Micheal - did you see his update at 6:40am? It didn't come loose - it sheared off.......not good.
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Impact probe screw failure & solution
- Thread starter Pestassassin
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Michael, I do not have an Impact; have not seen one in person, but have dealt with a TON of fasteners. To me, this looks like a failure of the set screw, where is sheared at the bottom of the socket. This would more than likely be from a poor or just plain bad temper on the fastener. I have purchased screws before that look and feel just as they should. But, in use, they are so brittle that any amount of force will cause them to shear (actually fracture is more appropriate). I had some that I could pop the heads off of socket head cap screws simple by applying a small amount of pressure with my pinky finger once the screws were finger tight... My experience has this problem being more predominant with plated or specialty coated fasteners vs. black oxide.
Generally, replacing the screw with one from a different batch has cured any issues I have encountered...
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I did not see that update. Although I've never seen a set screw "sheer off" (which i assume means "break") I will take Dave G's word that it can happen.
Pestassasin,
Could you show us some upclose pictures of the actual set screw in question?
Thanks, & we're glad you're ok.
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I was hoping to own an Impact one day but after reviewing some videos of how the probe is only held in place by a single grub screw definitely exposes a design flaw and safety risk. The probe either needs to be screwed in from the rear and held in place by a grub screw or redesigned to prevent the probe from exiting the rear in case of a failure with the grub screw. Each shot is upwards of 2,000 psi or more. That's a lot of energy and faith in that grub screw holding up. This story was bad but it could have been a lot worse if that probe struck someone in the face.
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Dang, glad everybodys ok, i just traded for Tominco's impact but we have a deal that we trade back if anybodys not happy
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Here are couples of pictures of what can happen to that screw. This could possible be a safety recall.
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Perhaps a larger set screw is needed or a duplicate to handle the force demands of the action.
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You didn't read his post completely, or didn't comprehend what he said. Simply put, the SETSCREW SHEARED OFF end of story. There is no speculation needed as to what might have happened.
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G
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WTF, very dangerous issue! 0.o
FX Airguns: "Shoot your own Eye out, in both directions!" lol
FX Airguns: "Shoot your own Eye out, in both directions!" lol
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G
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engineers missed the boat on this one. Trying to hold back all those forces with one set screw are you kidding me...
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I don't have an impact, but if I did it would be an easy "temporary" fix to put a correct hardness bolt in there. Just slot the end after cutting it the correct length and add a little Loctite. Most air gunners that have fixed vintage air guns have made those.
For anyone that had a impact set screw fail or even others. This temp fix doesn't change the fact FX needs to update the way they do it. I mean its a $2000 rifle, those you don't buy to have to tinker with on your own? I don't think I would want to shoot one with the original set screw?
Or like they say in Christmas Story! Shoot your eye out!
For anyone that had a impact set screw fail or even others. This temp fix doesn't change the fact FX needs to update the way they do it. I mean its a $2000 rifle, those you don't buy to have to tinker with on your own? I don't think I would want to shoot one with the original set screw?
Or like they say in Christmas Story! Shoot your eye out!
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OK, seeing the actual set screw, and the probe pocket it fits into, I can see exactly what happened. I would think that replacing the set screw with a hollow-lock set screw and steel pin would eliminate any re-occurrence possibility. Or, a slotted set screw vs socket head, if one could be found the right size.I know you all think you know how much force is imparted on what, but I assure you you are way off. My guess is that the depth of the pocket is what caused the issue with that particular chosen set screw, and I would also suspect that the temper on the screw is out of spec... It is a set of circumstances that would have to come together just right to create the issue (imho).
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It's probably too late, but try not to be too emotional when contacting AoA and/or FX. AoA will probably make it right; not sure what FX's response would be, but I'm sure it'll be better if you just give them the facts and emphasize that you don't want this to happen again, for safety reasons.
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G
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I'm supposed to picking one up next week but with this and numerous lesser reported incidents I'm going to have to reconsider.
So glad no one was seriously injured
So much for FX quality!
So glad no one was seriously injured
So much for FX quality!
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DaveG I don't think that is pictures of an Impact? Just examples of what a failed set screw looks like?
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The pellet probe grub screw is a M3x6. 6mm long but the top 3mm of that screw is hollow for the Allen key to go in. The depth of the hole in the probe is 3.5mm meaning the stress on the screw is on the top 2.5mm hollowed out portion of the screw. That screw will snap sooner or later. Major safety issue.
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Glad you are ok!! Wow, and I was complaining because the screw kept backing out and jamming the loading w/o loctite on it. Then, locktiting it with that little allen area made for a nice opportunity to strip it. But no one would have a way to know if their screw was about to sheer during the next shot!
I don't remember if there is enough gap when the bolt is open to put a piece of metal between the last gap before the but plate to keep it from coming back and out if this happens?
I second the idea of having a solid screw with a tapered base and normal straight screwdriver top; especially since it is (a) stronger and (b) FX doesn't include the allen key with the gun.
I don't remember if there is enough gap when the bolt is open to put a piece of metal between the last gap before the but plate to keep it from coming back and out if this happens?
I second the idea of having a solid screw with a tapered base and normal straight screwdriver top; especially since it is (a) stronger and (b) FX doesn't include the allen key with the gun.
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My exact thought too, the bottom of the hollowed portion is almost inline with the edge of the retaining hole, So you're essentially asking a thin walled tube to arrest the backward facing force of something like an instant 100+ ft/lbs every time you fire the rifle. The shear force on the setscrew would be immense, and that on it's weakest part.
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that M3x6 grub screw use a 1.5mm allen key, a 3mm grub screw with a 1.5mm hollowed out for the allen key doesn't leave much metal left to hold that backward force. I would recommend anyone with an Impact to adjust the recoil-pad to cover the back opening if they are going to continue to shoot their gun until FX come up with a fix for this problem.
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