[modernprecision]

Hello. This is my first thread and post. I'm interested in buying the three bearings for the top and bottom on the spindle for the Bridgeport Series 1 2J Head 2HP. If anyone has the OEM's for sale please post or PM me. Thank you very much.
-MP

[davo727]

Hi, Rex-supply.com has parts breakdowns and genuine bridgeport parts catalog pages 1676 to 1680. https://www.rex-supply.com/REX/Order...1676&page=1676 Dave

[modernprecision]

Hi, Rex-supply.com has parts breakdowns and genuine bridgeport parts catalog pages 1676 to 1680. https://www.rex-supply.com/REX/Order...1676&page=1676 Dave

Thank you.
I'm looking for someone to already have the bearings to ship.

[NC Cams]

Some of the OEM style Bridgeport bearings were ONLY supplied by Bridgeport. Why? Because they used size coded OD's and ID's on the bearings to compensate for housings and shafts that were over or undersize ground at the time of manufacture. What BPT did was selectively fit bearings, spindles and housings to obtain what they considered to be suitable/proper operating clearances.

Few if any aftermarket bearings are TRUE OEM equivalents. Why? Because the aftermarket guts took the generic equivalent bearing "cores" and offered them for service.

Even if you did get a proper OD/ID size fit, Bridgeport also did some fancy stuff to qualify the bearings. Things like special ball tolerances, special greases and/or special preloads. Thus, unless you know how to engineer machine tool bearings, or have the true OEM bearing prints, you can't be assured of obtaining a true OEM performance replacement bearing.

It has been alleged that when Hardinge assumed the right to the Bridgeport "name", they did get a lot of the prints and specs for the various machine tools that were produced by Bridgeport Machines. However, it has also been alleged that not even Hardinge is truly in posession of nor do they actually care anymore about servicing the "old" Bridgeport hardware.

I'd suspect that the current Bridgeport mills that Hardinge made would accept OEM supplied bearings and they'd provide OEM fit and finish. However, I'd have my doubts that the old selective size bearings are rarer than hen's teeth and you'll have a hard time finding TRUE 2J drop in replaceents anymore - drop in as in the selectively sized bearings that BPT machines used way back when.

I learned of this whole scheme when I did a lot of OEM bearing engineering work when employed as the machine tool bearing engineer for a major machine tool bearing supplier. Perhaps if you provided the OEM part numbers for the bearings you're looking for, I could give you some guidance as to what might work or what might work better than the selective fit stuff you might be stuck with trying to replace...

[gus]

there is no reason this would be necessary, especially on a manual mill. A few tenths of runout is well within the norm

[modernprecision]

there is no reason this would be necessary, especially on a manual mill. A few tenths of runout is well within the norm

well I have Bridgeport Series 1 2J 2HP with Hurco KM-1 CNC setup.

I have decided to buy the Fafnir bearings.

[NC Cams]

Some of the OEM bearings at one time were supplied by Fafnir. However they were supplied to a special Bridgeport FS spec and Fafnir and Bridgeport at at that one time were under the same corporate umbrella.

If Fafnir is still following that spec today, you should be OK. If not, and/or you have a under/oversized situation that needs a selective fit bearing deal, you may have some issues.

True "Bridgport quality" stuff is not readily available anymore - some of the OEM quality qualifiers didn't survive when Bridgeport went bell up when they did.

[desk farmer]

Hi,

I've got two a same model BPT mills in this thread. One has the factory bearings in it (I've known the machine for 23 years) and the other had a local "machine repair" guy replace the bearings.

From the quality of the surface finish produced on the two machines, the machine with the factory BPT bearings is much better than the "repaired" machine. (This repair guy was a hack.....fodder for another thread.)

My quesion is what to do with the repaired machine? I understand that the inner and outer race spacers should be the same length for modern replacement bearings. I'm sure I could put new bearings in but I'm not even sure where to start after reading spindle threads. Is the best answer to do a web search for a decent BPT spindle repair company and just send it off?

Square One,

Desk Farmer

[NC Cams]

First, do a "Bridgeport spindle" or "spindle bearing" or "spindle repair" on this website via the search engine. You should be able to find a detailed explanation as to why it is not a simple "remove and replace" repair to install bearings into a Bridgeport spindle.

If you can provide an OEM part number for the spindle bearings that were used in your spindle, I should be able to provide the part numbers for aftermarket bearings that can be installed or adapted for installation into your spindle. THESE RECOMMENDATIONS WOULD BE BASED UPON THE SPECS FROM EXACT OEM BEARING DRAWINGS THAT I ACQUIRED OVER THE COURSE OF MY CAREER.

HOWEVER, if you have one of the odd sized spindles that Bridgeport is known to have supplied over the years, you're going to need to either grind the spindle shaft and/or housing to a nominal "standard" size or perhaps flash chrome plate the shaft/housing if the units are some of the undersized offerings that BPT supplied.

When you know what you have, you can then decide what to do. But first, find the prior post where the vagaries of Bridgeport spindles were discussed.

BTW, there are some former factory guys out there who still service BPT spindles. These were the same guys who built them using the selective fit methods that were used. One such guy who does the work or knows who can do a factory quality rebuilds (outsided of Hardinge) is Brian at BPT Machines in Carrol Steam Illinois (360-781-9942).

Don't bother to call for DIY instructions - he sells his services at a fair price and he's the ONLY guy I let touch my machines - and he's several states over from me!!!!.