"Karl Townsend" wrote in message
...

You need a good interchange chart to double check but in all likelyhood
the first 2 on your list are simply #206 in Barden and something like
2mm9206 in fafnir for example.

http://www.ntnamerica.com/product-su...rchange-search


The last few digits (IE the "ctc/c7xx" ) part of the bearing are
generally not important for the purposes of a spindle bearing--main
thing
needed being physical size ( ID OD and thinckness ) and actual contact
angle.

Can you tell me how to measure the contact angle on my existing
bearings by chance? here's the chart i got from the above link with
the numbers off the bearing itself (SKF7206 B G)


Sorry no way to measure after the fact

http://www.ntnamerica.com/products/b...id=RBSRA&ctc=B

It gives me the code for contact angle not the actual number


As a practical matter, contacy angle will vary depending upon the ratio of
how much load is to be placed on the end of the spindle as compared to side
loading.

So for machine that is used mostly for drilling you want to take that in
consideration as opposed to if you are going to be millling all of the time
then you want a higher rating in the direction so your bearing set will more
closely approximate a standard ball bearing IE something like 15 degrees


Reason I ask, I found this in a fafnir 3M (25 degree contact angle)

25 or 30 degrees is about middle of the road for a milling machine although
Fadal uses a 15 deg in the lower set and 30 deg in the upper so YMMV

http://www.ebay.com/itm/FAFNIR-3MM20...em4cfadc db80

Sounds like a really good bearing pair


pinch them together in a vice with a shim on the outer race and jiggle the
inners to measure preload (if any ) if you are unable to obtain specs from
the manufacturer.

But if I my memory of Fafnir's numbering systemthat is correct that is a
matched set that's intended for duplex universal mounting which means they
can be mounted face /face or back /back and either way you will end up with
zero preload.


Thanks for your help, I'm studying this.


No prob, I'll be out for the weekend but I'll check back when I return.