Bower Springs

I thought I'd show you another stop on the Kelham Furnace Trail. At Bower Spring (do not be misled by the idyllic-sounding name) are the remains of two cementation furnaces.

Unlike the nearby Doncaster Street furnace, these are ruined, so you can see inside. Unfortunately that is not the only difference between the two sites: these furnaces are on a site that does not appear to be particularly well cared for, neither are they very welcoming for visitors at the moment.

Bower Spring is adjacent to the new section of the Inner Relief Road. The road avoided the furnaces, but the site is littered with junk that has apparently been left behind by the road's builders: traffic cones, roadworks signs, buckets, discarded clothing and other assorted litter are all strewn around the site.

The furnaces are a scheduled monument, so they are are fenced off - and quite right too. The furnace structure needs protection and the unwary visitor could easily cause damage to themselves or to the remains on the site. Unfortunately the manner in which the area is currently fenced off is awful - it is a mixture of security fencing and partially collapsed temporary fencing of the type that normally surrounds building sites. In short it is both ugly and ineffective, plus it obscures the ruined furnaces. I hope that this situation is just a temporary hangover from the construction of the new road.

The only concession to visitors seems to be a sign, mounted high on the security fence:

"Bower Spring Furnaces
These remains of 19th cent[ury] furnaces for making cementation steel are a scheduled monument.
They belong to the South Yorkshire Industrial History Society.
Contact point: Kelham Island Industrial Museum."

It seems that it is not just the Furnace Trail web link that is not yet ready for visitors, this part of the actual trail is currently somewhat less than welcoming.

However, despite the sorry state of the site, it is still most definitely worth stopping to look. Where else could you can see exactly what a cementation furnace was like inside?

These furnaces were obviously much smaller than the one on the Doncaster Street site, I found it hard to imagine how cramped the working conditions must have been. One furnace has been reduced to little more than a tell-tale outline on the wall at the back of the site, but the other is still partially intact.

One of the stone coffins is still in place, this is a large chest that held the iron bars and charcoal which were converted to blister steel during the cementation process. Next to the coffin are brick built structures which were part of the flue system. A small section of the furnace wall is still standing, as is part of the vaulted section over the coffin - the surface of which is heavily glazed from the heat experienced during firing. Away from the furnace itself, some brickwork hints at the existence of the cellar, where the coal was fired to heat the furnace. The holes in the picture below almost certainly belonged to a completely different type of furnace: crucible furnaces were often found along cementation furnaces, including at this site. The whole structure resembles a kind of 3D cut away model.

The Doncaster Street furnace is impressive, but left me wanting to see inside, here it is possible to do exactly that.

Links
This furnace is part of the Kelham Furnace Trail. A leaflet describing the trail is available from local bookshops, including the one at Abbeydale Industrial Hamlet. The leaflet gives a link to Upper Don Walk trust's site but there don't seem to be details of The Furnace Trail online just yet.

All my posts about the Kelham Furnace Trail

My Flickr photoset for this furnace

The Winter 2005/06 edition of the Historical Metallurgy Society's newsletter includes an article about Bower Springs and the archaeological research carried out here before the road was built. [pdf document]

Events listings for the South Yorkshire Industrial History Society


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Originally published here on my main blog http://three-legged-cat.blogspot.com/
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The Last of its Kind

Travellers using Sheffield's Inner Ring Road might just catch a glimpse of part of the city's industrial heritage. Standing in HSBC's car park on Doncaster Street is the only complete cementation furnace left in Sheffield. The furnace is a large bottle shaped structure, outwardly similar to the bottle kilns used by pottery manufacturers. It is an unusual structure, very different to everything around it, but it is constructed from red brick, so it is surprisingly easy to pass by without even noticing it.

The cementation process combined carbon with iron to create bars of blister steel - named for the characteristic blisters on its surface. The process involved heating wrought iron bars and charcoal. The raw materials were packed in layers into two large sandstone chambers, known as coffins, which were sealed off with a mixture of clay and waste from grinder's wheels before the furnace was fired. The entrances to the chambers (known as charging holes) were also sealed up with bricks and clay.

The furnace was coal fired and heated the iron until it was red hot, but not molten. Once heated to this state, the iron softened and reacted with the carbon in the charcoal to form steel. Firing was a lengthy process typically lasting for around 7-10 days, followed by several more days of cooling before anyone could enter the furnace to remove the newly formed blister steel. The furnace had a surprisingly large capacity - a plaque at the site reports it at 40 tons. Let me put that in perspective for you: as an engineering student (studying metallurgy and materials science), I did a work placement at a local company that still makes special steels for the aerospace industry; their furnace had a capacity of 10 tonnes, although the firing was a lot faster than at Doncaster Street.

Blister steel was an important product in the Sheffield steel industry that was used to make a variety of tools. Unfortunately it also contained impurities which adversely affected the quality of the steel. Huntsman's crucible process could remove many of the impurities in blister steel to create a much better quality product - but more about that another time.

The Doncaster Street furnace was built in around 1848 and was one of five operated by Daniel Doncaster, a well known local steelmaking company. It was last fired in 1951.

One interesting feature of this particular furnace is the slightly odd structure on the top. This dates from World War II (although it has been restored somewhat). The top of the flue would be easily visible during firing, but given that the firing lasted for days and couldn't be stopped at short notice, a method of concealing the flue was needed. The solution was basically a metal flap that could swing down to cover the top of the flue in event of an air raid. The flap is attached to a frame and has a lever to assist in lowering it. I suspect that actually operating this when the furnace was being fired would be quite difficult.

The furnace is in very good condition, having been restored by Midland Bank (now HSBC) during the early nineties. It is fenced off (no bad thing), so it is not readily accessible, but it is easily visible. The sign states that a key is available on request from the curator of Kelham Island Museum - although the phone number is out of date and the museum is still recovering from flood damage, so we didn't try this. It didn't matter - we had a good view of the furnace from the street and from just inside the bank's car park. We visited on a Sunday, when few people were working there, I don't know if the same relaxed attitude to sightseers would apply in the week.

I'd love to actually get inside it, but somehow I suspect that wouldn't be allowed.

Diagram from the information board at the site

Links
This furnace is part of The Furnace Trail. A leaflet describing the trail is available from local bookshops, including the one at Abbeydale Industrial Hamlet. The leaflet gives a link to Upper Don Walk trust's site but there don't seem to be details of The Furnace Trail online just yet.

All my posts about the Kelham Furnace Trail

My Flickr photoset for this furnace

--
Originally published here on my main blog http://three-legged-cat.blogspot.com/
Comments on the original post