5 ms·

This would be a lot more interesting if it could cut steel and titanium. I guess that is more difficult. Added: a dumb question, if the main cutting device is

This would be a lot more interesting if it could cut steel and titanium. I guess that is more difficult. Added: a dumb question, if the main cutting device is a router with a spinning bit, how do you cut angles? One thing I'd like to make is a 4mm hexagonal hole in a piece of steel, to turn little hex drive screwdriver bits and the like. Is it even possible to make that with a mill, or do you need a different machine?

aaronblohowiak 2y ago
Steel is sooooooooooooo much harder than al, it’s not even in the same ballpark. Aluminum is about as hard to cut as wood. For non round holes, you are looking at approximations or broaching. Look up manual hex broaching
Animats 2y ago
That's usually done with something called a rotary broach.[1] This is a clever trick. You first make a round hole. The rotary broach is a hex-shaped cutting tool. Both workpiece and tool are clamped in a lathe. But the center of the tool is slightly offset from the rotational center of the workpiece. Both spin, but the eccentricity makes it cut a hexagonal hole. Here's the process.[1] A milling machine can cut a hexagonal hole, but the inside radius at each corner cannot be smaller than the radius of the cutter. A 4mm hex hole would require a tiny cutter to do a good job. Here's that process for a larger hole.[2] If the hole goes all the way through, just get a hexagonal punch. Might need to drill a round hole first. Or just buy a 4mm socket with a T-handle. Cost US$4.99.[3] [1] https://www.youtube.com/watch?v=_AYEFjbGaL4 https://www.youtube.com/watch?v=_AYEFjbGaL4 [2] https://www.youtube.com/watch?v=zOqSIRuBgCY https://www.youtube.com/watch?v=zOqSIRuBgCY [3] https://www.amainhobbies.com/rc4wd-metric-hex-twrench-tool-4.0mm-rc4zf0031/p667266 https://www.amainhobbies.com/rc4wd-metric-hex-twrench-tool-4...
- throwaway81523 2y ago
  Thanks, yeah, a separate 4mm socket with a handle is certainly a possibility, but I liked the idea of a 4mm hex hole in something like this, to accompany the holes that are already there: https://knifeworks.com/crkt-9100kc-eatn-tool-black-oxide-finish/ https://knifeworks.com/crkt-9100kc-eatn-tool-black-oxide-fin... I'll look at the rotary broach video. Yes the hole would go all the way through, so a punch sounds ok. Anyway it's not about making this one hole. It's more an example of the kind of stuff I'd like to do with metalworking gear if I had access to it and knew how to use it. It does sound like hard materials are an obstacle as well. Aluminum is a start though.
  - Animats 2y ago
    Ah. Here's the tool for that job - a Roper-Whitney hand punch.[1] This is like a hand paper punch, but stronger. Costs $85. Made in USA. With a punch and die, you get clean edges on the hole on the exit side. Scroll down for how to order the specific punch and die you need. Hex punches are not common, but are available. If you fill out their form, and tell them you need to punch 3CR13 stainless, they'll tell you what to order. Might need something with more leverage than the small hand punch. Lubrication helps. Most machine shops will have such a punch, but they won't have a 4mm hex die in stock. Or you could drill an undersized round hole and file it out to a hex hole. Maybe use the existing round carabiner hole. There are touch-up kits for guns, called "gun bluing", to make your shiny new hole black. This is all do-able but way more trouble than it is worth. [1] https://www.roperwhitney.com/our-products/no-5-jr-hand-punch/ https://www.roperwhitney.com/our-products/no-5-jr-hand-punch...
  - throwaway81523 2y ago
    Cool, thanks, yeah for a single hole, doing it by hand with a needle file sounds more practical. Does something like this seem CNC-able? https://sakparts.com/products/can-opener-diy-tool-part-for-84mm-91mm-111mm-victorinox-swiss-army-sak-knife https://sakparts.com/products/can-opener-diy-tool-part-for-8... The idea isn't to duplicate an existing can opener, but rather to make custom specialized tools to fit into a SAK, or replacement knife blades out of specialty knife steels (i.e. very hard, so probably difficult to machine). It wouldn't just be for SAK's but also for other folding knives, each with its own special cutting pattern to work with its pivot and locking system. Titanium is another material of interest, for ultralight gear. All of this is probably impractical at the hobbyist level with limited work space, though. Oh well.
    - Animats 2y ago
      DIY knife forging is common. Search "knife forging". Look around for classes and forges with training. There's a huge amount of info on knife making and metallurgy. People obsess on this stuff. A good knife is a trick of metallurgy. The blade must be hard at the edge to be sharp but ductile in the body so as not to be brittle. How to do this is well understood today, but there was much mystery around it for centuries. If you're fascinated by metalworking, but don't have to make machine parts, that's a hobby direction. Victorinox knife manufacture.[1] Stamp, heat treat, grind, polish. They're not exotic blades, just good manufactured stainless steel parts. A primer on machining titanium.[2] [1] https://www.popularmechanics.com/adventure/outdoor-gear/a35130112/made-here-swiss-army-knife/ https://www.popularmechanics.com/adventure/outdoor-gear/a351... [2] https://www.harveyperformance.com/in-the-loupe/titanium-machining/ https://www.harveyperformance.com/in-the-loupe/titanium-mach...

