Sharpening scissors

[rahimlee54]

My wife sews alot and was complaining about her scissors, so she wants me to sharpen them. Is there anything to know as far as sharpening them go, and how high of a grit should I take them?

Thanks
Jared

 

[Eamon Burke]

I find scissors are kind of like straight razors in my limited experience--the more polish, the better. But you gotta make sure the finish is very even, especially for fabric, so that it cuts the same at all points in the scissors.

 

[EdipisReks]

keep the existing bevel and you can't really go wrong. i find that an aoto edge works great for fabric. i've turned some old carbon steel scissors i found at work into some really killer snippers just by keeping the existing bevel. if you take enough material off, you have to deal with modifying them to keep the flats in contact properly, but you probably won't have to deal with that for a good long while.

 

[SpikeC]

The important thing to remember is to never touch the long side, just the edge.

 

[Chef Niloc]

And don't touch the inside

 

[EdipisReks]

And don't touch the inside

a lot of scissors are concave on the inside, so you'll have to eventually, if you take enough material off, over time. i have no idea how good scissors are tempered, though, so perhaps you just throw them away before they hit that point?

 

[SpikeC]

And don't touch the inside

That is what I meant, just badly phrased!

 

[tkern]

I sent a message to Dave a few weeks ago about sharpening shears. My g/f is a dog groomer and has some shears that cost as much as my knives. He said the german single bevel kind were possible but leave the concave ones alone. After trying to sharpen a crappy pair of germans and making a convex edge on it, I'm going with Dave on this one. If some of you guys are having better success, congrats.

 

[Eamon Burke]

Concave scissors are no joke to sharpen. Luckily those are almost all hair shears

 

[Chef Niloc]

Just so you know I wouldn't bother to even try. Send them to Dave he does them better then he does knives. He loves the girls at the hair salons .

 

[ajhuff]

a lot of scissors are concave on the inside, so you'll have to eventually, if you take enough material off, over time. i have no idea how good scissors are tempered, though, so perhaps you just throw them away before they hit that point?

Probably no temper to speak of. The basic all metal shears, a la Fiskars, are mild steel. Low alloy, pearlitic rather than martensitic as a quality knife blade would be. High dollar shears might be more akin to a knife blade, but not the basic shears.

-AJ

 

[ajhuff]

Addendum.

Speaking the carbon steel shears, not the stainless ones out there.

Interestingly, Gingher says their shears are made from hot forged high carbon cutlery steel. I don't remember them being high carbon, but then again 0.95% doesn't jump off the page at me as high carbon. They are low alloy though, that I know for sure.

I would also be concerned sharpening shears that have a hard chrome finish on them. I don't think you want to remove the chrome face.

-AJ

 

[tkern]

When I was looking into grooming shears, I found most were made out of 440. One guy was using vg10 and a couple others had some damascus. Not sure of what content they were.

 

[ajhuff]

When I was looking into grooming shears, I found most were made out of 440. One guy was using vg10 and a couple others had some damascus. Not sure of what content they were.

Well there you go, stainless shears are mostly 440 and carbon steel shears are mostly high carbon low alloy. And a few oddities mixed in.

-AJ

 

[Rottman]

Murray Carter carries Japanese shears that use the same steel he uses for his knives: white#1.

 

[Dave Martell]

Most shear blades today are crap, the exception is what comes out of Japan with a higher price tag attached - their low end stuff is crap too. If you can find shears in 440C they're usually a bit better than the typical "surgical steel" we've all got used to using.

The important thing for me when selecting quality shears (as well as sharpening shears in general) is the set and how that's dealt with. The angle of the edge and blade material/hardness is only part of the equation to how shears work - the biggest thing of all is the most overlooked - that's the set - or the tension.

The way the blades are bent/twisted/ground and then tensioned against one another is what really makes shears cut, the steel type, edge angle, and how the blade is sharpened equates to edge retention more than how the shears work. Yes edge angle and how a blade is sharpened can also effect how shears work too but assuming that they're done somewhat OK in those regards that becomes a small part of what's going on.

Case in point, take most any pair of household scissors and sharpen them up and see how they cut. I'd bet that about 8 out of 10 won't cut good at all even though the blades are super sharp. You'll likely have to twist (or rack) the blades together to make a cut. I'd then bet that about 1/2 of those can be made to cut nearly perfect by adjusting the set (tension) correctly.

In shear sharpening our biggest enemy is stripped and rusted screws and bent blades. Fixing this stuff is often needed to get shears to work right but too often the price of the shears aren't enough to warrant the expensive of labor to attempt to correct the situation. High priced hair shears and fabric shears are most often what we'd do this work to, most all others are throw away.

So my point is that while it's easy to sharpen shear blades that's only 1/2 of what you need to do to get shears to work properly, the second part is adjusting the tension correctly.

 

[ajhuff]

And this then presents the difference between shearing and slicing. Good info Dave.

