"Lost"....forging skills?

A machinist friend who has an interest in blacksmithing and old machinery recently pointed out a couple of marvellous examples of forging, seen in the photos of a George Watkins book "The Steam Engine in Industry vol 1".

I particularly like crankshafts forged from round stock - and here is a fairly massive (9" dia) example.

I can't say such knowledge is lost, but how would such a shaft be forged so tightly and neatly?

The photo was taken in 1935 and shows the pumps in Southhampton Waterworks. They were driven by a Easton and Anderson rotative beam engine. They were built in 1879.

"The crankshafts were splendid examples of smiths work, in wrought iron 9in diameter machined only for the pump rod bearings, which had a collar forged on either side of the brasses".


And a bit more about the pumps:

"Each engine drove by a cast iron pinion 3ft in diameter to a mortise gear 6ft in diameter upon the pump crankshaft. the teeth were 9in wide, those of the larger mortise wheel being made of apple wood, with twin tails passing through slots in the rim, and held in place by round pins driven through the tails. the teeth were lubricated with a mixture of blacklead and tallow, the central platforms giving access for this and to the oil holes in the top brasses of the pump connecting rods."
The pumps were 8 1/2in x 2ft stroke.




The next photo shows a beautiful inverted vertical engine built in 1890 by Robert Daglish for St Helens Waterworks. It has cylinders of 35 and 60 inches, with a 6ft stroke.

What interested us in particular is the eccentric rod forging, which the third photo shows closer up.

"The eccentric rods are fine forgings with the rod, forked top-end, and the top half of the eccentric strap in one piece."

Try and make that! The flywheel is 16ft in diameter, so the eccentric rod is around 7-8ft long.

Peter,

Those crankshafts are fantastic. Two planes, not flat. I can’t imagine how they’d go about forging them accurately – and quickly! The smiths wouldn’t want to keep whipping them back into the furnace every 10 minutes.

Easton & Anderson was a fascinating company. Their predecessors, Easton & Amos, built the Westonzoyland pumping engine whose workmanship I often admire.

Amazing to think that the ornate Daglish engine was built down to a price!

I don’t suppose there’s more than one of their engines left. I first heard of the firm in an account of working peoples’ lives in the 1920s (‘Industrial Town’, by Charles Forman). One of New Zealand’s Premiers, Richard Seddon, served his apprenticeship there. He was sacked for demanding more money for apprentices.

One former Daglish employee recalled a horse straining to pull an engine part out of the works yard on a cart. ‘The horse was leaning right over forwards. Mr Dalgish came out and said, ‘I say, lad, you’d better look after that horse, it costs money. I can get men for nothing’.

Another Daglish employee’s father was leaning over to look into the bore of an engine cylinder being machined. ‘One of the belts broke and lapped round his arm, flung him to the roof and catapulted him into a 80 horsepower steam engine which ran the whole shop. That killed my dad when I was 18 months old and my brother was 13’.

The Daglish eccentric rod in the photo is a work of art. It must have been forged pretty close to finished size, given the need to minimise the extent of filing and machining.

I don’t have photos of anything comparable, but I did admire this:-



The engine (at Crofton) was built in 1812, but I don’t know whether the forged rod is that old.

Sort of like pouring crucible steel with the shanks of the tongs resting on your knee and only wet rags to protect you from the near 3000 degree (F.) pot about 18" from your body.


Hard to find anybody to do such things anymore, let alone long enough to become skillful at it (If the "teemer" "catched" the stream of steel on the side of the ingot mold, he flunked on that ingot)

John

The forged rod is a lovely example of turn of the century work..These techniques are essentially the same as if someone made the same piece out of 1/2" round working at the anvil..Just bigger..

At least that's the way we made 'em on the steam hammer where I was..I think a lot of other trades sometimes don't realize that most of the time, a forging like that starts with a much larger block
that gets necked down and drawn out to leave a smaller shouldered "head" on the end of a shaft.

