hovrin

I served my engineering apprenticeship at Morris Cranes in the 60's. I was sad to see the state of the old place when I was last there a few years ago. However, most of it has already gone and I suspect the rest is too far gone to save. From what I remember of the original interior it wouldn't easily convert to residential use so I would rather see it demolished and redeveloped for housing - far more useful.

Just a point to note. Don't do what many people do and pass the chain through the wheel - make sure you pass it through the frame. So many people do this without thinking and the sneaky thieves just pinch the bike and leave the wheel. ( Of course, if the thieves are really sneaky they will pinch the wheels and saddle and leave the frame )

Let me say straight out that I have no knowledge of this particular setup. However, I have seen many similar arrangements where one, two or even three grub screws have been used to secure a sprocket or gear wheel on a shaft. The key transmits the drive and the grub screw(s) keep everything in place. If there is a hole through the shaft in line with the grub screw holes then I suspect you should have a taper pin as mentioned earlier and the grub screw is a 'bodge' to replace it. More likely, I think, is that the whole thing was designed to have two grub screws holding the gear wheel in place. As you have found, one will do the job but I would fit another when you have time just to be sure.

Time for the Small Claims Court perhaps??

Taking measurements from the picture, (highly inaccurate I know), I think the one on the right is 3/16 BSF. However, as others have said, it would be easier to obtain 5mm bolts and fittings these days and just use them. If you really want to replace like with like then find your local bolt stockist or general engineering firm and ask them to match the one you have - much easier and more accurate than working from a photograph.

Bump

Sorry, Lee but no. I am a retired maintenance engineer in Lincolnshire and my experience of boats is zero. I have seen these in the past on various machinery drive systems but it was some time ago now. I would suggest a boat engineering company would be your best bet and failing that possibly somwhere like Bearing Services Ltd (BSL) if they are still going. Sorry I can't be more help.

If this is what I think it is it should have six 'legs' sticking out at equal angles and equal sizes, there are only two left. It should fit between the engine drive plate and the gearbox driven plate so that there is a 'leg' between each pair of drive dogs. That way the engine drive plate dogs push the rubber 'legs' and the rubber 'legs' push the gearbox driven plate dogs. They also smooth the drive by acting as a buffer when the the gearbox drives the engine, for example on the overrun when closing the throttle. If you are making this yourself you should try to get all the 'legs' as accurate as possible to be the same size and the same angle apart otherwise one 'leg' will be doing all the work. Also it needs to be a nice fit - too tight and it will put extra stress on the bearings and too slack and it will give a sloppy drive and wear out quickly. I don't know anything about the rubber on eBay but I supect it will be too soft and not up to the job. These are actually precision made parts - I wish you luck making one but I think you would be better of taking the whole coupling to an engineering bearing factor and getting the proper spare part.

Could you not replace the cap with a 21/4" nipple and then fit a 21/4" to 1" reducing socket?

Make sure you are only clamping, (reading), the feed wire,(Red or Brown). If you clamp the whole of the 3 core cable the amperage reading for the feed is cancelled out by the neutral.

I don't see why you can't drill and tap the filing hole and use a threaded setscrew as a plug, although if the rudder is hollow but sealed I don't see why you would want to fill it anyway - not 'having a go', just wondering! I would suggest caution with your other idea, however. The rudder has a large surface area and when it is turning the boat I would have thought that it would impose a large shear force on the screws, even at 12mm dia.. I am quite open to being corrected by those with more knowledge/experience but I suspect a pinch bolt arrangement would handle the torque and resultant shear forces better.

As a naive fitters apprentice in the late 1960's I was sent to the stores for a handful of 1/4 inch olives. I refused to go because I thought I was being fooled but my fitter took me by the scruff of the neck and 'enlightened' me. He needed some small pipe fittings which were, and still are, called olives. Oh to be that naive again!!

Many years ago, when I was an apprentice in Loughborough, they used to claim it was the oldest pub in England. Enjoyed many great nights there.

And if it comes to that, Grimsby is right next to Cleethorpes - which has one of the best beaches in the country (not too sure about the town though, and I live there :-) )