Turn Your FX-120i into a Prometheus

[Kiba]

OK, here's some pics and youtube videos of my automatic measure working.

Credit goes out right now to Twoboxer for his post here for the storage cube idea. It was cheap, fits everything perfectly, and works as a good draft shield. He had a very good idea and I thank him for saving me the time of building an enclosure on my own! Can't beat $12 for the storage cube from Amazon.

Also, huge thanks to Adam for making the trickler in the first place. Seeing what he had developed was the push I needed to make this happen even though I had been kicking the idea around for several years without actually building anything.

Quick system rundown:

• Arduino controlling the servo driving a Harrell's BR measure. Servo gently "double taps" at the top and bottom of the stroke to help settle the powder in the measure then backs slightly off the hard stops of the powder measure so the servo isn't sitting stalled. Plenty of power to cut the errant kernel, you can hear it but it doesn't slow down or stall at all. One thing I have noticed is having the powder measure servo controlled and consistently cycled the same way every time is that dispensed charges are more consistent than when I run it by hand.

• Potentiometer adjustable delay time from 0.250-2 seconds in the "drop" position to allow for large charges or powders that don't drop cleanly. So far it doesn't seem to be needed, even with the measure at maximum volume the 0.250 second minimum delay is plenty of time to drop the charge

• Manual actuation pushbuttons for now. Also used initially to manually dispense charges to set the Harrell's for the bulk charge

• Angled drop chute and tall sided powder receptacle to avoid splashes. I dispensed about 200 40gr charges of Varget tonight and when everything was done I found about a dozen stray kernels sitting either on top of the plastic part of the scale or in the bottom of the enclosure that bounced out of the receptacle when dropping the bulk charge. While not perfect, I can live with a dozen stray kernels... or I can further experiment with slightly restricting the outlet of the drop chute to further slow the powder.

As of now the measure is manually cycled by the pushbutton and because of how Adam's trickler works I'm having to throw a bulk charge about 1.5gr below the target weight so the system doesn't get the occasional overthrow in the event I'm a second or two late with the cycling button. If the trickler is already running and I cycle the measure it sees the sudden weight change, stops a moment, and then resumes trickling. (You can see an example of this at 38 seconds in the "full cycle" video.) That's a little lost time.

If and when both systems are integrated I'm thinking a 7 second per charge cycle time is possible. I'm picturing the final workflow like this:

1. Place pan back on scale
   
2. If weight is approximately >-0.02gr and <0.02gr the system interprets this as an empty pan, cycles the powder measure to drop the bulk charge, pauses approximately 1 second for the scale to settle, then trickles up to final weight. This should allow the bulk charge to be set about 0.3-0.4 gr below final weight for minimal trickling time.
   
3. If the weight is >0.1 gr, assume a partially filled pan has been placed back on the scale for a "do over" and the measure is not cycled but the trickler drives to final target weight.

Yes, the final system did take more time and money than expected. Kicking around ideas with Adam for a cheaper and easier to produce version to make available. While the current system works I'd consider it more a "lab prototype" because of the tuning needed for each servo and mechanical setup combination. As things wear I'll have to tweak the code and that's not something I would consider acceptable for a production piece, for the end user it needs to be simplified to be "setup and go" over the long haul much like Adam's trickler.

Anyways, pic and video of the current version...

 

[rardoin]

Forshizzle my nizzle....I love it, Kiba!

 

[Mark Johnson]

Sign me up for the preorder!!

 

[Twoboxer]

Nice, neat, creative, effective work! Now there's a next step for me to take when I get the itch for further improvements . . . or just for a new toy lol.

The problem of powder bounce interests me. I'm no expert in material flow characteristics, but I've wondered if there aren't some shapes that are more able to control flow speed and therefore powder bounce. For example:

1) While spirals aren't always the best pipe design for smooth flow, maybe the right twist rate would create enough friction to slow the powder flow to the point where flow is maxed and bounce is minimized or eliminated.

2) I've had some small successes minimizing bounce using shapes like the RCBS Powder Funnel Pan. Directing the flow into the "cup" area (assuming no/blocked funnel) seems to help. The angle of your outlet tube suggests testing this would be easy enough.

