Sprocket conundrum

[Cardo]

Good morning, y'alls

So, back to sorting out this steering palaver!

I'm replacing the existing hydraulic pumps on the boat with proper hydraulic helms. However, I have hit yet another snag! The setup on the boat is that the wheels drive chains which in turn drive the hydraulics. There is simply not enough space where the wheels are to fit the hydraulics directly.

The existing pumps have taper sprockets on them, which I was hoping to be able to swap over to the new helm pumps. Unfortunately, the taper on the old pumps is smaller than the taper on the new pumps. Gah!
The new pumps have a 3/4" "standard" taper on them. The sprockets have the marking "10BZ=14K" on them. Don't know what most of that means, aside from the 14 is the number of teeth!

So, can I buy a new sprocket to fit the new pump? Or do I get the current sprockets modified to fit?

Thanks!

 

[john_morris_uk]

If the old sockets can be machined to fit the new pump that sounds like a fairly straightforward bit of machining. Lots of hobby machinists or small machine shops would do the job for a few beer tokens.
Unless I am understanding you incorrectly and the old sprockets tapers are too big for the new pump. In which case you've got more problems. Boring out the old taper and welding in some suitable stock steel before boring out and machining the correct taper is one option.

The problem with all these solutions is ensuring that the sprockets end up in exactly the same plane. In other words the chain has to run straight and true. I imagine that there is some mechanism to tighten the chain to minimise backlash between steering and hydraulic pump?

 

[Cardo]

If the old sockets can be machined to fit the new pump that sounds like a fairly straightforward bit of machining. Lots of hobby machinists or small machine shops would do the job for a few beer tokens.
Unless I am understanding you incorrectly and the old sprockets tapers are too big for the new pump. In which case you've got more problems. Boring out the old taper and welding in some suitable stock steel before boring out and machining the correct taper is one option.

The problem with all these solutions is ensuring that the sprockets end up in exactly the same plane. In other words the chain has to run straight and true. I imagine that there is some mechanism to tighten the chain to minimise backlash between steering and hydraulic pump?

Thanks, looks like machine shop it is, then! Getting the sprockets lined up is not a problem, the pumps will be mounted so the chain is straight.

I'm not aware of any way to tighten the chain, to be honest. I don't think there's that much strain on the chain, so once it's fitted, it's unlikely to stretch like a motorbike chain would.

What do you mean by backlash?

 

[Bilgediver]

Good morning, y'alls

So, back to sorting out this steering palaver!

I'm replacing the existing hydraulic pumps on the boat with proper hydraulic helms. However, I have hit yet another snag! The setup on the boat is that the wheels drive chains which in turn drive the hydraulics. There is simply not enough space where the wheels are to fit the hydraulics directly.

The existing pumps have taper sprockets on them, which I was hoping to be able to swap over to the new helm pumps. Unfortunately, the taper on the old pumps is smaller than the taper on the new pumps. Gah!
The new pumps have a 3/4" "standard" taper on them. The sprockets have the marking "10BZ=14K" on them. Don't know what most of that means, aside from the 14 is the number of teeth!

So, can I buy a new sprocket to fit the new pump? Or do I get the current sprockets modified to fit?

Thanks!

Check out these folk.....You can get sprockets of all types including machined for taper lock bushes. You can machine the taper lock bushes to suite!

 

[john_morris_uk]

Thanks, looks like machine shop it is, then! Getting the sprockets lined up is not a problem, the pumps will be mounted so the chain is straight.

I'm not aware of any way to tighten the chain, to be honest. I don't think there's that much strain on the chain, so once it's fitted, it's unlikely to stretch like a motorbike chain would.

What do you mean by backlash?

Sockets in my previous should have read sprockets. (I blame the spelling checker...)

Backlash is the amount of play in the system. In other words the amount you turn the wheel backwards before the pump starts to pump hydraulic fluid in the direction you want.

 

[Cardo]

Check out these folk.....You can get sprockets of all types including machined for taper lock bushes. You can machine the taper lock bushes to suite!

Who?

Sockets in my previous should have read sprockets. (I blame the spelling checker...)

Backlash is the amount of play in the system. In other words the amount you turn the wheel backwards before the pump starts to pump hydraulic fluid in the direction you want.

Ah. Our cockpit helm has a minor amount of backlash, but we have become accustomed to it. It's just how the steering system behaves. It's very minor, so we don't find it to be a problem.

 

[john_morris_uk]

Who?



Ah. Our cockpit helm has a minor amount of backlash, but we have become accustomed to it. It's just how the steering system behaves. It's very minor, so we don't find it to be a problem.

Might I humbly suggest that although you might have 'got used to it' you shouldn't ignore any opportunity that presents itself to eliminate slackness in the steering system. Serious amounts of slack or 'backlash' takes much away from the pleasure of steering a boat. Can you not elongate the holes that the pump bolts through so you could slide it and take up any loose slack in the chain?

 

[Cardo]

Might I humbly suggest that although you might have 'got used to it' you shouldn't ignore any opportunity that presents itself to eliminate slackness in the steering system. Serious amounts of slack or 'backlash' takes much away from the pleasure of steering a boat. Can you not elongate the holes that the pump bolts through so you could slide it and take up any loose slack in the chain?

Thinking about it, the way the mounts are bolted on would allow these to be moved slightly to take up any slack if required. Though, it really isn't that much of an issue currently. There's maybe 5 to 10 degrees of movement of the wheel the other way before it starts turning the rudders.

Seeing as the new helms are requiring new brackets to be made, and the chains will have to be extended slightly anyway, I'll make sure they're nice and "tight" to reduce the backlash as much as possible.