Blackbird blade chatter

A bend blade is under tension ,
pressing against the underside of the cap.
Thus ,it requires the same or bigger force
in order to move to the opposite direction,
away from the underside curvature of the cap.
But rigid ,no it is not.
Physics is not a matter
of business experience or opinion.
A spring under tension is harder to bounce ,but rigid it is not.

Blade rigidity is achieved when :
1 ) The free end distance of the blade equals
the clamp distance.
And
2 ) When both are kept as short as possible.

If the clamp distance is greater than the
free end distance ,no matter in what degree
the blade is bend under the cap,since it
has the ability to move,given the circumstances it will move (vibrate aka chatter ).

This phenomenon will not occur to everyone,
of course .
Folks with hard,dense and thick stubble are
more prone to experience it .
Especially when shaving against the grain.

Angle of attack does play a role ,
but will not make the shave much
more comfortable ,for those few with
steel-wire stubble.

I'm not sure if this was intentional, but I enjoyed the poetic structure of this. In terms of content, you're sort of right, except that in this case we don't actually care if the blade bends downward. We care if the blade bends upward as that is the direction shaving occurs in and that requires a somewhat different interpretation of the physics involved.

So I put the black bird away for a while and got it out a few months later remembering not to short myself on lather and boom what a wonderful shave.

I've always wondered if it works the other way around, where you do great with a razor based on crappy technique, put it away, then come back to it as an experienced wet shaver and absolutely hate it.

A bend blade is under tension ,
pressing against the underside of the cap.
Thus ,it requires the same or bigger force
in order to move to the opposite direction,
away from the underside curvature of the cap.
But rigid ,no it is not.
Physics is not a matter
of business experience or opinion.
A spring under tension is harder to bounce ,but rigid it is not.

If it's bent in one direction, it's hard to bend in another direction. It may not be the same thing as rigid clamping, but from a practical standpoint, I think it should be close enough. I'm getting a Blackbird Ti from someone soon, so I'm excited to test out how it shaves versus blade-rigid razors, which constitute the majority of my collection, and against the Rockwell 6S.

Just to chime in, blade rigid razors don’t work that well for me on my neck. I think because there’s no give to the blade.

I find non-rigid designs like the blackbird actually give me less irritation. But that’s just my skin and beard.

Any razor that borrows it’s basic
design principles from the Merkur razor
1929 patent does not work for me.

Used to have quite a few of such razors ,
like Muhle R41 ,R89 ,Rocca R96 .Also
I ‘ve tried Gibbs adjustable,the Blackbird ,
couple of ATT ,Paradigm 17-4 and few more.

When I tried my first rigid design ,
a Tatara Masamune it was ,never looked
back to the Merkur -based designs.
Karve followed ,Timeless then and
the final “revelation” came with the
“humble” Game Changer 0.84-P .

Maybe not the most efficient shaver
out there ,but the comfort and smoothness that this razor brings to my shaving rituals
are next to no others.

At the end of the day,what really matters
(at least for me) is the sheer pleasure
and joy that those 20-30 minutes,
while shaving lasts ,are full of .

Tugging , chattering , blade and soap dependant unpredictable razor behaviour
as also few other menaces and hazards that occur from anything less than rock-solid blade support ,thankfully are not part of my shaving anymore.

Btw,when shaving WTG the forces applied
to the blade tend to press the blade edge
against the cap (the blade is pushed “upwards”) .That’s fine ,indeed.

But when shaving ATG ,the blade edge contacts the stubble in such manner ,
that the blade edge is pulled away from the cap ,until the hair strand is cut .Then the
blade edge returns to it’s “rest position”,
against the cap.And a vicious cycle of
back and forth (or inwards and outwards,
or upwards and downwards) movements
of the blade edge starts.
If the blade is not clamped close to it’s
edges,no matter how bend/curved it is ,
the vibrations (aka chattering) are unavoidable.

Luckily ,more and more DE razor designers and makers are adopting the modern rigid “vice” design ,which -if I’m not mistaken - it was firstly introduced by Wolfman razors.

Any razor that borrows it’s basic
design principles from the Merkur razor
1929 patent does not work for me.

Used to have quite a few of such razors ,
like Muhle R41 ,R89 ,Rocca R96 .Also
I ‘ve tried Gibbs adjustable,the Blackbird ,
couple of ATT ,Paradigm 17-4 and few more.

When I tried my first rigid design ,
a Tatara Masamune it was ,never looked
back to the Merkur -based designs.
Karve followed ,Timeless then and
the final “revelation” came with the
“humble” Game Changer 0.84-P .

Maybe not the most efficient shaver
out there ,but the comfort and smoothness that this razor attributes to my shaving rituals
are next to no others.

At the end of the day,what really matters
(at least for me) is the sheer pleasure
and joy that those 20-30 minutes,
while shaving lasts ,are full of .

Tugging , chattering , blade and soap dependant unpredictable razor behaviour
as also few other menaces and hazards that occur from anything less than rock-solid blade support ,thankfully are not part of my shaving anymore.

Btw,when shaving WTG the forces applied
to the blade tend to press the blade edge
against the cap (the blade is pushed “upwards”) .That’s fine ,indeed.

