My rope launcher (pneumatic)

What is the range of Rockwell Hardness on your blades ?

I recently bought a couple carbon steel kitchen knives w/ a higher than "normal" hardness of 65.
They really seem to hold the edge significantly longer.
 
GregManning said:
What is the range of Rockwell Hardness on your blades ?

I recently bought a couple carbon steel kitchen knives w/ a higher than "normal" hardness of 65.
They really seem to hold the edge significantly longer.
Click to expand...

65 seems a bit excessive for anything except maybe hxp, 1095 gets really hard and it's maxim as quenched hardness is 66 if you drop blades that hard they shatter like glass. Mine are right around 61 for both the 15n20 and aebl, for most steels it's the around the optimum hardness for both toughness and edge retention.
 
Vicente said:
65 seems a bit excessive for anything except maybe hxp, 1095 gets really hard and it's maxim as quenched hardness is 66 if you drop blades that hard they shatter like glass. Mine are right around 61 for both the 15n20 and aebl, for most steels it's the around the optimum hardness for both toughness and edge retention.
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Because they are carbon steel, the edge is easy to re-set.

The vender says the edge is 65 RW hardness, while the spine is treated differently to a lower RW for durability.
 
How did you narrow down into your choice of diaphragm valve? That always seems to be the pita component for these air launchers. Hair trigger is where it's at. The archery release does the same for the slingshots.
 
Bart_ said:
How did you narrow down into your choice of diaphragm valve? That always seems to be the pita component for these air launchers. Hair trigger is where it's at. The archery release does the same for the slingshots.
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My first prototype used a ball valve, throwing it Threw off the accuracy. I then decided on a solenoid. It Was Hard to find one rated high enough in psi for only 12 volts for my needs without spending a fortune. I eventually found one on Amazon of all places lol. The trigger is a micro momentary switch. Very little pressure is needed so that’s why I added the safety switch in front of it. So basically it now has a hair trigger.
 
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Vicente said:
@GregManning me to it's one of my favorite general use designs knives with straighter edges generally do better at most utilitarian tasks imo.

@Whisper the top one is 15n20 high carbon steel the bottom 2 are aebl hc stainless, and yes I need to clean up my shop pretty badly, I need to build a secon shed to store stuff in my shop is to small to hold all my tools and work in very easily.

@LBF you can get into blacksmithing really cheap if you just want to start out making little stuff.
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At least around here people seem to want stupid money for anvils. I’d like a decent sized anvil and forge, but probably half of what I’d do with it all would be forging parts for my projects. Re bend a control arm or bend some 1/4” plate for a mount or something. Stop using a torch and welder with a big hammer so much for that stuff. The rest would be the fun stuff, lol
 
Whisper said:
D3699853-F916-44F1-BA1C-37FD80A24C37.jpeg
My first prototype used a ball valve, throwing it Threw off the accuracy. I then decided on a solenoid. It Was Hard to find one rated high enough in psi for only 12 volts for my needs without spending a fortune. I eventually found one on Amazon of all places lol. The trigger is a micro momentary switch. Very little pressure is needed so that’s why I added the safety switch in front of it. So basically it now has a hair trigger.
Click to expand...
 
Modified sprinkler valves do a very good job using a blow gun to release pressure. Not quite a hair trigger, but it doesn't take much to release. You don't risk moving the whole apparatus squeezing the trigger. I'm not sure you are going to make 1" groupings with any throw weight launcher.

I imagine solenoid would be better...but then you need power to it.
 
ATH said:
Modified sprinkler valves do a very good job using a blow gun to release pressure. Not quite a hair trigger, but it doesn't take much to release. You don't risk moving the whole apparatus squeezing the trigger. I'm not sure you are going to make 1" groupings with any throw weight launcher.

I imagine solenoid would be better...but then you need power to it.
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I thought of doing that but i also dabble in robotics so the electrical component of the project was a natural fit. You are correct though this ain’t a sniper rife so tight grouping’s are out. :)
 
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p/n or spec on the solenoid? I have a bit of history with pneumatics and robotics. Ever supercharge a magnetic circuit after assembly Billy? -scene from cockpit in Airplane movie - :) Watch the inductive rating on the switch contacts. Maybe tag on a good ol' fashioned condenser. Tuned LC baby! High tech! You'll have to retro to the 60's to research that one... :)
 
No meaningful specs on Solinoid. That’s what you get out of China these days. No data sheets available. Its 1Mpa 12v. I Have a void in handle under grip for additional electronics if required. If I could’ve thought of the purpose for a Leonardo (Arduino) I would’ve put one there. Yeah I’ll keep my eye on induction. :). I was born in 62 so I get all (read : most) of the old time references.
 
Bart_ said:
p/n or spec on the solenoid? I have a bit of history with pneumatics and robotics. Ever supercharge a magnetic circuit after assembly Billy? -scene from cockpit in Airplane movie - :) Watch the inductive rating on the switch contacts. Maybe tag on a good ol' fashioned condenser. Tuned LC baby! High tech! You'll have to retro to the 60's to research that one... :)
Click to expand...
Sobrobotics and hydraulics huh? I guess that means you could make a pretty cool automated log splitter/sorter. I’m actually looking at getting a log splitter and I’m already thinking about how I can hack it.
 
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Whisper said:
145 psi (1 Mpa) rated solenoid, green laser, 1 inch barrel and 1 1/2 inch barrel. Assorted 3-D printed parts. Three 16850 batteries 12v. Safety switch momentary launch trigger.
This was a winter project. I also make my own plastic throw weights with the 3-D printer. I’m designing a needle shaped BB filled weight. Printing as we speak should be done in four hours.
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Here’s the 3D printed throw weight. https://www.treebuzz.com/forum/threads/3d-printed-throw-weights.46936/
 
Vicente said:
I do to I just don't really like to tinker with work related stuff at home even though I really like what I do I just don't feel life coming home and doing more of it. It's been a while since I gotten a blade out of the shop but here's my current tinkering project.
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Sweet! I am saving all my worn out chipper knives and manual saw blades for stock to make knives, hatchets and axes. No point in tossing out good steel. I tried making a knife from a hold hand pruner blade but burnt it up in the process..
 
evo said:
Sweet! I am saving all my worn out chipper knives and manual saw blades for stock to make knives, hatchets and axes. No point in tossing out good steel. I tried making a knife from a hold hand pruner blade but burnt it up in the process..
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Ha, and now I read though to see we are back on topic... Too bad
 
If I recall its either orifice size rough equivalent or usually CFM at 100 psi or other specified pressure drop dry air.

One time I reviewed a phd thesis where the simple Gsuit and positive pressure breathing spring/ball valve was possibly to be replaced by a motorized ball valve or throttle-like valve, I can't remember, and what struck me was trying for a high flow spec with very low pressures and pressure drops. Point being ya gotta port and flow bench your engine, I mean apta valve for the most horsepower. But make it too big and you'll lose torque. Well, not really, but at a certain point you won't be gaining much more. I think I've encountered valve overlap, in a sense. :)
 
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