Alex Jackson Coupling Hook Angles

[GarethSmith]

In Brian Self's article on AJs in S4News 210 he gives the actual angle between the shank and the nose of an AJ coupling hook as 39 degrees 14 minutes. After making the first bend in the wire when making a coupling he suggests drawing this angle out on a piece of card and lying the wire on that to check the angle. I have made and fitted a number of AJ couplings and found this an easy way to check the angle of the first bend.

There is no reason why this method cannot be used to check the remaining angles on an AJ coupling hook. However, when I looked I was unable to find the shank-tail and nose-tail angles. Everywhere I looked the various descriptions give the angles when the coupling is viewed either sideways (at right angles to the shank) or end on. I have worked out these other angles although if anyone does know anywhere they are published I would be interested to know. The full set of angles are:

Angle between
shank and nose: 39.2 degrees
shank and tail: 63.4 degrees
nose and tail: 153.2 degrees

I have given these to a decimal fraction of a degree (rather than degrees and minutes) and although I have checked my methods I welcome anyone else confirming them. Again I would like to emphasise these are the angles with the the two parts of the coupling lying flat on a surface (or 'in the same plane').

I have found that drawing these angles out on a piece of card then holding the coupling flat to that (with the third leg of the coupling sticking out away from the card) a simple way to check the angles. I realize that many people have successfully made AJ couplings without using the angles in this way - but having gone to the trouble of working them out I hope this may be useful to some. Of course this does not aid with orientating the coupling when mounting on a vehicle, only with checking for a correctly formed hook.

[Jol Wilkinson]

I have always found it easier to make up AKs using one of the jigs that have been made available over the years, through the S4 Stores.

I would think I would be unable to bend the wire to better than +/- a couple of degrees, never mind to one decimal place.

[Julian Roberts]

I quite agree with Jol.

I find the jig obtainable from the EMGS further helps get the angles right. I wrote about it here, the last post on the page -

viewtopic.php?t=2934&start=50

[Daddyman]

Unless I'm missing something (quite possible - I haven't yet tried AJs), I'm pretty sure these angles are included in the piece in MRJ 55: tail to shank = 60; shank to nose = 30; nose to tail = 150. Either way, the article does contain the proviso, "These angles do not have to be accurate to the last degree - it is sufficient to judge bends of 1/3rd, 1/2 and 2/3rds of a right-angle."

[ralphrobertson]

You can find full specification and more details here http://www.mmrs.co.uk/technical-articles/alex-jackson-coupling/

Ralph

[davebradwell]

Much of the confusion with 'Jacksons arises from the drawing which is at best unhelpful through misleading to just plain wrong. Take the only dimensions given, the lengths of the hook - we know these should be measured along the wire as when we add 2.25 and 2.75 we get 5mm which agrees with the depth of the hole in the jig we are told to make. Trouble is it is dimensioned in a vertical plane so the correct conclusion without an appropriate note would be that the hook is 2.6 long due to it being at 30 deg to the viewing plane - clearly not what is intended as the tail would be short. It's a difficult drawing challenge as other more useful elevations would result in strange angles which might cause grief in our world. The drawing should certainly show the actual bend angles, possibly on an isometric view, as many descriptions actually say bend the hook to 30 deg angle rather than the correct 39, although I see the official site does qualify this with a subtle form of words.

It would appear Mr Jackson used a pair of flat smooth pliers as my pair give the correct 5mm distance to the first bend. I flatten this with serrated pliers which keep the wire in-line and continue with these pliers and thumbnail. Cut off any duds and repeat. Use of the original drilled brass rod jig causes the folded back bit to flip over and the head doesn't look like the drg. I've plenty made like this but never investigated whether it matters.

As we're listing jigs, there's a very good printed type available from Stenson models which checks the position and angles in situ.

DaveB

[steve howe]

I have the Stenson type jig and it is very useful as a check; its a block that fits over the rails with the appropriate angles moulded into the upper face. You just run the vehicle up to the block and if the coupling sits snugly in all planes job's a good'un I also agree that the full complement of Palantine bending and fitting jigs take a lot of the guesswork out of the issue>

Steve

[GarethSmith]

Thank you for these various comments on my original post. Regarding the use of jigs - I would also fully endorse using these. I use the Turner jig to form the hook however I have found that the bends in the wire are not sharp enough and need adjusting. Nevertheless having roughly the right bend in the right place in the wire it is then simple to tweak afterwards. (And of course maybe I am doing something wrong and this jig produces the correct angle for others.)