But when shaving ATG ,the blade edge contacts the stubble in such manner ,
that the blade edge is pulled away from the cap ,until the hair strand is cut .Then the
blade edge returns to it’s “rest position”,
against the cap.And a vicious cycle of
back and forth (or inwards and outwards,
or upwards and downwards) movements
of the blade edge starts.
If the blade is not clamped close to it’s
edges,no matter how bend/curved it is ,
the vibrations (aka chattering) are unavoidable.

Luckily ,more and more DE razor designers and makers are adopting the modern rigid “vice” design ,which -if I’m not mistaken - it was firstly introduced by Wolfman razors.

I believe if you look at a Gillette single ring you will see rigid,vice design well before Wolfman(which is a great razor)

Just to chime in, blade rigid razors don’t work that well for me on my neck. I think because there’s no give to the blade.

I find non-rigid designs like the blackbird actually give me less irritation. But that’s just my skin and beard.

I'm very similar. Seems like the super rigid designs give me the most irritation. My best shaving razors like the blackbird and CG level 2 don't have the best "blade clamping". I figured the blade having some flex made it a bit more forgiving.

Yes,indeed!

Rigid “vice” designs are not forgiving 
razors.One needs to be really light handed,especially around jawline ,
chin ,Adam’s apple and in some cases at the cheekbones area.

But they offer smoothness and comfort to 
those having dense and thick stubble,
when shaving against the grain.

From the other hand ,the 1929 Merkur pat. - based razors do offer some kind 
of blade suspension,thus rendering them 
quite forgiving .More than often ,
most aggressive as also most efficient razors ,do belong to this particular
“category” or “school” of DE razor head design ,like the Muhle R41 and the Blackland Blackbird.
It’s a way to counteract the sometimes 
excessive aggressiveness .
A way to tame the “beasts” .
But if one has tough and dense stubble,
using this type of razors and trying to shave ATG ,most probably will encounter 
blade chattering to a certain degree.

When shaving WTG the leading edge 
of the blade tends to press the hair strands downwards ,towards the skin.
While the blade edge is pushed against the 
underside of the cap.So far so good.
Any small anomalies of the skin ( scars,
moles,etc ) will be overcome by the blade 
flexing inwards .So far so good.
Any  small “misjudge” regarding applied pressure,might also be peacefully absorbed by the blade flexing.All good.

Turning the razor upside down and 
shaving ATG is a very different situation.
At this case ,the blade’s leading edge as it meets the hair strands from their “down-under” side ,tends to lift them up .
But since the hair strands do not have anything to stop their movement (at WTG pass the hair strands are pushed towards the skin and once in contact with it they stop moving whatsoever ) other than thin air,they also tend to lift the leading edge (which is already halfway into cutting the strands)
away from skin level,as also away from the underside of the cap.As the hair strands are fully sliced through ,the blade edge returns violently ( it is bend,under tension) to it’s rest position ,pressing 
against the cap’s underside-curvature.
Until the next “row” of stubble is met.
Then this phenomenon is repeated once again.

Depending on pre-shaving stubble hydration level,the blade used ,the hardness and the density of stubble ,what was described above may be experienced from being 
“ a light chattering”  to even “ a bang’n’stuck-like tugging”.

Well,actually none of these two “schools”
is better than the other.
It’s just a matter of personal 
preferences and needs,which of the two will be finally chosen ,or which one will better suit the user.

suum cuique !

I must be dense, or lucky. I don't remember ever experiencing blade chatter in a DE or SE in over 50 years of shaving. I haven't experienced tugging since I was a teenager shaving with the old Gillette blue blades. Quality blades and skin stretching techniques seem to give me a comfortable shave regardless of the tool I'm using to hold the blade. Different strokes for different folks. 

I have sat out of the discussion because I'm no scientist, I just like nice shaves. I am in the camp of liking a rigid held blade as I don't like the chatter when an unrigid blade meets solid stubble. An example of just 1 razor is everybody loves their Progress and Mergress razors and I love the look of them and have had a couple but they chatter more than anything. the ones that do best for me are the ones that are clamped and held tight so I'm looking forward to seeing what Shane comes out with. So while I have no idea scientifically what the reasons are or knowledge on the reasons why, I'll just stick with what I know works for me.

Myself I’m greek ( btw ,please do excuse me from doing any grammar or spelling mistakes or even wrong choice of words ,english is not my mother language) and having mediterranean genes (who knows from where else ,also) my stubble resembles much
to male velcro.During winter ,if the wind blows
my woollen scarf onto my face ,it just gets stuck there ,if I have more than 24h stubble)

While I could use my R41 to shave WTG & XTG ,going  ATG was much further than “out of the question” .
Simply impossible,no matter the
prep ,soap and blade.
Any other razor of such
head type ,did not offer “salvation”.
First shave with the Masamune  was an eye opener one .
Going ATG was smooth like ...buttah .
Skin stretching and such are basic parts
of my technique ,also .My grandfather was the
one who taught me to shave with a DE ,when I was a teenager.To exaggerate a bit ,
I think that my technique level allows me to shave blindfolded ,
standing on my one foot ,at a ship’s deck
during a hurricane !
But only with the right razor I’m able to
go against the grain.
Otherwise it is simply impossible !