VPA Penetrator spining >> HELP

[bowhunterportugal]

Hi gang,

I recently bought a 3 package of VPA Penetrator 150 grains from Big Jim Bow Company.

I haven't shot them yet but I spinned them in a arrow spinner, even after squaring the shaft and insert with an ASD from G5, and they are not strait!
Then I tried an O ring that I've putted behind the broadhead and one of them got better but the other two didn't improved.

I tried to make a small video of it yesterday and, although is difficult to get the image of the wobble, if you look carefully to the very tip, you can see what I mean. I also filmed a Magnus broadhead for comparison that doesn't wobble in none of my squared arrows. I used the same arrow to film all broadheads. They are slightly worst then what the video shows...    

Here's the video:  http://s1053.photobucket.com/albums/s462/bowhunterportugal/How%20to%20Resources/?action=view¤t=VID-20120621-00125.mp4

Can you help me? Is there another way or another thing I can do to correct this?

Thanks guy's

Diogo

[awbowman]

Send them back.  Im sure they will honor a warranty.

[Pete McMiller]

I can't tell from the video but is it the whole head that is not straight or is it because the tanto tip is not ground on center?  If the tanto tip is off center just slightly it could look pretty wobbly.  If just the tip, you could fix it yourself and save the return shipping.

[bowhunterportugal]

awbowman, I've send VPA and bigjim a e-mail to see what they say.

Pete, in the video it's hard to see, but let me try to explain.

When the broadhead is spining, the ferrule that goes  all the way to the tip becomes a cone (visual effect)right? this cone is miss aligned from the back to the tip. That is what seems to me anyway. The "cone" on the Magnus is strait and on the VPA's is not.

With the o-ring it got better but not strait.

The video was taken with my cellphone, so not enough frames to catch that view of the ferrule.

Can I explain myself? My English can trick me...

[Pete McMiller]

Yes, I understand now - your english is terrific.  I am surprised that the O ring has any effect at all on the alignment.  I would think that if the head is crooked the O ring wouldn't change anything.

[bowhunterportugal]

On one of them it did make a tinny diference. Perhaps because the base of the broadhead is tapered and the hole in the insert is not strait, its like a funnel, and the broadhead was screw completely and never touched the insert face. The o-ring forced the squared face of the insert to push the broadhead.

But even so, with or without O-ring, they wobble. Maybe the O-ring question isn't as true as I'm wanting it to be...  

[Zradix]

[NoCams]

Use a Micrometer or caliper to measure the diameters of the VPA and Magnus broadhead's shaft..... bet the ones that spin the worst are also the smallest. Maybe you also have an insert with an oversize hole ? You are getting wobble in your spinning assembly due to runout. Runout is caused by sloppy fit between the arrow inside diameter,outside and inside diameter of the insert, and finally the outside diameter of your broadhead's shaft and threads.

If your broadhead's shafts are all close to the same within a .001" or so try changing your insert, you got a max diameter inside hole insert my friend. I also explained all this on your other thread for the Arrow Squaring Devise in detail. Accumulated tolerances are adding up on you and giving you poor runout in your spinning assembly. Sure wish all the manf would agree to some tighter tolerances for all these components. But then again tolerance and accuracy cost $$$$ folks. JMHO

[bowhunterportugal]

I have a dz arrows, all assembled the same way, all got trough the ASD, etc.

The Magnus broadhead spins true on 10 arrows, the VPA's on none!?

The film was made with all 4 broadheads in the same arrow.
That's why I'm trying to figure it out if it's normal!


NoCams, I red your post and I thank you. It makes perfect sense. Does this mean I'm lucky with the Magnus being so true?

I was hopping a response from VPA to my e-mail before I shoot them. I could be making a storm in a glass of water, maybe they fly great...

[NoCams]

Did not know these were VPA heads when I replied on your other thread. Not sure how VPA's are made but they are not turned on a lathe like say, a Muzzy or other round ferrule replaceable blade broadhead. Again, when you get the chance use a micrometer or dial caliper to measure the shank diameter of the VPA's in comparison to the Magnus, bet they may be smaller ???

After watching your vid I agree with Pete above..... is it the entire ferrule area that has runout or JUST the tanto tip ? I cannot really tell from the vid.... Mount a pin or very sharp pencil above your arrow spinner and set it where it almost touches the largest part of the blade rear when the head is rotated to the 12 O'clock position. Then carefully rotate the arrow in your spinner 180 degrees to check the rear of the opposite blade. If this is off big time then the entire head IS off center and time to send them back to VPA. If not, then you may just need to regrind the tip to center it as Pete said above. JMHO

[bowhunterportugal]

That pencil trick is good advise.

Thanks

[Boomerang]

Diogo,
Don't worry about sending them back. I can tell by your video that it looks like it was machined off center. It should not be that way. We have another batch at heat treat right now and as soon as I get batch finished I will send you a new pack.
Go ahead and shoot them and use it for a torture test if you want. Do me a favor though and see how it flies compared to the others.

Thanks,
Boomer

[Rob W.]

Gotta love customer service like that.    


Best head out there IMO.


Rob

[NoCams]

Boomerang and VPA Archery......    

Now that is customer service ! When I need some new 3 blade heavy heads I know what I will buy !