Strop questions

[Prashun Patel]

I have been experimenting with a couple different strops.

However, I am conflicted about the best way to use a strop.

I have 3 shop-made strops. One is a piece of hard maple charged with Chromium Oxide. One is horse butt (hard side up) charged with Chromium oxide. A third is a piece of uncharged horse butt (I'm too tired to make a pun on that). I can't tell the difference; all 3 produce pretty good results.


What is your strop of choice?
How long do you strop for?
Do you charge it? With what?
Do you strop the backs of your plane blades?
Do you strop the backs of your chisel blades? If not, do you use a stone to remove your wire edge?
How critical is it to remove that wire edge completely? (I ask this because my teacher really stresses the importance of this - even when I think I've removed it, he can feel fine burr and maintains it's critical to getting this off. He also prefers to use his strop without any compound and uses cordovan leather. He does all this with tremendous success but I'd like to hear from others too.)

[Doug Hepler]

[QUOTE=Prashun Patel;2588160]

What is your strop of choice?
Hard felt wheel from LV running slow (about 400 rpm - I run it on my VS lathe) or any piece of hard leather glued to a flat surface (I bought a LV strop recently but have not used it much yet)

How long do you strop for?
A few seconds on the wheel or 2-3 strokes on the strop

Do you charge it? With what?
Yes, with almost any available rouge but I just bought a stick of green compound from LV with my strop. I also finish up with 1 micron sandpaper instead of stropping. You can buy sandpaper with finer and more uniform particle size than is available in rouge. It makes no sense to strop with rouge that is coarser than your honing grit, does it?

Do you strop the backs of your plane blades?
Occasionally

Do you strop the backs of your chisel blades?
Never
If not, do you use a stone to remove your wire edge?
Yes. Chisel or plane back flat against the stone or sandpaper

How critical is it to remove that wire edge completely?
Critical for plane blades and chisels because it will break off with first use and leave a less than sharp edge

Doug

[Pat Barry]

How critical is it to remove that wire edge completely? (I ask this because my teacher really stresses the importance of this - even when I think I've removed it, he can feel fine burr and maintains it's critical to getting this off. He also prefers to use his strop without any compound and uses cordovan leather. He does all this with tremendous success but I'd like to hear from others too.)

I hope that your teacher isn't a frequent visitor to this forum!

[Phil Mueller]

I can't really comment on my "favorite", because I've only Used one method to date. It's a piece of leather from Michaels, on a pice of maple, green compound, and closer to Paul Seller's 30 strokes. I do try to remove the burr on the final stone before stropping, and do strop the back of both chisels and plane blades a few times (not 30...maybe 3-4).

I'll be interested to see what more experienced folks have to say as well.

[Luke Dupont]

There's no "best" way to strop. I think you might get better advice if users proceed their question with a bit of context, so that's what I'll do:

I tend to finish on fairly coarse stones. In the past, this was 1200 grit diamond stones. Recently, it's been either an India or Hard Arkansas. I will be trying a translucent Arkansas soon, in which case I suspect I might find that I don't need a loaded strop at all, or I'll need far fewer strokes.

First piece of advice: Don't worry about the strop dubbing your edge. *You* might dub your edge with odd strokes, but the strop will not. Regardless of popular opinions and warnings, and what I'm sure many people will claim here, you can strop vigorously and as many times as you like, provided you keep the angle at or a little lower than you sharpen at. If you dub your edge, that's because you changed the angle, not your strop. This is, of course, provided that you have a strop with a hard back and not some insanely soft leather. My strops are probably on the stiffer side.

The only times I have dulled my edge are:
1. Goofing around and attempting to strop on my wallet, which *does* have way too much give and did roll my edge
2. Using a very moist dovo paste stropping compound, that did not stick firmly to the leather and moved around, allowing it to dub my edge. Your stropping compound should not be wet and smeary. I mean, it will smear a very little bit, but I mean it should not be like spreading butter, as mine was :P

If you already sharpen free hand, then I think you will have no problem with stropping. If you are taking consistent, well controlled strokes and not lifting up in some odd circular motion at the end, you will not dub your edge no matter how many strokes you take.

