Understanding DE safety razor parameters

[dawid]

Hi guys,

Even though I’ve been here on the forum for a while now, this is my very first post.
I’m glad to join the B&B community!

I switched to wet shaving around a year ago and like many of you, got a bit geeky about it too. Over the past months I read many topics on various DE razors and got especially interested in parameters and how they influence razors’ performance and feel, as I simply find it very interesting.
Even though we can find great amount of information on the matter on the forum (e.g. fantastic Safety Razor Parameters: Illustrated and Defined thread), there are still many questions unanswered to me.

Lately I’ve been on sick leave from work for almost two months now so had a lot of spare time and one day an idea came to my mind. The idea is to test various parameters of DE razors and understand how they influence shaving experience. I’m a mechanical engineer with CAD experience, so design is not a problem for me, and on top of that I already have a 3D printer at home which I can use for printing razors.

To start with, I created a design which allows me to change the following parameters independently one by one, without influencing other ones:
- Blade gap
- Blade exposure
- Neutral blade angle
- Guard span
- Cap span
- Clamp distance
- Guard/shave plane distance (I will elaborate on it in a separated thread)

After struggling with some technicalities and printing few prototypes, I finally managed to create a razor which can be used as a baseline:
- Blade gap: 0.65 mm
- Blade exposure: 0.00 mm
- Neutral blade angle: 30 deg.
- Guard span: 2.00 mm
- Cap span: 2.00 mm
- Clamp distance: 2.03 mm
- Guard/shave plane distance: 0.1 mm

I didn’t expect much from a 3D printed razor, but after shaving with it yesterday I was amazed how decent it was, even though I am a fan of high efficiency razors with strong blade feel (my daily razors are Muhle R41 and Rockwell 6C R6). If I needed to compare, I would say it was as mild as Muhle R89 but definitely more efficient.

I will be rating razors in scale of 1-5 in the following categories:
- Efficiency (higher is better)
- Blade feel (higher is better) – I enjoy blade feel, so higher is better to me
- Smoothness (higher is better)
- Aggressiveness (lower is better)
- Alum response (lower is better)
- Clogging (lower is better)
- 1 day razor bumps (lower is better)
- Overall score (higher is better)

Since I shave every 2-3 days it will take me some months to run the test, but I hope at the end of it we can get some added value and better understanding of DE razors parameters.
I would also appreciate your help along the way - it would be nice to collect questions related to parameters which then can be investigated and hopefully answered.

Thanks,
Dawid

 

[gdawg55]

Interesting. Cool you’re able to create your own 3D printed razor head. Look forward to reading how this goes.

Over the years I’ve come to the conclusion that I prefer positive blade exposure with a lower gap. Though I do have a few high gap low exposure razors that I like as well.

 

[DesertIguana]

Everyone's Face Skin, Beard Christi's, Growth Pattens is different. Two Member of Badger & Blade might report different finding on same Razor - Blade combination. Both could be right or wrong.

 

[dawid]

Everyone's Face Skin, Beard Christi's, Growth Pattens is different. Two Member of Badger & Blade might report different finding on same Razor - Blade combination. Both could be right or wrong.

Absolutely, and this must be kept in mind. I agree with that.

Nevertheless, I think there is a pattern among shavers and what they generally like - there must be a reason why so many people like e.g., Rockwell 6C/6S.
Also, I am not after fine tuning design to create a razor which would work great for me. My idea is to do rather big increments of same parameter between prints, so differences in shaving can be detected and general influence of a parameter found.

Either way, one man testing is not trustworthy, indeed. It would be nice if someone would be willing to join me in testing. If some of you has a 3D printer and would like to experiment a bit, I would be glad to share models.

 

[DesertIguana]

Go slow, don’t rush, don’t touch sharp edges, have septic pencil on hand.

Old guy taking 81 mags is Asperin, or blood thinners be extra careful.

 

[Frito Ray]

That sounds like a lot of fun.

One criteria that I’ve discovered over the years that is super important to me is comb length. Longer comb lengths prevent access to the corner of the blades and makes shaving under the nose difficult for some of us.

40mm combs makes shaving under the nose a breeze and 44 mm combs makes it impossible.

I tolerate my FOCS’s 42.5mm comb because of the great results I get in the other aspects of shaving. I’ve often considered taking a Dremel to it and grind down the corners.

 

[dawid]

That sounds like a lot of fun.

One criteria that I’ve discovered over the years that is super important to me is comb length. Longer comb lengths prevent access to the corner of the blades and makes shaving under the nose difficult for some of us.

40mm combs makes shaving under the nose a breeze and 44 mm combs makes it impossible.

I tolerate my FOCS’s 42.5mm comb because of the great results I get in the other aspects of shaving. I’ve often considered taking a Dremel to it and grind down the corners.

That's funny, I thought the same and earlier today implemented changes to the design
On one hand longer comb means that the blade is not sticking out on sides (which is a plus to me, as sometimes it cuts my nose), but on the other hand as you pointed out, it's difficult to shave around the nose.

What would you say about 38.5 mm comb length and hidden blade on sides too? See attached.
It's just a concept right now - I am planning to add some chamfers, so the blade is even more exposed, but this requires some additional, deeper design changes and thinking it through.

 

[blethenstrom]

Welcome to B&B! Greetings from Raleigh, NC.

What an introduction! This is a really cool thread and it will be very interesting to follow along. One thing when I read through your measurements and parameters that I think also is of importance is how much the head curves/bends the blade. Razors like the Gillette Superspeed for example bends it quite a bit and that has the effect of stiffening the blade more. This could be another aspect for you to put into your parameters.

