Old bearings never die...

Nicholas, you are right too ! I'd missed that. Thanks for letting me know.

G.

Normally if there are specific requirements outside those controlled by the standard specification of a part the specification number would not be called up in the drawing or parts list. Typically either the equipment OEM would specify their own part number or they would call up a specfic part manufacturers stock or part number. This part manufacturers number might be a special for the aplication. Using their own part numer has the added benefit of controlling the market. Sometimes a standard part will be purchased and then one or more of inspection (often for specific characteristic(s). test, modification, treament carried out before using their own number for the part.
For aviation at least this means you should always refer to the approved documentation. Just because it says ACME 1234 on the part doesn't mean you can just buy an ACME 1234 and fit it. The OEM may have bought thousands of ACME 1234s and then selected the "best" ones for their application.

Robert.

Hello Gerry,
Year of manufacture marking would have been a single letter - on this vintage it would have been stamped on the soft outer ring before HT and grinding . Kicking myself now for not retaining a personal copy of the date tables! There was a workaround for work in progress left over at the end of the year - a single dot was chemically etched at final assembly to the right of the letter on the hardened and ground ring face to indicate 'year plus one'. Current methods of laser marking don't half make such things easier.

WTLD isn't a familiar part of the bearing designation - it may have been a 'special' for a specific customer. Internal clearance (axial in this case) would be denoted by a letter C followed by a number: 2 for one class less than Normal; 3 for one class more,etc.
J.

John, WTLD is definitely not part of the designation - I should have made clear that the positioning of this stamping on the ring, relative to the stamping of its basic designation. So you don't have your date tables any more, but what about the site of manufacture ? Since the bearing was made in this country there are only two possible sites, Luton and Irvine. One or more of these letters should define that, should it not ?

Robert - I'm not quite sure where we are going on this , but yes you are basically correct in what you say in terms of the ideal aviation procurement procedures. But it's a fact of life that even in the aviation industry, as one moves down the technical spectrum from the turbine main-shaft application to, lets say, a seat adjuster mechanism, OEM bearing specs become increasingly vague. I haven't said where my RL10 sits on the spectrum and that was deliberate on my part to avoid excessive thread elongation. I did however hint that the original bearing was around 100 years old so I will leave to your imagination the quality of the 'approved documentation' that was written in that period, when the art of rolling element bearing manufacture (never mind of aircraft) was in its infancy.

Gerry

Edited By gerry madden on 01/10/2023 01:03:21

' John, WTLD is definitely not part of the designation - I should have made clear that the positioning of this stamping on the ring, relative to the stamping of its basic designation. So you don't have your date tables any more, but what about the site of manufacture ? Since the bearing was made in this country there are only two possible sites, Luton and Irvine. One or more of these letters should define that, should it not ? '

Hello Gerry,

Would have been made either in the old 1911 factory at Luton (which closed in the late 70s) or the 'new' post-war factory at Sundon Park (on the north side of Luton and still producing spherical roller bearings); just to keep things nice and complicated both were identified as Luton made products. Irvine only made water pump spindles, one high volume taper roller bearing and small deep groove ball bearings.

I'm still scratching my head on the WLTD bit!

/J