-AJ

 

[Seth]

Just a point of info, i have purchased a number of shears, Joewells, from tricut.com for grooming my Golden Retriever. I am not sure about what is needed for fabric but these shears are reasonably priced and are used by hair people. They are hollow ground and have tension adjustment screws. (there is a method for getting the right adjustment) i have sharpened only on my highest grit stone and as Dave points out, the even contact as the blades close is critical.
~s

 

[longhorn]

The important thing for me when selecting quality shears (as well as sharpening shears in general) is the set and how that's dealt with. The angle of the edge and blade material/hardness is only part of the equation to how shears work - the biggest thing of all is the most overlooked - that's the set - or the tension.

The way the blades are bent/twisted/ground and then tensioned against one another is what really makes shears cut, the steel type, edge angle, and how the blade is sharpened equates to edge retention more than how the shears work. Yes edge angle and how a blade is sharpened can also effect how shears work too but assuming that they're done somewhat OK in those regards that becomes a small part of what's going on.

Case in point, take most any pair of household scissors and sharpen them up and see how they cut. I'd bet that about 8 out of 10 won't cut good at all even though the blades are super sharp. You'll likely have to twist (or rack) the blades together to make a cut. I'd then bet that about 1/2 of those can be made to cut nearly perfect by adjusting the set (tension) correctly.

Sorry to revive an old thread but I found myself sharpening an old pair of scissors I had forgotten I had earlier today. I put a nice edge on them, not too sharp as they will have to deal with more heavy duty stuff like fish fins, lobster/crab shell, etc. and I found that they do not cut that well. So i searched the forum and once agan Dave has proven to be a wealth of information. I'm going to try them out but I think the issue with these is that after the metal removal the tension/spacing between the blades is no longer set correctly. I am scared they will just splinter some lobster shell instead of cutting it cleanly.

Which presents my question, these are a fairly cheap pair of pull-apart shears. Am I right in thinking that this problem will be pretty much impossible to fix without regrinding the entire area and mechanism where the blades come together and join? In which case I should just get a new pair of scissors right?

Dave, in dealing with more heavy duty operations like shellfish, fins, cartilage etc. would your recommendation still be the Kai scissors I saw you recommend in other topics?

Once again, sorry to revive and hijack this thread.

 

[zitangy]

Done a few for fun...

Applied the same theory as with knife sharpening...
analyse the edge profile,, straight bevel, concave or convex and follow that profile.AS long as teh 2 angles meet to a point.. shld be sharp. IF screws are adjustable.. tension adjustment comes to play. Trial and error to what feels right.

Most of the time I just need to remove the folded steel or burr and that does improve performance. If it can be taken apart easily better still . IF replacement parts are not available, I wld not dismantle them. Just spread them apart and gently remove steel of the entire length of the edge.

FInally I prefer to remove the minute amount of steel with sandpaper as I tend to have better control with uni directional strokes. I suppose depending what you are cutting.. in some instances, bite on the edge will be a consideration so that the material does not slip off.

Stay sharp and hv fun..

rgds
d

 

[Matus]

Concerning how good or bad scissors may cut - we have 2 medium sized scissors at home. One rather old (for hairdressers I guess) and one new (German).

The old scissors have the blades loose, but the blades are slightly curved so as you cut they touch ONLY at the point where the cutting takes place. This also means they do not tend to 'clamp' the material being cut. The fact that they are loose does not matter - the way one moves his hand during cutting pushes the blades towards each other and they cut fine. True is - this scissors would not work well in left hand.

The new scissors are much more 'stiff' - the blades are straight and completely flat - so they touch each other over a large area while cutting and give some resistance (because of the constant pressure the blades are pushed against each other). If I would cut a scotch tape with them and get a bit of the glue on the inner side of the blades the scissors get nearly unusable because of sticking.

I much prefer the old one eve though the new is technically sharper

 

[slowtyper]

Just so you know I wouldn't bother to even try. Send them to Dave he does them better then he does knives. He loves the girls at the hair salons .

Does dave have a sexier hair clipping scissor forum he is not telling us about?

 

[pete84]

What is the proper tension for take apart scissors? I've a pair of Tojiro inox take-aparts and after a thorough clean, I have no idea where to set tension to! T.I.A.

 

[Dave Martell]

What is the proper tension for take apart scissors? I've a pair of Tojiro inox take-aparts and after a thorough clean, I have no idea where to set tension to! T.I.A.

The proper tension set is individual to each shears/scissors but one common thing that remains a solid rule is that you only need the tension set as tight as it has to be to work properly. If you over tighten then it requires more hand pressure to make the shears work and driving the blades against one can serve to prematurely dull the edges.

 

[Dave Martell]

Concerning how good or bad scissors may cut - we have 2 medium sized scissors at home. One rather old (for hairdressers I guess) and one new (German).

