laminated irons (again)

[D_W]

https://www.youtube.com/watch?v=Qr4VTCwEfko

This video has the type of hammer I was talking about. The hammer is at 2:49 (and around 5 minutes, the shop master lights his pipe with a heated axe blank!)

While I find it satisfying to hammer the knife blanks out of old stuff by hand (it is), it's not very economical. I am using a 4 pound hammer, too (if you had a hammer man, you could increase that by a factor of two to four for rough work). A die and a hydraulic press would make a lot more sense.

I'd bet that in the 1800s, if you were hand hammering, the ability to work wrought and laminate high carbon to it would be far less labor than just working all high carbon steel. It moves better, I'm sure it's easier on files and drills, etc.

I've bought some bench planes recently intentionally because they have laminated irons. My first laminated stanley iron was superb, but the last two have been a touch soft, so I'm not sure what they were aiming for or if that changed over time. The harder iron was older than the two softer laminated irons.

All of the record irons that I've used have been a touch on the soft side, but they're nice, as are the softer stanley irons. Just not quite as hard as I'd like in a smoother, but excellent for jack, jointer, try plane stuff. I don't know why that is (that it seems nice to work with softer irons in coarser planes), but it's just so.

 

[nabs]

thanks that is a good film.

From what I have read if you have a 19C laminated iron made in sheffield then the chances are it was forged by hand on an anvil in a small workshop housing one or two blacksmiths.

It seems Sheffield's reputation for quality + an abundance of good steel and hand skills meant the old methods could continue for a long time despite mechanised competition from abroad, however, by the 20th century foreign competition was having serious impact on trade in GB and something had to change, and it did. Thus as we learned earlier in this thread, the Stanley and Record laminated blades were, in comparison, modern tools made from a 'cast-on' laminate and rolled and stamped out by machine.

I am not sure when automatic heat treatment techniques were introduced. Is it possible that even the modern thin blades were still hardened and tempered by hand and that explains the variations in hardness you found?

 

[Cheshirechappie]

Couple of points. Firstly, Sheffield adopted the use of 'power' hammers sooner than some might think. The standard small (spring) hammer for toolsmithing was made by Pattinson Brothers, and was of about 1 cwt capacity, depending on the dies fitted. Ashley Iles started his business with one just after WW2. They're still using it. I don't know when spring hammers were first introduced, but by WW1 they were everywhere in Sheffield.

The second point is about metallurgical development. The techniques of making edge tools and cutlery evolved around the use of wrought iron and plain carbon steels because until the end of the 19th century, that's all there was (Bessemer added bulk mild steel in the 1860s, but didn't crack tool steel manufacture by his process). However, experiments with alloy steels started in the mid to late 19th century. You've mentioned Mushet's air-hardening steel on your blog, and another example of early commercial success was Robert Hadfield's 1882 discovery of Manganese Steel.

More pertinently from our point of view is the development some time in the 1890s of what became known to us today as 01. Straight carbon steel was used for all manner of applications were a hardenable steel was needed, including engineering gauges. Carbon steel has a couple of snags, in that when quenched on hardening, it is prone to distortion and also to slight dimensional changes; neither of these properties (whilst pretty much immaterial to edge-tool makers) help gauge-makers maintain accuracy of their products one bit. However, 01 can be hardened in oil rather than water, and is thus much less prone to distortion and dimensional change. It also makes pretty good edge tools. Tool makers soon found that they could do things with O1 that they couldn't with straight carbon steel - bevelled edged chisels being an example (try finding any examples in the catalogues much before 1900).

O1 changed edge-tool making, possibly spelling the beginning of the end of laminated blades, I reckon.

 

[nabs]

that's very interesting CC - hopefully you can save me some reading (I have read quite a lot of stuff up to about 1885!): is O1 a particular alloy or a group of steels? Do you know who invented/discovered it?

 

[nabs]

PS I came across a number of references to 'goff hammers' in the 19th C literature (normally criticising their use by 'foreigners' to make inferior goods ! ). Are they the same as spring hammers?

 

[Cheshirechappie]

No. Unfortunately, I've never been able to pin down exactly who or when. It was during a time when lots of experiments were going on. Hadfield's steel is often quoted in the history books because it was one of the first. Molybdenum steel followed soon after, because the railways found they could use it in rails, particularly the ones on pointwork that saw a lot of wear. A later example was Harry Brearley's discovery of stainless steel (or 'rustless iron' as was originally called in 1913. Brearley was looking for longer-lasting steels for gun barrels, and discovered that a high chromium content resisted the etching power of the acids used for metallurgical examination preparation. Many other alloys came about during that time, and in the years after WW1.

