RCBS 5-10 scale

[piie]

Hi

Been using an RCBS 5-10 scale in combination with a Hornady auto-dispenser and Hornady electronic scale for a while now.

I acquired another 5-10 scale since I wanted to move away from using electronic scales altogether, but since I've always noticed the "quirks" with balance beam scales also not always 100% reliably returning to zero or "zeroing" on a known weight - I thought having two scales would be even "safer"...

I've been using a "system" of zeroing the scales before each reloading session but also testing a known 140gr weight. IOW - I would zero the scale AND ensure that it balanced on a known 140gr bullet before I would start using the scale(s).

During that time I would also allow the electronic dispenser and bench scale to warm up and calibrate each.

I would then dispense powder with the dispenser, transfer the measured powder to the electronic bench scale and verify they read the same, then transfer to one of the balance beam scales, and then do a final check on the last balance beam.

What I've noticed however is that sometimes, just moving the main poise or adjusting the tenths screw - as is required during a ladder test loading session - the one 5-10 (or both sometimes) would start settling slightly below or above the expected balance point.

Tapping the balance beam so that it makes a few larger oscillations and then settle, sometimes corrects the reading, but sometimes I would need to move the balance beam on its bearings and re-align vertically so that the copper plate goes symmetrical through the damper groove.

The short of it is: is this just simply the "quirks" of balance beam scales, or am I looking at scales with damage/worn-out parts?

These scales are both "inherited" so I don't have the full history of either. Am I doing something wrong, or is there something I can do to make the perception of accuracy/reliability better?

Thanks.

 

[Nick Caprinolo]

Sounds like you might need new, for want of a better word, bearings. These are the whit things the cross bar rest on. RCBS sent me a new pare free. Solved my problem.

 

[Rsadams]

The bearings , sharpen the knife edges and make sure the wire that holds the pan to the balance bar isn't rubbing the bar.... Try a search for Boyd Allen scale advise...

 

[1066]

The RCBS 5-10 is a fine scale - it uses exactly the same beam as the 10/10 and should reliably return to zero without any tapping. If it's not doing that then you have a slight problem somewhere. The scale probably needs a good service and clean to get it back working as it should. If you have a little basic mechanical feel you should be able to do this yourself with a bit of care.

 

[snoopy001]

Sounds like you might need new bearings, ............... RCBS sent me a new pare free. Solved my problem.

I have the same problem on the 10-10 model.
Do you think RCBS will have spare bearings available for them ?

 

[1066]

The bearings very rarely give any problems - they are very hard, made of agate. Under normal use they should last a lifetime and never wear. I have seen the odd one miss cut or with embedded impurities in the stone. The usual problem with the bearings is that they have, over the years, accumulated a film of dust, sometimes hard like shellac. If you take the bearings out and soak them in some sort of spirit/alcohol and give them a good scrub with a toothbrush or fine brass brush and dry them with a lint free cloth they should be fine. The bearing housings often need cleaning out too, the bearings should be free to wobble on the little pillow bump they sit on.

Most of the problems with the 5-10 or the 10/10 will be found with the knife edge or the pan hanger stirrup or occasionally very fine wire hairs stuck to the damping magnets touching the copper damping blade.

 

[Nick Caprinolo]

I have the same problem on the 10-10 model.
Do you think RCBS will have spare bearings available for them ?

Yes they will. The bearings appear to be the same fr all of their scales

 

[snoopy001]

Yes they will. The bearings appear to be the same fr all of their scales

Many thanks,very kind

 

[Homerange]

My old Ohaus scales were giving similar issues and it turned out that a cleanup of both the knife edges and the agate bearings fixed all problems. Mostly dust and a teeny bit of corrosion on the knife edges.

 

[Whit holman]

It does not take a lot of dust to get under those bearings to create scale to act stiky

 

[piie]

Thank you to all for your comments, as well as to very helpful advise via PM.
I've started cleaning the scales with some ethanol - paying special attention to the agates, the housing of the agates and the knife edges.

