Merkur open comb curvature

[huracan]

Hey Gents, have a question for the lot.
Yesterday I got a HD open comb and even though I have been shaving with a Barber Pole Open comb for the last couple of weeks, I did not notice until now a slight curvature of the head.
What I mean is the outer teeth sit lower than the center ones, forming a very slight bowed shape. The top though does not follow the same curvature, so that when it clamps down the center of the blade sits closer to the teeth than does the tips of the edge; the difference is very slight.
This doesn't appear to be a manufacturing defect because both razors have this, as well as looking even and true in every other respect and not showing evidence of being torqued out of shape.

In any case I have my doubts this is supposed to be like that. Keep in mind I'm not talking anywhere near what a slant does, just a very slight curvature.
I couldn't find any mention of this during a search and I wish I could show a picture tonight to show you what I'm talking about. I'll do as soon as I can get a decent shot.
Any thoughts.....from those that own or have owned one, but any comments welcome of course.

The both of 'em shave superbly, by the way.

 

[jkh]

I just got an 11C HD open comb and mine is exactly the same. Without a blade installed the gap between the outside teeth and the head on both side is just slightly larger than the gap between the inner teeth and the head.

The difference is so slight, I figured it didn't matter. My shaves great, too.

 

[huntmol]

It's late, but I had to get out of bed and walk into the bathroom to check this out.
HOLY CRAP you're right!

I am shocked to my very core.
Does anyone have any idea what purpose this could possibly serve?

 

[talibeard]

I don't think this is meant to be; my 25C (3-piece open comb) is just straight with and without a blade in.
My guess is that molding the bigger piece is the main reason.

 

[huntmol]

Tailbeard, are you absolutely sure? I thought mine was straight until I removed the blade and "top piece" and set the razor upright on the table and looked at it from the side. The teeth should have lined up perfectly, but there was a very, very slight curvature.
I'm talking about tenths of a millimeter here.

Then again, it might just affect the 2-piece open combs.

 

[Haiku]

I don't think this is meant to be; my 25C (3-piece open comb) is just straight with and without a blade in.
My guess is that molding the bigger piece is the main reason.

Funny, this was the first thing I noticed about the razor when I got mine, and
I've always thought that it's the way these razors are designed. (mine is the open comb HD is that the 11C?)

The curved shape creates a curved "bump" on the skin when the razor is in touch with one's face. This makes the hair stand up more to more easily be shaved closer than would otherwise be the case.

One of the things that we all overlook is that skin does not sit flat when you put your razor to it. Skin actually bulges. Because of the bulge, adjustable razors work by opening or closing the gap between the blade edge and the safety bar. When there's more gap, the blade shaves higher up on the bulge created by the pressure of the razor on the skin.

The design of the Merkur results in a bulge that forces the hair to stand up just a bit more than it would if the comb was flat.

I tried to explain this in the context of adjustable razors in a post here:

http://badgerandblade.com/vb/showthread.php?t=27914&highlight=dialing+adjustable

 

[Aaron01]

My Hoffritz 3 piece, which I'm assuming is a rebranded Merkur, has straight teeth

 

[talibeard]

Tailbeard, are you absolutely sure? I thought mine was straight until I removed the blade and "top piece" and set the razor upright on the table and looked at it from the side. The teeth should have lined up perfectly, but there was a very, very slight curvature.
I'm talking about tenths of a millimeter here.

Then again, it might just affect the 2-piece open combs.

I am pretty sure (and I am also used to look closely at machined products but didn't use any measuring instruments) it is within less than 0.10 mm.
Are you talking about a 2- or 3-piece Merkur? My theory is that because the 2-piece main part has a great variety in thickness of material combined with lots of angles and cavities the product does not cool down evenly and so creating internal tensions that lead to loosing the intended form of the end product.
Just a theory.

 

[jeremy]

Interesting. I've actually noticed something kind of similar in both my fatboy and my slim - but in the blade, not the razor itself. I can't remember which way the curve goes off the top of my head, but I noticed that when the blade is bent into the razor, the edge has a slight bow to it - I'm assuming due to the cut down the middle of the blade making it bend differently than the 'ends'.

I wonder if the razor is meant to mimic this slight curvature of the blade?

 

[talibeard]

Interesting. I've actually noticed something kind of similar in both my fatboy and my slim - but in the blade, not the razor itself. I can't remember which way the curve goes off the top of my head, but I noticed that when the blade is bent into the razor, the edge has a slight bow to it - I'm assuming due to the cut down the middle of the blade making it bend differently than the 'ends'.

