Frustrated with RCBS 502 beam scale

[Marksman762]

Perhaps some here have come across this issue:

Each time I load I zero my RCBS 502 scale using RCBS check weights. Most of the time, as I check every 10 rounds or so, the scale holds its zero. However there are times where the zero seems to vary by as much as 3/10ths of a grain.

Today for example: I zeroed at 42.5 grains. I loaded ten rounds then checked the zero again using the check weights. The needle was pointing about 3/10ths above the zero mark on the scale. I re-zeroed the scale to the check weights and rechecked each of the ten rounds I charged. Of course, all ten were loaded too hot. After I re-charged each case I checked the scale again with the weights. To my frustration the scale was off again by about 2/10ths of a grain in the opposite direction.

The scale is advertised to be accurate to within 1/10th of a grain. Is mine simply defective in some way? Is there something I am seriously overlooking? It just seems like some days the scale wanders around.

Any and all input is appreciated! There must be something I am missing here...

 

[cinosbus]

Re: Frustrated with RCBS 502 beam scale

Any kind of airflow around the scale will effect it. Turn off the A/C, heat, and any other fans. Don't work in a drafty area and also check the knife-edges that the scale pivots on for corrosion or gunk. Scrape it off and steel wool it if it is there. Light gun oil will help prevent the corrosion, but may gather dust and gunk, YMMV.

Make sure you don't accidentally trickle powder UNDER the pan when you are filling cases and moving the pan around. This is easy to do if you have a trickler set to dump into the pan and bump it while the pan is away. That phillips screw head under there will hold a lot of powder!

Those are just some things I've had to sort out with my scale - that you would have to watch with any scale.

 

[barrett1142]

Re: Frustrated with RCBS 502 beam scale

I have a beam scale as well, and ran into this. If my AC unit in my house was blowing, the slight breeze from the overhead air ducts would through off my scale. I also have to hold my breath when trickling powder in the pan or breathe under the edge of my reloading bench. I know it sound stupid but once I saw it, and stopped it, it worked.

 

[Victor N TN]

Re: Frustrated with RCBS 502 beam scale

Have you tried calling RCBS and asking for help? It can't hurt.

 

[TaterInTheSouth]

Re: Frustrated with RCBS 502 beam scale

with a Q-tip, I Wipe the knives and bearings with denatured alcohol.
I then blow them with compressed air to dry them.
When not in use, drape a clean-X tissue over the
Bearings/pivots.
HTH

 

[Marksman762]

Re: Frustrated with RCBS 502 beam scale

Thank you for all the comments so far! One thing I did just consider is nearby music. I was listening to music a bit louder than usual while I was loading that day, perhaps bass vibrations were causing the issues.

Other then that, I have no AC or fans in the room and I store the scale in it's box in a drawer when not in use.

I'll try again without music and see what happens. Any further issues and I'll call RCBS as mentioned above and see what they say.

Thanks again!

 

[1066]

Re: Frustrated with RCBS 502 beam scale

Hi
Another thing to check is that the bearings are free to move in their housings, they should wobble about a bit. You can take off the bearing covers and remove and clean the bearings and housing with spirit etc. Also have a look at the little stirup piece that the pan hooks onto, it should be free to move. These scales, although very basic work exactly the same and are as accurate as any other beam scale. Have a look at the post "accurizing the 502 scale"
1066