A number of saw teeth were found buried in the mill at Hafod Las - I've no doubt there are many more. Given the recognised nature of the site now, digging it up to find more would probably be considered vandalism. There are probably numerous ones wherever Hunter saws were employed, if they could be but recognised. I think the area where the Hunter saw was at MaenOfferen (the old Lower Works Mill) has been completely obliterated. The Oakeley Slab Mill at Gloddfa Ganol has also been gutted a couple of times, so again chances are low. I don't know what remains at Braich Du above Trawsfynydd, but they had at least two saws there. Graig Ddu had at least one. Caen 'y Coed had a couple. The Llanberis Slate Co. employed one if not two tunnellers for while...

Regarding speeds etc. I can do no better than post a report by the late Rodney Weaver which he wrote while we were surveying HafodLas, and also post a paper read to the Society of Arts in London by W.F.Cooke (of telegraph fame) on the subject of the saws and the tunneller.

I'll put them up shortly, along with some scans of the saws.

Talking of speed, watching a Kellow drill bite its way into slab at 6" plus a minute is something else as well!

Graham

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... but how does it actually work?!
Presumably you need a fairly decent power source behind it, which must come in through the shaft at the back. Putting aside the fact that the drive shaft doesn't look thick enough, it then seems to split the power to a shaft either side though a magical-looking system and then drives what I presume is the twin cutting head.

I'd guess that the double cutting head rotates around the long axis of the device, which gives you a round bore. Admittedly that introduces a bit of an issue in terms to the amount of rock/cutter contact, but that's probably resolvable somehow.

But... the chassis doesn't look as if it does allow rotation and in the plan view, it looks like it's got three drums which cut - a large centre one and two smaller outer ones. That's going to result in a very odd-shaped tunnel which isn't actually of much use unless you go back and re-do the edges.

So... where have I gone wrong?

I'm coming in rather late on this one, but having looked at the drawing again I would guess:

1. Power was delivered to the machine by a belt running on the drum on the rear cross shaft.

2. The axial shaft ("the shaft at the back" above) is the feed screw which moves the machine forward into the cut. It is driven by a worm on the rear cross shaft.

3. The supports for the cutting-drums shaft are S-shaped to pass between the central and outer cutting drums - they look a bit flimsy though.

Dave

I've got rather tied up at work, so what I wanted to post is still under construction... however, two interesting snippets.
1. Abercwmeiddaw - In 1871 the tenants were W.F.Cooke and G.Hunter, and in 1871 when it was up for sale amongst the plant was 1. a tunneler, 2. an undercutting machine, 3. a "double" saw and 4. a planer. So I rather think that my previous comments about a Brunton tunneller creating the "binoculars" there were wrong - it was Cooke and Hunter again.
2. Here's a picture of a Hunter cut slab from Hafodlas, you can see how the slate has been chipped out by the teeth...
🔗Personal-Album-54-Image-032[linkphoto]Personal-Album-54-Image-032[/linkphoto][/link]

🔗Personal-Album-54-Image-033[linkphoto]Personal-Album-54-Image-033[/linkphoto][/link]

And here's a rough diagram of the beast that did it... the Hunter & Cooke patent saw. The blades are 4ft in diam...
imgurl]Personal-Album-54-Image-034[linkphoto]Personal-Album-54-Image-034[/linkphoto][/link]

More info if I get a chance.

Graham

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Thank you for the images.
I've been getting strange looks in ByC as I peruse the cut slate work! Altogether most interesting!
So, from where did the inspiration come to use a circular cutter/tooth? The Cook/Hunter cutters are very reminiscent of "Arbortec" tungsten carbide cutters and similar tooling.
The fact that the cutters could be removed for service and sharpening is interesting and telling.
Making the cutters would seem to have been fairly easy, as would sharpening them. I assume that this totally pre-dates any form of diamond technology and that the steel alloys used were fairly primitive. This might suggest sharpen once or twice and then throw away, replacing with new. If sharpened, then every tooth on the blade would have to be very similar to prevent putting undue strain on one area of the blade.
I can see that the saw and the first tunneller, worked, but it must have been "something else again"! However, I fail to grasp how sufficient power could be supplied to the second tunneller of 1866. Was it some form of solid shaft drive?
The V belt drive to the first version must have been a pain in the neck to get correctly tensioned, needing not only the machine to be anchored but also the drive source.
What happened when quartz or another, hard intrusion was hit?

