Scissors sharpening

[Old Noober]

I've had a pair of scissors for a couple of years, still cuts well. Just wondering if they ever start to dull, which I'm sure it's inevitable.  How would you sharpen them?

[Ferg]

I have a Tormek system. Have sharpened a number of scissors and like tools including knippers/shears for trimming goats hooves. 

Folks they were for, said they were sharper than original. further proof that most all so called sharp tools from sellers are simply not sharp. lol

 

Ferg

[Art]

Scissors can go from simple to complex to just crazy.  Simple blades are the typical disposable ones and usually anything under $15.  It varies, but we get on average $7 to sharpen the average "dressmakers" shears.  Since we "service" technical shears (read that as high dollar beautician/stylist/barber shears/thinners etc), we charge as high as $20 on a 3 to 4 month basis.  That 3 or 4 months of cutting is approximately equivalent to a lifetime for household instruments.  So how long does a sharpening last.  It depends on what you are cutting, and the quality of the manufacture of both the shear AND the material the shear is made of.  Some shears are so technical, they vary the angle of the edge from the tip to the throat about 10 or more degrees.  But even dressmaker shears can be "technical". Some makers will use a different angle on each of the blades.  Some "technical" brands and models will succumb to the yo ho who sets his TAS (Twice as Sharp) to 45 degrees for EVERYTHING.  Most shears will cut that way, well maybe not as designed, but they will cut, kinda, maybe.

So, firstly, do not use a bench grinder running at 3450 rpm to ruin a good pair of shears.  I try never to use any vertical wheel grinder for shears, not even the Tormek, because even with the best sharpening job, they put a hollow grind on the blade.  The hollow grind doesn't last as long, but then again if you have a Tormek and the jig, you can always sharpen when needed. Secondly, you need a jig system to do a good job, there just isn't any way way to hold the exact angle necessary without years, maybe decades of experience (I've seen Japanese team members at the factory do it, I drink too much coffee for that routine).

On quality shears, the relationship of the ride and the line (or the whole blade if not inside hollow ground) must be established or often re-established.  It is not that this area is unimportant on inexpensive shears, its just that nobody seems to care except good sharpeners who are going to charge more than the shears cost to "service" them.  Also, you can't service them if you can't take them apart completely and subsequently put them back together again (not a reflection on someone trying to sharpen them, more a denigration of the company that is too cheap to use screws).

Of course the final element is testing.  First on rabbit fur (no, we're not having poor helpless bunnies skinned just to test scissors and clippers, they are a by-product of the rabbit meat market, that we get from France), next we cut a double of Viva paper towels, in all cases they must cut all the way to the tip cleanly and not grab, especially at the tips.  Next comes the Kleenex, then a single ply of kleenex, then we wet a single ply and all of these must pass.  Then we try human hair extensions which must cut without pushing.  Kind of the final failure point.

A TAS or a Tormek will do the job, you just might have to sharpen more.  Good steel and good manufacture will go a long way to making a fairly long lasting shear for home use.  However, for something a seamstress or seamster or tailor will use every day repeatedly, 6 months to a year is more the norm.  For a cutter (I don't know if those folks still use hand shears anymore), I would imagine that 3 to 4 months would be about normal, maybe less.

I love those big shears the cutters use, don't see much of them anymore.

I spent 10 years sharpening and knifemaking, and just do it now to keep busy (retired).  Ask any questions about the business, I like the technical side.

Art

 

[Gunnarsson]

On ‎2016‎-‎07‎-‎27 at 2:15 AM, Art said:

I spent 10 years sharpening and knifemaking, and just do it now to keep busy (retired).  Ask any questions about the business, I like the technical side.

Some great info there, thanks. I have spent quite some time searching and reading info about sharpening scissors, and there just isn't a whole lot of good info out there. On the other hand, countless people keep saying that cutting sand papper or tin foil is great for making scissors sharper...  Well, if they're dull enough to begin with, perhaps that makes them "better".

