Slightly off topic, interesting project/situation.......

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
High-PSI
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Tue May 08, 2012 3:44 pm

Hey Guys,

A friend of mine is CEO of an air nailer company. He and I began talking about his nailers. I asked him questions regarding trigger air useage, tank to cylinder ratio, etc. He had no clue. So, as the conversation wore on, I asked if he would like me to research his nailers to see if I can find some added efficiency for him. This is important because if efficiency can be increased 33%, one compressor could go from running 3 nailers, to 4. Or, it would run far less to keep up with the nailers being used. Theoretically, the nailer could also be made smaller and lighter.

Anyway, I am not sure if I can post pictures of the insides of these as I mod them. But, I wanted your input on this.

Here are a few things I am going to experiment with;

#1 A shutoff valve that will only allow a metered amount of air into the gun with each shot, rather than the line always open to the gun. There are various reasons I want to try this.

#2 Reduce the tank volume and see how much (if any) power is lost in doing so. This could be an extremely easy way to increase efficiency.

#3 Reduce the air consumption of the trigger mechanism, or find a way to recycle that air into the nailer, rather than exhausting it straight out as a total loss.

#4 Mess around with the bore of the nailer. This is a bit tougher as I would have to machine a new piston and cylinder. But, it is worth a try.


Oh, lastly, these nailers are designed for multiple length nails. However, the stroke of the nailer is not adjsuted for this. A 1 inch nail still uses all 2 inches of the piston stroke. That is very wasteful. This is something that is much tougher to address, though.

If you guys have any input, I would appreciate it.

Matt
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Tue May 08, 2012 4:49 pm

For the piston stroke problem, try a small needle valve of some sort to restrict air flow, and prevent it from going a certain distance.

#3, easy solution, just have it vent into the piston on the forward stroke.

All I can really input right now, I haven't taken a nailer apart yet.
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Technician1002
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Tue May 08, 2012 11:14 pm

This falls under the catagory of "Don't try this at home"
[youtube][/youtube]

Hint; the trick is safe. Don't use a stock nailgun.

Ontopic, don't use a needle valve to "restrict flow" to save air. The restriction is a huge power waster. A metered chamber, possibly variable displacement, with unrestricted valving can provide high energy conservation and use less air for the same power.
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Tue May 08, 2012 11:47 pm

High-PSI wrote:#1 A shutoff valve that will only allow a metered amount of air into the gun with each shot, rather than the line always open to the gun. There are various reasons I want to try this.
Don't nailers already have a three-way valve which shuts off flow from the air line when the trigger valve is pulled?
#2 Reduce the tank volume and see how much (if any) power is lost in doing so. This could be an extremely easy way to increase efficiency.
Smaller chamber -> greater pressure drop -> less power, it's unavoidable.
#3 Reduce the air consumption of the trigger mechanism, or find a way to recycle that air into the nailer, rather than exhausting it straight out as a total loss.
A nailer has an exhaust valve, and as such the pilot volume is always wasted, however it represents a small percentage of the total air used per shot. Still. Or go valveless :D
#4 Mess around with the bore of the nailer. This is a bit tougher as I would have to machine a new piston and cylinder. But, it is worth a try.
I don't think "messing around" will cut it, you need to know what the industry standards for nail depth in a given material is etc. , that means quite a bit of rigorous scientific testing.
Oh, lastly, these nailers are designed for multiple length nails. However, the stroke of the nailer is not adjsuted for this. A 1 inch nail still uses all 2 inches of the piston stroke. That is very wasteful. This is something that is much tougher to address, though.
Limiting piston stroke won't affect efficiency. What is certain is that a 1 inch nail needs less force to be driven into a given material than a 2 inch nail, so...

Image

... set your regulator to lower pressure :D
If you guys have any input, I would appreciate it.


To be honest, I'm not very much in agreement with this spirit of this thread. What this amounts to is consultancy, which is far from being gratis in the real world. One would hope that if you did make a couple of bucks out of it, some of them would go towards the upkeep of this forum :)
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POLAND_SPUD
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Wed May 09, 2012 7:47 am

Anyway, I am not sure if I can post pictures of the insides of these as I mod them. But, I wanted your input on this.

Here are a few things I am going to experiment with;
None of these make sense. Don't you think it's a bit naive to assume that over the last 50 yrs or so no one tried to improve efficiency of nailguns ??

Want to improve efficiency ? design the internals in a way that would present least obstruction to the airflow (but that won't help much).

EDIT
spelling corrected (bc I don't want that wanker to comment on it again)
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Wed May 09, 2012 9:57 am

Technician1002 wrote:This falls under the catagory of "Don't try this at home"
[youtube][/youtube]

Hint; the trick is safe. Don't use a stock nailgun.

Ontopic, don't use a needle valve to "restrict flow" to save air. The restriction is a huge power waster. A metered chamber, possibly variable displacement, with unrestricted valving can provide high energy conservation and use less air for the same power.
. This is off topic but he really wasnt counting anything in the video. Anyone who has used a nail gun knows you have to put a certain amount of force on the object your nailing with the gun, every time he put the gun to his hand he was just pulling the trigger on the gun and not putting force to his hand making this a so called safe trick. Sorry if I spoiled the fun for ya!!
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Technician1002
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Wed May 09, 2012 10:03 am

