How to accurize your beam scale?

[CRM284]

I'm a bit old school in the fact that I prefer a properly tuned beam scale over a digital scale. There's very little that can go wrong with a beam scale, where as a digital can have battery issues, ect..... Plus, top of the line, super accurate and consistent digital scales are outrageously expensive for my blood. I have better things to put that money towards. I've also seen where a properly tuned or accurized beam scale can literally measure single granules of powder. Usually these are done by Scott Parker or a guy in England. I'm not to a point where I need to measure single granules of powder, but it's nice to know that your scale is that sensitive, accurate, and consistent. I've made an extended pointer , added padded buffers, and in the near future I'm going to hook up a camera to make it easier to read as well.

So, have any of you guys accurized your 10-10, 5-10, or older rcbs, Lyman, and ohaus scales? If so, how did you go about doing it? How do you sharpen the blades and polish the bearing surfaces?

Thanks
Craig

 

[George P]

If the check weights still indicate everything is fine, i do not mess with it. haven't had to mess with my 5-10 in almost 40 years, including moving it about a dozen times (kept the original box just for that reason

 

[Archie]

Not much to accurize, they are what they are. You should reasonable often check the zero, also make sure there's no crud or build up at the balance point.

 

[PWC]

I have an 80 yr old Pacific powder balance, not a scale. Use calibration weights to zero, then any powder added and zeroed out is correct.

I have used a magnifier on a stand and the flat back side of a piece of broken granite tile left from kitchen counter upgrade to just polish up the knife edges of the beam. Do not use a file or change the angles. Under 10X magnification, the pivot bars had no flat spots or grooves.

My balance is my standard..used for my Lyman Pocket Touch. Cal the scale, and weigh case (very rarely) or unknown bullet. My powder measure is set to my balance, and every 10-15 powder drops are checked.
Scale is not used directly to measure powder unless it's breaking down an unkn round.

Lyman Pocket scale is another discussion, (Digital Scales) found here on THR. I find it to be a good accurate, inexpensive ($25) scale, easy to use, if outside influences are kept away.

 

[Ironicaintit]

Mine’s just a plain old Lyman. Make sure it’s clean, oil free and level, and it’ll register single granules of short cut extruded powders.

 

[buck460XVR]

Seems regardless of charge weight(6 gr or 40 gr) it's always about a .1 lighter than what shows on my digital. But, it's consistent. I use the digital to verify my charge weight to make sure I have the beam balanced and set correctly.

 

[rfwobbly]

It's very important to keep the teeter-totter knives sharp. This is not an issue on new scales, but if the beam has endured several hard knocks or is repeatedly removed, then the knives can be damaged. The more usual case is that the steel knives are in a humid environment and tiny amounts of rust start to bloom on those edges. I buy a lot of used scales and what I do is hit the knives with a very fine (1000 grit) polishing stone just to insure they are sharp. The rust can be kept at bay with a very thin layer of waxy case lube.

In the accident prevention department, I highly advise placing the scale on a small shelf about 14" above the bench surface. This will also make reading the scale much easier.

Then keeping the pivot points clean with an alcohol swab clears all oils and trash from the pivot seat.

Other than general cleaning, that's about all the maintenance they need.

 

[FROGO207]

There are several scale mod threads on here if you take the time to search. I did a quick one and did not find much though. Our member 1066 is the scale expert as far as I can see. Might PM him with a question or search his threads. Also member jmorris made an auto fill balance scale that was something else. I find keeping things clean and sharp knife edges go a long way to keeping things running smoothly.

 

[mdi]

(This is gonna get some folk's panties in a bunch, but...). I have weighed a piece of tissue paper, smaller than a postage stamp, on my Lee Safety Scale. I just keep the knife edge/fulcrum and bearings clean and don't let my scales set out, they either are but back in their box or under a hard cover, zero every use and occasionaly use check weights. But my favorite scale is an old RCBS 5-10...

 

[murf]

an rcmodel tip, that i took a few years back, is to make sure your scale is balanced side-to-side. i set a bubble level on the scale and shimmed up one side with a regular washer to get the scale to set level on my loading bench. i stash the washer in the scale pan when not in use.

luck,

murf

 

[GT1]

I have read in the various forums about 'super tuned' beam scales over the years, and it always ruffles feathers when I point out the obvious. A fool and their money, every time.
The agate bearing needs to be clean, the fulcrum edge that rides in the bearing should be clean smooth and sharp, and a bit of graphite will not hurt in there.
Keep the dust out/cover on it, it will be as accurate as it can be just as is, and will be the same forever.

