Magnetic Blackbird Auger Shaft

[Parellax]

I did a single test without the agitator into a bucket of water with the new motor. In one pull of the trigger the counter ended at 76. There were 78 bb's in the bucket.

[Parellax]

BTW. This trap is a full length piece of 3/4" EMT conduit directed into a 5 gallon bucket that is stuck in another bucket. The water level is four, or five inches from the top. The bb's are starting to make the first bucket leak into the other one at 1K psi.

[camracer]

The reason I chose the ones I tried was because Hodaka found that trying magnets that are polarized like the ones you are considering barely have any pull on the sides. The bb's just snap to the ends.

Yes, but if you separate axially magnetized magnets by something non-magnetic, like plastic, you will get stronger attraction between the magnets. Here, let me illustrate this idea. In this photo in the bottom right are 1/8" x 1/4" rod magnets sticking together. The bottom left are the same magnets separated by about 1/8". At the top of the photo is a plastic tube with separated magnets inside. See what happens?

[camracer]

Like I said before, I don't know exactly how strong the pull force needs to be, but if Hodoka's shaft has too much pull, this is the way I would fix that issue. Anyway, it might be fine just the way it is.

BTW, these are the smallest diameter rod magnets with diametric magnetism. (1/8" x 1/4") If you want to experiment.
http://www.kjmagnetics.com/proddetail.asp?prod=D24DIA

[Hodaka]

I was thinking about using three instead of four magnets and leaving the very end non-magnetized. That would keep the spring from being pulled so much and rubbing and lord knows, I don't want my "shaft" to have too much pull!?! I think I will rip apart the ones I have waiting for the lathe and re-do them!

[Parellax]

Very interesting Cam. I just did some more testing with a stiffer spring on the clutch. I got 3K 100% at ten round bursts. I also got 38 bb's with 38 on the counter at 3K. There is something not quite right with the firmware at 4K I will have to go over with Sergey though so I can't cet an accurate count. I tried to use the prototype 4K board, and burnt a mosfet so it will be a while before I can say definitively if it is shooting 4K 100%. All I can say is that it feels like it is. I will try to make a video today.

[Parellax]

Here is the video...

https://www.youtube.com/watch?v=d-B0_E75JpA

[camracer]

I was thinking about using three instead of four magnets and leaving the very end non-magnetized. That would keep the spring from being pulled so much and rubbing and lord knows, I don't want my "shaft" to have too much pull!?! I think I will rip apart the ones I have waiting for the lathe and re-do them!

Good thinking. The output end does not need to be magnetized.

[camracer]

Here is the video...

https://www.youtube.com/watch?v=d-B0_E75JpA

I like your bb trap. You just need to extend the pipe into the bucket and/or seal up the hole in the lid around the pipe, eh?

Ok, now things are looking quite promising, but there is a but. You need to test with longer bursts than 20-30 or so shots. The neck of the magazine contains about that many bb's. The action of the air flowing from the valve into the barrel creates a vacuum that will suck the bb's from the neck of the magazine. Kind of like how a strafer bb machinegun pulls bb's from it's "magazine". You may see this if you turn off the motor and fire the gun with just the neck full of bb's.
I would suggest doing 100-150 round tests.

[camracer]

I was just thinking, as an addendum, the vacuum effect may not be as bad if you have done the magnet mod in the neck of the magazine...

[Parellax]

On this mag I am using a 30 rnd valve body with no magnets at all. The end of the barrel doesn't seem to be taking any damage. After I receive another MAS I will test it with longer bursts. I broke the prototype doing another test later that day.  The next ones should be Parellax proof. I don't really think the vacuum effect would go past the vent ports.

[Hodaka]

Yea, my bad, I knew solder wouldn't hold long but figured I would get you one fast for testing.  The rest will be pressed, epoxied and turned! Parellax proof for sure!

[TBK]

Great news you are making progress!  Keep at it.

Parellax, what issue did you find with the 4K speed?  Is it not doing 4k?  What happens between 3K and 4K?  All work but 4k?

[Parellax]

I think there is a glitch in the code. When I switch from 3K 10 rnd burst to 4K full the counter runs at 4K full, but the gun only delivers a 10 rnd burst at 3K. When Sergey get's back to Russia he is going to take a look to see what might be going on. I haven't tested the between settings. Just before I went to Canada I broke the MAS. Hodaka was aware of the potential problem, and has corrected it. I fixed it this morning for some more tests, and discovered why bb's were going everywhere.

[Parellax]

I did some more testing today with the Nichibo, and the SB-4K. I was able to get it to reliably fire 3K. Everything I did to get it to 4K did not work. Half were air shots at best. I am still not ruling out the Nichibo because I still have some clutch adjustment left, and I haven't brought the motor to the point of stalling. I was able to fire three 10 rnd bursts at 4K with the new motor with reasonable success. The first shot 11, and the second two shot 9. I think I will have it tomorrow.

TBK. There is nothing wrong with the firmware on the SB-4K. I discovered that in all of the testing I have been doing my valves have been taking a beating with all of the air shots. The valve was just hanging up after a consistent amount of shots had been fired at 4K. I figured it out when a valve became stuck open. A little time with the Dremel, and viola! 4K works fine now.