Active TopicsActive Topics  Display List of Forum MembersMemberlist  Search The ForumSearch  HelpHelp
  RegisterRegister  LoginLogin  

Home | Load data | Articles | Ballistic Calc | Energy Calc
General Discussion
 Handloads.Com Forum : General Discussion
Subject Topic: Check weight procedure Post ReplyPost New Topic
Author
Message << Prev Topic | Next Topic >>
Paul5388
Moderator


Avatar

Joined: October 16 2003
Location: Long Branch, Texas
Posts: 19523
Online Status: Offline
Posted: March 22 2008 at 8:10am | IP Logged Quote Paul5388

If you zero the pointer/scale with no weight on it, it should be zeroed for any weight.

There are 15.43 grains in 1 gram, so if you use M2 check weights like I do, the weight selections will roughly be in 15 grain increments. However, the better the quality of the check weights, the less deviation you have to contend with in the weights. A 1 gram M2 weight is accurate to 3 milligrams, but the tolerance is different for each weight in a set.
weight tolerances pdf

Here's the proper procedure for checking the accuracy of a scale/balance.

Quote:
     6. The accuracy of the weight set used to check balance calibrations must exceed the accuracy of the balance. Visually inspect the working weight set. If the weights are soiled or corroded, prevent use by labeling and segregating. Take appropriate action to ensure that the affected weights are cleaned or repaired followed by calibration. Corroded weights must be discarded and replaced.
    7. Verify that the working weight set has been checked to a standard weight set. If not checked by the due date, check the calibration based on the tolerances listed in Exhibit 2.
    8. Use the working weights or use tare zero (0) and working weights that bracket the range of the item(s) to be weighed to verify the accuracy of the balance. The results of the working weights must fall within the posted tolerance limits of the balance. Document results in the scientific notebook or as a QA record.
    NOTE: Use cotton or equivalent gloves and padded or nonmetallic forceps suitable for handling weights without scratching them. Metal forceps can scratch or pit weights, affecting the calibration of weights.
    a. If the balance measures the weights inaccurately, it is considered out of calibration. Tag, segregate, or otherwise control the balance to prevent its use until recalibrated.



As you can see, the scale is checked with the weights, it isn't zeroed with the weights.
Back to Top View Paul5388's Profile Search for other posts by Paul5388 Visit Paul5388's Homepage
 
Rigmarol
Senior Member


Avatar

Joined: January 11 2005
Location: Menifee, California
Posts: 11354
Online Status: Offline
Posted: March 22 2008 at 11:15am | IP Logged Quote Rigmarol

I've got 3 scales; 2 elecronic and one RCBS balance beam.

I check one against the other to be sure they match.

That's how I found my cheap pocket electronic scale is bad.
I may be doing it wrong, the check weight method is the correct way but I only 2 check weights and they are in grams so I have to convert on the beam scale.

Thanks for the info.

__________________
"When you do things right, people won't be sure you've done anything at all." - Futurama
Back to Top View Rigmarol's Profile Search for other posts by Rigmarol
 
Paul5388
Moderator


Avatar

Joined: October 16 2003
Location: Long Branch, Texas
Posts: 19523
Online Status: Offline
Posted: March 22 2008 at 11:56am | IP Logged Quote Paul5388

I probably should have addressed the .1 gr accuracy of most reloading scales. 3 mg = .003 g (the error in a 1 gram M2 weight) If that error is calculated in grains it would be equal to .003 * 15.43 = .046 gr. That's ~1/2 the accuracy value of the scale and can be used to calibrate/check a scale that is accurate to .1 gr. That's also something that can be seen on a beam balance, but can't be seen on an electronic scale. With a little practice, that 1/2 of a tenth of a grain can be "guestimated" pretty accurately.

M2 weights are the cheap ones and can be purchased in a set for less than $20. When you get to Class 2 weights, a set is about $700 or more.

I have never seen a check weight, that comes with a scale, that has any indication of the accuracy level of the weight. They are normally stuck on the scale somewhere to accumulate dust and debris, which alters the weight. They usually don't give any directions/instructions for handling and storing, in order to maintain their accuracy.