I wonder if the razor is meant to mimic this slight curvature of the blade?

No way !

 

[huracan]

Being that the ones comming up with the issue are the 2 piece razors, I wonder if it has to do with the manufacturing; when the comb plate gets attached to the handle the force of the press attaching the 2 parts leaves said plate with a slight bow.
The 3 piece razors never get pressed into anything, so they retain their flat shape.
What about the safety bar heads? I can't comment on them since I don't own any 2 or 3 piece versions, but my 4 piece travel Merkur has a flat bottom plate.

 

[jkh]

hehe ... the safety bar on my slant is really off.

 

[huracan]

hehe ... the safety bar on my slant is really off.

Good thing it's got a lifetime warranty

 

[Haiku]

Interesting. I've actually noticed something kind of similar in both my fatboy and my slim - but in the blade, not the razor itself. I can't remember which way the curve goes off the top of my head, but I noticed that when the blade is bent into the razor, the edge has a slight bow to it - I'm assuming due to the cut down the middle of the blade making it bend differently than the 'ends'.

I wonder if the razor is meant to mimic this slight curvature of the blade?

I have four fatboys (don't ask) and they all do the same thing. My 1948 SS does this as well. And so yes, I believe that it's the design.

 

[Haiku]

Being that the ones comming up with the issue are the 2 piece razors, I wonder if it has to do with the manufacturing; when the comb plate gets attached to the handle the force of the press attaching the 2 parts leaves said plate with a slight bow.
The 3 piece razors never get pressed into anything, so they retain their flat shape.
What about the safety bar heads? I can't comment on them since I don't own any 2 or 3 piece versions, but my 4 piece travel Merkur has a flat bottom plate.

The Merkurs in question are actually three piece razors (slant, HD, HD open comb). The adjusting knob just pulls right out. And the bottom plate of the heads are in fact pressed onto the handles. I really don't think it's a manufacturing defect, I really suspect it's the design.

 

[huracan]

The Merkurs in question are actually three piece razors (slant, HD, HD open comb).

I see what you're saying, I went with what seems to be the common consensus in calling the razors with fixed to the handle bottom plates '2 piece' and the ones that have a handle that screw to a two piece head '3 piece'; with the so called travel razors with a handle that unscrews in two '4 piece'
Is there a better name to differentiate between the types?

 

[Haiku]

I see what you're saying, I went with what seems to be the common consensus in calling the razors with fixed to the handle bottom plates '2 piece' and the ones that have a handle that screw to a two piece head '3 piece'; with the so called travel razors with a handle that unscrews in two '4 piece'
Is there a better name to differentiate between the types?

You know, that's a good question. I don't really think that there's much consensus other than the obvious labels: TTO and three piece.

The ones that most folks think of as two piece, such as the HD, the slant, the HD handle open comb are in fact three piece razors like the Bostonian for example. Now, there are other three piece razors that have a cap, a bottom plate and a handle that connects it all together such as the Gillette Tech which is also a three piece.

And so I guess it's probably accurate to say that there are two flavours of three piece razors.

OC

 

[huntmol]

I am pretty sure (and I am also used to look closely at machined products but didn't use any measuring instruments) it is within less than 0.10 mm.
Are you talking about a 2- or 3-piece Merkur? My theory is that because the 2-piece main part has a great variety in thickness of material combined with lots of angles and cavities the product does not cool down evenly and so creating internal tensions that lead to loosing the intended form of the end product.
Just a theory.

I'm talking about 2-piece ones, but I think you're right about the difference being caused by the manufacturing

 

[huracan]

Well, turns out there are official names for 'em

Long screw mounting and short screw mounting, per Merkur itself. The teenager in me cannot say it with a straight face
Check out the panphlet I found here in the forums:

http://www.dovo.com/pdfs/MERKUR_web.pdf

 

[scottish steve]

I've experimented with my HD Combhead and Single-ring and the straightness of the blade seem to depend entirely on tension adjustment. Its possible to have a straight blade, tho the combs are a tiny bit arced on my 11C and not on my single-ring but with both razors, if you're not careful you can get a "crinkly" blade, so this is something I'd look out for when loading. Its the same with the Slant..you need to line everthing up right before use. This is one big advantage of silo & Tech heads (and probly a lot more i'm not familiar with)...everything's just set up fine