I have kind of fallen in love with old dressmakers shears, and I have bought a couple of abused and neglected ones for something like $3 each. Being old and neglected they ofcourse had some rust damage, on top of being dull. On the edge where you normally regrind scissors it's no problem, rust there gets removed with a "standard regrind" to the original angle. I used a ordinary coarse/fine stone (not really fine by knife sharpening standards) and tried to stay at the original 30 degree angle there.
The inside of the blade was my biggest problem, they are hollow ground and the pitting caused by the rust forced me to regrind that side too, to be able to get a good edge. Eventually I figured out that the curved edge of a schythe hone had close enough to the radius of the hollow grind to work, so I could use that to regrind the inside of the blades to more or less the original shape. It might not be perfect by the standards of someone used to professionally serviced shears, but they do cut fabric and just about anything else very well so I'm happy with the result.

I would greatly appreciate any pointers about sharpening scissors, both those that are in fairly good shape but dull, and the old neglected slightly rusty ones you can pick up for $3 at swap meets. (As you may have figured out I like fixing stuff myself, so while sending them off for a professional regrind might get the best results there's no fun in doing that.)

[Sonydaze]

I didn't have much success with sharpening scissors until I got my Tormek.  It does a decent job.

[Gunnarsson]

Yeah, I want one of those, or something like it. Unfortunately I want food to eat and a roof over my head even more, so the Tomek will have to wait until I've got the money.

[Sonydaze]

Gunnarson, I hear you.  I choked on the price of the Tormek system for a long time, but it has proven to be worthwhile. As it greatly shortened the time I spend sharpening as well as sharp tools are more efficient than working with sorta sharp ones. Sharpening for me was frustrating, some days I was the sharpening master, other days I felt like I could make a dull edge worse, with Tormek's jigs it is relatively easy to get a consistent good edge. 

Btw I have no affiliation with Tormek other than owning one.

[Art]

I have a S-2000 Tormek, which is an older version of the T-7.  Got it as a gift around 2001, so I've had it a while and probably know it as well as anyone.  It is a great machine although even in 2001 it was quite expensive.  The S-2000 and T-7 are made of steel, the T-8 appears to be zinc; ok for a casting, but I'll take real steel anyday.  Still good machines.  Mine has been updated whenever an update was available so I guess it is really a T-7, though most of the updates were insignificant but of some value.  The Tormek is, like all vertical wheels, a hollow grinder.  The good thing is that the wheel has a 5 " radius (10" diameter sounds more significant) and doesn't have the pronounced grind of a 2.5 or 3 inch wheel.  That being said, the hollow grind (despite the prevalence of the Wolff Twice as Sharp or TAS) is not the grind for stylist/barber and dressmaker shears and scissors.  The concave or hollow grind takes a lot of metal from behind the edge, making it less durable but a lot easier to sharpen.  The hollow grind is great for hunting knives where sharpening in the field is a pretty distinct possibility.

With technical scissors and shears, the flat of each blade is mostly not flat.  The blades are hollow ground to eliminate as much drag as possible.  Remember mostly?  There is an area called the ride back toward the pivot point (screw or ghod forbid rivet) and the ride line along the edge and usually around the back of the blade most of the time meeting up with the ride back at the pivot point.  The two blades ride on the ride and the ride line to do the cutting.  It is necessary for the sharpener to re-establish the ride lines if the shear is to cut properly.  I usually dress the ride with a 5000 grit stone and sometimes follow that with an 8000 depending what the shear is used for and how it will be used to cut.  The sharpener has to determine what the stylist cuts (hair texture, wet or dry, and clean/dirty), how they cut, and what they expect from the shear.  It is not uncommon for a stylist to have 5 or 6 pairs of shears for different cutting methods.  You might use a 35° angle for a pair to do slide cutting, but 45° for a pair that will be blunt cutting most of the time.  You will be successful if you can solve problems.

 As far as training goes, you need to get the training for whatever equipment you will be using.  The most expensive machine is not necessarily the best, neither is the cheapest.  If the sales spiel for a machine sounds like hype, it is hype.  Call some folks who have the machine and check it out.  There are a lot of DVDs out there, but most are not free, and please, believe NOTHING you see on youtube.  There is some good stuff out there, but there is also some really wrong stuff, and there is NO peer review.

Art 

[Gunnarsson]

On ‎2016‎-‎09‎-‎08 at 10:54 PM, Art said:

The blades are hollow ground to eliminate as much drag as possible. ... There is an area called the ride back toward the pivot point (screw or ghod forbid rivet) and the ride line along the edge and usually around the back of the blade most of the time meeting up with the ride back at the pivot point.  The two blades ride on the ride and the ride line to do the cutting.