Made sure the housing "clamps" are not too tight - made sure the agates can wobble when prodded with a q-tip.

Next steps will be to gently work the edges of the knife blades, as I am still not satisfied with the scales after the cleaning. Whenever I get them to zero nicely and consistently return to zero when disturbing the beam slightly and then move the poise to weigh a known weight - either the reading of the known test weight will be slightly off, but it will zero again when returning poise to 0, or it will balance the test weight, only to be slightly off zero when resetting everything.

The one scale is slightly more prone to this behaviour and I've noticed a few things "odd".

1. The knives look ever so slightly concave - it doesn't look like anyone has tried to sharpen them - the cutting edges looks too "perfect" to have been done by hand.
2. The main poise on the beam is very slightly off alignment with the marks on the ruler. When you touch the poise while it is inside a groove, you can feel it has a bit of "give" to either side, while my other 5-10 feels completely "solid" when it is settled in a groove. I noticed that there is a little screw with a washer that looks like it is eccentric, and probably made so that it can be adjusted to have more or less of the washer's edge engaged with the teeth. I've tried playing with this a few times, but it doesn't matter how much/little of the washer's edge I expose, the poise still feels "wobbly" and is off-center. This has not bothered me too much, since I figured the explanation lies in point 3...
3. The "ruler" strip on the beam looks like it has a slightly larger "gap" on the indicator side of the bar - having the effect of moving all the numbers and lines ever so slightly to the right of the beam - compared to my other scale. It appears as if it's about by this margin that the poise is off-center wrt its allignment with the grain lines. Not sure if this could really cause anything, so I resisted the temptation to try and pry the strip (assume it's a thin aluminium strip?) loose and re-attach it more centered...

 

[JFrank]

I’m waiting for a fresh new quality beam scale to be produced, the old ones are still very popular it only makes sense to me that they would sell.
J

 

[Rsadams]

Rcbs has gone to ceramic bearings , they do go in and out of stock , order now , should be free... But be sure and look up Boyd's post on what you can do to fix/tune it up....

 

[Rsadams]

I’m waiting for a fresh new quality beam scale to be produced, the old ones are still very popular it only makes sense to me that they would sell.
J

Agree , but the world has gone digital and it doesn't seem like balance beam scales are being made by anyone but China... I still like my 10/10 and with a little help from Boyd Allen it has tuned up very nice.... We all spend all this time weighing powder and alot of the good guys are loading with charge masters and Dillon 550s.... BcZ sent me a nice rcbs range master digital scale and I have really enjoyed it for spot checking my Dillon , it sure makes life a little easier and faster for .223 and pistol... My recommendation for digital is to leave it on , only turn it off when you know your not going to load for a long time...

 

[JFrank]

I agree to the 10> and ya don’t find better guys than BCz and Boyd either.

 

[Bc'z]

I agree to the 10> and ya don’t find better guys than BCz and Boyd either.

I appreciate that.
And the 1010 that I got from you.
I honestly feel my groups have shrunk since I started using it.
Way to much drift with my digital unit, even knowing and understanding its quirks
Just cleaned agates and lubed knives Saturday.

 

[JFrank]

I had to clean the agates on my D5 this weekend also. Man what a difference it makes, one Kernel resolution again.

 

[mousegunner]

Cleaned my bearings as well, rubbed on some graphite with a q tip, lightly touched up the knives with a fine flat ceramic stone. One grain of Varget will move the beam.

 

[JFrank]

Cleaned my bearings as well, rubbed on some graphite with a q tip, lightly touched up the knives with a fine flat ceramic stone. One grain of Varget will move the beam.

Where ja get that ceramic stone man ????

 

[JFrank]

This new family member weighs this extra pan correctly at 114.3 and my 89.6 check weight but will stick a tiny tiny, I’m leaning towards a touch up a the knives and a good alcohol bath.
J