Turn Your FX-120i into a Prometheus

[memilanuk]

Not to be too much of a distraction, but an update on the servo operated automatic powder measure for the bulk drop that I mentioned a few days ago...

Kiba,

That sounds pretty awesome!

Have you seen this page?

http://singlekernel.com/pm.html

I ran across it on arf.com, and talked with the guy a little. IIRC, he's controlling the whole thing using an interface created with Processing from his laptop (to run the Arduino, etc.). He hasn't updated the page for a little while, though.

Keep us posted!

Monte

 

[Kiba]

Kiba,

That sounds pretty awesome!

Have you seen this page?

http://singlekernel.com/pm.html

I ran across it on arf.com, and talked with the guy a little. IIRC, he's controlling the whole thing using an interface created with Processing from his laptop (to run the Arduino, etc.). He hasn't updated the page for a little while, though.

Keep us posted!

Monte

I ran across that page this weekend. Looks like we both ended up buying parts from ServoCity; can't say I'm surprised as they offer a large assortment of components at reasonable prices that suit themselves very well to this kind of project. His end result is very similar to what I'm building, although I chose to go chain drive from the servo to the powder measure drum to to eliminate a lot of the brackets that he used to mount the servo. I figured the chain setup will be more tolerant of tolerance stacking and any movement of the powder measure or flex in the mounting brackets since the chain will allow some movement and misalignment without skipping. With gear drive everything needs to be rigid to maintain proper mesh. Regardless of drive method the end result is the same.

Did some more thinking last night and realized that rather than having a potentiometer adjusted delay time at the "drop" portion of the stroke, if I integrate it with Adam's measure it will already know the target weight defined by the user; thus a simple lookup table could be applied. For example, if the final weight is between 10-25 grains then the drop delay could be set to 0.2s, for 25-35 grains it could be 0.35s, 35-45 grains 0.45s, etc. Only bad thing about this table lookup approach is that there is no way I could test all powders and all charge weights that someone might use, so the preprogrammed delay times may not work for all combinations. That puts me back thinking that an end-user potentiometer adjustable drop delay is still the best approach. Still learning the Arduino code as I go but this user adjustable delay parameter looks easy to implement.

Next hurdle to overcome will be pricing... right now I'm in it much more than I expected just in parts. The two areas with the greatest gains in terms of cost savings are the powder measure and servo. I'm using a Redding 3BR powder measure for this first test unit because I already had one from my pre-Chargemaster days; but a cheaper Uniflow or Hornady powder measure would also get the job done for less money since it will just be used as a simple bulk charge dropper. The $150 servo I chose may end up being overkill and a cheaper servo with less torque and a lower transit speed may be perfectly adequate.

Anyways, hope to post more updates and hopefully a video of it up and running this weekend provided I can snag some machine time this week to machine the drum to sprocket adapter and drop chute adapter.

 

[memilanuk]

Anyways, hope to post more updates and hopefully a video of it up and running this weekend

Sweet... but in all fairness to Adam, it might be best to start a dedicated thread just for your creation so as to not muddy the waters. Just a thought.

Good luck,

Monte

 

[1lnbrdg]

Now needed, a better scale pan that doesn't let powder bounce out when it's thrown straight to the pan.

 

[jlow]

Now needed, a better scale pan that doesn't let powder bounce out when it's thrown straight to the pan.

Wow, really? That RCBS pan has just about the tallest sides I have seen and have never had a problem with stuff bouncing out even when I don't use Adam's "height adjuster". If you are really having problem, just throw an "almost full" charge and the autotrickler will throw at a reduced rate since it knows it is getting close to the final weigh.

 

[1lnbrdg]

Adam's unit works fine by it self. Just trying to figure out how to speed it up with a powder measure with a tube/hose to feed into the pan while it sits on the scale.

 

[Cujo]

It's pretty neat that some of you have the ingenuity to take on projects like that. For me, the LEE scoop (whole set was around $12 shipped on EBay) works just fine with Adam's trickler. It kind of reminds me of the story of how how NASA spent thousands of dollars to develop a pen that could write in space. The Soviets just used a pencil.

 

[jkl]

That was the second thing I ordered Lee Dippers. Simple and easy.

John

 

[sparky123321]

"It kind of reminds me of the story of how NASA spent thousands of dollars to develop a pen that could write in space. The Soviets just used a pencil."

Love it!

 

[memilanuk]

Yeah... I got a set of powder scoops a while back. Tried them with this setup. Not a fan of reaching inside the glass hutch on my GD-503 with a scoop full of powder - way too much of an invitation to bump into something and slosh powder kernels everywhere. For others... enjoy your $12 el-cheapo solution. I'll keep working with my $20 Lee PPM thrower

 

[jlow]

Yeah... I got a set of powder scoops a while back. Tried them with this setup. Not a fan of reaching inside the glass hutch on my GD-503 with a scoop full of powder - way too much of an invitation to bump into something and slosh powder kernels everywhere. For others... enjoy your $12 el-cheapo solution. I'll keep working with my $20 Lee PPM thrower

That's why you need two powder weighting pans of exactly the same weight. Put light powder charge into one pan sitting outside with the scoop and then exchange the pan inside the balance with the properly weight powder charge with the one outside with the light charge ready to go.

 

[BoydAllen]

How to drop powder directly into scale pan...

 

[jlow]

How to drop powder directly into scale pan...

Boyd – it’s a very nice invention, I really like the idea of the baffles slowing down the powder but I guess the question is would the effort and cost to incorporate this into an FX-120A and the auto-trickler be worth the effort?

