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270908 | Thomas Conroy | 2020‑05‑17 | Scissors---re-establishing the geometry of the flats, in theory. |
O Galoots: Some more thoughts about how to deal with scissors that have been trashed by grinding on the inside ("flat") surfaces. This is from theory for me, not (as far as I can remember) experience. If you have good scissors that are soft enough to resharpen with a file, then you might be able to make some improvement by bending the blades. There are two types of curvature to the "flat" surface, resulting in a compound three-dimensional curvature. First, the whole face is hollow-ground by the maker with a big wheel, maybe two or three feet in diameter. To properly re-establish this by grinding you would need a comparably big grinding wheel, or a special- purpose belt grinder, and a lot of skill. Second, there is curvature along the length of the blade; this is what results in your being able to see lots of daylight between the blades when the scissors are closed and the blades touch at tips and axle. Scissors Sam calls this second curvature the "spring." Sam says that you can re-establish the spring of blades that don't have it it: "In this case I take a pair of heavy pliers and very slightly spring the thinner of the two blades inward at about two-thirds toward the tip of the blade, then again at about half an inch from the tip. If you examine quality scissors closely, you will find that one blade is always thinner than the other. This is the shearing blade. Always spring the thinner blade....The very hard crystalized scissors will never be sprung out of shape. Usually I get them with the points broken off. They are very brittle and will break easily. Before I attempt to spring scissors, I test them with a file. Scissors of softer metal that can be sharpened with a file will not usually have broken points." A thought of my own is that if the problem is a counter-bevel, that is to say a loss of the hollow of the hollow grinding, then we might take thought to how Japanese plane blades are treated when the hollow on the back of the blade has been flattened away. The blade is put flat down on a wooden block, edge sticking out a little way, and the bevel is given a series of lots of light taps to turn the edge downward. The taps must be given well back from the edge, on the soft iron of the back of the blade, not on the the hard brittle steel of the edge. The metal doesn't have to be moved very far. The technique is somewhat skilled, but it is well within the capabilities of the individual woodworker; when I took Japanese sharpening classes, many years ago, the teacher (Jay vn Arsdale) re- established the hollow of a number of students' blades in this way. I think a similar approach might be taken to the blades of good shears. If (when) I try it, I would probably hold the blade in a vise while I did it; and after tapping over the edge I might just barely touch the flats of the blades near the edge to fair in the shape---very carefully so as not to destroy the hollowness created by tapping. After all, as Scott says, what do you have to lose? I wouldn't want to experiment on treasured big bankers' or tailors' shears with either of these techniques, because I think they would need a bit of practice. And I don't, at the moment, have any scissors that have buggered-up flats to try them on. But sooner or later I will end up with a pair that needs the techniques, and I intend to try them then. By the way, in the twists of trying to clear up my backlog of email, I only just read Scot's long screed on sharpening scissors. I agree with every word of it, even when it is different from what I wrote. Of course, I agree with myself as well. And I agree with Claudio too. There is an awful lot of room for varying methods in sharpening scissors, as long as you understand the geometry. And never touch the insides of the blades with abrasives. Tom Conroy. Oh, and never cut sandpaper with scissors. But none of use would do that, would we? Sam gets quite heated, by his lights, about a household-tips newspaper column that advised housewives to sharpen their sewing scissors by cutting sandpaper with them. The damage is completely untreatable after a few repetitions. This is about the only damage he seems to give up on. But we wouldn't ever do that. Or touch the insides of the blades with abrasives. No indeed. |
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270915 | Bill Ghio | 2020‑05‑17 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
> On May 17, 2020, at 4:40 AM, Thomas Conroy via OldTools |
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270947 | gary may | 2020‑05‑18 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