Keep the weights clean (i.e. store them properly) and don't handle them with your fingers.
Back to Top View Paul5388's Profile Search for other posts by Paul5388 Visit Paul5388's Homepage
 
Roudy
Senior Member


Avatar

Joined: December 09 2005
Location: Missouri
Posts: 564
Online Status: Offline
Posted: March 22 2008 at 1:07pm | IP Logged Quote Roudy

I have an RCBS beam scale that I've used for many years. It is 'magnetically dampened' so I assume that there are small magnets built in to speed up stabalizing when weighing something. Anyone know how this dampening may effect the accuracy from one use to another?

Roudy

Rig, I too have a cheap digital scale but have never had the courage to weigh powder charges with it. However it is handy for weighing cast bullets to within one grain.

__________________
Marines DO have one fault, excess humility!
Back to Top View Roudy's Profile Search for other posts by Roudy
 
Paul5388
Moderator


Avatar

Joined: October 16 2003
Location: Long Branch, Texas
Posts: 19523
Online Status: Offline
Posted: March 22 2008 at 5:24pm | IP Logged Quote Paul5388

Roudy,

Just check for replication by lifting the pan with a pencil and let it settle back down. If you do that several times, you'll get and idea of how well your scale will replicate the results you're getting.

You can also pour what you weighed into another container and dump it back into the scale pan to see if it gives the same results each time.

I always bring my scale up to the weight from a lower weight and if I put too much in, I take more than needed out and bring it back up to weight.
Back to Top View Paul5388's Profile Search for other posts by Paul5388 Visit Paul5388's Homepage
 
TexasHunter
Senior Member


Avatar

Joined: January 22 2008
Location: Thicket, Texas
Posts: 652
Online Status: Offline
Posted: March 22 2008 at 9:42pm | IP Logged Quote TexasHunter

I check back and forth like rig does. I sat down tonight and checked a bunch of 9mm loads I made. Out of 50 rounds I found two that were not within the "window" of what I consider consistant. Pretty good I think. Those two may have been that third shot "stringer" that we sometimes get.

__________________
"I believe that a man's moral compass can be determined by how he references free men to defend themseves." - Ted Nugent   
Back to Top View TexasHunter's Profile Search for other posts by TexasHunter
 
The_Shadow
Senior Member


Avatar

Joined: January 12 2007
Location: Southeast, LoUiSiAna
Posts: 5912
Online Status: Offline
Posted: March 24 2008 at 6:57pm | IP Logged Quote The_Shadow

Well I have a RCBS 5-10 beam and the Frankford Arsenal Digital scale.

I set the tare/zero the Frankford Arsenal Digital scale with my scale pan from the RCBS on it. This way both scales use the same pan.

Place a measured weight on the RCBS scale weigh it, then transfere the scale pan to the Frankford Arsenal Digital scale to confirm exact same weight. This works with check weights, powder, bullets, what ever to compare what one scale says against the other!

Good discussion!

__________________
The
Shadow

LoUiSiAna
NRA Life Menber
BASS Life Menber
Back to Top View The_Shadow's Profile Search for other posts by The_Shadow
 
dukers65
Senior Member


Avatar

Joined: May 11 2004
Location: s.e. mi.
Posts: 2293
Online Status: Offline
Posted: March 25 2008 at 4:40pm | IP Logged Quote dukers65

i went thru 3 of those frankford arsenal scales before i gave up and went back to my rcbs scale.

__________________
you can't tell the depth of the well by the length of the handle
Back to Top View dukers65's Profile Search for other posts by dukers65
 
Cracker
Senior Member


Avatar

Joined: March 01 2006
Posts: 826
Online Status: Offline
Posted: March 25 2008 at 7:03pm | IP Logged Quote Cracker

Rigmarol wrote:
That's how I found my cheap pocket electronic scale is bad.


I still have my original Lyman balance beam scale and it still does a good job. It's just not as convenient as I'd like.

I also have a Lyman digital electronic scale. It has never worked consistently, something that drove me to distraction until I found something that did.

My Dillon digital electronic scale, recommended by a lot of people in this forum, works much better and is much more consistent, than anything I've tried before.

Lee
Back to Top View Cracker's Profile Search for other posts by Cracker
 
ancien
Senior Member


Avatar

Joined: May 27 2004
Location: Traveling the West
Posts: 2302
Online Status: Offline
Posted: March 25 2008 at 11:59pm | IP Logged Quote ancien

Paul,
I use one of two electronic scales, both RCBS scales, and
one balance beam scale (again, a 10-10 RCBS scale) to weigh my charges, along with bullets and cases.