I've posted an extract from Cooke's paper which he read to the Society for Arts in 1867.
http://www.aditnow.co.uk/documents/personal-album-54/The-Tunnelling-Machines.pdf 
The figures in it make interesting reading - the tunnellers were slow! Eight inches per hour is mentioned.

Enjoy.

Graham

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Is the William Fothergill Cooke, of the 1866 Patent, the Sir W.F. Cooke of the Cooke/Wheatstone Electric Telegraph who retired to Portmeirion?

Is the William Fothergill Cooke, of the 1866 Patent, the Sir W.F. Cooke of the Cooke/Wheatstone Electric Telegraph who retired to Portmeirion?

Indeed it is, Cooke appears to have invested the money he obtained as a result of the telegraph patents etc. into Welsh Slate Quarries and into financing George Hunter's machinery. Within a very short period of time in 1861-68 we have Cooke arriving at Aber Ia (the forerunner of Portmeirion), the formation of the original MaenOfferen Slate company, George Hunter arriving at Maentwrog to manage the Braich Du Slate Quary above Trawsfynydd, saws and planers installed at both quarries, joint patents, Cooke becoming involved in Hafod-Las quarry, Hunter saws installed, Cooke & Hunter become involved in the Llanberis SLate Co. and the tunnelling machines used both at MaenOfferen and at Llanberis, but by 1871 they are both at Abercwmeiddaw and after that it all goes quiet. Of Hunter I know he produced a couple more patents on his own, but Cooke died in obscurity and apparently penury in 1879. At least one reference says that he lost all his money in slate quarrying ventures in Wales.

Graham

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Thank you for the confirmation, Grahami. You're probably way ahead of me on the connections but it's interesting that Cooke should lease from David Williams whose family were connected to the Greaves family. The Williams family became Williams-Ellis and thus the connection to Cpt.Martyn W.E., Llechwedd,1919.
Is the John Dickinson Brunton of the Channel Tunnel,1882, the same as he of Maenofferen?
Any who are following this thread may be interested in Fred Hapgood's article, try, www.mindfully.org/Technology/2004/Underground-Boring-M
Also, Tunnelling.Management by Design. Wood. ISBN 13 978-0419232001
The "hardcore" tome is Handbook of Mining & Tunnelling Machinery. Barbara Stack,1982. ISBN 978-0471279372
:thumbsup: Gwyn.

Is the John Dickinson Brunton of the Channel Tunnel,1882, the same as he of Maenofferen?
Gwyn.

This is where I'm not sure - I havn't "dug" into that chain sufficiently - there seem to have been several Brunton's inventors, engineers and surveyors. I did think initially that they were one and the same, but I don't have enough evidential links to confimr it, and what little I have found suggests that it may simply be coincidence. Curious though, in view of the tunnelling machine business.

Graham

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Thanks, Graham.
I came to this by looking into why the Tunnellers might not work! I've been researching, for instance, into wire rope which led to Roebling and thus to manual/ mechanised shield tunnelling. There in the literature are the brothers, J.D. and George Brunton with a patent in 1876 for a tunneller which seemed designed for clay or very soft rock and had an internal conveyor system to clear waste. This was in use in 1882 and is reported to have worked 12-17M/day. It suffered unresolved maintenance problems.
Anyway, back off to swim in a sea of paper work!

I,m not sure if this has been mentioned before in this thread but there is an interesting article on Sub Brit about the 1880's Channel Tunnel attempts which has illustrations of the Beaumont-English TBM and a later Wittacker machine, from the 1920's, sticking out of the cliff!

