Cincinnati No.2 Tool and Cutter Grinder

[RayG]

Thanks .RC very timely information.

I found 2305 's on vxb do these look right? 2305 Self Aligning Bearing 25x62x24 Ball Bearings

The fafnir 2mm305WIDUL, do they only come as a matched preloaded pair? I found these on ebay, but unless it's a matched pair inside the packet and abec7, I suspect they aren't going to be much use...

Although I guess I could buy 2 and shim them to get the preload... no... on seconds thoughts that's a bad idea...

Regards
Ray

[RayG]

What is the biggest diameter wheel that the grinder runs? and or what is the normal spindle speed? Just wondering if they were supplied with different sets of pulleys for when smaller cup wheels are used. Different sets of pulleys can though be dangerous in the hands of careless operator.

Thanks Log,

There are two different pulley diameters at the motor end, and each one runs to a different side of the top pulley. The largest wheel I think is 6 x 3/4", .RC might know for sure, but the diameter max I'm pretty sure is 6". I'm running off a VFD so I can dial up whatever SFPM I need.

Not sure what size cups RC is running, probably 4" I'm guessing.

Regards
Ray
PS The varnamo gets a drink of oil every so often to keep her happy...

[Graziano]

Found some drawings on the keyed and non keyed spindle tapers on the Sopko website:

Precision Grinding Wheel Adapters and Spindle Accessories from William Sopko & Sons Co., Inc.

It looks like the only difference is the key, that said, the Topwork site don't say anything about left hand and right hand threads. I'll have to take some measurements on a mate's Makino grinders and see if they are the same as the Cincinatti one

[.RC.]

Ray, 2305 bearings in basic grades are easy to buy, but as it is a grinder spindle you probably should look at P2 or P3 (Abec 7 or ABEC 9) bearings..

The 2MM 305WIDUL should be a pair... That is what the D means... Duplex... The U is Universal in that you can mount them back to back or front to front and still get the required ground in preload... L means light preload...Cannot recall off hand what the WI means but the 2 refers to the contact angle I think (15 degrees) and the MM probably means ball...

You do not shim these bearings to get preload, the preload is ground in during manufacture, that is why the tolerances for the bearing width is huge, to allow room for preload grinding...

Phil is the one to talk to about bearings, I am just a novice with them...

Just add on edit, sometimes people buy sets of bearings like 2mm305WIDUL but only use one in the packet to make up a triplex set or something like that...

Here is an example of a set missing a bearing... There should have been two in this packet, but one is missing http://www.ebay.com/itm/FAFNIR-PRECI...item5646b75d43

And also if they are not in a gold box they may not be ABEC 7 or better grade...

[Anorak Bob]

Found some drawings on the keyed and non keyed spindle tapers on the Sopko website:

Precision Grinding Wheel Adapters and Spindle Accessories from William Sopko & Sons Co., Inc.

It looks like the only difference is the key, that said, the Topwork site don't say anything about left hand and right hand threads. I'll have to take some measurements on a mate's Makino grinders and see if they are the same as the Cincinatti one

I might have slipped into the service not provided by Sopko the other day but talk about a comprehensive selection and well presented website. Nice that you have a machine of repute and that spares are accessible.

Thanks for the photos Ray. Sadly they serve to emphasise how poorly equipped my grinder is.

BT

[Graziano]

Nice that you have a machine of repute and that spares are accessible.


BT

I don't own any T&C grinders at all at the moment, I just head round to a mates place, he's got two fully tooled up Makinos and a Cincinatti, maybe a No.1. There seem to be a lot unused T&C grinders out there in the back of machine shops, it's a matter of being at the right place at the right time. This little guy sold for $600 a couple of years ago at the same auction I bought my Jafo FWD 32 Mill at for $600. It has a fancy sine bar head attached for generating spiral flutes for making reamers and drills from scratch and came with a extra rebuilt spindle cartridge.

Edit: By the time all the fees taxes and freight & travel up and back was paid the $600 became $1500, so the expenses were significant.

[Machtool]

Ray.
I’d be concerned with that Ebay listing, when they say things like this.

New in Factory Box - 2MM 305 WIDUL - FAFNIR ANGULAR CONTACT BALL BEARING (Single Bearing)

That part number is definitely for an Abec 7 pair. That’s not an original box also. The precision stuff is gold or green, and will say precision or super precision.

