Blade gap/exposure

[Space_Cadet]

I wonder why all the razor manufacturers only mention the blade gap of their razors, and almost never bother to mention the blade exposure?
Isn't the blade exposure a very significant factor? I personally would always like to know what is the blade exposure of a razor I am considering purchasing. Can you offer any explanation to this phenomenon?

 

[jmudrick]

I wonder why all the razor manufacturers only mention the blade gap of their razors, and almost never bother to mention the blade exposure?
Isn't the blade exposure a very significant factor? I personally would always like to know what is the blade exposure of a razor I am considering purchasing. Can you offer any explanation to this phenomenon?

It's a combination of uneducated consumers focusing on gap and perhaps laziness on their part . But you are certainly right it's crucial and I appreciate when manufacturers like Karve and Tatara do publish the spec.

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[Ron R]

To declare exact blade exposure you have to have strict quality control of everything about the razor head. Blade gap is easier to determine and measure what it is but blade exposure is influenced by safety bar and front edge of top cap. If the Manufacture has large tolerances it will change the exposure on a fixed razor IMO.
Example: if top is machined thinner or not wide enough than specified and safety bar is thinner or base plate is machined narrower you would get a slightly more blade exposure. Blades can also influence blade exposure also, Kia DE blade is approx .009 thousands of inch wider than a standard Gillette or Personna blade. People like Kia blades if they have a mild razor and want more blade exposure for aggression and efficiency.

Have some great shaves!

 

[jmudrick]

To declare exact blade exposure you have to have strict quality control of everything about the razor head. Blade gap is easier to determine and measure what it is but blade exposure is influenced by safety bar and front edge of top cap. If the Manufacture has large tolerances it will change the exposure on a fixed razor IMO.
Example: if top is machined thinner or not wide enough than specified and safety bar is thinner or base plate is machined narrower you would get a slightly more blade exposure. Blades can also influence blade exposure also, Kia DE blade is approx .009 thousands of inch wider than a standard Gillette or Personna blade. People like Kia blades if they have a mild razor and want more blade exposure for aggression and efficiency.

View attachment 1108959
Have some great shaves!

FWIW in the course of the lawsuits defending the Gaisman patents it was asserted that .004" was what Gillette believed was optimum exposure. In the Tech patent the target tolerance re blade exposure was approximately .001".

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[RayClem]

Blade gap and blade exposure are both critical to the efficiency and face feel of a razor. Within a specific manufactuers line of products, I suspect you will find that razors with small blade gaps will have small, or even negative, blade exposure. Then as the blade gap increases, the blade exposure will also increase. However, when you are talking about razors of differing design, razors with similar blade gaps may not have the same blade exposure. As has been mentioned, few manufacturers provide data on blade exposure. With today's precision machined razors, that is possible, but with plated razors there may be differences depending upon plating thickness.

 

[Ron R]

FWIW in the course of the lawsuits defending the Gaisman patents it was asserted that .004" was what Gillette believed was optimum exposure. In the Tech patent the target tolerance re blade exposure was approximately .001".

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Interesting information Jim, I know you also have books about razors that most folks will never see that has this interesting information. Have a great day and of course some great shaves!

 

[jmudrick]

Interesting information Jim, I know you also have books about razors that most folks will never see that has this interesting information. Have a great day and of course some great shaves!

Nothing like reading patents and 90 year old lawsuits to pass the time [emoji2]

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[RayClem]

Nothing like reading patents and 90 year old lawsuits to pass the time [emoji2]

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It sounds like a good cure for insomnia.

 

[romsitsa]

Blade gap is easier to determine and to visualize.
For eg. the difference between 0.04 mm vs. 0.1 mm positive exposure won’t be visible or easy to measure, but the face feel will be very diffferent.

Adam

 

[Woofbark]

Interesting information Jim, I know you also have books about razors that most folks will never see that has this interesting information. Have a great day and of course some great shaves!

It's amazing how a slight difference in blade gap can make a big difference in the shave. Would you happen to know the blade gap on the Black Tie Razors? The gap and aggression on the Black Tie Razor seems perfect for me

 

[Ron R]

It's amazing how a slight difference in blade gap can make a big difference in the shave. Would you happen to know the blade gap on the Black Tie Razors? The gap and aggression on the Black Tie Razor seems perfect for me

Unfortunately I do not have one, But that does not prevent you from figuring it out. if you access to feeler guages you can quickly get very close to the gap of your razor. Keep a used blade in it before discarding and measure the gap carefully until you are just barely feeling a little resistance and try that a few times and average the results.

 

[BigJ]

Blade gap and blade exposure are both critical to the efficiency and face feel of a razor. Within a specific manufactuers line of products, I suspect you will find that razors with small blade gaps will have small, or even negative, blade exposure. Then as the blade gap increases, the blade exposure will also increase. However, when you are talking about razors of differing design, razors with similar blade gaps may not have the same blade exposure. As has been mentioned, few manufacturers provide data on blade exposure. With today's precision machined razors, that is possible, but with plated razors there may be differences depending upon plating thickness.

Great points!

 

[Fedsbackhand]

It's a combination of uneducated consumers focusing on gap and perhaps laziness on their part . But you are certainly right it's crucial and I appreciate when manufacturers like Karve and Tatara do publish the spec.

It's the first thing I check when considering a new razor. I find it really frustrating when some artisans like to keep this information for themselves, e.g. Charcoal Goods or Wolfman.

 

[JacobW]

the whole geometry of the head matters every point that makes up the whole ... gap says nothing special.