Reason: I like the idea of the taller "powder pan", but it makes it harder to remove some powder to give the trickler a second chance when it needs it.

 

[Kiba]

True, the taller powder pan did solve one problem (splashout) but created another (it's now difficult to take a little powder back out if it slightly overcharges.)

However, given the speed of the system (especially once it's integrated and automatically cycles), in the event of an overcharge it will probably be faster to dump the overcharge, put a fresh pan on, and let the system do it over rather than scooping a little bit of powder out to let the system re-trickle up to final weight.

I experimented last night with putting a 0.250" ID reducer on the end of the drop chute. The powder backs up behind the outlet reducer and "hourglasses" out more slowly at a lower velocity which further minimizes splashing and would allow the use of a receptacle with shorter sides that would be easier to scoop overcharges out of. With the 0.250 outlet baffle I bet a shorter sided 1.5oz stainless sauce cup would work, but the exiting powder still isn't slow enough for your typical reloading shallow powder pan. Slowing the powder down does add time to the drop cycle too. It is possible to get the powder slow enough not to splash out of a standard powder pan, a few pages back someone posted a video of a ribbed & baffled chute that someone made which dispensed into your typical low profile powder pan without any splash or spill. A baffled powder chute to allow use of a standard powder pan could be 3D printed very inexpensively... but I'd need to buy a 3D printer first. Just what I need, more toys. I mean tools. Need to watch that terminology.

 

[memilanuk]

What about something like the drop tube mod shown midways down the page here:

https://www.shootingsoftware.com/smallprojects.htm

 

[Kiba]

What about something like the drop tube mod shown midways down the page here:

https://www.shootingsoftware.com/smallprojects.htm

Played with that too. Getting the cut, heat, and twist right to not have it trap powder is an exercise in frustration. The plastic I had just didn't want to cooperate.

Going to try a different exit baffle in a couple days to see if it will allow use of a 1.5 oz stainless sauce cup. The sauce cups are 1.5" at the bottom, 2.25" at the top, and 0.875" tall so they would be easy to scoop an overcharge out of while still having taller sides than a standard powder pan to better contain splashes and spills.

 

[memilanuk]

Played with that too. Getting the cut, heat, and twist right to not have it trap powder is an exercise in frustration. The plastic I had just didn't want to cooperate.

Kinda wondered about that. I've meant to try that mod myself on other powder measures over the years, but never seemed to have a suitable plastic on hand to test with.

What about the combo powder pan/funnels from Lyman & RCBS... would the 'hooded' section help contain the splash enough to be useful in this application?

 

[mtar15]

I finally had a chance to finish my bearing upgrade, it seems to work great and is very smooth. The last thing I had to do was chuck up the tube and take a few thousands off with some 200 grit and 00 steel wool so it would fit the ID of the bearings.

This trickler was a tester I purchased because I didn't want to take my autotrickler down and didn't want to test on it. Next I'll do my autotrickler trickler and will be good to go.

I'm very happy with the results.

Just to recap:

I ordered these bearings: http://www.ebay.com/itm/371702886611?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Drilled these holes with this bit:

The bearings are held in with Loctite 641.

Here is the final result:

 

[Kiba]

What about the combo powder pan/funnels from Lyman & RCBS... would the 'hooded' section help contain the splash enough to be useful in this application?

Have one of those RCBS hooded pans somewhere... when the weather conditions were "off" that plastic pan was a mess when it came to static and caused all kinds of issues with my scale and the powder would stick to it. Had to keep wiping it down with anti-static Endust. That's why I'm trying to use only stainless or aluminum powder pans now, conductive for static dissipation and non-ferrous so it won't interfere with the magnetic force restoration in the scale.

 

[Twoboxer]

Have one of those RCBS hooded pans somewhere... when the weather conditions were "off" that plastic pan was a mess when it came to static and caused all kinds of issues with my scale and the powder would stick to it. Had to keep wiping it down with anti-static Endust. . . .

