Effects of Draw.

I'm aware that the effects of draw on stropping are discussed periodically, but I'm thinking about it, so thought I'd post.

I know that the general consensus seems to be that draw has little effect on the finished edge. The same results are perceived to be achieved with strops creating both little & greater amounts.

What I'm interested in concerns the efficiency.

Basically, in my opinion, one of the greatest assets of the linen side is it's ability to warm the edge, allowing the leather to do it's job more easily. When the leather has more draw it would make sense that there is a greater amount of resistance, & therefore it's effectiveness is increased, due the the likelihood that it too is able to warm the edge to a greater degree as you strop. If the edge is warm, & therefore slightly more malleable, it will return to a performing edge quicker.

I'd like to hear the opinions of you chaps.

Good question . . . and I don't know.

This is one of those areas that is interesting, since essentially we don't know what is going on.

My immediate first thought is that there is a big assumption going on in your theory related to heat, there is also an assumption about linen, another that I don't buy either. Have you ever read the documented information about how linen is used to "rough up" an edge that no longer shaves because its too smooth? I've always suspected that the cause of greater draw after using linen would match this theory perfectly. Of course, most of our members don't buy into the traditional theories.

My second thought is that, from my perspective, only sharp razors draw, therefore I would not coorelate more draw to better performance. I would simply suggest that strops that draw give you feedback on when to stop.

I also have a personal theory, one that few people would ever believe, that it is the opposing bevel edge, the one not touching the strop, that produces the draw. I believe when the edge becomes sharp enough that both bevels make coincident contact you get draw. I can polish an edge and strop it and get no draw because the edge is not sharp. That has often puzzled me.

The other, more common theory, that works a little against mine, is that the polished edge produces the draw. This theory is also problematic because the bevel isn't the same as the edge. Those with this theory have never tried stropping a polished dull edge though, or simply ignore this observation. But in this case the draw produced by the bevel may not effect the edge much at all.

So if your theory is correct than why do both strops seem to work just as well?

I've always been more of a "the strop 'smears' the steel" vs. heat kinda guy though.

Assuming that heat plays a part in the process (since speed seems to be an issue this could make sense to me too) I think I would have to ask this question:

What if strops that draw are producing heat (and tension) on the bevel and edge and strops that have no draw only produce heat and tension on the edge where you can't feel the effects?

Those are my thoughts . . .

I don't believe that the linen warms up the blade to any appreciable extent. I think that the reason the linen does what it does is that it's just rougher and more abrasive than the leather.

I also believe that the draw is more related to the oil or moisture in the surface of the strop more than it is to any characteristic of the blade. When I was doing my experiment trying to sharpen a dull razor with the strop, I found that even when the blade was dull it would still draw on the leather. I would do about 400 laps on the linen then flip and do a couple hundred on the leather, and invariably the draw would start building around lap 30 or so and reach its peak around lap 60. Flip back to the linen, do another 400 laps, flip back and the same thing would happen. After about 1400 laps on the linen the razor was passing my various armhair tests, and the final stropping on the leather went the same way as the first leather stropping when it was dull. I think that what was happening is the passage of the razor flattened down the nap a bit, and worked the oils up to the surface where they would make the surface a bit tackier. I've also taken heavy-drawing strops and cleaned the oils out with brake cleaner and reduced the draw considerably.

Also, somewhat interestingly, is that the linen side also builds draw, though on a much lesser scale. I think this is because of the rougher texture means fewer contact points, and lower oil levels unless you regularly strop sopping-wet razors on them. Also newspaper builds draw pretty well, more than linen, even with a clean edge, but again I suspect this is because it's smoother to start out with and smooths out to a glossy finish over the next hundred or so laps, also the ink uses an oil-based carrier which has dried but the constant working by the razor may be loosening it up a bit.

Edit: Just read afdavis's post. We've talked about this off and on for a couple of years now, and for whatever reason we see different effects from the strop. I have no explanation for why this is :confused:.

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Originally Posted by mparker762

Edit: Just read afdavis's post. We've talked about this off and on for a couple of years now, and for whatever reason we see different effects from the strop. I have no explanation for why this is :confused:.

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Could it be that AF isn't doing 1,400 laps ? :) Your mention of oils corresponds with what Tony Miller once told me regarding neatsfoot oil.... that if applied to a strop it will increase the draw.

I find it interesting that professional barber's strops sold in the heyday of men routinely going in to buy a shave were almost exclusively made of horsehide. Isn't it established that horsehide has little of no draw compared with cowhide ?

Whatever heat is generated through the friction is certainly long gone by the time the razor gets to the whiskers. OTOH, many tutorials of bygone days recommend dipping the blade in hot water immediately before attacking he whiskers. So the hot knife through butter theory seems to be applicable. I know I do it whether or not it makes any difference. :shrug:

I bought two razors from an ebay seller/forum member that were probably the sharpest I've ever encountered. In corresponding with him I found out that he sharpens them on a Norton 1k to set bevels, then the 4/8 pyramid as described in Lynn's SRP Wiki tutorial. Following the hones he goes to a series of balsa flat beds with 1.0, 0.5, and 2,5 diamond paste.

So upon receiving each of these razors I immediately found that they would easily pass HHT on my fine hair all along the blade. I shaved with both and then the next time around they would not pass HHT. I stropped my usual 50/50 and they would pass the HHT again. The same results on three occasions with each of the razors and so far no visible deterioration of the edge under the 30x.

