Lucky Duck
Well-Known Member
I notice many sets include both metric and imperial sizes, on a modern(ish) boat are the imperial ones ever going to be used?
Imperial Sockets & Spanner Sizes
- Thread starter Lucky Duck
- Start date
Seven Spades
Well-Known Member
The bolts on Blakes seacocks on my boat are imperial sizes.
PetiteFleur
Well-Known Member
Yes - but they are Whitworth - none of the 'imperial/metric' sizes fit exactly, so you need 5/16" Whit. Just done my friends seacocks but had forgotten to bring my original Britool spanners so had to use a small adjustable........ it was a very restricted space, left handed by feel only - it was not easy!
NickRobinson
Well-Known Member
1/2" and 13mm interchangeable, especially on older rusted nuts.
Others too are either good fits or a reasonable 'hold still' on a bolt while the correct spanner pinches the nut.
In decades spannering stuff, I've never found a use for a 3/8" spanner EVER. (but an open end one can be ground to make an emergency 10mm!)
Others too are either good fits or a reasonable 'hold still' on a bolt while the correct spanner pinches the nut.
In decades spannering stuff, I've never found a use for a 3/8" spanner EVER. (but an open end one can be ground to make an emergency 10mm!)
VicS
Well-Known Member
You may need Imperial A/F sizes for some engines and outboards. My Evinrude is about the only thing I need them for now.
Whitworth sizes turn up from time to time. Blakes' seacocks, as already mentioned, and Seagull outboards spring to mind. Boats built before the late 1970s will probably have Whitwoth fastenings but anything more recent is more likely to have metric fastenings..
Comprehensive spanner and socket sets also have far more sizes than you will ever use.
I have Imperial A/F spanners and sockets from the days when most cars were all imperial that I have never used and never now will. Similarly metric sizes that I will never use.
IMO the most sensible approach is to make sure you have the sizes on board that you will actually need and likely to use, and leave the big flashy comprehensive sets on the tool store shelves
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prv
Well-Known Member
No imperial fasteners anywhere on my boat - I've probably had every single one apart over the last three years (except the guts of the engine) and I only have metric spanners and sockets on board
However, I recently bought a Johnson outboard, and had to buy a handful of imperial spanners to work on that. Bloody Americans
Pete
Lucky Duck
Well-Known Member
Engine is a Yanmar 3YM20 (I also have a little used Tohatsu) so Metric should be fine?
prv
Well-Known Member
Should be. I would have an adjustable on board as well, just in case. This will cover the occasional situation where you need two spanners the same size, and if one day you turn up a non-metric fastener in some unsuspected corner.
Pete
rotrax
Well-Known Member
Do you mean 3/8 AF or 3/8 Whitworth-entirely different sizes.
The AF is smaller than a 10mm and the Whitworth about 16mm across the flats!
vyv_cox
Well-Known Member
I filed the nut and bolt heads down to the next metric size to avoid the need to carry any imperial spanners.
RichardS
N/A
I was working on both the gas fittings and the fuel fittings on my boat this winter and they all seem to be imperial.
I had to buy a set of small imperial sockets as I didn't have one small enought for the Racor filter bowl housing. From memory 1/4 inch AF.
Richard
I had to buy a set of small imperial sockets as I didn't have one small enought for the Racor filter bowl housing. From memory 1/4 inch AF.
Richard
DanTribe
Well-Known Member
Mostly metric on my boat but still have to keep some imperial sockets/ spanners for certain bits. CAV fuel filter, Blakes seacocks and battery terminals mainly.
I also have to have imperial allen keys for winch servicing. I have got a "metrinch" socket set which is supposed to fit metric & imperial but not sure that was a good investment.
I've also got a set of BA spanners, but can't remember what they are for.
My tool kit is full of odd size spanners aquired from years of owning old British iron motorbikes and cars.
I also have to have imperial allen keys for winch servicing. I have got a "metrinch" socket set which is supposed to fit metric & imperial but not sure that was a good investment.
I've also got a set of BA spanners, but can't remember what they are for.
My tool kit is full of odd size spanners aquired from years of owning old British iron motorbikes and cars.
prv
Well-Known Member
That's interesting. Racor filters one would indeed expect to be imperial since they're American, but the bleed screws on mine are very definitely 10mm. Maybe they make some parts in metric for the euro market?
Pete
srp
Well-Known Member
Many silicone bronze fastenings are imported from the US and so are imperial sizes. I would also check stainless rigging fittings, as some of them may be imperial, especially on an older boat. In any case, a really good quality adjustable spanner and a couple of universal sockets might be worth carrying just in case.
In my experience Yanmar engine bolts are made of cheese and torqued up in the factory by a team of gorillas, so the likelihood of rounding a head is fairly high, so you need something to tackle those situations:
In my experience Yanmar engine bolts are made of cheese and torqued up in the factory by a team of gorillas, so the likelihood of rounding a head is fairly high, so you need something to tackle those situations:
Avocet
Well-Known Member
Those sockets with the moving pins in them don't get good reviews on various motoring fora that I hang out on. General consensus seems to be that if the fastener is pretty tight, they're just not stiff enough. if it's seized, they just chew the corners off the hexagon.
Aside from that, I don't think anyone has mentioned rigging screws yet. They can have all sorts of odd imperial locknuts on them.
Aside from that, I don't think anyone has mentioned rigging screws yet. They can have all sorts of odd imperial locknuts on them.
chewi
Well-Known Member
I thought I only needed metric until I tried to undo the clamp bolts holding my cast aluminium stanchion bases to the aluminium toe rail on a 1983 Cobra. the nut was set in a counterbore & was between 10mm and 11mm. 10mm would not engage the nut, and 11mm was too big to fit the counterbore. I think I used a 13/32 socket in the end having turned my garage upside down. Nothing metric would do it. I think battery clamps are usually 7/16 . I seldom use the imperial, but I keep them there nonetheless.
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NickRobinson
Well-Known Member
Ground out to 10 mm? Guess! (I have had a bronze, anti spark, oil refinery WW ring spanner, c. 1.25" across flats, for 40yrs, one day I'll find a use for it...) (And don't get me started on bicycle nut sizes!)
vyv_cox
Well-Known Member
I have one slightly smaller to the same specification. I carried it around for years without use until I found it is exactly right for Bukh anode nuts.
VicS
Well-Known Member
nothing to beat a good selection of adjustable spanners like those below but note that some are left handed, some are metric and a least two are Imperial AF. The one extreme right is of course Whitworth
vyv_cox
Well-Known Member
There are times when the one shown at the right is extremely useful. I have an identical one that has got me out of difficult situations several times.