These would be a better option.

http://www.ebay.com.au/itm/NSK-7305ATDBC7P4-SUPER-PRECISION-BEARINGS-NSK-7305ATYDBLP4Y-/330638091105?pt=LH_DefaultDomain_0&hash=item4cfb90e361

That’s a 15 degree light preload pair. Your going to have to turn over all the redundant stock places to find medium preload.

Phil.

(On edit) I just check Lewis International. They have nothing in medium. They do have a few options in Nachi & RHP 15 deg lights. I can get a price in the morning

[RayG]

Thanks Phil, I'll go with that one you linked to.

eBay Australia: Buy new & used fashion, electronics & home d

That price is well within the budget, I was earlier looking at $300 upwards so at $150 plus postage that's a very fair price, not quite as good as RC's $50 fafnir deal.. but still...

Also, the box looks genuine, (as in a bit beat up) so probably not a chinese knock off..

Regards
Ray

PS I was going to ask what difference the light versus medium preload would make, but I'll do some homework first.

[.RC.]

Ray you might want to pull your spindle first and see what you have in there...

I only mentioned what size mine had, yours could be different to mine like it is different in the way the table traverses...

[RayG]

Ray you might want to pull your spindle first and see what you have in there...

I only mentioned what size mine had, yours could be different to mine like it is different in the way the table traverses...

Thanks RC,

I got as far as getting the dust covers off, and can see the numbers, what you said was correct. 7305 AC at one end, and 2305 self-aligning at the other.

I like the idea of using a precision bearing both ends like you've done, but haven't been able to find a 2305 other than "normal" tolerances, On the SKF site they have 2305's rated for different speeds and maximum loadings, but not tolerances.

Makes me wonder why Cincinnati did it that way, perhaps they used to make a higher tolerance self-aligning in the past?

I'm doing a bit of geology today, collecting rocks..

Regards
Ray

[Machtool]

Ray.

Lewis got back to me, I’ve forwarded it to your email, but your email normally bounces me.

1 pair 7305 TADULEP7 RHP $160

1 pair 7305CDU/GLP4 Nachi $160

Those prices will be excluding GST

Phil.

[.RC.]

Makes me wonder why Cincinnati did it that way, perhaps they used to make a higher tolerance self-aligning in the past?

I'm doing a bit of geology today, collecting rocks..

Regards
Ray

I think it was done that way as the spindle is a two piece job sitting in a bored housing... To protect against any misalignment they would have put that in there..

Also those grinders would have been made if not in their millions then at least in the hundreds of thousands.... First came out in the 1930's.... Made in the US and UK at the very least under the Cincinnati name and clones were made under other names (like Macson)... With such a large number made, getting custom bearings made would have been easy for such a large company...

[RayG]

Hi Phil,

Some more dumb bearing questions...

Thanks for getting those quotes, although I've got those NSK ebay ones coming I can't see a set of those Nachi 7305CDU/GLP4 going astray, (I'll send an email later with details, and grab a pair.)

I assume that's P4 precision, which is about the same as abec7 from what I can tell.

What's the precision of the RHP 7305 TADULEP7 bearings? P7 doesn't appear in the tables..

One more question, with the 2305 self aligning spherical bearing, (at the other end of the shaft) as RC has already mentioned they don't appear to be available in precision, so what RC has done is put a precision bearing in place of the generic 2305, but it's not a self aligning type.

Do they make a 2305 in precision grades, or is it that the "self aligning" feature negates the precision anyway?

I'm liking what RC did in abandoning self aligning in favour of precision? Any thoughts?
I guess if they don't in fact make a 2305 in precision grades, then Cincinnati must have thought it wasn't critical...


Regards
Ray

PS.. We had a successful geological expedition to Mount Gregory, and found some nice granite rock samples...

Here's that Bearing Precision Comparison

[RayG]

I think it was done that way as the spindle is a two piece job sitting in a bored housing... To protect against any misalignment they would have put that in there..
.

Hi RC,

We cross posted.

Yes that makes sense, particularily if Cincinnati specified a custom made 2305 bearing, the free end of the shaft would have to be able to float axially to allow for temperature changes, what you've done makes perfect sense, the run-out (eccentricity) difference between abec1 and abec7 is 13 microns to 2.5 microns. which is a lot for a precision grinder spindle.

Regards
Ray

[.RC.]

Just for comparasin sakes. I just stuck my Tesa 1 micron indicator on the spindle and TIR of my spindle taper was in the order of 2 microns... When it gets down to measurements I take them with a grain of salt as I do not know if it was just a total fluke or is a repeatable measurement... a micron is such a small amount...