 

[FROGO207]

I have no problem with the Lee safety scale. It is a good scale but can be a bit "fiddley" and most don't know how to read a vernier scale and get frustrated fast. I have one, as well as the Ohaus version of the 10-10. They both will detect 3 kernals of IMR 3031 dropped onto the pan. Plenty accurate for me. I also like the fact that in all these years I have never had the gravity run out. Not so with the batteries in the electronic one that is used to weigh bullets.

 

[CRM284]

I appreciate all the replies guys. I'm glad I'm not the only one that has atleast seen or heard of these "supertuned" scales.
I guess the theory behind it is less friction equals more sensitive, so they're sharpening the blades and buffing the bearing surfaces. It makes sense to me, but how to go about making those blade edges razor sharp is beyond me. I feel like it would mess something up. I did buff the bearing surfaces tho, that was easy.

With the m500 the bearings are ceramic. I also noticed with the 500 the blade posts can rub the flange that holds the ceramic bearings in place. So I'm going to modify that as well. I placed an extended pointer on the scale as well. I used a paper clip, then colored it black with a sharpie. At some point I'm going to mount a camera and see just how sensitive the M500 is to single granules of powder.

 

[CRM284]

Here's a pic of the extended pointer. It really helped me to tightly zero in. The little triangle thing that is factory was tough to read. And as you can see I also hot glued a trimmed earplug as a buffer to keep the been from slamming down.

 

[1066]

A good reliable and repeatable beam scale is a joy to use, if you don't abuse it, it will last a lifetime (and more). Unfortunately not all beam scales are equal, even when new, or I might say, especially when new if we are talking about any beam scales made in the last 8 years or so. Most of them probably come within the standard +/- .1 grain but I have seen plenty that don't and very often their owners are totally unaware there's anything wrong until it becomes obvious.
A tuned scale is like blueprinting a race engine, just getting back to basics and making sure everything is just as it should be. The scales are made just good enough to do the job, no more. The knife edges are ground to around 60 degrees, just like a cold chisel when seen with strong glass, not because that gives the most sensitive scale but because it gives a passable performance but will also put up with a quantity of abuse from uncaring users and still function.
This is a photo of a standard factory knife edge from a well known brand and next to it is a handmade knife edge. - Now, I rarely need to make a knife edge, but if the tips are damaged there's no repair or regrinding that can save them and no spares available.

If anyone is interested I have several video's on YouTube concerning scales.

 

[CRM284]

A good reliable and repeatable beam scale is a joy to use, if you don't abuse it, it will last a lifetime (and more). Unfortunately not all beam scales are equal, even when new, or I might say, especially when new if we are talking about any beam scales made in the last 8 years or so. Most of them probably come within the standard +/- .1 grain but I have seen plenty that don't and very often their owners are totally unaware there's anything wrong until it becomes obvious.
A tuned scale is like blueprinting a race engine, just getting back to basics and making sure everything is just as it should be. The scales are made just good enough to do the job, no more. The knife edges are ground to around 60 degrees, just like a cold chisel when seen with strong glass, not because that gives the most sensitive scale but because it gives a passable performance but will also put up with a quantity of abuse from uncaring users and still function.
This is a photo of a standard factory knife edge from a well known brand and next to it is a handmade knife edge. - Now, I rarely need to make a knife edge, but if the tips are damaged there's no repair or regrinding that can save them and no spares available.
View attachment 912182
If anyone is interested I have several video's on YouTube concerning scales.

I watched a bunch of your videos last night, and I'm impressed with your work!

That's a HUGE difference in blades!! And the blades on my M500 look the same as those factory issued blades. I also have a 505 I'd like to tune up, but I'm afraid I'll ruin the knife edges. I've been try to figure out a good way to sharpen the edges and can't come up with a good solution. I figured I'd practice on the M500 if I found a good way to do it.

 

[CRM284]

I played with the M500. I actually have it tuned to the point I can see deflection with one grain of H414. With 3 grains it moves my pointer completely off the white line on the beam. I'm happy with that sensitivity.

