# Pneumatic staple gun misfires



## ship

Pneumatic Medium Crown Gun set up for the normal other than "slam fire" mode. Since it was new, it has always double and at times tripple fired given a PSI of about 110 to 120 PSI. Have to be really careful in pressing the trigger for it not to do so. Often the extra staples either don't go in all the way or jam the tool.

What's the perspective causes to this and solutions? Say a Senco medium crown staple gun - thats a decent brand one would think.

Note other guns don't seem to have problems with this pressure but it's the only one of this type that's new and or of this size given the others are firing narrow crown or finish nails and brads. System pressure is also good given a huge tank & lots of 1" tubing between the tank and minimum of 3/8" hose. Granted there is long runs but at theoretical volume sized tubing and little to no other use of the air while using the tool.


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## Footer

The last senco gun I used that double fired (and put a staple through my finger, that was a ton of fun...) the cause was a faulty spring in the trigger mechanism. The trigger would not reset and it would fire twice on one pull.


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## Radman

Only experience I have with pneumatic crown nailers firing inappropriately is when my coworker / good buddy was using one as a weapon against me. Not cool. Do not try at home kids. Those suckers can really fly.


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## Van

110PSI ! That's about 20-30 PSI too High!

< that ryhmes if tyou say it in greek, you know PSI= "Sigh"> < Obvisously I've gotten sleep recently> 

A. Turn down the pressure to about 80 - 90 Max. 
usally a double firing gun is doing so beacause the safety is being tripped by the excessive force of the return due to over pressurization, and worn out springs. I gather you've got it set to "semi-automatic" Ie. theoretically you need to lift and reposistion between each trigger squeeze to make it fire. As opposed to "Full Auto" where you can pull the trigger as many times as you want and it just keeps firing or where you you simply hold the trigger down and tap the gun down wherever you want a staple. 

Most likely this gun is in need of a trip to the repair shop. In addition the the springs or saftey mechanisms needing to be looked at, it probably will need a piston rebuild kit as well. As far as the additional staples jamming, typically when a gun double fires the second shot goes right on top of the first, the gun is trying to dive a staple though a staple, that's not easy to do. The extra force has got to go somewhere so typically the second staple buckles slightly while still in the throat of the gun over time this will cause the throat to open wider and wider, the wider the throat the more likely the gun will try to shove 1 1/2 - 2 staples out at the same time, more jams more bending, and cycle repeats. Operating Pnuematics at that high of pressure can severely damage the piston, rings, diaphragm........ 

Oh and Vans other big pet peave. Check the gun ! Most Pnuematics need 2 drops of oil placed in the air inlet before each use. However if there is a "no oil " symbol on it do not under any circumstances place oil in it. 

Hope that helps a little.


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## ship

Radman said:


> Only experience I have with pneumatic crown nailers firing inappropriately is when my coworker / good buddy was using one as a weapon against me. Not cool. Do not try at home kids. Those suckers can really fly.



At an old shop I worked at, used to fire them about 100' at the rats in chasing them out of the building. Only time I fired them really for other than their purpose. Gotta find that release lever to do so.

This as opposed to the electric staple gun I have which I fire at will at a certain crew chief when ever he gets obnotious. I warn others in the area they had at best move away.

Got famous for another person for not missing - ever with a pneumatic. This be it rebound or what ever. Staples sticking out of his stomic by the time I was done...

err, was that me, na I imagined such a concept of using a woodworking tool for chasing people away in a specific way - this especially if one found a sewing machine atop my work table and I was busy.

For techies that don't costume, at very least a electric staple gun is a must as long as you do so at their mid section, won't get fired by way of doing something very unsafe, and they really really disserve it.


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## ship

Slam fire where if the trigger is pulled the staple gun will fire as soon as the safety release is pressed as opposed to trigger fire where it would not fire until both the safety was released and trigger was pulled was the two options I remember in buying the gun. This for the primary user of the shop manager who is at best trained as a garage type carpenter when I bought it, and the little need to have speed in stapling as if on an assembly line was what I bought. Very important setting and concept in buying such tools out of safety. Also one to mark the tool as so you cannot say get a staple in the leg. Or in one case a 12d nail thru the finger I once in college pulled out of someone’s hand - this given he didn’t know safety and either double fired in it moving, hit something with the safety before he was ready or missed in a nail hitting his hand supporting the material below that of his aiming point.

I digress, this tool was set up for as it were trigger fire. 20 to 30PSI too high is correct in my own assessment in what was wrong here and is still wrong here. Amazing that this new tool said about 90 to 100 PSI yet older guns work fine at this pressure. This as with other types of narrow crown and finish nail guns also don’t operate in such a condition given the pressure. Yes, it causes problems with the seals and pads or where they buffers, but overall they operate. The Larger M-gun of a newer version has problems with higher pressures it would seem.

So what to do? In the past I have used in-line regulators on the tool and even did so for this tool. They work sufficiently in keeping the volume up but one has to know it needs to be added to the tool before use. One must also know the system pressure before using the tool, and that of the tool’s seeming operating pressure. Requires a certain knowledge of what one is doing.

