7.25 inch gauge Milner Hunslet

[jma1009]

May 22, 2022 21:38:44 GMT jma1009 said:

Hello Ed,

Going back to page 1 of this thread, we had 'bouncing', then this evening we have "derail"

Many of us contributed on page 1 of this thread, and we don't seem to have had a proper update. You have fitted stronger longer springs but where are they? Are they still between top of axle box and top of horn cheek? Or as I recall they were on the example of Milner's design that I had experience with?

Cheers,
Julian

[terrier060]

Well Julian I have compromised. I still have the bouncing as stated above and with the 0-4-0 wheel arrangement and consequential weight distribution this is to be expected. The new springs are in their original position. Altering them to the Milner design would be a big job and mean removing the boiler which I am not prepared to do at present. Part of the trouble was that with the original springs, they became completely unloaded when the axleboxes were at the bottom of their travel. This is not the case with the new springs, and the loco is better balanced with the adjusted weight ditribution. When the loco derailed it was on a slow bend and I had a fairly solid coupling between the engine and tender which used to cause the tender to push the rear of the loco down. I now have a fully flexible coupling using a Go-kart tie rod.

[jma1009]

Hi Ed,

May I suggest that on page 1 of this thread you were provided with very valid and considered suggestions based on sound engineering principles and experience.

The springing of your 7.25"g Hunslet needs either full leaf springing as suggested by Ed P, or a reversion to the Milner design with 2 springs either side each axlebox that I am familiar with.

I don't think either of the above requires a boiler lift off the chassis, and you have apparently already replaced the springs without this being necessary.

A spring arrangement with the springs between top of axle box and underside of the horncheek is always going to be inadequate and 'compromised'.

Not your "compromise". Instead "compromised".

Cheers,
Julian

[NickM]

May 26, 2022 22:49:13 GMT jma1009 said:

Hi Ed,

May I suggest that on page 1 of this thread you were provided with very valid and considered suggestions based on sound engineering principles and experience.

The springing of your 7.25"g Hunslet needs either full leaf springing as suggested by Ed P, or a reversion to the Milner design with 2 springs either side each axlebox that I am familiar with.

I don't think either of the above requires a boiler lift off the chassis, and you have apparently already replaced the springs without this being necessary.

A spring arrangement with the springs between top of axle box and underside of the horncheek is always going to be inadequate and 'compromised'.

Not your "compromise". Instead "compromised".

Cheers,
Julian

You tell him Julian. Nice to see you being your charming self as usual!

[nonort]

Can I humbly suggest that there was nothing wrong with the springing of the loco but that it is a phenomena caused by the valve events or and axle pump. If you are suffering an over compression at the end of the exhaust stroke. after short time it will cause a cyclic bounce to be transmitted to the chassis. I have had this with an engine that was very well built to the drawings etc. after much head scratching I removed five thou from each end of the slide valve exhaust pocket and it seemed to solve it. Just a thought.
All the best.

[jma1009]

Well, whether or not I am 'charming' or just plain blunt does perhaps require a bit of clarification.

I've known Ed for some 5 years when we first met. (We had exchanged emails etc some time prior to this.)

We have both been guests at each other's respective homes in South Wales.

Nonort raises a very valid point about the compromised Milner valve gear, but if you look through Ed's replies you will see that I had previously raised this possibility and you can see Ed's response.

Ed could easily run the Milner valve gear on the Hall valve gear simulator on his computer to understand the deficiencies with the valve gear and that you can't 'notch it up' without the beat going haywire and creating oscillations.

Then there is the matter of the springing of the loco.

I don't want Ed's lovely acquisition to be a problem on the track, and I do very much want him to arrive at a solution. Otherwise I wouldn't have bothered to engage in this thread.

The Milner Hunslet isn't superheated, and with it's deficient valve gear shouldn't be 'notched up' and both are relevant considerations.

Ed's acquisition is a lovely loco and I would like him to enjoy running it without the worry of it be 'bouncy' or derailing. As any fellow model engineer and friend would want.

Cheers,
Julian

[terrier060]

To close tnis discussion I am now fully satisfied with the loco and am enjoying hauling passengers with my fellow model engineers. Members will tell you I am over fussy and Nick has said all along the bouncing was nothing to worry about when he has driven it. It was the initial hard coupling that caused the problem, the weight of the tender banging down which caused the front of the loco to lift. As far as the valve gear is concerned it runs fine and has a modified valve gear. Like good Stevenson's gear it will run quite happily in mid- gear in either direction, once it is moving.

Yes Julian you can be blunt and sometimes I get exasperated, but I know you mean well. We must get together again sometime, with Roger would be nice.
Ed

[jma1009]

Hi Ed,

Yes, it would be great to meet up again as we haven't met
up since just before lockdown in 2020.