The reason I say this is in order to get this to work, you will need first a powder dropper, then you need this device in the video, you then still need to incorporate this into the FX-120A. This last part will probably require you to cut open one of the screens or make a custom one that fits into the FX-120A. This is important because generally speaking, it’s best to have 3 walls up to attenuate any effect of moving air on the accuracy/precision of the balance. That setup the guy has to me is huge and will take a huge amount of desktop space but I think one could probably reduce it to something like ¼ of its size, still a lot of desktop real-estate and we have not even talked about the powder drop…

So let’s say you got it to work perfectly, the question is how much work does that reduce? Well, you still got to reach in to remove the powder weighting pan that the auto-trickler has trued to the weight you want, while that is out, you still got to put an empty pan in for the next charge. So compared to what I am currently doing, what you will not need to do is to scoop once into the powder bottle and put that in the pan, but of course you will instead need to reach up and pull that lever. Neither will spill powder in the balance.

Sorry, I see ZERO return for all the work a person has to put into this… I am a big into gadgets and automation but I put this in the same draw as sparky123321 pen/pencil example. It’s a bit of a fool’s errand that may look cool but does absolutely nothing.

BTW, I am not saying this would not be useful if you are manually throwing charges, it's just does nothing for what we are doing because the first throw we do does not require any accuracy/precision, it just to reduce the run time of the autotrickler.

 

[BoydAllen]

Some time back, just for the fun of it, I figured out how to throw powder from a measure directly into a balance type scale's pan before finishing the charge by manually trickling. I have tuned my own scales, and had set up a web cam so that could eliminate parallax and have a greatly magnified image to reference. Comparing the time it took to complete a cycle by removing the pan from the scale to throw the charge, as compared with throwing the powder directly into the pan on the scale, the latter sped things up by a few seconds per cycle. My inspiration for this was the Prometheus powder measure. I was basically seeing if I could come up with a budget setup to do the same thing. The one feature that I did not figure out a way to duplicate was the Prometheus' dropping the charge as the measure handle is raised to fill the measure cavity. In any case, the only reason that I put the video up was to show one way that powder could be thrown into a scale pan, without the powder bouncing out, not to suggest that this particular device was suitable for incorporation into the system that is the topic of this thread. I was just showing what was possible, to get some potentially imaginative wheels turning.

 

[jlow]

Thanks Boyd - I think one big difference between what you were doing, and what the auto-trickler is doing is the speed of the auto-trickler, because it is so fast, you really don't have to throw a charge as close as possible to the final weight. In fact, it's a bit of disadvantage as what I have found is it can fool the auto-trickler if you throw it say a few kernels off from the final charge as it would just sit there and think it is done.

 

[BoydAllen]

Yes, I get that....and admire it. Now imagine that you had a funnel that was on the outside of a scale's enclosure, that extended through the side of the enclosure and ended far enough above the scale's pan so that it was easy to get the pan on and off the scale, so that you could either dump a scoop, or throw a charge from a measure into the funnel...a parallel setup to the trickler. Admittedly, this might not be commercially practical, but sometimes we do things that fall into that category just to please ourselves.

 

[jlow]

Boyd – I understand what you are trying to do but if we have that funnel that can deposit the short charge directly inside the scale, you would still have to take the pan out to get at the auto-trickled charge and you still have to put it back so that you can throw a charge and then auto-trickle to get it dead on. So the only thing you are saving in terms of actual work is you don’t have to throw the short charge outside but you still have to pull the lever to throw that short charge from your powder dispenser.

Trust me, having now done this for a for weeks and hundreds of charges, having to put a scoop inside the bottle and throwing a very approximate short charge into the pan is not worth the effort of putting together this elaborate setup. I think for this to be remotely beneficial, you have to be doing many hundreds of charges all the time, even then I cannot see it. Remember, the more mechanical things you put in the process, the more things can go wrong and that means having to fix the problem which consumes time.

 

[adamjmac]

So suppose I were to offer a thrower for say $200 that integrated with the trickler to automatically drop near the target and then the autotrickler would finish. All you have to do is put the empty pan on, and then take off the completed charge 15 seconds later. Assuming the speed is similar. Would you buy it?

 

[jlow]

Adam, an interesting idea that I am sure some would be interested in. One key factor I think is size, the FX-120A at least for me is already huge (coming from a GemPro 250) and the auto-trickler of course takes its own space. I personally like to have 3 wind screens and the top on and so not a lot of space left since you still have to be able to reach in and take out and put in the pan. To me, putting a low charge in has never been a bother but others may think differently.

 

[Kiba]

Part of my reasoning for building an automated powder measure for the initial bulk charge is I do a lot of high volume varmint shooting... and that means a lot of high volume reloading sessions. Even if the automatic measure for the bulk throw only shaves a few seconds per round over using the dippers that adds up-- and not having to use the dippers is one less repetitive motion for my hands and fingers to do.

I can see how using two scale pans adjusted for identical weight can speed things up. However, by using two pans and placing them back onto the scale with a light charge already on them means you aren't taking advantage of the FX120i's automatic zero drift compensation-- so you should occasionally place an empty pan back on to check that the zero is still true. With an automatic dispenser and the process flow I have in mind you're always placing an empty pan back on the scale and the automatic zero drift compensation will work every charge. Since I don't have my FX120i yet I can't say how big of an issue zero drift over a reloading session is-- but my inner OCD voice is telling me that if you're trying to load to 1-2 kernel accuracy then placing an empty pan back on the scale every time so the scale can check and compensate for drift isn't a bad idea.

Finally, I like silly side projects that allow me to play with new things... so that's really all the motivation I needed.