Wednesday, July 22, 2020

The double iron blade

Or a cap iron screwed unto a blade.  I am not going to debate the merit or not of such an addition , simply point out some details I came across while cleaning a bunch of them.

 In the beginning, our planes had only one blade.  Usually tapered in thickness, being thicker at the cutting edge. Said cutting edge was a hardened piece of steel (tool steel) forged welded to a softer iron blade.  Similar to how axes are bited.

Everything worked fine, but the addition of the second blade (cap iron, chip breaker) around 1760 accomplished two things:

- It helped curled up the shavings faster near the cutting action, and
- It trapped water condensation between both blades.  A perfect recipe for rust to take hold.

I'm guessing they recognized that problem early on because for a while they were covering the back of the cap iron (chipbreaker) with some sort of blueish coating.

Take a look at the two chip breaker back.
The older Stanley one (second from left) has a blueish coating.
The newer one to its right does not anymore, they long stop doing that.

But that practice long preceded Stanley.  I do not know if it was the same process (coating) but you can often see remnants of it on older cap irons.

You can clearly see some sort of coating remnants peeling off  (abraded).
Whatever is left is still solidly attached.

So the question is:  Does it helped at all?
Debatable but here is what i often see.

Yesterday while re-conciliating my physical count with my data records, I came across an early Canadian plane, Dawson, from Montreal.  So even if I said I was done and had already cleaned up and put stuff away, you know, I just could not sleep if I did not stop the rust carnage's 

Dawson Montreal
1851-1874

And the poor blade stuck inside.  Its a small smoother.
Look pretty sad, but nothing that i cannot fix.

So put my tally sheet down, looked around and came up with a few more blades

In progress. Still shows brown spots after the wire wheel, 
back soaking after a quick sanding with 80 grit

Recognized the blade?
Evaporust, brushed, wire wheel, spot sanded, rust eraser then wiped and buffed with Autosol

The blade may be practically worn out, but there is still cutting steel at the end and plenty of good metal to raise a good edge.

Talking of worn out blade, that one is definitively pass its best before due date.

So why bother?
Because it is part of the tool history.
All I am after is to stop further rust damages.
Pic in progress

Done.  Also addressed some damages to the edges

I came across lots of damaged top edge, from using a metal hammer harder than the softer iron blade.
That would be just about any decent hammer BTW.  A Brass hammer head  would deform before it deformed the soft iron.  These must be addressed to stop the damages and to render the blade safer to be hit later on.

I often see also lateral damages to the blade, from hitting the sides to adjust lateral.  Which is why Stanley invented the lateral adjuster later on :-)

This one has damages to both top and sides, but it is the cap iron, not the blade!!! 

Here is an interesting details I came across in this short marathon.
How the cap iron is fastened to the blade.

Notice how the screw shrunk.
Interestingly, the bolt diameter and thread sizes seems to have remains
 pretty well the same all along and not just Stanley.
Which just add to the confusion, which belongs to which?  
Hint the bolt should go all the way thru cap iron and be flushed on the nut side.

These last two have the same threads but not cut the same.
Take a look at the base

The screw length changes along the way it was attached.  I have no idea which methods came first in what order, but we all know it finished with the shorter screw to attach a thin steel cap iron to a thin steel cutter.

In no particular historical order

This one, rarely come across this one,  use a separate nut and screw

The nut is filed to slide between the slots of the blade.

Attached

This one is yet different

No more loose nut to loose.  
The nut is solidly embedded into the cap iron



The one most often seen, mostly British tools

The brass dome nut is also embedded solidly 


This is a new one on me.
That is from my Dawson blade

The nut is not attached, but is machined from a thicker stock


Pretty solid, probably the most secured


And of course the Stanley design we are all familiar with.
The top horizontal slot is to engage the depth of cut adjuster.
This design forced Stanley to move the hole location on the blade slot from the top to the bottom.


This design also introduced a small irritation factor with today's unwary woodworkers.
Because we rely on that slot located at the top of the chip breaker to adjust our cutter in and out... Guess what?

It had to be adjustable to compensate for the inevitable wear and tear on the blade which will be sharpened umpteen time in its life.  That's the reason for the slot in the blade.  Problem is, they are a lot of Stanley clones out there but no one ever seems to came up with a standard location ...

Notice anything different??
If you do, that is the reason why it gives you headaches when you attempt to swap blades :-)
And if you thought that the two outer ones were the same...

NO, not even close. Both now on right.
From L-R Stanley's regular bench planes iron (first 3), 
Stanley No 113 compass plane blade, and a transitional plane blade.

In these pics I lined them up by the cap iron edge, not the cutting edge.  The three regular Stanley are various vintages and the hole location changed a bit, but not enough to cause much trouble.
The Compass plane No 113 however will have a hard time to give you any cutter exposed to cut if someone swapped the cap iron or the whole blade assembly with a regular one.  That is because of the flex sole, the frog surface is longer than on regular planes.  Buyer beware.  Oh and also the lever cap is slightly different, longer. Also sometimes swapped on unsuspecting would be buyer.  Finding original spare parts?   You will have better luck lining up to get your bucket of prop wash filled :-)

Similarly, in a transitional plane, the yoke adjuster sit higher on the frog, so the slot location is yet a bit higher.  because the small frog sit on top of a 2-1/2 in thick chunk of wood.