^^^ Nice guess.. Not correct. Hint. Count the number of nails a strip holds and count the number of shots.. A nail gun safety prevents event the piston from operating. It locks the trigger. Obviously that one is defeated so it will cycle even into nothing.
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Wed May 09, 2012 10:19 am

now isn't it surprising that the air compressor hasn't really turned on and off even once ?? :D
Also I noticed that there is something rather surprising about the nails - ie. I can't see any recoil and they are not perpendicular to the board even if the nailgun was almost perfect when it (suposedly) fired

my guess the nail gun doesn't really shoot nails - the nails are already in the table
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Wed May 09, 2012 10:30 am

I use a nail gun just about every day, my answer is not a guess and it is also correct, as for the compressor, its a big one, and the power was probably turned off so the compressor wouldnt turn on. However your theory Tech is also a possibility!
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Wed May 09, 2012 10:56 am

POLAND_SPUD wrote:None of these make sense. Don't you think it's a bit naive to assume that over the last 50 yrs or so no one tried to improve efficiency of nailguns ?
It's also a bit naive to say that nail guns have reached the peak of their development and can't possibly be improved.

Manufacture is always a compromise. If you're building a custom one-off with a limitless budget, you can make a brilliant nail gun, but not one you can mass produce and sell at a reasonable price.
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Wed May 09, 2012 11:21 am

Manufacture is always a compromise. If you're building a custom one-off with a limitless budget, you can make a brilliant nail gun, but not one you can mass produce and sell at a reasonable price
almost as if I hadn't known that :D


If some manufacturer could produce a noticeably more efficient design for the price of a typical nailgun their company would dominate the market
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High-PSI
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Wed May 09, 2012 12:44 pm

jackssmirkingrevenge wrote:
POLAND_SPUD wrote:None of these make sense. Don't you think it's a bit naive to assume that over the last 50 yrs or so no one tried to improve efficiency of nailguns ?
It's also a bit naive to say that nail guns have reached the peak of their development and can't possibly be improved.

Manufacture is always a compromise. If you're building a custom one-off with a limitless budget, you can make a brilliant nail gun, but not one you can mass produce and sell at a reasonable price.
I completely agree! Anything can be improved.

Your comment about piston travel that was posted earlier, is incorrect, however. If the stroke could be limited, you would use 1/2 the volume of air to drive the 1 inch nail versus the 2 inch nail. You still would need a decent amount of pressure, but 1/2 the volume overall.

Also, no, these guns do not have a shutoff valve to meter the air going into the gun. The chamber is always open to the line.

Remember, I am completely open to the fact that these guns may be refined beyond my ability to improve them. But, it is fun trying to find out. Besides, I think it would be cool to make a completely custom setup for my own use. I am ordering a paintball tank and reg for my 1/2 inch gun anyway. So, I think I will set this up to run off the paintball tank for testing also. What the heck, it will not cost me anything additional.

Oh, I am thinking about building a super custom nailer using solenoid valves for trigger, and metering, just for fun. :D

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Wed May 09, 2012 5:20 pm

There is no 'best' design, as stated above. It's easy to make a nailgun which uses the air in its chamber very efficiently; just use a small chamber with the biggest, heaviest piston you can get and a high-flow valve.

Unfortunately this might not be practical in terms of power. The only solution to making an ideally efficient gun is to let the user set it for what they need. E.g, make a chamber with variable volume @ whatever pressure is available.
If you're only going to be working with soft pine you set the chamber to a very low volume, with hardwoods you could just dial it up until you get reliable penetration.


For the most efficient valve, I'd go with a QDV design, but make the piston open forward to use as your nail driver. I can see a nailgun built around a QDV using a couple moving parts if you're clever about it. A slide valve to isolate the air input could even be integrated into the QDV piston.
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Wed May 09, 2012 9:56 pm

Spoiler.. Highlight to reveal the trick.

The nailgun does not ever fire nails. They are in the board already. The magnet on the nailer lifts them. This is why the trick is safe. It will never shoot a nail. This is why you never get to see the top of the board. The air is for noise only. They slid the board on the metal.. They could not lift it without revealing the nails in the board already. The steel plate hides the down nails from view. The nails are not over the steel plate. They let you assume it is over the plate.
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Thu May 10, 2012 1:24 am

High-PSI wrote:Your comment about piston travel that was posted earlier, is incorrect, however. If the stroke could be limited, you would use 1/2 the volume of air to drive the 1 inch nail versus the 2 inch nail. You still would need a decent amount of pressure, but 1/2 the volume overall.
Disagree.

When you pull the trigger, the chamber volume is dumped. Whether the piston travels one inch or two inches, the chamber is still dumped, so limiting the stroke does not save air.

Check out this funky animation from howstuffworks:

http://static.howstuffworks.com/flash/n ... umatic.swf
Also, no, these guns do not have a shutoff valve to meter the air going into the gun. The chamber is always open to the line.
Also disagree. Keep the trigger pressed and no more air will escape.
Remember, I am completely open to the fact that these guns may be refined beyond my ability to improve them. But, it is fun trying to find out. Besides, I think it would be cool to make a completely custom setup for my own use. I am ordering a paintball tank and reg for my 1/2 inch gun anyway. So, I think I will set this up to run off the paintball tank for testing also. What the heck, it will not cost me anything additional.

Oh, I am thinking about building a super custom nailer using solenoid valves for trigger, and metering, just for fun. :D


This design I posted recently would make a pretty good nailgun with some slight modifications :D imagine one belt fed with pneumatic cartridges...
For the most efficient valve, I'd go with a QDV design, but make the piston open forward to use as your nail driver. I can see a nailgun built around a QDV using a couple moving parts if you're clever about it. A slide valve to isolate the air input could even be integrated into the QDV piston.
Those are some valuable pearls of wisdom from our resident philosoraptor.
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