Are Kai Blades Actually Wider?

[ThinkStopThink]

I seemed to see this quoted often that Kai blades are slightly wider than the specification. Is this actually the case, or is it something of an urban myth? Or, where there was a production irregularity and someone measured an aberration? I no longer have access to my micrometers/calipers, or I'd just measure a few random samples myself.

I really like Kai blades (no printing and no wax!), and I certainly thought I was getting a tad more blade feel in my Karve with the SB-B plate. As a matter of fact, I prefer the SB-B plate with a Kai blade over the SB-C plate with another brand. So, smaller blade gap, but slightly more blade exposure. However, with all the other variables, was it just wishful thinking? The preference for a more esoteric setup?? Some sort of confirmation bias???

The scientist in me wants to know...

 

[Cal]

Is this actually the case, or is it something of an urban myth?

It's true. Standard DE blade width is 22.0mm, Kais are 22.2mm wide which gives you an extra ~0.1mm (a standard blade thickness) exposure each side.

For reference check the good ol' B&B Wiki HERE.

 

[SharpieB]

Yes. Wider. By about the width of 2 human hairs. I don’t really notice the difference but apparent many do.

 

[Ron R]

I had a few used blades that I used for this comparison, the Kai has 10 shaves on it and the others 2 blades have 5-6 shaves on them. I was not going to use new blades for illustrations. These are barely holding in-between the Vernier calipers and are measured in .5/1000 of a inch accuracy(I like to use imperial measurements still). Seeing is believing so I thought I had 30 minutes to play with this thread. Blades are made to certain +/- tolerances in the factory when grinding and they use more than likely optical comparators for their production runs for quality control. B&B Wiki has blade widths and the person used new blades with micrometers that are more accurate than these Vernier's.
A extra 3 to 4/1000 of a inch per side gives a nice pick up in blade feel of blade exposure, you do not get the full benefit of the extra width because the blade is arced downwards when clamped, but you still get more efficentcy & aggression regardless.
A lot of 3 pc razors might only have 0 to 2 /1000 thousands of a inch per side of positive blade exposure from the factory when blade is arced when clamped.
(blades lightly clamped about 2-3 inches above paper, then zeroed, Kai SS blade with 10 shaves on the right side of picture.)

Have some great shaves!

 

[ThinkStopThink]

It's true. Standard DE blade width is 22.0mm, Kais are 22.2mm wide which gives you an extra ~0.1mm (a standard blade thickness) exposure each side.

For reference check the good ol' B&B Wiki HERE.

Thanks for the link! I had looked at that some time ago, but had forgotten about it.

This data I was after is here. Sixteen samples, bias reduced in this manner:

Selection bias was reduced by measuring blade samples from different boxes/packs/tucks and other groupings, which were often purchased separately. Purchase dates and grouping data were recorded.

I've very happy about this. I didn't imagine the feeling of slightly more blade exposure. And it makes my SB-B Karve plate just about grail worthy...

I wonder if anyone knows why Kai makes them wider?

 

[Ron R]

Thanks for the link! I had looked at that some time ago, but had forgotten about it.

This data I was after is here. Sixteen samples, bias reduced in this manner:

Selection bias was reduced by measuring blade samples from different boxes/packs/tucks and other groupings, which were often purchased separately. Purchase dates and grouping data were recorded.

I've very happy about this. I didn't imagine the feeling of slightly more blade exposure. And it makes my SB-B Karve plate just about grail worthy...

I wonder if anyone knows why Kai makes them wider?

They must had customers asking for this many years ago and Kai wanted to offer their blades for mild razor users.
I like using Kai blades in my mild razors and beats using shims.

 

[ThinkStopThink]

I had a few used blades that I used for this comparison, the Kai has 10 shaves on it and the others 2 blades have 5-6 shaves on them. I was not going to use new blades for illustrations. These are barely holding in-between the Vernier calipers and are measured in .5/1000 of a inch accuracy(I like to use imperial measurements still). Seeing is believing so I thought I had 30 minutes to play with this thread. Blades are made to certain +/- tolerances in the factory when grinding and they use more than likely optical comparators for their production runs for quality control. B&B Wiki has blade widths and the person used new blades with micrometers that are more accurate than these Vernier's.
A extra 3 to 4/1000 of a inch per side gives a nice pick up in blade feel of blade exposure, you do not get the full benefit of the extra width because the blade is arced downwards when clamped, but you still get more efficentcy & aggression regardless.
A lot of 3 pc razors might only have 0 to 2 /1000 thousands of a inch per side of positive blade exposure from the factory when blade is arced when clamped.
(blades lightly clamped about 2-3 inches above paper, then zeroed, Kai SS blade with 10 shaves on the right side of picture.)
View attachment 1363983
Have some great shaves!

Thank you very much for that. Calipers are good in a pinch, but a optical comparator is the way to go, we had a number of them in the first large shop I worked in. The height gauge and 1-2-3 blocks I had in my last shop would have given a reasonable level of accuracy.

Oh, and those aren't Verniers, those are digital readout calipers. I started with verniers, but that was a very long time ago.

 

[ThinkStopThink]

They must had customers asking for this many years ago and Kai wanted to offer this for mild razor users.
I like using Kai blades in my mild razors and beats using shims.

Hmm, interesting. I wonder if it was medical customers. As I mentioned above, it is nice to be able to tweak how a three piece functions without changing anything other than blade selection.

 

[Walleyeb]

I don’t know about the wider part, but I did notice when I put one in my EJ de89 the blade slid around a lot. I could see how if you weren’t paying attention you could end up with it being terribly misaligned.

 

[Rivers23]

I don't know if it's the width or the thickness but I feel it they're different very very obviously in my R41, it feels bulkier than other blades. Personally, I'm not a fan at all, it feels weird on my skin. I imagine it does well on mild whiskers but on mine it tugs and pulls a lot, just doesn't deliver a smooth shave for me.

 

[Suddenlythisoverview]

The tabs are also slightly smaller, so on some razors you have to be careful about blade alignment.

 

[Cal]

Kais are typically 0.2mm wider (W) than standard DE blades (so, an extra 0.1mm [thickness of a standard blade or sheet of paper] each side).

More info on the B&B Wike HERE.


EDIT:
Whoops! sorry to repeat myself (but then so many people only read the OP).

 

[cyberdog]

Not but much, as posted, but what wasn't really mentioned is that MANY DE blades are actually SMALLER than the 22mm standard, so it may depend what you accustomed to, as to whether you actually notice. They also feel 'thicker', and flex less than many other blades, and just use what must be a higher grade steel, making them more rigid.

Toss them in my Rockwell, and she sings totally different than any other blade, and feels more efficient or aggressive, so there's something different about them. I find they're good for a good dozen or so shaves per blade as well, and have actually hit around 20 shaves, depending upon the razor.

 

[Ron R]

I think you have to look at the extra width as a razor with 1-2/1000 of a inch positive blade exposure(common mid range) with a standard Gillette Astra SP and when you place a Kai blade in the razor now you would have 3-4/1000 of a inch blade exposure because of blade being bent slightly you would not receive the full amount of extra width of a Kai blade. Basically you gained some nice blade feel instantly with out shimming.(Click on pictures to enlarge, photo's from my archive)
Most blades are 3.5/1000 of a inch thick so you use it as a comparison gauge to the lines drawn as a reference.

I believe this picture hand a Astra SP blade in it (picture below)

Have some great shaves!