Freenet]

Ok! this sounds quite good, for now I will keep the Oilite bearings as they are as I never used the machine, I will work on them later, if required. The work to get this bearing out is ~20 minutes.

From your experience what would you consider to be the max acceptable wear? (The machine manual specifies to use a thin oil, SAE 20).

In the mean time i made a replacement nut for what i suppose it would be the X axis of this machine.

 

[benmychree]

If the wear effects the operation of the machine, that is the time to fix it, a light oil is necessary if using oilite, it needs to penetrate the material easily. Personally, I do not like oilite for anything but very light duty applications.

 

[Freenet]

I am quite confused as why Boxford used Oilite radial bearings on this machine but thought to use axial ball bearings on the same shaft! I explored the option of using needle bearings and found something that it would work as a direct replacement but requires a hardened shaft. Every shaft on this machine is made of very soft steel, so in the future it would make sense to recreate the shaft in a hardened steel version.

Thank you everyone for your quick input!

 

[RaisedByWolves]

I am quite confused as why Boxford used Oilite radial bearings on this machine but thought to use axial ball bearings on the same shaft! I explored the option of using needle bearings and found something that it would work as a direct replacement but requires a hardened shaft. Every shaft on this machine is made of very soft steel, so in the future it would make sense to recreate the shaft in a hardened steel version.

Thank you everyone for your quick input!

No offense, but you are looking to solve problems that don’t exists and in the process causing more issues.

On a shaft that is just carrying a pulley .015 wear might concern me for that size shaft, might not. Can’t say for sure as I don’t know the machine.

As to recreating the shaft and hardening it?

Better be prepared to grind it to final size in at least three places because it will not go through the hardening process without warping to a degree.

 

[Freenet]

No offense taken, I do not want to overthink it, that is why I asked, I have no experience with bronze bearings and the shaft seems to be "sloppy" when compared to the other shafts on the machine. I consider this bearing important because it's near a pinion driving the bull gear (on the same shaft on the opposite side there is a pulley, this bearing is fine). Will see how it works and fix it if required.

 

[RaisedByWolves]

No offense taken, I do not want to overthink it, that is why I asked, I have no experience with bronze bearings and the shaft seems to be "sloppy" when compared to the other shafts on the machine. I consider this bearing important because it's near a pinion driving the bull gear (on the same shaft on the opposite side there is a pulley, this bearing is fine). Will see how it works and fix it if required.

Ok, yeah while it might seem like an issue, those two gears will be happy for a looong time with way too much clearance.

I can’t touch it to get a feel for how much play you’re experiencing but often these things become bug bears in our minds and seem more acute than they actually are.

Not sure where the ball bearing is in relation to the two olite bushings, but that was an acceptable cost saving measure in boxfords eyes, so based on their reputation I’ll give them a pass.

A $1 bushing here that is easily replaceable probably saved the original purchaser $200 in added costs to have bearings in their place.

 

[Parlo]

Don't know if this helps but 19.05 is exactly 3/4" .