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Forging scissors - photos of my current process


Jeff Amundson

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First I fuller vertically to divide the blade from the shank. The tooling is mounted in a treadle hammer. The steel is 1018 CRS, 516" X 5/8". 

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Next I weld the cutting edge - 1075, 5/32" x 5/16". It took me a while to get used to putting the cutting edge on top like this. It looks wrong if you're thinking knives. 

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The weld is blended in and forged back to the original dimensions. This is a combination of hand forging and power hammer.

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The shank is drawn out square.

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The horizontal fuller is the tricky one. It provides a thickness target for subsequent forging and grinding. It also provides some clearance in the pivot area. I have to eyeball its location relative to the first fuller. This is on the treadle hammer again. I have to take it slowly, because the little humps sticking out the sides of the bar get real big if I don't correct it often. 

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Next I draw the blades out to uniform thickness. This is done on the flat dies of a power hammer, taking little bites at a time so the blade grows in length but not much in width. There's plenty of hand forging to keep the cutting edge straight. As I approach the final thickness, I focus on flat and straight. It makes for easier grinding. 

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The last forging will be to draw out the shanks and bows.

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You want complete? I thought I  could let people imagine their own bows. Actually, it was lunch time. I can finish the hot work to be true to the post's title. I've got about 1 1/2 hours into this, with many more to go.  The grinding, finishing, and assembly work don't belong in this thread. Thanks for the compliment. 

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Here's the rest of the hot work on these scissors. At this point the shanks and bows can take many different shapes. I've been designing shapes that are usable as-forged, because I don't like the grinding and polishing that's required on the inside surfaces of the bows. This design uses a very long taper, mostly round, that gets wrapped around a mandrel to form the bows, like this post.

 

 

I use drawing dies on a power hammer as much as I can, but these small pieces go wonky easily, so I spend plenty of time on the anvil. When I'm rounding everything, I have to remind myself it's what I do instead of grinding. 

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Pivot holes are next. I use a laser to help align the blades to the centerline. I drill one side, then transfer punch to drill the second. One hole is tapped, one is reamed. You can see that the blades are different lengths. That's because I forge them to thickness, not length. I align the shoulders of the shanks, not the ends of the blades, before I drill. 

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The shanks are formed. Everything needs a tool. 

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This is the fixture for shaping the bows. The oval mandrel is adjustable left and right. The mandrel is replaceable with a different shape or size. For this design the center of the mandrel is offset 3/4" from the centerline. I use an o/a torch to do the wrap.

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The laser helps me keep track of the centerline in space.

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This pair has asymmetric bows. The thumb bow is moved 1/4" closer to the pivot to better match the anatomy of the hand. These are ready for a pickle before grinding.

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What do you use for the pickle solution Jeff?

"The way we win matters" (Ender Wiggins) Orson Scott Card

 

Nos qui libertate donati nescimus quid constat

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Here's how I currently grind scissors. It's based on my understanding of how scissors are supposed to work and the tools available to me in my shop. 

 

I do most of my grinding freehand on a 2x72 using both platen and contact wheels. I grind the inside faces flat on the platen. Then I add a hollow grind to those faces with an 8" contact wheel. I use the same wheel to grind the primary and secondary bevels on the outside face. After grinding, I sharpen the edge using diamond stones. The stones are pretty demanding when it comes to flat and straight.

 

I don't grind much before the heat treat. I do grind the blade ends even, the inside faces flat, and I start the primary bevel. I leave the profile grinding for later, because the hollow grind gets difficult if the tips are pointed. 

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I use an electric oven to normalize, austenize, and temper the 1075. I quench in Parks 50. I get very little warpage. 

 

After heat treat, all grinding is done to 320 grit, which seems to be fine enough for the rust blue finish I use. I start on the platen to get the inside faces flat. I also grind the cutting edge straight. More on why the edge needs to be straight later.

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Switching to the 8" wheel, I grind the primary bevel on the outside face. This bevel is mostly for weight reduction and cosmetics. I aim for a thickness under 1/16" at the edge.

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The hollow on the inside provides clearance for the cutting edges. The hollow extends from the tip to the pivot hole. What remains of the flat face is referred to as the ride line - where the blades contact each other running the length of the cutting edge and wrapping around the pivot hole. 

 

This hollow grind is why my scissors have straight edges. My blades have straight edges because I don't know how to grind a curved hollow with the tools in my shop.

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This is the tooling I designed to help me improve the secondary bevel grind. I borrowed the idea of the guide rod from the sharpening system I use. It is set to grind 35* off 90. Said another way, it's a 55* included angle on the blade.

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Finally the profile is done. The next steps are to sharpen the edge, make the screw, blue everything, and do the final assembly. 

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I had to modify the sharpener so the angle I want is in the middle of its adjustment range.

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Sharp blades with a screw. The blades are still flat.

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The screw is really an adjustable rivet. Locking the final adjustment is still an adventure for me. Peening the end of the screw without changing the adjustment or damaging the screw head is a challenge.

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It looks crude, but this is the only tool I need for adding a curve to the blades. I start at the tip and work my way back as necessary. The blades are mostly mild steel, so it doesn't take much force. 

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After adding the curve, the points cross slightly. These blades are about half open.

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When closed, the blades touch at the tips only. The thin white line is the gap between the blades. 

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Cutting paper is easy, so I test using flimsy produce bags from the grocery store instead. I get a smooth cut all the way to the tip.

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1 hour ago, Alan Longmire said:

The pin is now in.

Thanks, Alan. I hope this helps others the way this forum has helped me. I expect I'll look back at this thread with a tinge of embarrassment, but I hope the pin marks the starting point for others. 

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