Off of the fairly coarse stones that I use, I usually strop 30-40 times on the bevel, somewhat vigorously. On the back side, I am much more careful; if using a soft strop, I take about 10 light strokes. If using a hard strop such as wood charged with chromium oxide, I take more. The coarser my finish stone, the more strokes on the strop I need, and the heavier strokes I take usually. The finer the stone, I find that I can take fewer strokes and stay light. You might find far fewer are necessary if you're ending on a much finer stone. But don't be afraid to go far enough to get the full benefit of the strop.

The key is to keep going until you find the maximum level of sharpness that the medium will give you. Most people, I think, probably under-strop. Strop a bit, test it, and repeat. See if your edge keeps getting sharper or not. When it stops improving, that's about how many strokes you need after your chosen finish stone. It's like cooking; add little by little, and taste it, rather than relying on some set-in-stone recipe that may not suit your particular parameters.

If you're worried that you're changing the geometry of your edge too much, place it bevel down on the edge of some wood, and see what angle it's cutting at. Unless you're doing something drastically wrong, I think you will find that edge geometry doesn't change all that much. It will change by maybe 1-2 degrees, but rarely ever more than that.

I use Green Chromium oxide, which I would recommend, unless you are finishing on a super fine stone already.

Removing the wire edge completely is critical IMO. This is what the strop is excellent for. I go one step further, and after stropping, run my edge through end grain on some soft wood. That usually helps to remove any traces of a burr that may be left.

One more tip: If you grind a flat bevel on your tools, I would suggest relieving the top of the bevel by rounding it over a bit. If you leave it at a hard angle, it will tend to tear compound off of your strop. Convex bevel tools behave wonderfully on the strop for this reason. But even on my flat bevel tools I just take a few strokes on the stone to soften that angle, and they do just fine. It also helps prevent suction-sticking and racking on stones during sharpening, I find.

[Patrick Chase]

I think Luke has the right answer: It depends on the rest of your workflow, and specifically on your polishing stone (if any).

If you end on a coarse or medium stone then you are relying on your strop to polish the bevel, and you'll need to charge it with something like green compound. Luke is a particularly extreme example, ending on a #1200 diamond plate and relying entirely on the strop to refine the edge from there.

Conversely, if you end on a fine polishing stone then you are only relying on the strop to "clean up" the very tip of the edge by removing any residual burr. No compound required.

The argument for completely removing the wire edge in a controlled fashion is that if you don't then it will break off in use. When it does so it may break off fairly far back into the edge, leaving a blunted edge and/or chips. I don't know how valid that argument is, but it's convincing enough to me that I'm careful to remove the wire edge completely.

I almost always end on a #8000 or higher polisher, and usually #10000 or #13000. Even after some wear-in I find that the green compound doesn't improve the finish from my polishing stones (and may degrade it), so I don't use it.

[Reinis Kanders]

You can look under magnification to see if there is any tiny burr left. Even 10x should show whether edge is polished and burr free. Magnification in general can be helpful when trying to play with ones's sharpening regimen. I have a lot of stones and it fun to see how they work together.
I am no expert though and I strop based on how I feel about the edge after sharpening, sometimes on plain leather, sometimes on leather with the green stuff from LV.

[Prashun Patel]

Thanks, Everyone.
Yes, my teacher is frequent and esteemed here

Thanks for the tip about relieving the top bevel, Luke. I like that and can see how this will help me.

I polish 1000, 4000, 8000, so I suppose I don't need compound.

If the burr is small enough that I can't easily feel it, is it good enough? Or do I really need to loupe-de-loupe? I am trying to train my fingers to recognize a ready edge. I am so getting there with the exception of being able to feel tiny wire edges. Brian's like the Princess and the Pea in his ability to feel the burr.

[Luke Dupont]

Thanks, Everyone.
Yes, my teacher is frequent and esteemed here

Thanks for the tip about relieving the top bevel, Luke. I like that and can see how this will help me.

