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Olives that aren't


Stephen Jeavons

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Can anyone tell me why the traditionally-shaped copper olive (ferrule) was replaced with the tubes of copper that all manufacturers of brassware now pass off as olives on smaller sized fittings? (See photo).

With traditional olives (upper one in the photo) you can get a perfect seal by tightening a compression fitting by hand plus a quarter turn. The lower one requires you to tighten a full further turn just to get the pipe to be gripped and then some to get a good seal as they're not tapered as they should be. I've found myself having to overtighten everything to ensure a good gas seal.   

olives.JPG

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If you don't like "copper tube" version then you can get proper ones on eBay, in either copper or brass (for different applications) for about 10p each.

I also don't like the tube ones, I've sometimes had to tighten joints just a tiny bit more than I like in order to get them to seal, and they are just not as satisfying to look at. A collection of good small pipe fittings is a very nice thing to look at.

..............Dave

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3 minutes ago, Stephen Jeavons said:

Sure they do, after you've almost stripped the thread cos you had to tighten it so much.

Funny how decades of an acceptable design which works perfectly suddenly has to change (for the worse!)

 

They haven't changed. They've been like that in proper "Wade" brand fittings for as long as I can remember. Nor does the thread almost strip when tightening them.

Are you a competent LPG installer? It doesn't sound like it.

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10 minutes ago, Stephen Jeavons said:

Sure they do, after you've almost stripped the thread cos you had to tighten it so much.

Funny how decades of an acceptable design which works perfectly suddenly has to change (for the worse!)

Okay, I exaggerate. However you have to admit that you need to tighten them a helluva lot more to get them as tight as traditional olives. Incidentally, the photo with the "correct" olive (which wasn't squashed into that shape if you look carefully) was from a disassembled 3/8" Wade fitting. I have a few old fittings made by Wade in my plumbing kit that DO have the correct olive! I don't doubt that they've had tubular ones for a while. My question was why did they change? 15mm, 22mm, etc fittings still come with proper olives

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The amazing thing is, for tightening all manner of engine nuts and bolts and stuff, tightening torques are quoted for torque wrench use, but for tightening up big safety things like gas fittings there appears to be no such thing, I think.   Its all about experience and FEEL. 

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1 hour ago, bizzard said:

The amazing thing is, for tightening all manner of engine nuts and bolts and stuff, tightening torques are quoted for torque wrench use, but for tightening up big safety things like gas fittings there appears to be no such thing, I think.   Its all about experience and FEEL. 

 

From Conex, the brand leader in compression fittings:

Assembly • Ensure the tube and fitting sizes are compatible. Cut the tube end square, and ensure it retains its shape. • Deburr the tube, both inside and outside. • Remove the capnut and compression ring from the fitting. • Slide the capnut, and compression ring onto the tube. • Join the fitting onto the tube end, and slide the compression ring, and capnut towards the fitting. • Hand tighten the capnut. • With suitable flat-faced spanners, tighten the joint to the recommended minimum number of turns

http://www.conexbanninger.com/uploads/8343e9b5fd467a0419d8634207af3ba48dfa3060.pdf

They publish a table telling you the number of recommended turns according to pipe size and material, but I can't find it immediately on line. 

 

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1 hour ago, RLWP said:

Most cylinder head bolts are tightened by angular displacement these days. It's a more guaranteed way of getting the right tension

Richard

What is angular displacement, in the context of tightening up head bolts? 

A brief perusal of the Wikipedia page on angular displacement was no help at all.

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20 minutes ago, Stilllearning said:

What is angular displacement, in the context of tightening up head bolts? 

A brief perusal of the Wikipedia page on angular displacement was no help at all.

The Bolts are Nipped up and tightened  and then Rotated X Degrees more  to cause  correct Tension ,Torque can be Misleading do to Varying Friction on Nuts/Studs.

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Used generally on more modern engine head bolts because of the long threaded portion of the bolts that screw into the cylinder blocks can cause a torque wrench to go in jerks therefore likely to give a false reading on the final round of tightening. Engine manufacturers have different methods and sequenses for doing it the angular way.  A rough example is.  Nip all the bolts up to say 10 lb ft or the equiv nm's  with torque wrench and then turn all the bolts say exactly one half a turn, and then, say, finally exactly one quarter turn each which should bring the bolts torque to the correct manufacturers torque setting. I used to hold a protractor above the socket and bar or over set torque wrench to do this.

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36 minutes ago, bizzard said:

Used generally on more modern engine head bolts because of the long threaded portion of the bolts that screw into the cylinder blocks can cause a torque wrench to go in jerks therefore likely to give a false reading on the final round of tightening. Engine manufacturers have different methods and sequenses for doing it the angular way.  A rough example is.  Nip all the bolts up to say 10 lb ft or the equiv nm's  with torque wrench and then turn all the bolts say exactly one half a turn, and then, say, finally exactly one quarter turn each which should bring the bolts torque to the correct manufacturers torque setting. I used to hold a protractor above the socket and bar or over set torque wrench to do this.

Have you ever worked on a Kelvin?  The service manual contains this rather unhelpful advice:

The attachment of the cylinders to the crankcase is very important. The nuts within the crankcase must be drawn up very tight.

  • Greenie 1
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4 hours ago, dmr said:

I've sometimes had to tighten joints just a tiny bit more than I like in order to get them to seal, and they are just not as satisfying to look at. A collection of good small pipe fittings is a very nice thing to look at.

If you can still see the olive when you have made the joint, you ain't doing it right!

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3 hours ago, RLWP said:

Most cylinder head bolts are tightened by angular displacement these days. It's a more guaranteed way of getting the right tension

Richard

Ooh, ooh, I’ve learned something new again today :)

49 minutes ago, koukouvagia said:

Have you ever worked on a Kelvin?  The service manual contains this rather unhelpful advice:

The attachment of the cylinders to the crankcase is very important. The nuts within the crankcase must be drawn up very tight.

Known as FT in the trade I believe ;)

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2 hours ago, bizzard said:

Used generally on more modern engine head bolts because of the long threaded portion of the bolts that screw into the cylinder blocks can cause a torque wrench to go in jerks therefore likely to give a false reading on the final round of tightening. Engine manufacturers have different methods and sequenses for doing it the angular way.  A rough example is.  Nip all the bolts up to say 10 lb ft or the equiv nm's  with torque wrench and then turn all the bolts say exactly one half a turn, and then, say, finally exactly one quarter turn each which should bring the bolts torque to the correct manufacturers torque setting. I used to hold a protractor above the socket and bar or over set torque wrench to do this.

I use one of these if you want to get odd angles which are sometimes specified.  Fits on a 1/2" drive ratchet.

CIMG9612.JPG

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51 minutes ago, David Mack said:

A friend once remarked that his wedding ring looked remarkably similar to a 22mm olive, and his wife's to a 15mm one. Only more expensive!

I'd been looking at a hard-to-reach pipe olive lying in the bilge for some months before I realised it was my wedding ring that I'd lost, probably having taken it off while working on electrics (safety first!). Had it stretched to fit my fingers that had grown a bit (muscle?), then lost it again when I shed a few kg.

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12 minutes ago, nicknorman said:

And another way of doing it is to measure the stretch in the bolt. Doesn’t work for compression fittings though!

So I put the bolt in, torque it up, take it out and measure it? :lol:

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