So far so good! That means no excessive powder charges aside from what I've programmed. And I double check during the process of measuring the powder charges. I usually/typically have two scales set-up to double check
the powder measurement. Along with weights, etc.

And when using my electronic scales, I make sure there are no electronics or fluorescent lighting anywhere near
the scales.

My biggest headache comes when I'm using a progressive
press where sometimes the powder measure sometimes fails
to drop either a full charge, or if there is a problem,
double charges the case. I've caught all of these so far.
But I often wonder what happens with those less attentive.







__________________
"A generation which ignores history has no past and no future."
Back to Top View ancien's Profile Search for other posts by ancien
 
denton
Newcomer




Joined: May 23 2005
Location: layton utah
Posts: 1
Online Status: Offline
Posted: April 11 2008 at 6:50pm | IP Logged Quote denton

Magnetic damping does not affect accuracy. On the Hornady balance, the magnetic damper is just a short aluminum stub at right angles to the main beam. It moves between the poles of a magnet. The magnetic field induces currents in the aluminum stub which oppose movement of the beam. When the beam is at rest, no currents are induced. The point is to make the beam come to rest more quickly.

If a beam balance is properly made, it requires only zeroing with no load. There is only one adjustment, and it needs to be made only at one weight. Any weight, including zero, will do equally well.

Electronic scales use electronic amplifiers, and both the gain and the offset can drift. Electronic scales need a two-point set up. Zero sets one point on the line, and some other convenient point sets the other. So you need one check weight.

If you don't want to assume linearity, then you need a five-point check of the displayed weight vs. actual weight curve.

__________________
Prove all things; hold fast to that which is good.
Back to Top View denton's Profile Search for other posts by denton
 
Bullfrog
Senior Member


Avatar

Joined: February 26 2004
Location: Colorado USA
Posts: 3870
Online Status: Offline
Posted: April 12 2008 at 12:55pm | IP Logged Quote Bullfrog

Ok ok so I checked my weight about each day before I lift and it was 156 , man was I happy, then I goto the docs and it is 172. What the hell? Oh crap, not that kinda weight

__________________
Bullfrog

The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it.
- Albert Einstein

Back to Top View Bullfrog's Profile Search for other posts by Bullfrog Visit Bullfrog's Homepage
 
TexIndian
Senior Member


Avatar

Joined: August 17 2006
Location: Texas
Posts: 3928
Online Status: Offline
Posted: April 14 2008 at 6:47am | IP Logged Quote TexIndian

Must be that $50 in nickels you carry in your pocket, Bullfrog.

About the magnetic dampening scales - the system causes a non-moving beam to have a resistance to movement, kind of like an increased moment of inertia if you remember your physics classes. If your beam is standing still and you add just a few pieces of powder, it usually stays right where it was even though the powder added is enough to register a change. Give the beam a touch to get it moving and it will settle at the new weight.



__________________
John

Who me? A hoarder?
Back to Top View TexIndian's Profile Search for other posts by TexIndian
 
Rigmarol
Senior Member


Avatar

Joined: January 11 2005
Location: Menifee, California
Posts: 11354
Online Status: Offline
Posted: April 14 2008 at 7:44am | IP Logged Quote Rigmarol

Tex, when using my RCBS beam, I can use a powder trickler and I haven't noticed any "stickiness". I can drop 2 or three pieces of powder and watch the scale react just fine. Maybe over time, the blade gets rounded or something? I dunno, but I'll be double checking in the future to be sure. I'll trickle up to weight then remove the pan and put the pan back in to double check to be sure I'm right. Thanks for the info.



__________________
"When you do things right, people won't be sure you've done anything at all." - Futurama
Back to Top View Rigmarol's Profile Search for other posts by Rigmarol
 
Paul5388
Moderator


Avatar

Joined: October 16 2003
Location: Long Branch, Texas
Posts: 19523
Online Status: Offline
Posted: April 14 2008 at 7:55am | IP Logged Quote Paul5388

Rig,

There's no need to remove the pan and reinstall it to double check. Just put a pencil, dipper, finger nail under the pan and lift it like there isn't any weight in it. It'll settle, just as if you were dumping/throwing the whole weigh of powder at one time.