That's odd . . . That RCBS is the only plastic pan I have never had powder stick to. Oh well, it wasn't about that specific pan, more about the shape.

If the powder were dropping into a completely enclosed container, bounce (and speed) don't matter. That kinda points to 2 solutions . . . one part of a complete enclosure attached to the drop tube and the other part the pan . . . or inject the powder onto the floor of something like the RCBS pan at a 45 degree angle and catch the resulting bounce in the semi-enclosed rear of the pan.

In one case you'd have to move the pan to "open" it for powder removal, in the other there should be enough powder in the forward part of the pan to remove some if needed.

Isn't it great to just throw out stuff without having to actually do the work ?

 

[stevenc23]

Drilled these holes with this bit:

Very nice and clean looking! Found the drill bit info a few pages back which answered my initial question. Thanks to Adam and everyone contributing to this thread! Installed bearings in my trickler and it runs like a dream

Thx

 

[jlow]

That's odd . . . That RCBS is the only plastic pan I have never had powder stick to. Oh well, it wasn't about that specific pan, more about the shape.

If the powder were dropping into a completely enclosed container, bounce (and speed) don't matter. That kinda points to 2 solutions . . . one part of a complete enclosure attached to the drop tube and the other part the pan . . . or inject the powder onto the floor of something like the RCBS pan at a 45 degree angle and catch the resulting bounce in the semi-enclosed rear of the pan.

In one case you'd have to move the pan to "open" it for powder removal, in the other there should be enough powder in the forward part of the pan to remove some if needed.

Isn't it great to just throw out stuff without having to actually do the work ?

You can do all that stuff and get a perfect drop without any spills but all that extra work to get there and difficulty getting the pan on and off the scale will wipe out any of the very slight advantage in speed you may get using that initial automatic dropper compared to me just using a Lee scoop....

 

[Twoboxer]

You can do all that stuff and get a perfect drop without any spills but all that extra work to get there and difficulty getting the pan on and off the scale will wipe out any of the very slight advantage in speed you may get using that initial automatic dropper compared to me just using a Lee scoop....

Maybe, but I'm the one who would be using the scoop

 

[jlow]

Maybe, but I'm the one who would be using the scoop

Right!

What you are seeing here is the problem with over addressing the solution with technology. I love tech but sometimes we all have to understand that the KISS solution is sometimes the most effective and efficient. The key to proper implementation of technology is always to know how much is enough and how much is too much.

 

[Mark Johnson]

You can do all that stuff and get a perfect drop without any spills but all that extra work to get there and difficulty getting the pan on and off the scale will wipe out any of the very slight advantage in speed you may get using that initial automatic dropper compared to me just using a Lee scoop....

Easier to run two pans with the setup above.

 

[IPSCNUT]

Right!

What you are seeing here is the problem with over addressing the solution with technology. I love tech but sometimes we all have to understand that the KISS solution is sometimes the most effective and efficient. The key to proper implementation of technology is always to know how much is enough and how much is too much.

I would imagine Adam appreciates all the free R&D you folks are providing on the device he designed. The real issue is will he stand behind his warranty on a buggered up auto trickler? Adam what say!!!!!!

 

[spclark]

... will he stand behind his warranty on a buggered up auto trickler?

Why would anyone expect that of him?

The trickler mechanism is pretty much as-supplied stock from RCBS. Anything done to it rightfully should be on the users' nickel.

From the o-ring drive down? That's Adam's contribution. Nobody's mentioned doing anything to 'improve' that that I've read here.

 

[jkl]

The trickler is a great product. Some people would complain about anything and others can wait to redesign something so simple that works great. I like the comments like, I was just thinking of that, I was just about to do that and I just didn't get around to that yet. But Adam did he deserves all he can get for it.

Just take it as a simple piece of automated old pot metal that throws a very consistent charge of powder and spend the rest of the time at the range emptying out the brass you loaded so you can fill it again with Adam's trickler.

John

 

[stevenc23]

Here is my setup. Thanks again to Adam and everyone for their tips and ideas. Set to dispense 42.68 grains of H4350.

Have an Omega trickler ready to go if it shorts me one kernel.