Is the only purpose of the hollowgrind to reduce drag?
Is there an ideal width of the flattened(?) ride along the edge?

As far as the Tormek goes, the T7/T8 does look like a fairly good option, but I'm still hesitant - I'd like a larger diameter stone. One option is ofcourse to get an old style large sandstone grinding wheel, they're still around (and new ones are available) and some are >24" in diameter. Downside is they never have any kind of grinding jigs, but some metalwork should take care of that.
I just got hold of an old 8" sandstone wheel, I'm looking for a suitable electric motor to drive it. That should be a nice step up from doing all the sharpening work by hand, but still, it's just a step along the way to the kind of machinery I really want - too small diameter to work well on some edges.

[Art]

The hollow grind on the flat (well not after you hollow grind it) portion of the blade is not only to reduce drag, but to be easier to attain the flat geometry along the full length of the cutting edges.  This is necessary because the edges meet, and any high points in the flat would cause the edges to pull apart.  The joint area or ride is where the geometry is established and this is carried all along the ride line.  The ride line (along the edge) can be anywhere from 1/32 inch to approaching almost  the full blade (to the halfway point on both sides).  The more the blade is sharpened, the more the ride lines will approach the middle aka a flat ground blade.  At this point there is little metal left to re-establish another hollow.  This can be 15 or more years for good scissors with good steel, getting 5 years from a cheap pair may be a little harder to attain.  Cheap scissors are made of cheap steel, usually 420, but quite often really south of that.  Heat treating at the best with this grade of steel usually is only on the less than HRc 55 and often below HRc 50.  Usually when sharpening these, if there are dings that have to be removed, they are usually quite pronounced, and a lot of metal has to be removed to get a smooth edge; add to that they have to be sharpened more often, typically twice as often as a quality shear.  

 

My Bader and Burr-King have interchangeable contact wheels.  I have a 14" that gives a pretty gentle hollow, but the 10" on the Tormek works pretty good also.  Nice thing about the belt grinders is the belts, they're available in just about any grit.  You can also flat grind and convex grind on the belt grinders, no so much with the Tormek.

Art

[Gunnarsson]

Thankyou! The next time I get my hands on old scissors I'll have a better idea what I'm doing - and a better chance of deciding if they're worth saving or too far gone before I've bought them.

[Gunnarsson]

On ‎2016‎-‎09‎-‎10 at 7:15 PM, Art said:

...The more the blade is sharpened, the more the ride lines will approach the middle aka a flat ground blade.  At this point there is little metal left to re-establish another hollow...

Hello again!

If the hollow is to be reground and there is enough meat left in the blade to do it, how would that be done?

Since last time I have made myself a jig for sharpening the "outside" edge on scissors to a precise angle on common hones so that part of a regrind is under control, but these old fabric scissors often also have surface pitting from rust all over the inside of the blades. I have been able to get the area near the edge good enough using a schythe hone (picture shows basic idea) but it isn't perfect, it isn't fast, and the closer you get to the tip where the blade is narrower, it's almost impossible.

[Colt W Knight]

I get by simply honing my nice scissors I use for cloth and garment weight leather. I take them apart, and run my find sharpening stone on the angled portion. Then strop it on a piece of leather with polishing compound.  I try not to touch the back side. If there is a nick or something, I lay the back flat and work the scissor back and forth to keep the back nice and flat while grinding off the imperfection. You can really get a lot of sharpening done with a nice whetstone if you know how to use it.

Edited August 22, 2017 by Colt W Knight

[DrmCa]

I get by by holding a needle parallel to the edge, i.e. almost perpendicular to the blade mating surface, and gently "cutting" that needle several times as if I was cutting fabric.

Needles are chrome-plated and chromium is the hardest of all metals, so it works well honing the scissor blades. I usually set aside one large needle just for re-sharpening scissors.

But as of lately I found that there are very inexpensive sets of TCN coated scissors available at Costco, which are razor-sharp and keep the edge much longer than bare steel. They cut through everything like through butter.

Edited August 22, 2017 by DrmCa