 

[DesertIguana]

The other thing is Razor builders are always trying to build a better Razor.

Back in the day even Mr. Gillette kept coming out with new models.

Today many folk shave with Razors older than them. Vintage Gillettes.

Guess the Vintages work well with modern blades.

 

[StewB]

...have septic pencil on hand...

A septic pencil might do more harm than good...

 

[mikhou]

I'm just pondering here, but I'm guessing that eventually you'll experiment with blade curvature as well.

 

[Goblin]

I have to say this looks like fantastic fun and is exactly the sort of thing I would do if I had the CAD skills.

My question is, will you be doing a design that has a more traditionally shaped top-cap, rather than the slab-fronted, Henson style cap with a fixed shave angle? I feel like the Henson design nullifies the advantages of a more blade-forward design somewhat because of this, so it might be that increasing specs like gap and exposure doesn't deliver the same kind of aggression that you get when doing the same thing with a traditional design?

It is possible I am mis-interpreting the images and it isn't as flat as it looks, in which case, ignore me!

My other question is, how about an open comb? Do you think it would work?

 

[Frito Ray]

That's funny, I thought the same and earlier today implemented changes to the design
On one hand longer comb means that the blade is not sticking out on sides (which is a plus to me, as sometimes it cuts my nose), but on the other hand as you pointed out, it's difficult to shave around the nose.

What would you say about 38.5 mm comb length and hidden blade on sides too? See attached.
It's just a concept right now - I am planning to add some chamfers, so the blade is even more exposed, but this requires some additional, deeper design changes and thinking it through.

Exposed blade tabs don’t bother me. I only cut myself with them a few times when I started a dozen or so years ago. As long as the blade corners remain accessible, I don’t see how your new design with covered tabs could be detrimental or a nuisance.

Could 38.5mm be too short? I don’t know, all I can tell you is that I have 40 and 40.7 both of which work fine. The KCG at 41.5mm is still acceptable though slight gymnastics are required.

Good luck with you designs!

 

[DesertIguana]

A septic pencil might do more harm than good...

That is my go too, better idea for blood?

 

[Frito Ray]

That is my go too, better idea for blood?

Styptic pencil.

 

[DesertIguana]

Styptic pencil.

I was a better SNAPPER then Writer.

 

[dawid]

One thing when I read through your measurements and parameters that I think also is of importance is how much the head curves/bends the blade. Razors like the Gillette Superspeed for example bends it quite a bit and that has the effect of stiffening the blade more. This could be another aspect for you to put into your parameters.

I'm just pondering here, but I'm guessing that eventually you'll experiment with blade curvature as well.

Thanks guys, I didn't consider it before thinking that free-end distance is crucial and more important than the bending radius. I can already control it indirectly to some extent in the design, so adding bending radius to the list.

At the moment it's already quite small and equals to r=21.3 mm (the smaller the radius, the stiffer the blade). Compared to other razors (give or take, measured from pictures takes):
- Muhle R41 r=55 mm
- Muhle R89 r=30 mm
- Rockwell 6C r=22 mm

My question is, will you be doing a design that has a more traditionally shaped top-cap, rather than the slab-fronted, Henson style cap with a fixed shave angle? I feel like the Henson design nullifies the advantages of a more blade-forward design somewhat because of this, so it might be that increasing specs like gap and exposure doesn't deliver the same kind of aggression that you get when doing the same thing with a traditional design?

I really dislike narrow range of shaving angle, so the top cap design is indeed more traditionally shaped. However, radius of the cap is a resultant of other parameters, so it cannot be controlled directly without influencing other parameters, unless I would give up on some of them.
The latest printed razor I shaved with has this issue and was my main complaint about it.

My other question is, how about an open comb? Do you think it would work?

Definitely, especially since I am enjoy open combs, Blackland Blackbird OC being my favorite. Adding this parameter to the list too.

Could 38.5mm be too short? I don’t know, all I can tell you is that I have 40 and 40.7 both of which work fine. The KCG at 41.5mm is still acceptable though slight gymnastics are required.

I will be testing and see there is a limit to it. I would expect that as always, balance is the key. Adding baseplate length to the list of parameters.

 

[dawid]

Please have a look at Missed parameter of DE safety razor? thread where I explain what I meant by the "guard/shave plane distance" parameter mentioned in the first post.

 

[Goblin]

I really dislike narrow range of shaving angle, so the top cap design is indeed more traditionally shaped. However, radius of the cap is a resultant of other parameters, so it cannot be controlled directly without influencing other parameters

Ah, I did wonder about that. Nevertheless this is a fascinating project and has the potential to be a really interesting thread. Obviously, your preferences are your preferences, but what you learn should be really informative for everyone. I know that I tend to focus a lot on certain parameters that others don't worry about so much, because they matter to me.

I really like your plan of using a screw through the centre of the cap. It looks like that would help with extra rigidity. It must be very satisfying to shave with a razor you designed yourself!

Definitely, especially since I am enjoy open combs, Blackland Blackbird OC being my favorite. Adding this parameter to the list too.

...that must open up a whole load of additional parameters regarding the comb teeth.

You know, by the time you have done all this research, you basically just need to find a machine shop that can manufacture metal parts and you will have a range of marketable razors....

Anyway, I am subscribing to this thread for updates.

 

[dawid]

I really like your plan of using a screw through the centre of the cap. It looks like that would help with extra rigidity. It must be very satisfying to shave with a razor you designed yourself!

It really is satisfying. Had a lot of fun last time, especially that the razor worked surprisingly well!