Martin

Is this Subterranea Britannica? Seems that money is req'd. to use its facilities.
Beaumont invented his machine, which had rotary picks, in 1875. English improved the design and it was tested for the Channel Tunnel in 1880. The 2.1m. wide machine had by Spring 1882 bored a tunnel 800m. long at Abbotscliff, as well as 1100m. of tunnel under the sea from a shaft at Shakespeare colliery. This was subsumed by some of the main working site of the present Tunnel.
Sparty_lea has an interest in Beaumont and has uploaded a document reporting his work with diamond boring in 1871/2. It is interesting to note that the works were superintended by a Mr.J. Vivian. This could be another false trail or another very interesting connection.

There's an interesting .pdf on tunneling with various illustrations at:http://www.tunnelsonline.info/Journals/Tunnels/Tunnels_and_Tunnelling/July_2007/attachments/00%20Harding%20Lecture%20_JKing.pdf 

I've just done some digging on the Bruntons - I'll post as soon as I can, it's a bit fraught here at the moment.

Graham

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Thank you very much for that Graham. :thumbsup:

I'm fairly certain Sub Brit is a free site, not cost me anything anyway. Mainly bunkers and defense stuff but a bit on mines etc.

Martin

Thanks Martin, I'll take another look.

And yes, thanks, I've found it! :stupid:
Interesting that Beaumont started with diamond drills, moved to soft rock/clay tunnelling and then invented a locomotive run on compressed air!

Here's a pic from today of the test tunnel:

🔗Maenofferen-Slate-Mine-User-Album-Image-088[linkphoto]Maenofferen-Slate-Mine-User-Album-Image-088[/linkphoto][/link]

Having had a quick look at the bore to the left of the two pictured,
there seems to be a circular cut into the rockface of the same diameter as the tunnel which suggests that the machine cut it and was then dragged back so that the cut rock in the centre of the circle could be cleared away?

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Here's a pic from today of the test tunnel:

🔗Maenofferen-Slate-Mine-User-Album-Image-088[linkphoto]Maenofferen-Slate-Mine-User-Album-Image-088[/linkphoto][/link]

Having had a quick look at the bore to the left of the two pictured,
there seems to be a circular cut into the rockface of the same diameter as the tunnel which suggests that the machine cut it and was then dragged back so that the cut rock in the centre of the circle could be cleared away?

Yes - with the trepanning type machine it would be driven in to the maximum depth of the cutter head, then withdrawn, the core broken off and extracted whole or smashed up in situ. I presume the former was done by something similkar to plug and feathers in the slot and then dropping it out onto a wagon. The mind boggles as to how this could have been achieved in a long level, one would have had to have a passbye or something so the debris could be extracted round the withdrawn borer. In view of this it's not surprising that the only tunnels we know of are relatively short. Later borers such as Bruntons and Beaumont/English's were intended for working in softer rock which the cutter head broke up and dropped onto a conveyor of some sort immediately behind the head which carried the waste behind the actual machine - much easier!

The second form with the rotating drums would have deposited its waste behind the drums and so could have used a conveyor, or scraper bar. However we have no physical remains by way of a test tunnel to see.

Graham

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If the two bores were cut alternately then the machine would only have to be reversed out as far as the shorter heading to clear each cut, although it would be a real pain to keep swapping from one bore to the other. The bores at Corris have tooling marks at a fine pitch where I assume the machine was actually cutting and a much coarser pitch as if it was moving away or towards the face with the head revolving.

Martin

If the two bores were cut alternately then the machine would only have to be reversed out as far as the shorter heading to clear each cut, although it would be a real pain to keep swapping from one bore to the other. The bores at Corris have tooling marks at a fine pitch where I assume the machine was actually cutting and a much coarser pitch as if it was moving away or towards the face with the head revolving.

Martin

Thanks for that Martin, I hadn't noticed the marks that way in the MaenOfferen bores, they may well be there too, but it seems reasonable. The underground bore also shows signs of a second parallel bore, though perhaps it was never properly started, there was not a lot of room in the chamber!

🔗Maenofferen-Slate-Mine-Archive-Album-Image-022[linkphoto]Maenofferen-Slate-Mine-Archive-Album-Image-022[/linkphoto][/link]

Graham

I wonder if the core could/would break off in the head and be removed with it. Cooke's account seems to suggest the core was removed entire.

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