During my first attempts I was holding a newly formed hook in front of the usual 60/45/30 angle diagrams but found it tricky to be certain they were correct. I had a tendency to 'cheat' - and move either the hook or my head to get it to line up. Furthermore although I was aware of the statement that the angles do not have to be that accurate I was unsure quite what level of error I could have. It was the ease with which I found I could accurately and quickly check the first angle after reading Brian's article that led me to try this approach for the other angles.

Dave's comments about the hook lengths and the way they are drawn are something I had not thought of at all. Thanks!

[Phil Eames]

I have the Stenson type jig and it is very useful as a check; its a block that fits over the rails with the appropriate angles moulded into the upper face. You just run the vehicle up to the block and if the coupling sits snugly in all planes job's a good'un I also agree that the full complement of Palantine bending and fitting jigs take a lot of the guesswork out of the issue>

Steve

Thanks for the thumbs up Steve, it is appreciated. With my traders hat on, they are available here

https://www.stensonmodels.co.uk/product/alex-jackson-coupling-alignment-jig-p4-gauge-sm30d/

However with my modellers hat on I have been fettling the stock to be used on the layout after nearly 3 years in storage and found one of the AJ couplings wasn't operating. Offering the coupling up to the jig it became immediately apparent what the problem was and it was quickly fixed.

[Tony W]

When I read Gareth's first post, and some of the replies, I started to get really, really, concerned about the direction this thread was heading and said to myself, 'this shouldn't be what the Alex Jackson Coupling is all about, especially in this day and age, as all the work on angles necessary was undertaken a long time ago'. I then questioned whether this was yet another attempt to 'reinvent the wheel'. I apologise for this perhaps sounding offensive to some, I don't mean it to be whatsoever but regrettably I read so many untruths about the Alex Jackson Coupling, by people who really should know better, that it is becoming harder to take an impartial view.

So, thank you Gareth, your last post really clarified an issue which many modellers have had issues with (including myself!) To accept that you were 'cheating' when looking at the coupling against a drawing to get the angles correct really does show you are getting to grips with the problem. As mentioned above there are jigs available for you to overcome this problem, and at this point can I also give a big thumbs up to the Stenson Models jig mentioned above. This jig will overcome the problem of 'cheating' as the coupling can be viewed hard up against the jig making it difficult for it to be viewed from an incorrect angle. I personally find it really useful to have two of them to check either end of the vehicle - its saves time if checking a lot of stock! There will, of course, be another quick (rough) check of the angles if fitting a hinged AJ as the coupling wont fit into the Pivot Plate Bending Jig.

Gareth, you say that you were not getting sharp enough angles when using the Turner Jig. What wire are you using? I've never had any trouble with guitar wire. I still only use the Turner Jig for forming the first 5mm bend followed by the 180 jig to complete it. I then use my original drilled rod (steel in my case) to complete the coupling. I am always very much aware when forming the tail of the turning motion Dave mentions in his post but this motion doesn't tend to happen if your first 180 fold isn't as tight as it should be as the coupling becomes more of a forced fit into the second hole - some you win!! Also if using drilled rod, and you haven't made a coupling for a while, it is essential to have a practise beforehand, to ensure consistency. Plenty of opportunity to cheat here - been there, tee shirt etc!! Also, you mention that you, 'are aware of the statement that the angles do not have to be that accurate'. I think I was responsible for that statement, which I believe still holds true but as you have found out, any inaccuracy is within limits, whatever those limits are. I, for one, have no intention of examining what they are. I said it to encourage people to make the coupling and not get too hung up on the angles, it was never intended to encourage inaccurate production of Alex Jackson Couplings - now that would be cheating!!

Hope that helps

Tony

[davebradwell]

Hope you don't think I was suggesting adjusting anything on the coupler, Tony, just pointing out that the drawing is misleading if read in accordance with whatever the standard is these days - it used to be BS308. A combination of some of the text, the original jig and some of the drg defines it however. Interesting that you mention the 180 deg bend as I've heard of couplers cracking here when crushed tightly but don't know where the wire came from.

IMG_5893.JPG

I use one of these for checking the angles - surprisingly, it's called a protractor and they're pretty cheap and very useful. To get the 15 deg side offset of tail with respect to hook (front view) I overbend then squeeze the whole thing with flat pliers which, after springback, puts it pretty well spot-on.

Rather obviously, shortened couplings can be used on coaches so the buffers are held in contact but you'll only uncouple them by hand and after a struggle.