I polish 1000, 4000, 8000, so I suppose I don't need compound.

If the burr is small enough that I can't easily feel it, is it good enough? Or do I really need to loupe-de-loupe? I am trying to train my fingers to recognize a ready edge. I am so getting there with the exception of being able to feel tiny wire edges. Brian's like the Princess and the Pea in his ability to feel the burr.

I've never used a fine polishing stone like that, so I can't say for sure, but I think that many people still strop with compound at #8000 grit. My impression is that it starts to become null in the 10,000-12,000 grit range, but it's worth trying both with and without compound and seeing for yourself. There's also a white compound (can anyone help me with the proper name for it?) that is finer than the green stuff. Of course, you might be just fine with just plain leather. The most definitive answer will always come from experimenting and confirming the answer for yourself. Note that most of what I have said here is just speculation/hearsay, as I haven't used a waterstone of that grit.

As for the last question about being able to feel the burr, that's something that I'd like to know myself! You can always strop for good measure of course, but like you, I try to remove the burr completely on the stone as good practice. The stones I'm using are not nearly as fine and are difficult to do this with, though. I'll be playing with a Translucent Arkansas soon, so I might have more relate-able experience in the near future.

[Patrick Chase]

Brian's like the Princess and the Pea in his ability to feel the burr.

I see a robe, some slippers, and a ruinously expensive set of JNats in your future.

[Malcolm Schweizer]

I am like you in that I use many different strops. Lately I have been using horse butt, but probably the one I use the most has been the one I got from (I think) Lee Valley. it is covered with a thin suede of very coarse knap, and it goes against everything I believe in regards to leather strops needing to be fine knap and very hard leather, but it works well. I believe it's because it's so worn in and nearly permanently charged with green chromium oxide from many years of use. Also it is my largest strop, and therefore usually it's easier to find, and so it gets the most use- I shamelessly admit.

I strop with a very light pulling motion, not pressing down hard at all. As said already, I like to charge the strop with green chromium oxide. Despite claims to the contrary, I find the one from LV to be very fine, and to leave a much finer finish than a Shapton 16,000 can get. I personally believe it breaks down into a very fine- around 30k grit, regardless of what it comes off the stick as. When I charge the strop, I will run a piece of metal over it to break down the green stuff in case of any odd particles... but only do this when I am trying to get a mirror finish for a chef that I am sharpening knives for, or if I'm setting up my super-duper-tuned LN plane that I use for very "angry" grain patterns. When sharpening the iron for the block plane that I abuse frequently, I usually strop on the green stuff as it comes off the stick, without the extra step of making sure there are no particles visible only to the tiniest mites and other atomic-sized creatures. I do, however, admit to being a hopeless sharpaholic, beyond any hope of recovery, and sometimes I sharpen things just to see if they can be sharpened. My 3-year-old daughter's pencil sharpener is now honed to 30k grit. I am shameless.

I strop only a few strokes, as that is all that's needed. It is important to fully remove the wire burr, but that should happen on the first two strokes. I do strop the back of the blade after flattening, and occasionally I will use the strop to buff the back and keep it polished. The same goes for chisels. I strop first on the sharpened bevel, and then I draw the iron or chisel on the back side one or two strokes, just to be sure there is no bit of burr that rolled over the back. To answer your last question, it is absolutely important to remove the burr. If you don't remove the burr, then you're basically trying to cut with part of the edge rolled over.

[Bill White]

Been using the green compound for a LONG time with good results.
Just resurfaced my strops yesterday. A VERY sharp block plane to trim off all the digs on the leather, new compound, and I'll be good for another few years (I hope).
Bill

[Jim Koepke]

I think that many people still strop with compound at #8000 grit.

Sometimes after an 8000 stone by blades are stropped, sometimes they are not.

It is possible to improve the blade by stropping after honing on an 8000 stone. It is also possible to degrade the edge stropping after using an 8000 stone.

As always, YMMV!!!.jpg

jtk

[Stanley Covington]

Heel of left hand. A bit of dried mud from natural finishing stone. Until it feels right.