 

[film495]

I refurbished an old Herter's scale, cleaned it up - and well, it still seemed to stick a little and could see the are hesitate at times. Took it all apart again, cleaned it better, sanded off the knife edge better, just used 400 grit sand paper and then 0000 steel wool, cleaned it more, cleaned it again, and then more. Put back together and it was smooth, seemed to operate well enough. It was a little off, the small adjustment weight had collected some goo that looked like lacquer dried to it. Cleaned that off with oil and 0000 steel wood and it was spot on with test weights and compared to a new digital scale.

 

[PWC]

Unless you have abused the blades, they don't need to be sharpened, only polished. Go to the drug store where they sell nail care stuff...get the finest nail polishing "emery" board. DON'T USE AN EMERYBOARD, THEY ARE TOO COURSE. If you do woodwork use 1000 or 1500 sand paper to just shine up the knife edges

 

[Dibbs]

As a point of reference, a quarter is very, very close to 1/5th of an ounce. So 5 quarters should tip your beam scale slightly the way of the quarters, when you place an ounce weight upon it.

 

[CRM284]

I should've said I polishes them, not so much sharpened them.

Here are pics of the scale showing deflection. It was zero'd, then I added one granule, then three granules total. In these pictures I tried to use the Lyman lettering in the background as a flatline reference point, so people wouldnt say my angle or eye level changed. I'm happy with these results.

 

[PWC]

I like your idea of the foam ear plug to limit the swing. My balance does not have the magnetic dampening of your scale and needs help in dampening out the + and - excursions. I believe I will copy it.

 

[JFrank]

A good reliable and repeatable beam scale is a joy to use, if you don't abuse it, it will last a lifetime (and more). Unfortunately not all beam scales are equal, even when new, or I might say, especially when new if we are talking about any beam scales made in the last 8 years or so. Most of them probably come within the standard +/- .1 grain but I have seen plenty that don't and very often their owners are totally unaware there's anything wrong until it becomes obvious.
A tuned scale is like blueprinting a race engine, just getting back to basics and making sure everything is just as it should be. The scales are made just good enough to do the job, no more. The knife edges are ground to around 60 degrees, just like a cold chisel when seen with strong glass, not because that gives the most sensitive scale but because it gives a passable performance but will also put up with a quantity of abuse from uncaring users and still function.
This is a photo of a standard factory knife edge from a well known brand and next to it is a handmade knife edge. - Now, I rarely need to make a knife edge, but if the tips are damaged there's no repair or regrinding that can save them and no spares available.
View attachment 912182
If anyone is interested I have several video's on YouTube concerning scales.

@1066 I’ll sharpen the knives with a fine stone as a last step, “cleaning” especially the V grooves using Alcohol and examining/tuning one area at a time really helps work my way through each scale until it repeats at a sensitivity level of as close to one kernel as I can get. I sold my 10-10 it was really very good’
My Scott Parker 500 gr is a pleasure to use, my 10-05 you helped me with is outstanding but now I’ve taken on an old m-5 that looks terrible but actually repeats nicely just needs a little love to get it to where I want it.
J

 

[CRM284]

I like your idea of the foam ear plug to limit the swing. My balance does not have the magnetic dampening of your scale and needs help in dampening out the + and - excursions. I believe I will copy it.

Awesome! Glad someone could use that tip. It works great. I did it for two reasons. One being it keeps the beam from slamming down on metal to metal when dumping than pan. And the second reason being it speeds up the process a little, by reducing the amount of travel by the beam when trickling in powder.

 

[1066]

I played with the M500. I actually have it tuned to the point I can see deflection with one grain of H414. With 3 grains it moves my pointer completely off the white line on the beam. I'm happy with that sensitivity.

Good job with the M500. This scale has exactly the same knife edge/floating agate bearings as used in nearly all the RCBS scales over the last 50 years, and I mean exactly the same, they're interchangeable. The M500, although being made in China (and maybe Mexico) is of better quality than the RCBS 10/10's and 505's I've come across made in the last few years of non-USA made RCBS scales. It's a simple two poise scale, a direct replacement for the RCBS 502 scale, the unique point is that the beam graduations are printed on both sides so can be used left handed.
The problem with this ambidextrous system is that, as CRM284 has discovered, the zero pointers are around 1/4" away from the face of the beam, this can easily lead to parallax error unless it's viewed from exactly the same angle every time. I cheap webcam or smartphone really helps get the best out of these scales.
Here's an experimental beam, using a replaceable razor knife-edge I made for the M500 scale:

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