This hammer build is going to be with the most basic of tools so those of you that do not have machining equipment can make one and save over $100 vs buying one. The materials should be around $15 max.
I will be using 4140 alloy steel also know as "chrome-moly".
From McMaster-Carr's website:
" Multipurpose 4140/4142 Alloy Steel: Also called chrome-moly steel because of its main alloying elements (chromium and molybdenum), which give it good fatigue, abrasion, and impact resistance. Readily formed and machined in its annealed state and can be heat treated to increase toughness and wear resistance. Material is a good choice for crankshafts, gears, axles, and shafts. "
From the encyclopedia of metallurgy:
"This chromium molybdenum alloy steel is oil hardening steel of relatively high hardening ability and is among the most widely used versatile machinery steels. The chromium content provides good hardness penetration and the molybdenum imparts uniformity of hardness and high strength. This grade is especially suitable for forging as it has self scaling characteristics it responds readily to heat treatment and is comparatively easy to machine in the heat treated condition. In the heat treated condition tensile strengths of 170,000 PSI. for small section and 140,000 PSI for larger section are attended all combined with good ductility and resistance to shock. This steel resists creep in temperature up to 540 o C and maintain its properties even after long exposure at these relatively high working temperatures (think forging). The wear resistance can be considerably increased by flame hardening or induction hardening. A very interesting and powerful surface hardening process could be a combinations of induction hardening with nirtiding obtaining a real improvement of surface.
Typical applications.
Shafts, gears, bolts, couplings, spindles, tool holders, sprockets, hydraulic machinery shafts, oil industry drill collars,Kelly bars, tools joints, so on."
The chunk is 1 1/2" square and 4" long. You can also use 4142, 4340, 1045,1050 or any carbon steel with a .40 carbon content or higher.
The first step is to find the center to start the eye. Make sure the exact center is found and punched for the drill bit.
Using graduated bit sizes start with a center finding bit and work up to a 5/8" hole.
Once the hole is drilled use your handle and trace around it. This will allow you to calculate what size holes to drill to get the oval shape. I will be using a drill hamer handle which is short and thick. It's dimensions are 3/4" x 1".
To get the oval I will drilling two smaller 3/8" holes on each side. To do this I swaged a chunk of 5/8" mild steel into the hole to support the bit. Just use/buy a 5/8" bolt because odds are your local hardware store will not have 5/8" mild round. If they did you would be buying a 3' chunk when all you need is 1 1/2". To get a tight fit hammer it on the side and upset it to thicken it slightly. You want to have to pound it in.
After it's swaged in find the centers on both sides of the 5/8" hole at the seams. Punch two start holes and use a center finding bit to start two holes for drilling. The center finding bit will not flex or chatter while carving between to dis-similar steels.
Using graduated bits, drill both holes to 3/8".
Then drift the 5/8" plug out with a punch.
It's easier to drill then file so we want to remove as much with the drill bit.
The next section will be cleaning out the hole with round and dome files.
I will be using 4140 alloy steel also know as "chrome-moly".
From McMaster-Carr's website:
" Multipurpose 4140/4142 Alloy Steel: Also called chrome-moly steel because of its main alloying elements (chromium and molybdenum), which give it good fatigue, abrasion, and impact resistance. Readily formed and machined in its annealed state and can be heat treated to increase toughness and wear resistance. Material is a good choice for crankshafts, gears, axles, and shafts. "
From the encyclopedia of metallurgy:
"This chromium molybdenum alloy steel is oil hardening steel of relatively high hardening ability and is among the most widely used versatile machinery steels. The chromium content provides good hardness penetration and the molybdenum imparts uniformity of hardness and high strength. This grade is especially suitable for forging as it has self scaling characteristics it responds readily to heat treatment and is comparatively easy to machine in the heat treated condition. In the heat treated condition tensile strengths of 170,000 PSI. for small section and 140,000 PSI for larger section are attended all combined with good ductility and resistance to shock. This steel resists creep in temperature up to 540 o C and maintain its properties even after long exposure at these relatively high working temperatures (think forging). The wear resistance can be considerably increased by flame hardening or induction hardening. A very interesting and powerful surface hardening process could be a combinations of induction hardening with nirtiding obtaining a real improvement of surface.
Typical applications.
Shafts, gears, bolts, couplings, spindles, tool holders, sprockets, hydraulic machinery shafts, oil industry drill collars,Kelly bars, tools joints, so on."
The chunk is 1 1/2" square and 4" long. You can also use 4142, 4340, 1045,1050 or any carbon steel with a .40 carbon content or higher.
The first step is to find the center to start the eye. Make sure the exact center is found and punched for the drill bit.
Using graduated bit sizes start with a center finding bit and work up to a 5/8" hole.
Once the hole is drilled use your handle and trace around it. This will allow you to calculate what size holes to drill to get the oval shape. I will be using a drill hamer handle which is short and thick. It's dimensions are 3/4" x 1".
To get the oval I will drilling two smaller 3/8" holes on each side. To do this I swaged a chunk of 5/8" mild steel into the hole to support the bit. Just use/buy a 5/8" bolt because odds are your local hardware store will not have 5/8" mild round. If they did you would be buying a 3' chunk when all you need is 1 1/2". To get a tight fit hammer it on the side and upset it to thicken it slightly. You want to have to pound it in.
After it's swaged in find the centers on both sides of the 5/8" hole at the seams. Punch two start holes and use a center finding bit to start two holes for drilling. The center finding bit will not flex or chatter while carving between to dis-similar steels.
Using graduated bits, drill both holes to 3/8".
Then drift the 5/8" plug out with a punch.
It's easier to drill then file so we want to remove as much with the drill bit.
The next section will be cleaning out the hole with round and dome files.
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