Member postings for gerry madden

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

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

G.

John, thanks for your post. But don't worry, all is under control safety wise.

However, being and SKF man, I wondering if you can help with manufacturing codes? My 'new' (1970s) bearing has the letters WTLD stamped on the outer ring. The original bearing had H6 stamped on the inner ring. From my own experiences, such markings generally indicate the manufacturing plant, manu. line or some other internal manufacturing-related information. Would you happen to know what these letters signify in the case of these two SKEFCO bearings ?

Gerry

Just to (almost) close this one, I can let you know that a kind member of this forum came up with exactly the RL10 bearing I needed. It came in a SKF box but surprisingly the rings were actually stamped with SKEFCO and GT. BRITAIN, and had the same type of pressed-steel cage as the possibly 100 year old original part on the aircraft. What a great forum this is !

The original bearing was unusable due to its inability to freely self-align. After a good inspection and measurement I put this down to a serious ovality and shrinkage of the outer ring, very likely as a result it being subjected to the heat of a fire at some point in its life.

I will continue my hunt for a RL4 of similar vintage and source.

Gerry

Thanks all for you additional thoughts. I have been meaning to buy some Evaporust since reading about it in MEW many years ago. This might be the excuse I need !

Pete/Michael, yes its not a critical precision thread as its just a crude height adjuster, as per the link. (The fine adjustment is a pillar that sits under the component support block on my unit.) So it doesn't matter if I lose some precision in the 'thread'. I suppose what I'm really aiming for is to get a finish in the grooves that has a similar shiney-ish finish as on the OD of the post.

In the meantime I'll re-look at some lathe mods and see if I can cut up some garryflex blocks into 5mm interference-fit strips and see if they have enough mechanical strength to be dragged along the grooves as it rotates.

Gerry.

Ady1, you are right.... I must have thought that a million times

Yes they are a lovely robust piece of engineering, aren't they. It will be a pleasure to play with when its looking respectable again and its secrets fully understood.

I think you may be right - honest hard work might be the only way !

Gerry

Bo'sun, no unfortunately not. I did think of a wooden block support but if its not perfect I can see the leverage mangling the chuck jaws and didn't want to risk this. .......But the idea is not 100% dead yet.

I have an oldish Sigma gauge that needs to be come useable again after years of living in seclusion in the dark recesses of the back of the garage. I want to polish up the main support post and the challenge is the dirty/rusty grooves. They are about 4 to 5mm wide and about the same depth.

Unfortunately the post is just an inch or two long for the centres on my lathe and its probably far too heavy to remove the tailstock and just 'chuck' it. My rotary wire brushes struggle to reach the bottom of the grooves, never mind the sides, and are more intent on rounding off the top edges.

I could mess around with bits the string smeared with abrasive but before I waste a day or so doing this, just wondering if anyone has done this kind of job before and has a well proven, tried and tested, method that might get it done in an hour or two instead ?

Gerry

Not always so Robert. Even in some mundane applications that call up standard catalogue products, the cage type is considered important enough that certain manufacturers can be precluded from supplying. One example that comes to mind from my memory banks was the spot-welded steel cages that became popular in 1970s 'pop met' single row ball bearings. And it all happened again with the trend toward plastic cages in 1990s.

Gerry

Thanks Nick, yes they may be options if Im unsuccessful in the search. I have already been offered the Hoffmann versions and if it was up to me I'd use these as its the place I first started working.

Circlip, its actually before WWII, but even so, I think the SKEFCO name was reserved only for the manufacture in UK registered arm of SKF. ...but of course one never really knows what went on in those days

Gerry

Baz - I'm afraid I cant divulge the type at the moment, but it is likely to be airworthy.

Old Mart - if I can get the original design and manufacturer, there should be no issue with airworthiness. Thanks in advance for your efforts,

If its of help, the dimensions of the two bearings are:

RL10: 1.1/4" x 2.3/4" x 11/16"

RL4: 1/2" x 1.5/16" x 3/8"

Gerry

Yes Neil, you are correct on that. But apart from different marking, the SKF version would not be manufactured in the UK. The original aircraft manufacturer wanted every part of the machine to be made in the UK and the current restorer wishes to maintain this philosophy if possible. But of course SKF, Fafnir or Hoffmann remains as an ultimate option.

Gerry

To help out a chap re-building an old aircraft, I'm looking for a couple of old bearings. He wants to maintain authenticity, so the challenge is that they must be of SKEFCO manufacture. The designations required are RL10 and RL4. These are double-row self aligning type in which the inner ring, cages and balls are free to swivel inside the outer ring..

I have tried various small businesses that specialise in procuring old bearings but with no luck. I feel sure that somewhere in the country these bearings could be hiding in private "collections" just waiting to find a purpose in life.

So does anyone have either of the two sizes that they would like to sell, or know of anyone that might be worth contacting ?

Ps, a little cosmetic damage or corrosion may not be of concern.

Gerry

He could still get 'inductive damping' (as in magnetic compasses), due to eddy currents

That's the trouble with folklore......

I notice there is a '0' mark adjacent to one of the key socket holes in the chuck. Isn't one supposed to tighten this one first to minimise runout ? (Another of those things I have meant to investigate the effectiveness of but just never seem to get around to doing.)

Gerry

...except I might add a note of caution. After a lifetime of operating with this abnormal behaviour one ends up with so many damn projects one wakes up in the morning unable to decide which one to start next

Gerry

Excellent repair, and I can confirm that the pitch is correct !

Gerry