I'm not drawing any conclusions from these observations other than stropping seems to be beneficial. What I've been experimenting with lately is AF's post on "Command Angle" here on decreasing the amount of pressure used with stropping which of course means less draw. It seems to me that I am getting even better results with this but it is difficult to quantify....for me anyway.

I have given by Lynn(thank you)Tony Miller's strop 3 in wide it has tons of draw . i can't do more then 20 laps on it . getting tired.

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Originally Posted by hi_bud_gl

I have given by Lynn(thank you)Tony Miller's strop 3 in wide it has tons of draw . i can't do more then 20 laps on it . getting tired.

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mparker762 must have forearms like Popeye. :)

I was doing those 1400 laps on linen - I wasn't counting the laps on leather in that experiment. So the leather was getting used only sporadically. My arm was numb for days after that session, though. Maybe I should have eaten some spinach.

There was a guy around here a few months ago with access to a SEM that I was hoping to talk into looking into the effects of stropping, but that seems to have gone phwut. Short of that all I've got are WAGs about what the linen and leather really do, much less how to get them to do whatever it is they do more efficiently.

AFDavis, I too have noticed that as the edge becomes really keen the draw increases. I've seen the effect described as though the razor is being sucked down onto the strop. It is a little reminiscent of that.

I've never measured the temperature created by stropping on linen. Whether there is enough generated to warm the blade sufficiently to aid the alignment of the edge, I don't know for sure. I suppose it's just a theory that I am inclined to agree with.

mparker, it's interesting that you've experienced draw with the linen side too. I don't think I've ever done more than 100 laps over it in one go, & never noticed any appreciable draw. I'll have to pay more attention.

Jimmy, it was the effect of the warmth generated in relation to stropping, rather than keeping the heat in the blade to aid it's ability to cut whiskers. If you want the heat to help with that hold the blade in a blow torch. They'll melt right off your cheeks! :D

There's certainly plenty there for me to think about. I think I may be out of my depth!

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Originally Posted by ben.mid

Jimmy, it was the effect of the warmth generated in relation to stropping, rather than keeping the heat in the blade to aid it's ability to cut whiskers. If you want the heat to help with that hold the blade in a blow torch. They'll melt right off your cheeks! :D

There's certainly plenty there for me to think about. I think I may be out of my depth!

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Ben, I see what you mean, I wasn't thinking of the heat in relation to aligning the edge. You very well may have something there.

I am still fascinated by the admonition seen in the 1961 barber manual and elsewhere to always follow the honing on leather only. I also find it interesting that the author of that manual in talking about the linen says that there is a controversy as to the effectiveness of the linen back then. That among professional barbers with some for and some against the linen.

As far as being out of our depth, if mparker762 and AFDavis are still learning I'm still wet behind the ears. :)

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Originally Posted by ben.mid

AFDavis, I too have noticed that as the edge becomes really keen the draw increases.

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I think that under normal circumstances (with a razor that is shave sharp) this is correlation without causation; it takes about 30 laps or so for the strop to do it's work, and coincidently takes about 30 laps or so for the oils in the strop to work up and increase the draw.

Here's an experiment you can do - take one of the razors in your rotation and strop it the way you normally would for shaving, taking the edge to your usual definition of "really keen". Set it down without oiling it and go away for 15 minutes, then come back and strop it again. The edge shouldn't have deteriorated appreciably during this time, so it will be interesting to see if the draw increases the way it did that first time. When I do this it does increase right on schedule, but for afdavis it starts off drawing heavily and stays there, so it'll be interesting to get a wider range of results. Also let us know what leather you're using, since it's possible that this is significant.

I am using a Tony Miller Vegan strop, and the amount of draw I get on the vegan leather side is amazing. It takes a bit to get used to, but there is an appreciable amount of resistance when you are stropping a razor. You really have to use light pressure.

One time I was stropping fairly quickly, and I noticed that the razor got quite warm. It was not just where I was holding it, but the entire blade was noticeable heating up the more I stropped. I though I was crazy at first, so I brought it over to my girlfriend and said "feel this, is it hot??", and she indeed felt the heat too. So there is definitely a correlation between amount of draw and heating up the razor. This really isn't surprising to me since draw is typically defined as the amount of resistance there is during stropping. Resistance is nothing more than friction on the strop, so you're basically giving your razor rug burn. :p Now whether the amount of heat has any direct effect on the quality of the stropping is something that I haven't experimented with, but I would be suprised if it didn't have some connection. I would think the heat would only help with the stropping action, since the metal would be more malleable.

Jimmy, you sound a bit surprised that back then everyone had different ideas about the right way to shave!

mparker, I have done your experimental strop. I stropped it 35 laps over the leather in actual fact, then left it for around fifteen minutes. When i started to strop again, the increased draw was there after two laps.
The strop i used was a Jemico Russian.

I hadn't realised that the action of stropping would cause oils in the leather to work their way to the surface.

Dave, your last comment was what i was wondering. I really don't know how much heat it would take to help, but since the edge is so fine, not a lot i would imagine.

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Originally Posted by ben.mid

Jimmy, you sound a bit surprised that back then everyone had different ideas about the right way to shave!

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Yes I suppose I do. The more things change the more they stay the same. :)

I have strops that exhibit draw and strops that don't and there is absolutely no difference in the end result.