I'm in the process of looking at another scale (as if I don't have any ). The My Weigh iBalance 101 is accurate to .005 g (.077 gr) and only cost $134.50 with a 30 year warranty. The other one is the Acculab Vicon VIC 123 for $239.95 that is good to .001 g (.01543 gr).
Back to Top View Paul5388's Profile Search for other posts by Paul5388 Visit Paul5388's Homepage
 
STCM(SW)
Senior Member


Avatar

Joined: February 17 2007
Location: Eastern Washington
Posts: 8879
Online Status: Offline
Posted: April 20 2008 at 10:51pm | IP Logged Quote STCM(SW)

I still us my Ohaus scale, been refurbished once in the last 35 years by Ohaus 18 years ago.
Cheap electronics scale is not accurate at all...

__________________
NRA Life Benefactor Member
USN MCPO Ret. 1960-1992
Si vis pacem, Para Bellum!
Back to Top View STCM(SW)'s Profile Search for other posts by STCM(SW)
 
Paul5388
Moderator


Avatar

Joined: October 16 2003
Location: Long Branch, Texas
Posts: 19523
Online Status: Offline
Posted: April 21 2008 at 12:48am | IP Logged Quote Paul5388

The i101 comes with a 100 g F2 check weight that's accurate to 1.5 mg (.023 gr), which is over 3 times as accurate as the scale. However, to get the most resolution, it would be necessary to use the g readout and convert to grains. That's a little awkward for a lot of people.

I'm checking on a couple more scales that will readout to .002 g and .001 g.
Back to Top View Paul5388's Profile Search for other posts by Paul5388 Visit Paul5388's Homepage
 
Rigmarol
Senior Member


Avatar

Joined: January 11 2005
Location: Menifee, California
Posts: 11354
Online Status: Offline
Posted: April 21 2008 at 8:25am | IP Logged Quote Rigmarol

Paul5388 wrote:
Rig,

There's no need to remove the pan and reinstall it to double check. Just put a pencil, dipper, finger nail under the pan and lift it like there isn't any weight in it. It'll settle, just as if you were dumping/throwing the whole weigh of powder at one time.

I'm in the process of looking at another scale (as if I don't have any ). The My Weigh iBalance 101 is accurate to .005 g (.077 gr) and only cost $134.50 with a 30 year warranty. The other one is the Acculab Vicon VIC 123 for $239.95 that is good to .001 g (.01543 gr).


You are absolutely correct! I was going for simplicity in my description.

__________________
"When you do things right, people won't be sure you've done anything at all." - Futurama
Back to Top View Rigmarol's Profile Search for other posts by Rigmarol
 
engshooter
Senior Member


Avatar

Joined: December 08 2004
Location: cumbria (united kingdom)
Posts: 173
Online Status: Offline
Posted: June 07 2008 at 2:37am | IP Logged Quote engshooter

I own a set of rcbs beam scales and have so for the last five years or so i have never checked them with check weights do you advise that i buy a set and check them

__________________
GOOD SHOOTING TO ALL
Back to Top View engshooter's Profile Search for other posts by engshooter
 
Paul5388
Moderator


Avatar

Joined: October 16 2003
Location: Long Branch, Texas
Posts: 19523
Online Status: Offline
Posted: June 07 2008 at 7:58am | IP Logged Quote Paul5388

Colin,

Beam scales are usually pretty stable. As long as the level is right to make your point read zero, it should be very close to actual weights.

With that in mind, I don't think I would buy a set of weights, but might think about getting a 1 or 2 gram weight to check the lower range or even the normal working range for accuracy.
Quote:
There are 15.43 grains in 1 gram, so if you use M2 check weights like I do, the weight selections will roughly be in 15 grain increments.
Here's a UK site that has individual M2 weights, with a 1 g weight costing about 2.70 GBP.
Back to Top View Paul5388's Profile Search for other posts by Paul5388 Visit Paul5388's Homepage
 

Home | Load data | Articles | Ballistic Calc | Energy Calc

Page of 4 Next >>
  Post ReplyPost New Topic
Printable version Printable version

Forum Jump
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You can vote in polls in this forum

Powered by Web Wiz Forums version
Copyright ©2001-2008 Web Wiz Guide

This page was generated in 0.1719 seconds.