And to add to the fun, others would be Stanley clones used all kind of slight variations in slot location, more pronounced than the slight variation shown.  Oh and they varies location thru the years.  Ever noticed why most modern blades maker have a disclaimer on their Stanley replacement blades? May not fit all models produced thru the years etc

Moral of this story, to keep your sanity and let the plane works as intended, if you want to swap blade, you may want to re-use the original cap iron, just saying.

And since I had the Evaporust bath set up again, I may as well ...

This is what I ended up with and it is all Dawson's fault :-)


And then I drank a Coke to dissolve all the rust I have no doubt ingested.
Like my Dad, I am a Coke man, we both flunked the Pepsi challenge :-)
Dad was so pissed when they tried to changed his Coke.  It taste like $@^# Pepsi!!


Bob, all rusted out from de-rusting umpteen tools saving them from a slow but inexorable death.
You know, they used to say, You are dust you will return to dust when you die.  Well with today's micro plastics being everywhere, soon it will be: You are plastic you will be recycled when you die :-)

12 comments:

  1. I know fully the headache with trying to swap irons between chip breakers. I keep them together now and don't bother swapping irons to keep planing.

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  2. Does the blueish coming from some coating or is it the result of metal forging?

    Lionel who does more gardening and carpentry than woodworking these days.

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  3. Its not from the metal forging steps. Its definitively an additional coating of some sort either blueish or black on British cap iron. What it is or was i have no idea, but an added coating

    Bob, who do lots of gardening projects also :-)

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  4. I have a Silver@$%! plane, new from manufacture, where I had to remove a few mm at the edge of the cap-iron, otherwise I could not fully retract the cutting-iron.
    As the cutting-iron/cap-iron assembly must be able to slide between the frog and the lever cap to allow easy depth adjustment, everything must be smooth on top of the cap-iron and back of the cutting-iron.
    The underside of the lever cap, including the spring, must also be smooth. It makes adjusting the lever cap pressure less finicky.
    It only takes a few minutes.
    Sylvain

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  5. Guessing your plane is a Silverline tools.
    https://www.silverlinetools.com/en-GB/Product/Woodwork/Planes
    They have sprouted on the UK and European markets a few years ago. They look promising (from a distance) but the reviews I read all too often complaints about fit and finish. They had to be fettled to work properly. Sounds more like a kit for a fresh tool out of the box!than a tool. They are made in China i Believe, and as anything coming from over there you get what the vendors asked them. Make me a cheaper version of this tool, must look flashy to sell as a premium tool... Premium it is not. The same manufacturer can get you better product they just deliver what they were asked to do. They also shows up under a few other house brand names.

    Indeed the blade assembly must be able to smoothly move up/down the frog. A common problem with any Bailey style planes is to over-tighten the lever cap then try to adjust the depth of cut. That put serious stress on the cast yoke.

    ReplyDelete
    Replies
    1. Yes I had to fettle it (with the help of P.S. videos) and it works since.
      Although making things smooth for easy depth adjustment was my own conclusion after reading someone else's blog about adjustment difficulties.
      Sylvain

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  6. The bluing on the back of the cap irons is an interesting question. Your initial observation about dust attracting moisture between cap iron and blade to cause rust is accurate but is the result of disuse.

    If any of those planes had been in regular use the frequent sharpening, especially using oilstones, would keep rust at bay.

    Secondly, the bluing is on the lesser of the parts. The blade will suffer far more performancewise from rust than the chipbreaker. The functional part of the chipbreaker on blued Stanleys is the edge, which has no blueing since it's ground flat.

    My guess is the stock is blued during heat treatment like spring steel is. During manufacture, the bluing would removed from the show side and left on the back to save time, which is money.

    To add the bluing to one side would be hard to do for the sake of corrosion protection. I believe the process would most likely e done in a bath or continuously for a coil of material (also through a bath).

    One of the saw makers who sold parts sold the saw plates with the bluing still on and it was up to the customer / amateur sawmaker to remove the bluing.

    In the end, the bluing isn't especially good at corrosion prevention.

    ReplyDelete
  7. Interesting comments. Make sense
    Appreciate Steve

    Bob

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  8. The other way to have the blue would be through oxide formation, like when you overheat a tool at the grinder. Then it would be from heat treat and definitely not on only one side.

    The Stanley cap irons aren't very hard so not sure where the bluing came from.

    ReplyDelete
  9. Steve, could it be something like a gun bluing liquid painted over?
    I understand that would be another time consuming steps to do them all, on by one. Rust do take hold on them but it appears that it can resist a bit longer? (empirical observations)

    I long wonder what it is

    Bob

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  10. BTW, according to types studies and Patrick Leach, that blueish coating in the back of the cap iron cease with Type 12 (1919-1924) with the introduction of the high knob.
    Now in addition the British blades look like they had a similar but black coating, again according to my empirical observation.
    Ill look at it under the USB microscope to see if we can determine anything else.

    Bob, whose curiosity has been awaken by Steve this AM :-)

    ReplyDelete