Homemade Lasagne I seem to recall here with your brother and Roger Froud.

[terrier060]

In the meantime we are getting my friend's boat ready for the season, having the dirty job of sweeping the flues and remembering how to put the boiler together again before boiler inspection. It all needs a good clean after the winter. We gave it a coat of antifouling as well.

The metal tube running along the underside of the hull is the condenser, one each side.

Cleaning the flues by ed cloutman, on Flickr

[terrier060]

Lunch break yesterday, passenger hauling at the Bridgend club. They are a great bunch and we had two locos in steam as well as the regular non-steam engines. It was mostly sunny and warm, though a strong wind kept the worst of the exhaust from blowing in my face. The loco ran well with the new buffers and has roughly equal weight now on both axles. The engine runs fully notched back and easily climbs our steep gradient with a load of passengers on board. The two of us who have similar Hunslets only pull one trolley on our track because of the gradient. I have pulled two full trolleys, but it requires full gear on the gradient and puts unnecessary stress on the engine for regular passenger hauling so we both stick to one trolley. Actually both my tender and the trolley are very heavy unloaded. Now I need to make the tender match the loco with a good coat of black paint!

Lunch Break 11_06_22 by ed cloutman, on Flickr

[terrier060]

Been away to Ironbridge to see the first manufacture of cast iron. Great day out and have year ticket to visit again. It needs more than a day to see it all. Highly recommended. Then went the whole line on the Gloucesteshire and Warwickshire railway and as I am a volunteer to the South Devon Railway, they very kindly gave me a tour round the sheds and workshops. Stopped in at the Dean Forest Railway on the way there and back. Also nice group of lads and lasses.

The steam valves on my injectors were leaking (not shutting off properly) and the injectors were getting hot and not starting properly, so I made some PTFE inserts and now they seal well, but one has to be gentle as they need very little pressure to close them once the PTFE gats hot.  I think I may need a different (more expensive) grade of PTFE, though these work well as long as you do not get a driver who unwittingly exerts too much pressure when shutting them. They really only require the tip of a finger on the edge of the wheel to shut them.

Back to work on the Terriers' vallances tomorrow!

[penybontshed]

I shall remember that Ed next time I drive her!

[terrier060]

The Hunslet has been working hard, passenger hauling. I am making some more PTFE inserts into the steam valves, because for some reason they have all started leaking. The water is not supposed to be hard here, coming off the peaty Welsh mountains, but several members have had deposit buildup on their fittings.

I am looking for a stationary boiler so that I can experiment with my Froud-style injectors. I suppose I could use my 3.5in Bassett-Lowke boiler, as it is all in pieces, but it has too low a working pressure (75psi) and I need at least 100psi.
Any suggestions - yes, why don't I make my own - I know!! Rather try and get on with the Terriers!
Ed

[jma1009]

I am looking forward to seeing pics of this passenger hauling on the excellent Bridgend MES Facebook page.

[terrier060]

At last perseverance has paid off and I have two working injectors to more-or-less Brown's 26oz design and they work well. They both pick up instantly from 60 to 100psi with no adjustment of water, but will still work to about 30psi with water adjustment. They 'tweet' quite loudly, like a small bird! With the Hunslet they can be left running most of the time as they do not reduce the boiler pressure to any extent, and the large Hunslet copper boilers can easily cope as they are very free-steaming. I have a No5 commercial injector which puts in a much greater volume of water, and is good for reducing the boiler pressure quickly. We have a steep gradient at the track and hauling a heavy tender and long passenger trolley tends to build pressure quite rapidly by the time the top is reached.

I am now modifying the injector body to make it simpler to build, keeping the sloping airway from the ball valve to the overflow within the body cavity.

Injector Body Sept 2022 by ed cloutman, on Flickr

[terrier060]

Another bit of luck - I managed to get a piece of 6in diameter seamless steel tube with 7.3mm thick walls. Also some 10.3mm plate for the cylinder ends. The lads are all coded welders and they said they would weld the ends on for me after I have drilled and tapped them. The back end has a hole for a 2800W heater element used in coffee maker machines. The boiler is designed to run at 100psi although I suspect it would be safe to a much much higher pressure.

Test Boiler by ed cloutman, on Flickr

[simon6200]

It is tremendously satisfying to run your engine with injectors you have made yourself. My B1 has two Brown style 26 oz injectors which work perfectly without fuss. I made them from square bar though which was much easier and avoided that troublesome cover piece. I’m not sure why yours tweet though. I understand that injectors should be silent.

[terrier060]

Interesting. Maybe my cones are not perfectly aligned?

[simon6200]

I’m not sure. Julian will know. If they work well, it probably doesn’t matter. It is still a great achievement.

[jma1009]

'Chirping' is air being drawn into the middle of the combining cone via the injector check valve that is not providing a 100% seal when the injector is feeding.