aaronblohowiak 2y ago

Steel is sooooooooooooo much harder than al, it’s not even in the same ballpark. Aluminum is about as hard to cut as wood. For non round holes, you are looking at approximations or broaching. Look up manual hex broaching

Animats 2y ago

That's usually done with something called a rotary broach.[1] This is a clever trick. You first make a round hole. The rotary broach is a hex-shaped cutting tool. Both workpiece and tool are clamped in a lathe. But the center of the tool is slightly offset from the rotational center of the workpiece. Both spin, but the eccentricity makes it cut a hexagonal hole. Here's the process.[1] A milling machine can cut a hexagonal hole, but the inside radius at each corner cannot be smaller than the radius of the cutter. A 4mm hex hole would require a tiny cutter to do a good job. Here's that process for a larger hole.[2] If the hole goes all the way through, just get a hexagonal punch. Might need to drill a round hole first. Or just buy a 4mm socket with a T-handle. Cost US$4.99.[3] [1] https://www.youtube.com/watch?v=_AYEFjbGaL4 https://www.youtube.com/watch?v=_AYEFjbGaL4 [2] https://www.youtube.com/watch?v=zOqSIRuBgCY https://www.youtube.com/watch?v=zOqSIRuBgCY [3] https://www.amainhobbies.com/rc4wd-metric-hex-twrench-tool-4.0mm-rc4zf0031/p667266 https://www.amainhobbies.com/rc4wd-metric-hex-twrench-tool-4...

throwaway81523 2y ago
Thanks, yeah, a separate 4mm socket with a handle is certainly a possibility, but I liked the idea of a 4mm hex hole in something like this, to accompany the holes that are already there: https://knifeworks.com/crkt-9100kc-eatn-tool-black-oxide-finish/ https://knifeworks.com/crkt-9100kc-eatn-tool-black-oxide-fin... I'll look at the rotary broach video. Yes the hole would go all the way through, so a punch sounds ok. Anyway it's not about making this one hole. It's more an example of the kind of stuff I'd like to do with metalworking gear if I had access to it and knew how to use it. It does sound like hard materials are an obstacle as well. Aluminum is a start though.
- Animats 2y ago
  Ah. Here's the tool for that job - a Roper-Whitney hand punch.[1] This is like a hand paper punch, but stronger. Costs $85. Made in USA. With a punch and die, you get clean edges on the hole on the exit side. Scroll down for how to order the specific punch and die you need. Hex punches are not common, but are available. If you fill out their form, and tell them you need to punch 3CR13 stainless, they'll tell you what to order. Might need something with more leverage than the small hand punch. Lubrication helps. Most machine shops will have such a punch, but they won't have a 4mm hex die in stock. Or you could drill an undersized round hole and file it out to a hex hole. Maybe use the existing round carabiner hole. There are touch-up kits for guns, called "gun bluing", to make your shiny new hole black. This is all do-able but way more trouble than it is worth. [1] https://www.roperwhitney.com/our-products/no-5-jr-hand-punch/ https://www.roperwhitney.com/our-products/no-5-jr-hand-punch...
- throwaway81523 2y ago
  Cool, thanks, yeah for a single hole, doing it by hand with a needle file sounds more practical. Does something like this seem CNC-able? https://sakparts.com/products/can-opener-diy-tool-part-for-84mm-91mm-111mm-victorinox-swiss-army-sak-knife https://sakparts.com/products/can-opener-diy-tool-part-for-8... The idea isn't to duplicate an existing can opener, but rather to make custom specialized tools to fit into a SAK, or replacement knife blades out of specialty knife steels (i.e. very hard, so probably difficult to machine). It wouldn't just be for SAK's but also for other folding knives, each with its own special cutting pattern to work with its pivot and locking system. Titanium is another material of interest, for ultralight gear. All of this is probably impractical at the hobbyist level with limited work space, though. Oh well.
  - Animats 2y ago
    DIY knife forging is common. Search "knife forging". Look around for classes and forges with training. There's a huge amount of info on knife making and metallurgy. People obsess on this stuff. A good knife is a trick of metallurgy. The blade must be hard at the edge to be sharp but ductile in the body so as not to be brittle. How to do this is well understood today, but there was much mystery around it for centuries. If you're fascinated by metalworking, but don't have to make machine parts, that's a hobby direction. Victorinox knife manufacture.[1] Stamp, heat treat, grind, polish. They're not exotic blades, just good manufactured stainless steel parts. A primer on machining titanium.[2] [1] https://www.popularmechanics.com/adventure/outdoor-gear/a35130112/made-here-swiss-army-knife/ https://www.popularmechanics.com/adventure/outdoor-gear/a351... [2] https://www.harveyperformance.com/in-the-loupe/titanium-machining/ https://www.harveyperformance.com/in-the-loupe/titanium-mach...