Edit to add - not sure about 'Goff Hammer', but this is the sort of spring hammer much used in Sheffield;

https://www.youtube.com/watch?v=obAOFfPbuRs

 

[AndyT]

PS I came across a number of references to 'goff hammers' in the 19th C literature (normally criticising their use by 'foreigners' to make inferior goods ! ). Are they the same as spring hammers?

According to this excellent book(only £5!) a goff hammer is a "fast-running powered trip hammer used in forging."

 

[Cheshirechappie]

On the basis of that definition, a Goff hammer and a spring hammer are probably pretty much the same thing, or different names for the same thing.

Just a thought - hand forging a pen-knife blade by hand hammer is one thing, but a plane iron would be an altogether different undertaking. Some smiths used a striker with a bigger, long-handled sledge, but my guess is that for bits bigger than small knife blades, gimlets and the like, as the spring hammer could give more and heavier blows per minute it would increase a man's productivity significantly.

 

[D_W]

On the basis of that definition, a Goff hammer and a spring hammer are probably pretty much the same thing, or different names for the same thing.

Just a thought - hand forging a pen-knife blade by hand hammer is one thing, but a plane iron would be an altogether different undertaking. Some smiths used a striker with a bigger, long-handled sledge, but my guess is that for bits bigger than small knife blades, gimlets and the like, as the spring hammer could give more and heavier blows per minute it would increase a man's productivity significantly.

A little bigger than pen knife. So far, I've forged blades of 2 (that's a pen knife), 3 1/2 and 5 inches.

Out of files and chisels. I don't have anything large enough to forge into a plane iron (especially not reasonable quality wrought iron) or I'd give it a shot.

I'd guess a power hammer would increase production by a factor of five or more in large things. Perhaps ten - and it would allow hammering of larger items from less perfect starting sources of stock.

I'm sure I could hammer a 2 1/2" wide iron, though - but I wouldn't want to do it out of high carbon steel. What I'm not sure of is whether or not I could get a forge weld between wrought and something like 1095 steel. I heard that in making irons by hand (which they did at colonial williamsburg here) that they had trouble with steel of the garden variety for tools (1% carbon range) and ultimately decided to use 1070, which forge welded much more easily.

If they're having trouble with it, what's going to happen with a guy who has a couple of propane bottles and no helper?

In terms of increasing productivity beyond the power hammer, the mid-level japanese makers (who make chisels for about $50 each), or at least some of them, use dies and a hydraulic press. They smash the soft iron (you can get wrought, but the price is higher) and hagane layer together and shape all at once and then use grinding jigs to do the rest of the work.

The process that die forges razors (and is still in use) is a two step squash from a large hammer and then a trimming die to remove the excess. that's not laminating, but still an illustration of how much faster die forging is and there's no real loss of quality vs. a skilled user working a power hammer. An unskilled laborer can then run the die forge process and the result is much closer to final shape than it would be if someone attempted to do something by hand. You can see the point in history where razors went from being less precisely shaped billets turned into wedges to finely made hollow ground razors that resulted from die forging.

If there was a demand, I'd imagine that a shade tree type person could make a die and laminate with a hydraulic press. There's no demand that I'm aware of. It's probably difficult to get people to even pay $70 for a milled tapered iron, and even those irons have lost some of the subtleties that make for a good wooden plane iron (a hollow along the length of the iron, etc, to make sure they will bed on the right places even if the plane moves a little with the seasons).

I've thought about giving some of this a try. Not the laminating, but forging a plane iron. The reality of it, though, is a high quality O1 iron that's heat treated properly is really difficult to beat. The dirty secret (well, not dirty) is that the better oil hardening steel irons actually outperform A2 in use in normal wood, wearing at a similar rate but staying more even wearing and providing a better finish as they do. Or, in short, I'm sure the iron that I drill, saw and file out of western-made O1 stock will be better than one that I hammer out of a large file. I don't know what the file is made of, but I know O1 stock is very easy to harden and temper if you're willing to stick to a certain mfr's stock and do the same thing each time. My best plane iron, aside from two japanese irons, is an iron that I just cut and filed out of starrett O1 stock and tempered right at 60. It is a better iron than Hock's (hock HCS irons chip), though maybe not quite as good as the irons steve knight had made.

