Knurled nobs on impeller lid

MartynG said:
One of the original brass screws lost its head on my engine.
I replaced it with a stainless button head screw that I happened to have spare . That was a few years ago.
Don't recall the diameter but they were from Screwfix.
A2 stainless but seem fine.
View attachment 126440d
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Good idea except I use A4 ( 316 SS) & socket head as they allow a larger allen key
socket head
 
MartynG said:
One of the original brass screws lost its head on my engine.
I replaced it with a stainless button head screw that I happened to have spare . That was a few years ago.
Don't recall the diameter but they were from Screwfix.
A2 stainless but seem fine.
View attachment 126440d
Click to expand...
Surely one of the main advantages of the knurl headed screws is that they are easier to grip, and therefore less likely to be dropped into the bilges. Fiddling about with little button headed screws and small Allen keys, loses that particular benefit.
 
A smug git writes :

I carry a ready-use spare pump. In an emergency I can swap the pump on my BUKH engine in a few minutes. Loosen 2 hose clips, unscrew 2 machine screws, swap the pumps, re-assemble, and the job's done.

Overhaul the faulty pump when I have time.
 
NormanS said:
Surely one of the main advantages of the knurl headed screws is that they are easier to grip, and therefore less likely to be dropped into the bilges. Fiddling about with little button headed screws and small Allen keys, loses that particular benefit.
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Yes
But perhaps easier to use a small allen key than a screwdriver .
 
Many years ago discovered that that the Knurled side bolts used to secure CB radios to mounting brackets brackets fitted my raw water pumps on my VP diesel engines.
The bolts were made of some sort of brass alloy which was chrome plated.
Initial tightening ie finger pressure only. Did the job without leaks before boat was sold.
Must admit did apply light assistance with pair of pliars for last fraction of a turn
Think they came in 3 metric thread sizes.
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Continuing the smug git theme
Forgot to turn on the raw water valve on one engine. . After 20 mins underway, alarm went off. 20 mins later , had found the spare impellor, lifted saloon floor, dug out what was left of old impellor, fitted new one and was under way again.
 
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tudorsailor said:
Even the knurled screw is a bit difficult to undo after others have over tightened. I wondered about changing to a wing screwView attachment 126598

Is that a silly idea?

TS
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Not silly at all. I once had a pump fitted with studs and wing nuts, and it worked fine but if the mating faces of the pump body and cover, and the gasket, are in good condition knurled screws and nuts work fine.

The Speedseal cover was sealed by an O-ring and very little pressure was required to ensure a good seal. A little more pressure is needed with a paper gasket, but my octogenarian fingers have no problem achieving it.
 
Praxinoscope said:
Sorry but don’t see any advantage of studs over the standard screws from Hell, the nuts will be as fiddly and droppable into the bilge as the original screws, give me the big furled thumbscrews of acSpeeseal any day.
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Pop the plate over the studs, then you have two hands to deal with the nuts. And you're more likely have to spare nuts than spare stupid little screws.
 
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