DaveB

[bécasse]

Half a century ago, Bembridge, effectively a pioneer P4 layout, used AJ couplings throughout (after we had seen them initially on John Langan's Presson when it appeared at Central Hall in 1962, with our choice further confirmed by a demonstration by a Merseyside member at the 1969 MRC show). The couplings, using guitar strings, were bent up by hand using pliers, the first carefully trying to get the angles about right and the remainder by matching the first one as closely as was practical by eye - so they were all more or less the same even if they weren't quite right. We did have the odd 180° bend break during the manufacturing process and when that happened we just cleaned off the broken end and used the remainder of the wire to make a new coupling, none broke in service.

The main problems that we had in service were:

1) initially some of the stock was too free running to couple readily - a pin head's worth of paint in the axle bearing cup cured that,

2) soldering the droppers (made from paper clips) to the guitar string wire was a more trying task than we had imagined even though they were bent up in an inverted-L so that there was a length to solder along the wire,

3) couplings depressed for uncoupling didn't always rise back up in the right place, which we cured by added a small piece of ^ shaped black plastikard behind the buffer beam to help centre the coupling wire.

4) one coupling at one end of one vehicle proved to be exactly the right length to pick up resonance from the rectified 50 hertz AC that powered our electromagnet uncouplers, which we cured by adding a tiny lead fishing weight to the wire quite close to where it was soldered to the vehicle effectively damping out the resonance.

Today, I have some jigs acquired a couple of decades ago or so (from Martin Brent?) and I use those when I need to make up some couplings - but really only because I have them and might as well use them.

[Paul Willis]

1) initially some of the stock was too free running to couple readily - a pin head's worth of paint in the axle bearing cup cured that,

This is a touch of genius.

For a couple of (too) fre-running wagons, I've been contemplating some sort of foam sponge arrangement rubbing against the axle. A spot of paint in the bearing is far easier to set up, and much, much less visually obvious.

Thanks for the tip.
Paul

[Tony W]

Dave Bradwell wrote:

Hope you don't think I was suggesting adjusting anything on the coupler, Tony, just pointing out that the drawing is misleading if read in accordance with whatever the standard is these days - it used to be BS308.

No Dave, that thought hadn't even entered my head - and apologies if I gave the impression that that was what I was thinking.
The issue of the cracking wire is one which I've never been able to solve. When I used to form the 180 bend using my steel rod jig I'd use two pairs of pliers to complete the bend. Sometimes I'd go through half a guitar wire before I'd get one without cracking. I came to the conclusion there must have been some inconsistency in the way the wire was manufactured. This happened with different brands of wire. However, when I started using the Turner jig followed by the 180 jig this problem reduced significantly even though a satisfactory bend was achieved using either method. I can only conclude that there really must be some form of vagaries with guitar wire manufacture. At the end of the day non of this is that much of a deal because, as bécasse suggests, all that is wasted is 5mm of wire!! Nowadays I tend to put a sliver of solder between the 180 fold (nose) and the start of the tail - not entirely necessary but it saves damage if the tail gets caught in transit.

Tony

[zebedeesknees]

1) initially some of the stock was too free running to couple readily - a pin head's worth of paint in the axle bearing cup cured that,

This is a touch of genius.

For a couple of (too) fre-running wagons, I've been contemplating some sort of foam sponge arrangement rubbing against the axle. A spot of paint in the bearing is far easier to set up, and much, much less visually obvious.

Thanks for the tip.
Paul

And there was I, http://www.clag.org.uk/wagonbrakes.html trying to get it ALL right... There's a carriage version too... http://www.clag.org.uk/memory-brake.html

Ted.

[davebradwell]

The cracking seems more widespread than i thought but obviously not a significant problem. Another reason, perhaps, for not crushing the fold too tightly. It's never happened to any of my couplings which are made from a large (several hundred metres) coil of #2 Roslau music wire from a piano repair supplier. Must be because it's German! The large quantity wouldn't suit most, though and I have the hassle of straightening it.

Could never get on with the soldered droppers so use Chris Pendlenton's clip-on design together with his pulling posts.

DaveB

[GarethSmith]

To answer Tony's question - I have been using 11 gauge guitar string as is suggested. I have been following the approach in the AJ book along with bits taken from other articles in S4 News and MRJ. I have used the Turner jig to produce all the bends in the hook with a bit of tweaking as required. I have not yet encountered the problem of the the wire cracking - although that may also be because I have perhaps not bent it so tightly.

Working out these angles was a bit of a distraction - well also partly a challenge to see if I could. When I first put up the post I thought someone would just come back and say that these angles were documented somewhere else that I hadn't found. However, it is in the way of such threads that instead it has delightfully led to the idea of putting paint in axle bearing cups. Thank you.