Amal Throttle Control - Tiller Clamp Screws.

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Chris B
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Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Fri Jan 24, 2020 4:05 pm

I've yet to encounter an original (unrefurbished) Amal throttle control on a Seagull outboard that didn't have rusty tiller clamp screws.

It's nice to have shiny screws but there seems to be quite a bit of uncertainty about the screw type used for the Amal throttle clamp. And having solved that problem, where do you buy them? So for the benefit of anyone who wants shiny new throttle clamp screws, but is pondering over what they are (thread system, diameter etc.) and where to buy them, I can clear up both problems.

The correct screw is:

1 BA x 9/16" slotted filister head screw. (N.B. A filister - or fillister - head is a raised cheese head).

Not such an easy item to find these days but there happens to be a UK company that specialises in weird / obsolete / imperial thread system fasteners. The business is based in Darlington and trades under the name of "Stig Fasteners". Among piles of other stuff, they happen to have Amal throttle control clamp screws available off-the-shelf, except theirs are stainless steel instead of the original plated mild steel.

The screws are listed in their item specification as: "Amal Control Lever Screws" and the specs are:

Construction: cold forged stainless steel. Rolled thread.

Size: 1BA x 9/16"

TPI: 28.22

Thread angle: 47.5 degrees.

TIP. Before you go looking for screws, check the depth to which the female threads have been cut in the screw holes. Buy 9/16" if the female threads for your throttle clamp don't extend to the bottom of the holes. If the threads extend almost the full depth of the holes, you should be able to use up to 11/16" screws instead. Same price and it opens up your options a little.

You can order any of their stuff online and they accept Paypal.

Hope this helps somebody with rusty old clamp screws...

C.
Last edited by Chris B on Sat Jan 25, 2020 3:24 pm, edited 2 times in total.

RickUK
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by RickUK » Fri Jan 24, 2020 4:54 pm

Good info Chris - I used to get mine from Custom Fasteners in Newton, Powys (they have a website) who supply stainless and plated bolts etc., but was an either/or across the range, meaning some sizes of item were in stainless and others in chrome.
I used to put some lube - I favour copper grease on the screws - when refitting, especially as the lever body is cast in zinc - aka pot metal or monkey metal - I believe.

Chris B
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Fri Jan 24, 2020 5:21 pm

Hi Rick -

I agree with you. Avoid fitting the screws "dry". Use a smear of lube.

While I'm here, I forgot to mention that the Amal throttle clamp screws available from Stig Fasteners have the correct filister head.

Within about 30 minutes of ordering mine online, they emailed me to tell me the order was on its way. I think I paid £1.20 (including VAT) per screw, plus Royal Mail postage on top. Which I think isn't too bad for the correct replacement item in stainless steel - especially as there won't be any of the wholesale cost savings associated with an item that's in high demand.

Chris

geofflena
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by geofflena » Sat Jan 25, 2020 1:26 am

Thanks -. I've never seen a new one !

The villiers lever ( afik ) is old - No 10 /42 unf - or newer no 10/24 unc

Any ideas, on the subject of hens teeth -and throttle cables - if anyone makes brass cable suitable for cable inners ?

Chris B
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Sat Jan 25, 2020 3:53 am

I haven't encountered brass control cable. I wonder if that's because stretch and / or early fatigue failure might make it unsuitable. Presumably you're concerned about galvanised cable eventually succumbing to rust. My solution to that problem was to make my own Amal throttle cables from stainless gear shift cable intended for bicycles, which uses 4mm diameter outer sheathing. The end ferrules supplied for terminating the 4mm outer sheathing fitted neatly into the cable sockets on my Amal carburettor and throttle control.

There'll be other people here who know far more about this than I do, but for what it's worth here's my little bit of experience on the subject...

If you decide to make your own, don't use bicycle brake cable. Brake cable is fatter than gear cable and the diameter of the outer sheathing end ferrules will probably be too big to fit in the terminal sockets on the carb and throttle control. If, on the other hand, you find the smaller gear cable ferrules are a little bit too loose in their terminal sockets (ferrules from different makers vary slightly in diameter) then you can sleeve each ferrule with a piece of heatshrink, which looks neat and adds a bit more weather protection.

You can use decent quality galvanised or stainless for the inner control wire. Galvanised is easier to deal with if you want to use soldered nipples - but if you prefer to use stainless wire then I'd suggest using a crimped nipple at the carburettor end. The throttle lever end will need a barrel nipple and you can buy lengths of inner cable with a barrel nipple already fitted to one end. (N.B. A pre-fitted barrel nipple will probably be too fat, so you'll need to grind / file it down to fit the cavity inside the throttle control). I couldn't be bothered with the filing and faffing around, so quickly made my own barrel nipple for the throttle lever from a slice of 1/4" brass rod, with a small hole drilled through its diameter to accept the control wire.

There are a couple of advantages to making your own control cable. The first is that it's inexpensive - very much cheaper than buying a ready made British Seagull cable. The second is that you can make the cable to whatever length suits you. In my case, I needed to mount an Amal throttle control a few feet from the engine. Using bike gear cable parts (bought new on Ebay for less than a fiver) I was able to make a cable of exactly the right length, so the end result looked neat and tidy.