There still are a few industrial forge shops capable of this kind of work.
And believe me, these forging were made in industrial shops, with big crews, big hammers, and big forges.
We tend to think of the old blacksmith under the tree, but these are industrial products- the heats to get a big piece like this hot are often 30 minutes to several hours in a gigantic forge.
I know a some guys who work at big industrial forges in the midwest, Scot Forge is one of them.
http://www.scotforge.com/sf_about.htm
They routinely forge pieces as bit as 10,000lbs, in a 20,000lb hammer.

Another guy I know of on another forum still works for a steel mill in Canada, forging huge items like this for in house use-crane hooks, tools for the mill- 2 or 3 guys to manipulate the work, another guy running the hammer.

A great book that shows step by step how they did this kind of work is "Blacksmiths Manual Illustrated" by JW Lillico.
It was written in 1930, when smiths routinely made all kinds of rods, levers, and shafts, and shows the techniques to put the material where you want it. Often available on abebooks for a few bucks, as it was reprinted in 78.

The skill, and even the shops, to do this kind of work is still around- of course, much less so than in the 30's, but its out there. But nowadays, these kinds of forge shops work with things like 3' long blocks of titanium, inconel, and other aerospace alloys.

Am guessing here, but...

To forge that crankshaft, a BIG power hammer and suitable dies. That would make it round and to size with a decent finish in reasonable time, providing you had enough heat and weight on the hammer to make it happen. Would also guess the bends were made hot using really massive bending dies, probably not one operation per bend. If the crank is built-up rather than one piece, it would be forged in sections and then joined end for end. Pressing cranks together is common practice now, but don't know back then. Something that big in one piece would be awkward, but it could've been done with a lot of extra work.

The eccentric could've been done in a similar fashion. A skilled man probably would work it at a smaller hammer, with the aid of a crane.

One thing is for sure: they had stuff big enough back then to do such work on a routine basis. Must've been something to watch.

I suppose it is possible that a firm like Easton and Anderson could have had the crankshaft forging done by a 'big' company who specialised in such work.

I would guess you need hydraulic power to get that sort of bend?

I think a lot of other trades sometimes don't realize that most of the time, a forging like that starts with a much larger block
that gets necked down and drawn out to leave a smaller shouldered "head" on the end of a shaft.

Click to expand...

Phaestos,

I have only learned this recently from the friend mentioned above - that is one of the things that "concerns" me about the eccentric rod job - how to calculate the correct sized piece to start with! And not have any scrapped "test" parts when you have finished!! Quite apart from not leaving any 'dings' in the finished job...

Ries,

both of the above examples are from 19th century, not 1930's!
Thanks for the book tip, does it have examples of large work like this, or is it hand sized work?

Asquith,

I just saw a photo of "King Dick" Seddon in this weeks newspaper, it was an article about a local lady just turned 100 years old, the famous (in NZ, anyway), Premier died in the same year she was born.

I came across the Lilico book early on in my training, but I didn't have as much interest in it as other books, for example Weyger's.
The Lilico book was too " old fashioned"
At the time I didn't realize what I was looking at.

In reality, Lilico was talking about making large forgings with simple tools, and how to go about forming them. It looks simple, and it is, but the reality of applying these techniques to something red hot and hundreds or thousands of lbs.can be a wee bit daunting to an onlooker.

But for the guys on the shop floor, get it hot and hit it! It was an everyday thing for them, thinking on that scale, because of the tools available to them, namely the steam hammer, made this possible. There was quite a race in Europe to develop the largest hammers to make the largest forgings, and this has all been happening for a few generations.Add in the influence of guilds and unions, etc. for training and standards, and then it's not so surprising that they could pull this stuff off. During industrial revolution times, this is where the money was.