The old scissors have the blades loose, but the blades are slightly curved so as you cut they touch ONLY at the point where the cutting takes place. This also means they do not tend to 'clamp' the material being cut. The fact that they are loose does not matter - the way one moves his hand during cutting pushes the blades towards each other and they cut fine. True is - this scissors would not work well in left hand.

The new scissors are much more 'stiff' - the blades are straight and completely flat - so they touch each other over a large area while cutting and give some resistance (because of the constant pressure the blades are pushed against each other). If I would cut a scotch tape with them and get a bit of the glue on the inner side of the blades the scissors get nearly unusable because of sticking.

I much prefer the old one eve though the new is technically sharper

Most often the straight (flat) bladed scissors don't respond so great to anything you do to them regarding tension or even sharpening. Fortunately these are also usually very cheap and can be chucked for a better pair at little loss.

Good shears/scissors should have a curve (and twist) ground and set into the blades so that only one exact spot along each blade's length contact the other blade at any given time.

Even well ground blades should not be loose though as being too loose allows the blades to fall closed and this is bad for edge chipping. Blades should never fall closed fully, they should stop within 1/2" of the tips closing.

The idea when tensioning shears/scissors is to get the proper fall to comply with the lightest tension on the screw that can be set to get a clean cut. So you want the blades to not close fully, the tension to not be so tight that you can't easily work the blades, and the cut should be clean through to the tip without snagging the material being cut.

 

[pete84]

Thanks for the info, Dave!

 

[Dave Martell]

Sorry to revive an old thread but I found myself sharpening an old pair of scissors I had forgotten I had earlier today. I put a nice edge on them, not too sharp as they will have to deal with more heavy duty stuff like fish fins, lobster/crab shell, etc. and I found that they do not cut that well. So i searched the forum and once agan Dave has proven to be a wealth of information. I'm going to try them out but I think the issue with these is that after the metal removal the tension/spacing between the blades is no longer set correctly. I am scared they will just splinter some lobster shell instead of cutting it cleanly.

Which presents my question, these are a fairly cheap pair of pull-apart shears. Am I right in thinking that this problem will be pretty much impossible to fix without regrinding the entire area and mechanism where the blades come together and join? In which case I should just get a new pair of scissors right?

Dave, in dealing with more heavy duty operations like shellfish, fins, cartilage etc. would your recommendation still be the Kai scissors I saw you recommend in other topics?

Once again, sorry to revive and hijack this thread.

The pull apart shears can be either junk or OK for sharpening/adjusting - sort of depends mostly on whether or not the screw is adjustable. If it can be tightened or loosened or if fixed does it have washers (shims) that can be removed. I've seen both as well as ones that the pivot bolt is welded in plus there's also models that are adjustable but so poorly ground in the pivot area that a simple sharpening makes the shears useless because there's no adjustment possible. These shears really vary a lot in quality.

I wouldn't recommend or use the Kai general purpose type shears for shellfish, for that I'd recommend high leverage shears (long handles - short blades) - I believe that Kai makes them as well though.

 

[gic]

I am curious about one thing: Is it true that one can sharpen scissors by cutting a graduated series of sandpaper or is this an urban legend....

(I actually was thinking about this as I used a scissors to cut some lapping film with small micron grits that I was going to glue to edgepro blanks to use for polishing some of my knives...)

 

[mpukas]

Interesting that this thread came back – I missed it the first time around. I’ve had a go at scissors recently.

One of my other big hobbies/obsessions/time+money-suck is fly fishing and fly tying. Scissors are one of the most important tools in tying good quality flies. I use Dr. Slick razor scissors (440 J2 HRC 55, fwiw). They’re some of, if not the best that are available/marketed to the industry, and they are quite good for what they are. Even though they claim to use Japanese steel, they’re made in Pakistan and the quality can vary widely.

For small trout flies, good fly tying scissors have to have very, very fine points that can cut a single feather fiber cleanly right at the tips. There are different scissors for different applications and materials; some heavier duty scissors are needed for thick hair, synthetic materials, wire, etc., but they are still fairly small.

I tried sharpening and regrinding the tips to be pointier on a pair of 4” razor scissors, and wrecked them (I have several pairs, and have dropped a couple of them on hard floors and bent the tips on at least one pair). I learned the hard way many of the things Dave have just talked about. Even though the blades are very sharp and the tips super-duper pointer and thin, they won’t cut at the tips. I screwed up how the blades meet pretty bad, and I hardly touched the back side.

One valuable thing I learned is that using a small course DMT plate for re-profiling is much easier and saves a Bester 500 from getting gouged.

Taking what I learned from that, I sharpened a pair of Wustie pull-aparts and a pair of cheap-o fiskars. Just did a few strokes to touch up the bevel, lightly de-burred on the back, and they cut very well now. The blades are sharper, and the set is still good.

 

[Dave Martell]

I am curious about one thing: Is it true that one can sharpen scissors by cutting a graduated series of sandpaper or is this an urban legend....

I've heard that too but never bothered to try it.