If you don't fancy making your own cable but still want a stainless replacement, or one of a funny length, just take your existing cable to your local bike shop and tell them what you want. If they're any good at all they'll make it for you and it should still be cheaper than the British Seagull version.

C

Chris B
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Sat Jan 25, 2020 5:22 pm

Returning to the question about brass control cable wire...

As said earlier, I haven't encountered such stuff - and also as said earlier, there might be very good reasons why brass isn't used. However, if in the interests of science you feel like experimenting, you could perhaps try the stuff that's used for hanging pictures. Called picture hanging wire, it's stranded brass cable, comes in different thicknesses, and some of it might be thin enough to fit through standard size control cable nipples.

Please be aware though, that picture hanging wire is highly likely to be a cheap alloy with a high zinc content, lacking in tensile strength, and it probably won't stand up at all well to constant flexing or a salt water environment.

If the lay-up of the strands as supplied is too slack, you could firm it up by putting one end in a vice, the other end in the chuck of your drill, and giving it a quick and very short spin.

Watch out for age hardening, fatigue fractures, and consequent strand failure. I'd be inclined to anneal the brass before making the cable. To be honest, I wouldn't use the finished item on a boat, but if you must then I'd be inclined to have a spare steel control cable very close to hand.

I'll be interested to learn how you get on with this...

C

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Charles uk
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Charles uk » Sat Jan 25, 2020 7:32 pm

The vast majority of Seagull throttle cables up to perhaps the mid 60's appear to have had a Bronze looking inner cable that it is very easy to soft solder nipples on the ends of, I assume that's what the Gentleman is asking about.

Chris it might prevent confusion if you posted clear pictures of the Amal throttle levers that these 1BA screws are used in, as some of the very early & a few of the late levers had different threads.
Make it idiot proof and someone will make a better idiot.

Chris B
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Sat Jan 25, 2020 8:07 pm

Aha! Bronze inner cable! Thanks for the heads-up on that possibility Charles. Different animal from brass and a whole lot better in bendy situations. For example, I've a superb vintage Hughes & Son compass and its integral shock absorbing mechanism uses 4 bronze leaf springs. After 80 years of flexing the bronze springs are still going strong.

Regarding pictures, I'll have to figure out how to do this newfangled photo uploading business. First though, I need to re-varnish my camera's woodwork and find a supplier of glass plate slides.

In the meantime, the Amal throttle control I'm referring to (with 1 BA x 9/16" clamp screws) is a pretty common one. It was fitted as standard to both of my 1970s Silver Centuries plus lots of other Seagulls, and it typically partners the ubiquitous Amal 46N and 46NE carburettors.

C

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Charles uk
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Charles uk » Sat Jan 25, 2020 8:42 pm

Our problem is the most of our readers are guests & use us as a reference site on all things Seagull, so we have a duty to keep all the information as clear, accurate & concise as possible for them.

We average somewhere between 800 & 1400 Man hours of visitors each day, depending on the day of the week & time of year.

The pictures will aid our visitors to know if theirs is the 1 BA style throttle lever.
Make it idiot proof and someone will make a better idiot.

Chris B
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Sat Jan 25, 2020 9:21 pm

In regard to a request for a picture, the Amal throttle control to which I referred is this one:

https://www.ebay.co.uk/i/183998249400

However, as the picture doesn't tell you a great deal without dimensions, I shall revert to words.

On the unit I have in front of me:

The tiller clamp's screw holes are on 30.56mm centres.

The circular part of the body is 35.6mm in diameter.

In plan view, the entire throttle assembly is 74.2mm long.

I trust this is suitably clear and concise.

C.

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Charles uk
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Charles uk » Sat Jan 25, 2020 10:23 pm

It's the side elevation that will show the lever shape & the clamp details that will give them a clear mental picture.
Make it idiot proof and someone will make a better idiot.

Chris B
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Chris B » Sat Jan 25, 2020 10:47 pm

If the throttle control "they" have looks like the one in the picture and has similar dimensions, they'll know if it's the same unit as theirs or not. As do you.

So for identification purposes, a side elevation is not necessary.

We're talking about two clamp screws for an Amal throttle control here. We're not servicing the Hubble telescope.

The throttle lever assembly has only two visible screw holes. If you have the presence of mind to turn the unit over, they will be clearly visible.

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Oyster 49
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Oyster 49 » Sat Jan 25, 2020 11:54 pm

Chris, you started this thread, so how about posting photos of the details you are talking about? That way we can all understand what you are going on about..

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Charles uk
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by Charles uk » Sun Jan 26, 2020 12:03 am

There are at least 5 different throttle levers used on Seagulls between 31 & 94, if I remember right it was H-A who posted the screw thread details several years ago & that some of the late levers had M5 threads.
Make it idiot proof and someone will make a better idiot.

geofflena
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Re: Amal Throttle Control - Tiller Clamp Screws.

Post by geofflena » Mon Jan 27, 2020 4:02 am

Cris - yes I make my own cables - and find galvanised easier to solder - Wilko inner is still galv. I have silver soldered stainless with mixed sucess - so don't bother with it. I think some types are treated with silicone nasties ?

I was referring to the early cable type - brass or bronze like ( hard to tell with aged colour ) - never seen it anywhere else ?
I have an old original villers which is split - so I use it as a pattern.

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