This granted at one point I had a dual air for air’s sake and dryer and oil regulated system set up in the old wood shop for use with pneumatic tools. Shop manager came back and quickly removed such things way back when in addition to going back to using the table saw table top for a fabrication table with glue drips and etc. Anyway, given a lighting shop, it was said that such hoses that might be fed by an oiler would potentially wind up spraying oil within them onto the lenses of lighting fixtures. Valid point unless marked as wood shop hoses as opposed to normal hoses. At that point it’s no worse than plugging a 30" industrial fan into a 50' 18/3 extension cord. Urr, gee... never mind this is your job not your career, just ask before you do such things in the future.

New wood shop doesn’t have oiler’s either and it’s doubtful the drips of oil I was also raised on given other than best circumstances where an oiler was added to the system. Also seems like they are also over pressure this given I wander over there at times in saying to those that mention that I’m in the wrong building, that I’m giving up lighting and going back to my carpentry trade again. They often say something like great, best solution for the company as a joke response. 

In still mis-firing, years after I bought the thing in it now having a home in a real carpentry shop I now get advice on it’s use by those who now use it. Gotta hold it in just such a way and it won’t double fire. This as opposed to a pressure regulator I will have thought of had I still been a carpenter for my living - believe my side of the complex still has some of them I made up for the tool available as with the oilers I also bought not in use....

Fascinating for me. Pick up a tool I thought years ago I figured out the problem with and solved, and years later I pick it up again and it still has the same problem. Says a lot about the carpentry shop in that they tend to hold the tool in just such a way, this much less they didn’t add an in-line regulator to it before now. I’m now a lighting guy that has use of the wood shop due to real scene shop training, my recommendations don’t go far when it comes to their world.

Next time I visit their world, I suppose I should just dig out the in-line regulators. This given the various piston seals are no doubt by now blown. This much from the shop manager that teaches safety yet screwed up the alignment of the drill press I also bought and now finally have in my department. This by way of getting a glove caught in the thing. Really injured himself good by doing that one, question is what was he doing wearing gloves while operating a power tool? Those that don’t study history or their field are resigned to re-live the past. Not to say that the shop manager and or others are not tremendiously qualified to do their jobs, or that I want any other career path than I'm on, just to say stupid mistakes and ways of doing stuff tend to also be really bad practice at times. I fight my own bad practices in at times also being wrong.

Must remember to bring regulators much less pneumatic tool oil on my next visit to the new wood shop. Hopefully as advised the tool is not totally toast. 120# pressure on a 90# gun is the cause not just, gotta use it in just such a way so it will only fire one staple.

Believe this is the cause of the problem.


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## gafftaper

Anybody hear the story last summer about the guy who was roofing his house with an air nailer. He had it set to the semi-automatic tap to fire mode. He was sitting in an awkward position and asked his wife to pass him the nailer behind his back so he could reach a shingle. As he passed the nailer behind his back he nailed his own butt to the roof. OUCH... 

Then there was the one about this guy who lost control of his framing nailer and it fired a 3 inch nail straight into the roof of his mouth... but he didn't know it was there for a week. Here's the full story on that one.


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## Van

Ok, I realize this will be indulging in a hijack,but..... 

A freind of mine was working on an addition to his house. This was years ago in Tahlequah,Ok. he was putting together Headers for a stud wall. Now get the visual; He had two 8' 2x4's run across his knee, he would shoot a 16d nail into the 2x's just to the outside of his knee, then slide the 2x and repeat. He was old school, "didn't need no sawhorses". well as you can imagine he slipped, shot a 16d nail right into the top of his knee. Being that he was all alone working on his cabin in the country, he hopped < literally> into his truck and drove himself to the emergency room. He hobbled up to the desk where the nurse on call said, " Can I help you, honey?" "Yeah, I got a nail in my knee", he said, pointing to the head of the nail just visible in the middle of a spot of blood on his jeans. The nurse came out from around the back of the desk. She looked looked at the nail head, looked at him,in the face, looked at the nail head again, Looked him square in the face and said, "Well honey, Why didn't you stop hammering?" 
Swear to God, Only on Oklahoma!.........


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## Chris15

Van said:


> Ok, I realize this will be indulging in a hijack,but.....
> Swear to God, Only on Oklahoma!.........



And are you telling me that I can't use the normal sort of thing for down here of "Only in America"?


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## ship

Footer, would you mind revising your post a wee bit? Given your quote and the reply to it, this lacks taste or tact in the way it can be implied.


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## Charc

ship said:


> Footer, would you mind revising your post a wee bit? Given your quote and the reply to it, this lacks taste or tact in the way it can be implied.



Ship, do you mean Footer, or Chris15?

If it's the latter, would you mind revising your post a wee bit? 
(As I'm currently a little confused)


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## ship

My apologies to all. Just got a bit close in the words or concepts behind Hijacking and followed by the concept of Olahoma for me to be comfortable with. I did not request a deletion, just a refinement in what on a broad view of reading didn't seem appropriate as it was worded as a pun or play on words.


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## Footer

ship said:


> My apologies to all. Just got a bit close in the words or concepts behind Hijacking and followed by the concept of Olahoma for me to be comfortable with. I did not request a deletion, just a refinement in what on a broad view of reading didn't seem appropriate as it was worded as a pun or play on words.



Oh... I get it, sorry I didn't even think of that it that way. I live 3 miles from the memorial and work 3 blocks away and even then it didn't click with me. Thanks ship.


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