Apologies for the tangent. I do intent to hammer out some larger knives, though, and would attempt an iron if I actually had wrought (that would be easy enough to fix with a little bit of spending) and thought I could freehand a forge weld (I have no confidence in being able to do that part).

 

[D_W]

https://s13.postimg.org/yn8ui6z1z/20180101_145842.jpg

This is the second knife that I've made - it's wharncliffe, so the sharp edge is the straight one and the groove on the back is a false edge to attempt that just for fun. Since it's only the second thing I've hammered, it's not an issue of actually wanting this particular knife (the chisel is junk - a long socket firmer from lakeside), but seeing if it was easy to forge one that's straight enough to be hand finished on files and stones (it is), which then means if you're going to do a project by hand (like making a lockback or slipjoint knife), you can make a fairly large one with a hand-made blade - more stimulating if you're the maker than belt grinding and filing (or milling if you're inclined) out of bar stock.

I also wanted to see if heating and hammering this chisel (which was no good) might help to make the quality of the steel a little bit better - and maybe that does sometimes, but it didn't do anything in this case. it still fails by chipping far more than decent quality O1 despite not being any harder than 60 hardness. I'm guessing lakeside was a second rate lower-cost maker.

I'd guess hammering time on this to get to this point (before hand filing and stoning) was a couple of minutes - three heats? a shade tree person could hammer a fat 1" wide chisel into an iron blank in about an hour (perhaps two inches wide - I ground away a lot of tapered hammered material), I'd guess - and at the cost of a couple of bottles of gas. It's not a small knife blade, though - 3 1/2 inches long or so with some excess ground off of the end. A can forge makes enough heat to do an iron 8 inches long or so if you're willing to do each side.

I may still attempt a solid steel forged iron if I can come across a wide and thick, but inexpensive chisel.

 

[nabs]

You can see the point in history where razors went from being less precisely shaped billets turned into wedges to finely made hollow ground razors that resulted from die forging.

this is a good example of the inertia that beset the Sheffield trades - the techniques for hollow grinding razors were actually invented in Sheffield, but it took makers in Hamburg to see the opportunity and put it to good use. By the time Sheffield cutlery makers realised that consumers wanted the newer product it was too late - by then the German makers had a well earned reputation in this area that was hard to dislodge.

I would be fascinated to hear more about real world experiences of hand forging plane irons so don't forget to film it if you do more experiments!

 

[D_W]

You can see the point in history where razors went from being less precisely shaped billets turned into wedges to finely made hollow ground razors that resulted from die forging.

this is a good example of the inertia that beset the Sheffield trades - the techniques for hollow grinding razors were actually invented in Sheffield, but it took makers in Hamburg to see the opportunity and put it to good use. By the time Sheffield cutlery makers realised that consumers wanted the newer product it was too late - by then the German makers had a well earned reputation in this area that was hard to dislodge.

I would be fascinated to hear more about real world experiences of hand forging plane irons so don't forget to film it if you do more experiments!

I'm scouting firmer chisels right now for one that can have the socket cut off and be hammered into a tapered iron. I don't know anything about forging in general, but would guess that hammering a laminated chisel below laminating heat might cause delamination, so I'm going to try first with a good quality all-steel firmer.

The trick is finding one about 7 inches long before the socket that is of a good make - I've learned already that hammering a junk chisel into a knife is a good way to make a knife that doesn't hold an edge the way you'd want one to. I could very well spend about $70 to end up with a $20 iron, but it should be a good learning experience.

I so value the way that the older sheffield irons are put together, with little biases in favor of the planemaker, that I won't use modern irons until or unless I absolutely have to. If I can hammer out an iron instead, it would be nice. If I can hammer one out of solid and then hammer one out of an old wrought firmer to compare, it would be doubly interesting. Just the shape of the firmers to start (fatter toward the socket) is a bit backwards, though.

This is the kind of thing i like to do, though - experiment first without reading too much about what you can't do, and then see how it goes. If I could get my wife to hold the iron with blacksmith tongs, I could hit it with a full sledge - but there is zero chance of that happening. Anything that isn't finished with the forging requires hand work (which is enjoyable, but not particularly productive).