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Screw loose

Timx

By Timx
in Boat Building & Maintenance

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Sir Nibble Veteran II

Sir Nibble

Posted
Posted
14 hours ago, Machpoint005 said:

And the engine was designed in the first place by an engineer (mechanical variety). He (or she) probably didn't intend the socket head bolts to be left loose.

I get this at work. I get consulted then it's passed on as "the engineer says". I've pointed out that I'm not an engineer, I'm a technician. I couldn't do the engineer's job and he couldn't do mine.

Just now, Timx said:

I tried but it says I can only upload 2.93mb 

?

I have had another look and see where it could come from, but it’s not from gear box or alternator, too far away and no empty holes I can see, so I will just go ahead , and hope it’s what the mechanic dropped

Ok, but it does look like a through bolt from the common type of prestolite marine alternator. That is, the bolts that actually hold the alternator together.

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Man 'o Kent Collaborator

Man 'o Kent

Posted
Posted

What is "interesting" about that bolt is that it is 'bright'. Most Allen screws are black being made from heat treated high tensile steel. The fact that this one is bright implies that it is made of stainless steel, not uncommon but normally only used where corrosion is a serious enough consideration to make the compromise of a lower tensile strength acceptable.

Also "interesting" is the shoulder under the head, this may well be a washer but if not it is unusual, making it a bit of a 'special'.

The fact that there are fretting marks on the shank of the screw shows that it had been loose for some time.

 

One plea: If at all possible when taking such pictures include a ruler of some sort in the picture as an aid to scale. "A picture is worth a thousand words." But something to give scale too can double that. The image in this post, as useful as it is, But is it 12mm or 2BA?

Any one care to make  guess?

 

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WotEver Veteran II

WotEverDonate to Canal World

Posted
Posted
50 minutes ago, Machpoint005 said:

I agree with the 'include a ruler' plea but in this case we can get some idea of the size from the battery isolator switch nameplate and the cross-head screw that holds it. It is bigger than 2BA, but certainly not 12mm. 

Looks like M6 to me. 

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Timx Rising Star

Timx

Posted
  • Author
Posted (edited)
On 23/09/2020 at 14:43, Man 'o Kent said:

What is "interesting" about that bolt is that it is 'bright'. Most Allen screws are black being made from heat treated high tensile steel. The fact that this one is bright implies that it is made of stainless steel, not uncommon but normally only used where corrosion is a serious enough consideration to make the compromise of a lower tensile strength acceptable.

Also "interesting" is the shoulder under the head, this may well be a washer but if not it is unusual, making it a bit of a 'special'.

The fact that there are fretting marks on the shank of the screw shows that it had been loose for some time.

 

One plea: If at all possible when taking such pictures include a ruler of some sort in the picture as an aid to scale. "A picture is worth a thousand words." But something to give scale too can double that. The image in this post, as useful as it is, But is it 12mm or 2BA?

Any one care to make  guess?

 

Thanks for all replies, but as I can’t upload anymore photos, it’s pointless to continue, but I have continued a 5 and 6 hour journey in last two days and nothing bad has happened so far. The screw does look like the ones off the alternator tightener, but it’s half the size, and would of had to of catapulted to get where it ended up.Thanks for taking the time to reply, annoying I can’t upload photos apart from original.

Edited by Timx
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WotEver Veteran II

WotEverDonate to Canal World

Posted
Posted
13 minutes ago, Timx said:

I can’t upload anymore photos

Sure you can, you just need to ensure they’re within the site’s size limit. I forget what that is but it’s over a meg which is a pretty huge image. 

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Timx Rising Star

Timx

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6 minutes ago, WotEver said:

I think your time would be better spent enjoying your boating :)
 

 

If I had not had someone in the engine bay recently, I would of definitely had known it was from engine, but hopefully he lost something and never told me, time will tell, thanks for replies.Thankfully it wasn’t on engine floor to make me more paranoid.

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Man 'o Kent Collaborator

Man 'o Kent

Posted
Posted
5 minutes ago, Timx said:

Can’t. Find a measure 

image.jpg

I remember when that stuff first turned up in our sailing club, so toothsome you could almost chew it. But them were the days when it was brewed not manufactured, nuffink lasts, gnat's p**s now.

 

As to getting a scale, almost anything of a regular shape that is in common use will do, a coin being a good example.

 

Thinking about the origins of that screw, I'm beginning to think it may well be an interloper.

 

 

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