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The One-Piece Sheet Can Opener: Point and Blade Struck From the Blank
Mary

Created by

Mary

6. October 2026FI
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The One-Piece Sheet Can Opener: Point and Blade Struck From the Blank

Can openers with several parts cost more to make and can get out of order. Charles F. Ritchel of Chicago received US 77,916, dated 12 May 1868, for "a cheap and substantial can-opener, not liable to get out of order": one piece of sheet metal, struck out by a die, with a point driven into the can as the fulcrum and a triangular blade, both turned off the blank, and the handle's edges bent down for grip and strength. This rung works out how many come from one sheet, then cuts and bends one from mild steel sheet and opens a can with it.
Beginner
About 2 hours

Instructions

1

Openers per sheet

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2

A one-piece opener before it

The embedded blueprint makes blade, fulcrum and handle in one piece of bar. Ritchel strikes a point and a blade out of one flat sheet blank.
3

Read US 77,916

"The operation of the opener consists in this, that the tool, being held in a vertical position, the point D is forced into the can, and the handle A is brought down, and the fulcrum for the operation of the handle being thus obtained, the blade E is forced into the can also, and the handle B is turned around with one hand, while the can is firmly held with the other hand, the blade E thus cutting a round opening in the can."
4

Cut the blank

Mark a blank 160 mm long on 1 mm mild steel sheet: a 24 mm handle, narrowing to 16 mm for the head. Inside the head mark a 6 mm tab at the end for the point and a 14 mm triangle 20 mm behind it for the blade. Cut with snips.

Materials for this step:

Mild Steel SheetMild Steel Sheet1 piece

Tools needed:

Tin SnipsTin Snips
Permanent MarkerPermanent Marker
RulerRuler
Leather Work GlovesLeather Work Gloves
5

Turn off the point and blade

Snip the triangle free on two sides. Bend the tab and the triangle down at right angles with the pliers.

Tools needed:

Tin SnipsTin Snips
Flat-Nose PliersFlat-Nose Pliers
6

Edge and stiffen

File the point sharp and the blade's leading edge to a bevel. Bend the handle's edges down 5 mm in the vice.

Tools needed:

Files (Hand File)Files (Hand File)
WhetstoneWhetstone
Bench ViseBench Vise
HammerHammer
Clear Safety GlassesClear Safety Glasses
7

The patent drawing

US 77,916 drawing sheet, public domain (expired patent).
Step 7 - Image 1
8

Open a can

Stand a sealed can on the kitchen scale. Drive the point in, bring the handle down so the blade enters, and turn it round; read the peak load and time a full circle.
Step 8 - Image 1

Materials for this step:

Tin CanTin Can1 piece

Tools needed:

Digital Kitchen ScaleDigital Kitchen Scale
StopwatchStopwatch
Leather Work GlovesLeather Work Gloves
9

An opener that folds, slips or tears

One-piece sheet can opener troubleshooting.

Flow

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10

History and honest limits

**Charles F. Ritchel** of Chicago received US 77,916, dated 12 May 1868. Opener and handle are joined by a slight curve for easier handling; the point is bent down or slightly curved to the front; point and blade are struck out by a die, turned off and trimmed, and steel-hardened if desirable, so the price becomes very low. His claim covers the one-piece opener with point and blade. **Honest limits.** Snips and pliers stand in for his die, and the sheet is not hardened. Your loads and times are the result.

Materials

2

Tools Required

12

CC0 Public Domain

This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.

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