It's difficult to see in the picture, but it looks as if the rod was perhaps necked down with a swage, leaving a block large enough to draw out into a "tee" shape. The tee could be refined and then bent into the finished shape. Of course, allowance would have to be made for the boss at the end of the "tee", but in the end, it was just a bunch of calculations for volume, remembering that things are just a bit bigger if you measure them when they're 1800 degrees. If you do it for long enough, it appeared that they wouldn't even calculate, but just grab the tongs and start working. A good "eye" was needed.

I find it difficult these days to run into many people who think like this..

The power hammer has been used in industrial forging since the 1600's or so.
This type of forging was more dependent on the availablity of good quality steel in big chunks, which is a late 19th century process. Previous to that, these would have been wrought iron, most likely, as many large anchors were.

The Heyday of large scale industrial forging are relatively recent- mid to late 19th century.
The tecnhology didnt change much between then and WW2.
Mainly just the addition of individual electric motors, instead of line shafts.
The Lillico book is describing the basic techniques used for these pieces. The techniques are not size specific- the basic process is the same, whether you are using a 2lb hammer on a piece of 1/2" round, or a 20,000lb steam hammer on a piece of 12" round.

The team that made these had probably worked together on large forgings for 20 or 30 years. They were incredibly skilled at working with large pieces. They used overhead cranes, or big tripods, to swing the work from forge to hammer.

Here is a pic from about 1988, of a similar team doing similar work, in the Cambria Ironworks in Johnstown Pa. This is the smallest hammer in the Cambria shop, a mere 600lbs or so, but they had much bigger ones, run by steam. 3" steam lines entered the blacksmith shop from the steam plant, almost a mile away.

One thing to bear in mind about a crankshaft made in 1879: it would be made of wrought iron.

I came across an article in ‘Engineering’ written in 1879 about the forging of large marine crankshafts at the Lancefield Forge, Glasgow. Incidentally, this was the forge entrusted with the onerous task of forging the 40 ton crankshaft for Brunel’s ‘Great Eastern’ in 1854.

The description is hard to follow, despite numerous illustrations, but some startling facts are apparent. Note that the crankshafts in question would subsequently be machined all over, unlike the shapely one in Peter’s photo.

The crankshaft did not start as a more or less homogenous mass to be forged to shape. It began with a ‘porter bar’, to which slabs of wrought iron were added. The slabs themselves were made up of bundles of iron rod, hammered and rolled and piled and hammered. Several slabs were piled on the end of the bar and heated in a furnace, then hammer welded together under the steam hammer. The mass was gradually built up in this way, but the forging was progressively finished while other stuff was being piled on. In other words, one end was forged to final shape while the other still had many more slabs of iron to be hammer welded on to it.

The piled mass had to be heated to high temperature while the finished part, weakened by heating, had to bear the weight of this mass. This could lead to defects in the finished part, leading to failure in service.

Further difficulties arose, partly from the nature of the wrought iron, with its slaggy fibres, and partly from the potential planes of weakness where slabs were hammer welded together. The article highlights the need to avoid having these welded interfaces unfavourably orientated in relation to highly-stressed areas, particularly at the crankpins. Lancefield Forge had developed ways of welding on relatively thin curved slabs to end up with favourable orientation of fibres and weld interfaces. Care also had to be taken to ensure that the shape of these slabs allowed slag to escape during forging!

My sketchy account can only attempt to highlight the difficulties, but it’s clear that such work is definitely a lost art.

As an aside, the article sheds light on the speed of communication in those pre-electronic mail days.
The article appeared in the August 15th issue. Its author wrote a letter dated August 18th correcting a few points and adding some new illustrations, and this appeared in the August 22nd issue.

Having mentioned the ‘Great Eastern’ and communication, it is perhaps worth noting that this ship laid the first successful transatlantic telegraph cable, in 1866.

While I understand that this discussion concerns hammer forging, forging with hydraulic presses is very much alive and well. The Wyman-Gordon company of Grafton, MA has 3 presses over 30,000 Tons capacity, one of which is 50,000 tons capacity, and claims to be able to do forgings up to 60,000 pounds.

