Tuesday, 23 February 2010

Don't assume.......

.....anything, especially to do with old narrowboats!

At the weekend I found the coupling plate on the gearbox output shaft didn't fit just right on the prop shaft coupling, the outside diameter was ok but the PCD (bolt holes) was slightly out and there was only four and not six. No big deal, I thought I'd just take it all home, slot the holes and of course pop two extra ones in, due to four not going into six, geometrically that is.

Having a bit of time spare today, I popped the shaft coupling on the Mill/drill, with it wanting four holes I set it up all square so I could just use the x-y index table to save messing about marking out. Using a slot drill to slot two of the existing holes and then plunge two new holes at 90 degrees. All went quite well until, I came to bolt the plate on the shaft coupling....arrrggg, (look of disbelief) two of the holes in the plate were miles out. After checking all my doings, I found the plate to be wrong, the holes are not at 90 degrees. Is it some boat yards don't know standard engineering practice, don't have the tooling to do the job or, just don't care. Or, am I missing something.
Not wanting to start making a new plate, I thought the best thing to do was, (what I should done in the first place) is bolt the plate to the coupling and drill through it. Wonderful thing hind sight!
You would have thought I'd learned by now, because everything on the boat is out of line, twisted or bent.


Mike and Chrissie said...

Quite right! An old fitter I once trained with always told me not to assume anything. He said "it only makes an ASS out of U & ME".

Sarah said...

I always find that one of the most irritatingly smug sayings going! Think what life would be like if you never assumed anything and had to calculate every decision from scratch... most assumptions (If I go to Sainsburys I will be able to buy food... Amazon will deliver a book to me if I pay them...If I punch that person on the nose he is quite likely to be cross) are perfectly well founded. People only say that when something goes wrong, and never notice all the times it doesn't.

fmc dove said...

Sarah, sorry for irritating you, but I use the phrase to warn others of the pit falls of old boats.
We do assume quite a lot in our lives, we have to assume a trades man knows his trade, as in this case.

Blossom said...

When I was an apprentice, about 17 I think, I was working with an old fitter on a job where we had to get a piece of equipment up and running 'at all costs' stated the gaffer followed by " just do a temporary repair to get us going". As we walked off across the works I turned to the fitter and asked "what's the difference between a temporary repair and a proper one" His reply was "the temporary one has to last longer" and walked off!

Mike and Chrissie said...

Hi Sarah, as irritating and smug the saying may be, where safety is concerned, it's well worth remembering, as it has saved both mine and other lives on occasion!