Vulcan malfunction
You may remember a while ago I posted my Vulcan blasted me in the face and wouldnt shoot after that. I was called all kinds of name and bad mouthed on this forum for reporting this. The cocking rod snapped. A new Vulcan was sent to me and this morning my first shot blasted me in the face. Again the rod has snapped on my 2nd Vulcan. As soon as I tear it down I will take pictures. the gun is still under warranty. I hope Topgun will send me a new type rod. I did send an email requesting one. I also have an Edgun and Cricket and I am not new to airguns, I treat my airguns like fine jewelry, the Vulcan was not abused, just a manufacturing defect. I probably have 1000 rounds thru this second Vulcan, the first broke after 56 shots. Lets see how Topgun handles the warranty, they treated me well on the first one.
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Even with the updated rod, the connection between the rod and bolt body is a high, repeated stress, joint.
The rod gets stressed in the plane of its greatest weakness (across the decreased diameter due to the drill holes)
That flex stress will worsen if the bolts are loose.
Also, the two bolts can have their loads converted into sheer instead of tension if they are loose.
1. What tension should we torque those bolts to keep the joint from slipping and turning into a sheer? (Joint failure = slip when tension too low to create adequate friction.)
2. Should we replace those two bolts on a scheduled basis to avoid their repetitive stress failure?
The tension is : Tighten untill the threads let go and back half a turn from there.
you can drop a little bit of Loctite between the rod and the runner. under the rod. so there will be much less stress on the bolts.
to release it you just apply heat.
was always wondering how could sniperqty load those badly deformed headed pellets.
I say don’t worry…..Be happy :8: and shoot that MF until it breaks…fix and shoot it some more! :4: Who knows tomorrow could end tonight! Enjoy 😛
I’m more worried about the bolts snapping than the updated rod breaking
Looking at the photo I think it is more poor quality metal or the metal was not tempered correctly. I’ll bet that rod is medium carbon steel hardened Rockwell 40 maybe 50. In my opinion that rod should be made from high carbon tool steel. If mine ever breaks I’ll have a machinist here in the USA make me a new one that will never break. I think if one used better steel that the rod would never break even if the screws were loose. It’s not that much force on the cocking rod.
Back to the topic…
Even with the updated rod, the connection between the rod and bolt body is a high, repeated stress, joint.
The rod gets stressed in the plane of its greatest weakness (across the decreased diameter due to the drill holes)
That flex stress will worsen if the bolts are loose.
Also, the two bolts can have their loads converted into sheer instead of tension if they are loose.
1. What tension should we torque those bolts to keep the joint from slipping and turning into a sheer? (Joint failure = slip when tension too low to create adequate friction.)
2. Should we replace those two bolts on a scheduled basis to avoid their repetitive stress failure?
This coming from a guy who never has an airgun in working operation? Funny how often you call Zonk’s imaginary friend to whine about your guns being broken. You have more problems than math book.
If that’s what you call him then yes – Casper.
You mean like Casper?
Imaginary friend ??
Of course Zonk the drunkin HillBilly is Rocking for his crazy imaginary friend Keysers response. You can’t believe anything The Keyser says. He is just a figment of your imagination a childhood nightmare.
:8: :8: :8:
I have to agree with Keyser Soze regarding the general feel I have for airgun dealers.
I am a newbie to the realm. It was really scary trying to figure out not only which PCP I wanted, but also which dealer I could trust.
The general reputation for dealers on the forums wasn’t great. The ones that sounded good, I couldn’t tell if the reviews were shills.
Some I tried contacting, well, never got back to me. It felt like I was dealing with shady characters that may or may not
deliver any goods once they have my money, let alone provide any semblance of after sales support.
It took a leap of faith when I ordered from Tony. Even so, it wasn’t until I saw an actual shipment show
up in tracking that I started to relax a bit. After all, for someone just getting their first PCP, a Vulcan
isn’t a cheap bet. Mine still wasn’t the best deal I could hope for, but I’m relieved it worked out.
Starting in this hobby is walking into a dark alley and hoping that all the bad stories you read about won’t
happen to you.
The inter-forum, inter-dealership wars don’t encourage any trust among newbies like myself.
You simply don’t know who to trust.
Evgeny’s taking time to actually answer my queries helped me decide on a Vulcan.
Tony had it in stock and actually responded. You guys, looked like real users, not shills.
But even so, I was pretty unsure if I had made a big mistake when I first placed my order.
If it affects ME like this, then imagine how many are being scared off from
making that leap.
I’m glad I found this forum and you bunch of characters.
Evgeny the maker and manufacturer of the Vulcan did everything he could to solve the problem I was having with my Vulcan. Mind you he did this without even seeing my gun over a few emails and a language barrier. His responses were quick and he shipped me out exactly what I needed to fix the problem. CHEERS to EVGENY. In the world of PCP airguns Evgeny is a shinning star!
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If you loose sleep over those bolts not being upto the task then i have a crazy idea : Replacement bolts in high grade/strength.
That’s what i did.