[modeleng] Re: Needle roller bearings

I did exactly this on my 2X Tich.  I wanted to use the hardened inner race so I 
reworked the journal so as to bring an axle stub end of decent diameter through 
to the wheel faces.  In order to accomodate the bearings and sleeves, yet keep 
things near to the original journal envelope a few compromises had to be made 
and a balance struck.  This wasn't as easy as it might spound.  Now, hearing 
Baggo's very interesting experience (and data), I'll think seriously about 
going IR-less on the next job.

I learned from experience that when using drawn cup needle roller bearings 
(DCNRB) it's important to adhere as closely as possible to the manufacturer's 
press fit recommendation.  I also am a proponent of dust seals, especially on 
the inboard sides, but between manufactured neoprene seals and O-rings a decent 
seal is relatively easy to arrange.

I also like central oiling and an oil hole in the cup is a necessity for this, 
however dispite what the catalogues say, DCNRBs with factory oil holes are 
becoming scarse to non-existant.  I used one of the single most widely used 
sizes of bearing from Torrington for my Tich, and OH (oil hole) type were 
listed everywhere, BUT they were't actually available, anywhere, even at he 
Mfg.  They would gladly manufacture my OH bearings for the paltry sum of $250 
each.  I could have them at the regular (and very reasonable) price IF there 
was a run plannned, but there was no demand, so no run was planned.  So much 
for the "Can-do" spirit in the USA.  I ended up putting oil holes in my shells 
using a diamond burr in a hand grinder and flushing fastidiously with 
pressurized solvent afterward.  So far so good.

After seeing the great difference in rolling resistance between stock with 
needle or roller bearings and those with plain bearings in operations at our 
club, I decided to always install rolling bearings of some kind on everything 
possible.

Regards,
Harry

-----Original Message-----
>From: David Archibald <deeja9@xxxxxxxxxxxx>
>I fitted them to my 5"g loco. I used plain steel axles and hardened sleeves, 
>but I recessed the axles where the sleeves go so the outside diameter of the 
>sleeve is exactly the same as the axle.

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