Tribute to the Lee Safety Scale

[big5ifty]

I've spent some time evaluating low cost electronic scales suitable for accurate weighing while powder trickling, and ended up with something interesting instead.

I have a RCBS Chargemaster 1500 scale. It works well enough. Drift is not bad, but it does drift, sometimes a significant part of one grain.

I am not prepared to spend what I consider a huge amount of money on a FX120i or equivalent, so I bought and tried a few different scales in the same price range as the one I have, and none of them are better.

They all drift.

I have an old 10-10, which weighs accurately, but does not have a fine enough resolution to easily indicate a single granule of powder being added to the pan.

I then recalled that years ago, when I first began reloading, my first scale was a Lee Precision. I also recalled that it was extremely sensitive, but a perpetual motion machine, making powder weighing an exercise towards sainthood. I also remember giving it away and buying something orange, can't remember exactly what it was.

I now bought another Lee, and tried to figure out why it could never stop moving. The reason is that brass or aluminium when moving through a magnetic field, experience a force to retard the motion. The magnets in the Lee scale are not strong enough to distract a compass needle, so I removed them and replaced them with rectangular neodymium magnets. Perpetual motion problem solved.

I have an old laptop - look up HP 6730b to see how old - that's too slow for anything useful, and an almost equally old USB HD webcam. I used them to give me a big picture of the scale reading. I used two strips aluminium tape superimposed on the scale to give a finer demarcation line.

I've checked what the Chargemaster 1500 says against the 10-10, and they concur.

So I'm trying a new thing :

1. use the 10-10 to weigh the initial charge, being accurate to 0.1 grain
2. zero the Lee using that charge
3. drop powder from the powder measure slightly below what's required
4. trickle up on the Lee while viewing on the laptop screen

So far so good. The video is showing 40.2 grains of N555. The resolution of the scale is such that it shows a change with just one granule of N555.

I've now got consistent charge weights to the granule, and I don't have to constantly re-check if the scale has drifted. 

Use this link to get the video clip -

Lee Safety Scale Revisited

[janfred]

Basically, that is how the Prometheus powder thrower measures loads.

The Lee scale always get a lot of hate. Most notably for the decimal adjustment. Personally I think that most just cannot believe the "cheap" bar can be accurate. Old man Lee claimed it is sensitive enough to show the change of weight of writing your name in pencil on a piece of paper.

I still have mine in the cabinet with a mark above and below the index point. Those two marks show 0.05gr above and below my desired load. As long as the pointer stopped between the marks I was happy. That simple step sped up my reloading by more than 50%. Judging by today's electronic scales, the Lee scale is still more repeatable. If I could only get the pan to stop swinging faster...

[oafpatroll]

I have yet to use a piece of Lee equipment that didn't do exactly what it said on the tin perfectly adequately and at lower cost than any alternative. At least some of the hate is from people who can and like to spend gucci money to get 'top tier stuff' IMO.

[big5ifty]

If I could only get the pan to stop swinging faster...

If you dampen the beam, it does a lot to dampen the swing of the pan as well. 

I had the pan swing dampened out completely, with a strong magnet about 10mm beneath the pan in the zero position.

The pan is aluminium, so it should not be magnetic, but for some reason after a few charges the magnet beneath the pan was affecting the reading, so I carried on without it.

[janfred]

Just don't use your finger to wipe away imaginary dust off the beam razor blade pivot.

No need to ask me how I know...

[Treeman]

I still want to put felt in the pan hanger ring to see if it reduces the swing.
My other I still want to do is to make the pin much larger, so as that its a 3 mm hole (curve in metal) in hanger and has a 2.8mm pin to swing on. I believe this will stop the swing dramatically faster.

[big5ifty]

I finished up two different batches or powder charges using this method, and I like it.

I like the fact that I can leave everything setup overnight, and if I come back the next day, I know the trickled charge weight is going to be identical to yesterday.

I like the fact that 100 grains on the 10-10 scale is going to be the same 100 grains next year, irrespective of the ambient temperature, humidity, cell phones, etc.

I like the fact that I don't have to constantly interrupt a session to reset the scale, or check if it drifted.

I've had the 10-10 sitting on the shelf for about 15 years. I stopped using it because it was very time consuming to find how much something weighed. That was when I got the Chargemaster scale. The way I'm using it now is to set it to the charge weight I'm looking for, and then trickle in.

The Lee scale is not being used to weigh the charge, just to make sure each charge as weighed on the 10-10 is the same.

I still have the original box for the Chargemaster, and I packed it away today. I also packed up two other electronic scales I bought to try out.

For the odd bullet or pistol charge that needs weighing, I kept one of the small, el-cheapo electronic scales out.