Introduction: Rebuilding Grass Shears
My wife has used our grass shears for many years. Finally, the upper cast handle broke near the action. I wanted to see if I could make steel parts to replace the cheap castings. The first photo shows my revised version complete and ready to use.
- 3/4 inch angle iron
- 1/2 inch steel rod
- 3/8 inch steel rod
- 1/4 inch steel rod
- 3/16 inch steel rod
- 3/8 inch bar steel
- 1/4 inch bar steel
- 1/8 inch bar steel
- 1/4 inch machine screws and nuts
- Spring clamps
- Flux core wire feed welder
- Drill press and bits
Step 1: The Lower Handle
I considered replacing only the upper handle with its casting, but realized the surest course would be to make steel substitutes for both the upper and the lower handles.
The first photo shows the lower handle pieces laid up ready to be welded. I chamfered the area where the weld is placed for a really solid weld.
I ground the weld bead flat and flush on both sides. I drilled holes to replicate the original lower handle. One is 3/16 inch in diameter. The other is 1/4 inch in diameter.
Step 2: Begin the Upper Handle Assembly
I used some 3/4 inch angle iron and some 1/8 inch bar stock to begin the upper handle assembly.
I am setting up for the welds with some aluminum angle. I used spring clamps to place a piece of 1/8 x 1/2 inch strap iron vertically and clamped the angle iron to the strap iron to hold it until I could tack weld the angle to the piece of bar stock to which the blades will be attached. After tack welding, I completed the full welds. Space is a premium and the weld beads could get in the way of 1/4 inch screws I will use to attach the blades.
Step 3: Mount the Blades to the Upper Handle Assembly
Grind the heads from all rivets on the old shears. Drive the rivets from their holes. Disassemble the parts.
I clamped the unfinished upper handle assembly to the blade assembly and used a drill to mark the center of the first hole. Then I moved to a drill press for more efficient drilling.
With the first hole drilled, I inserted a 1/4 inch bolt and tightened a nut. Then I marked the center of the second hole and drilled it on a drill press. I inserted a second bolt and tightened a nut on it.
Step 4: Drill for the Lower Handle Axle
The axle for the lower handle is 3/16 inch in diameter. It is helpful to use the old parts as aids for test fitting the parts.
See the second photo. I inserted a 3/16 inch rod through the hole in the upper handle and the lower handle. In the photo the 3/16 inch rod has not been cut yet and it runs vertically from the bottom of the photo.
Step 5: Weld the Upper Handle
I placed a spacer between the angle iron and the 3/8 inch rod for the upper handle. I welded the upper handle above and below the 3/8 inch rod. The view in the photo is from above the handle.
The second graphic shows a Google SketchUp drawing that gives a perspective drawing for the upper handle assembly.
Step 6: Finish
After the parts for the shears were assembled, the shears opened fully, but did not close fully. I had to grind on the face marked in the photo with red. I had to file the bottom of the elongated hole to make it still longer. And, I had to bend both handles a little so they would not come in contact with one another before the blades close fully. When I had done these three things, the blades close fully, and the action is smooth as if new.
I also welded short pieces of rod to the inner side of the handles to keep the return spring in place. See the second photo.
I ground away all sharp and rough spots. I will get some plastic or rubber hose to slip onto the handles for better gripping and reduced chance of slippage in the hands.
The original shears included a feature to lock the blades together. My revised version does not have that feature. I could add something to slip over the blades to hold them together.
There was some personal satisfaction in completing this project. But, it took much more time than it is worth. From the perspective of simple economics, it would have made more sense simply to buy a new grass shears.