Tom Conroy: Wonderful stuff! I keep meaning to ask; 'big banker's shears'? I'm tempted to look it up myself, but where's the fun in that? Thanks for all that you do yr pl gam in OlyWA How horrible it is to have so many people killed!---And what a blessing one cares for none of them! Jane Austen On Sunday, May 17, 2020, 01:40:32 AM PDT, Thomas Conroy |
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270950 | Kirk Eppler | 2020‑05‑18 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
https://archive.org/details/JWissAndSonsCatalog1911/page/n23/mode/2up Big. 18" long big. On Mon, May 18, 2020 at 1:02 PM gary may via OldTools < oldtools@s...> wrote: > Tom Conroy: > Wonderful stuff! I keep meaning to ask; 'big banker's shears'? I'm > tempted to look it up myself, but where's the fun in that? Thanks for all > that you do > > > I wouldn't want to experiment on treasured big bankers' or tailors' shears > with either of these techniques, because I think they would need a bit of > practice. > -- Kirk Eppler in HMB, winding down the last meeting of the day. And trying to keep the brain engaged by doing old tools stuff. |
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270952 | dks <dks@t...> | 2020‑05‑18 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
Strange that they would have been offered over such a wide range of lengths, no? Don ----- Original Message ----- From: "Kirk Eppler via OldTools" |
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270957 | Kirk Eppler | 2020‑05‑19 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
Nah, not really, makes perfect sense. The small town banker didn't need the 18" scissors. But the fat cat banker in NYC, he had the BIG scissors to show how he had made it. I suspect the paper hangers were much more pragmatic. It takes some strength to manipulate those big shears all day long, so the 5'6" tall guy had to work his upper body strength up to be able to use the 18", or he may have had to stop at 15" since the balance probably got to be awkward for his hands, or too big. The big guys could start at a larger size? OK, I've shoveled enough crap in my online meetings, and now it's carrying over to the tool world. Maybe I should go work in the garden instead. KE On Mon, May 18, 2020 at 4:52 PM dks |
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270958 | Bill Ghio | 2020‑05‑19 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
My banker scissors (J.A. Henkels) are 10 inches, which seems quite long. 18 inches, or even 15 inches, would be a lot to handle. But I do love the length of mine for trimming paper nice and straight. Bill, who only has ten pair of vintage scissors spread around the house. |
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270960 | Ed Minch <ruby1638@a...> | 2020‑05‑19 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
> On May 18, 2020, at 8:41 PM, Kirk Eppler via OldTools |
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270971 | Paul Honore <lawnguy44@g...> | 2020‑05‑22 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
Speaking of working with scissors all day, I'd like to see the forearms of the person who worked with these Sailmakers shears(?). 16" long and weigh approx 4 1/2 lbs. Made by T Wilkinson - Sheffield. Note only one side has a point. Is that usual? http://eastconn.com/Scissors/IMG_0431.JPG http://eastconn.com/Scissors/IMG_0433.JPG <http://eastconn.com/Scissors/IMG_0431.JPG> Paul H. Hebron CT |
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270973 | Ed Minch <ruby1638@a...> | 2020‑05‑22 | Re: Scissors---re-establishing the geometry of the flats, in theory. |
I can’t even open my hand that far. Yow. In serious sailing circles, where you may need to use your knife on quick notice, the knife does not have a point - rather sort of a sheepsfoot pattern - Google “sailor knife”. The reason is that you may be in a group and poking your knife towards a flailing sail or a whipping rope may result in someone else getting hurt. When someone asks for help in cutting a rope, you present your knife blade up, waist high, while not moving the blade once in position, and let the requestor pass the rope over the blade. I am thinking something like this, where the scissors may be used on deck with a sail in a pile and fellow crew all around. With symmetrical handles, this would let you pick which blade is hidden under the sailcloth Here is an amazing movie made by Irving Johnson, then a passeger on one of the giant cargo ships the Germans used to train merchant marine sailors after the turn of the last century. Trips between Germany and Chile with no engine in a 360 foot sailboat. In this time of looking-for-something-to-do, the whole movie is worth a look, but check at 12:30 for a minute https://www.youtube.com/watch?v=9tuTKhqWZso I climbed to the top of the mainmast of a sister ship, the Kruzenshtern. Lucky it was tied to a dock, because 196 feet is high enough without moving 30° either side of plumb Ed Minch |
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