Try www.wyman-gordon.com

Thermo1

I particularly like crankshafts forged from round stock - and here is a fairly massive (9" dia) example.

I can't say such knowledge is lost, but how would such a shaft be forged so tightly and neatly?

Click to expand...

I think I would start with a round bar that was equal or a little bigger to the diameter of the rod bearing journals.

Then neck/swage down the bar between the journals.

Then bend the crankshaft "throws" in a Bulldozer (below). Just a big mechanical horizontal press.

Then twist the throws into position.

All done hot of course.

I found an advert from 1891 that shows a two throw crankshaft with the cranks set at 90 degrees, like the one in the photo, although no idea of size is given.

The advert states that the crankshafts are bent to shape, and emphasises that the cranks are forged in their correct position, and NOT made in the flat and then twisted.

Still a contender for a lost skill, in my opinion!

Incidentally, the advert was for Woodhouse & Rixson of Sheffield, and I'm pleased to find that they have survived as Firth Rixson (see the Video Clips: Forging thread). Unfortunately, they've now set up a plant in China ....

The advert states that the crankshafts are bent to shape, and emphasises that the cranks are forged in their correct position, and NOT made in the flat and then twisted.

Click to expand...

If so what would the forging dies look like?

Forging in the "correct position" offers no advantage to twisting the throws into position regardless of what some promotional advert says.

Thinking about how to do it after I posted the above plan I realized that the throws could be made in the correct position by bending the throws that were in the same plane in one setup, then turning the crank in the bulldozer, then bending the other throws.

Repeat as needed.

The fun part would be doing those crankshafts ALL day..I can imagine how hot those days would be..

I was very happy to see the pic of the bulldozer.Brought back many memories. We had 6 of 'em in the shop, from a wee tiny one with a 24" wide bed, to a big hydraulic one 72" across..

The dies were mostly designed in shop, and I was always amazed with the amount of depth that went into the figuring so the parts came out right.
Talk about a lost skill..

beobe,

A fascinating topic.
I disagree on one point, and agree on another.

Twisting to set the second crank would be a Bad Thing. A wrought iron crank would have a distinct fibrous structure, and would be relatively weak across the fibres. Twisting through 90 degrees over the short length of the crankpin would result in the fibres being aligned in an unfavourable direction with regard to the stresses.

I agree that the crank could be made just by bending, without twisting. I’ve just made one out of Plasticene! (Plasticene is a type of modelling clay, as used in the manufacture of Messrs Wallace & Gromit). I couldn't manage the neat upsets, though, that constitute the flanges either side of the crankpin!

Asquith. The "upsets" aren't upsets. They are the original diameter of the stock. As always, drawing down to size is easier than upsetting.

Bending the separate phases of the crank throws in the bulldozer eliminates any stress problems that may have resulted by twisting.

I think we are ready to heat up the forge.

phaestos. I borrowed that picture from another thread at this site. Search for "bulldozer".

beobe,

Quite right, the collars wouldn't be upset. However, I'd be interested to know how they keep their shape when the adjacent material is sharply bent.

My point about stresses doesn't relate to twisting stresses - they'll tend to be relieved by heating. The issue was the location of the planes of weakness in wrought iron cranks in relation to the direction of the stresses arising in service. Cracks developing in crankpins have greyed the beards of many a barnacle-encrusted Victorian marine engineer, especially in the days of wrought iron crankshafts.

[ 02-23-2006, 05:24 PM: Message edited by: Asquith ]

According to the George Watkins description of the crankshaft - " a collar forged on either side of the brasses".

Not that I am any the wiser on how this was actually done!

Large objects are not shuttled back into the fire every ten minutes. Several hours of heating followed by several hours of forging. The Lillico book is now available free on the web from the rural crafts council in Great Britain.

Most of us make relatively small things using relatively large machine tools. I'm fascinated by the huge scale of the pictured machines and wonder how they were machined with relatively small machines. Maybe that's one of the lost arts.