Oh yeah! I bought one of his . . . what . . . blemished scales rather than one in mint condition. The problem was I had to search for the blem! I'm still not sure I found it!
Last edited:
On beam scales part two
- Thread starter sparker
- Start date
Oh yeah! I bought one of his . . . what . . . blemished scales rather than one in mint condition. The problem was I had to search for the blem! I'm still not sure I found it!
Brians356
Gold $$ Contributor
Update on N42 magnets in the M5:
Here are the OEM M5 magnets in place:
With these, after zeroing the scale, starting from full beam deflection against the bottom frame stop, after releasing the beam the pointer traverses "zero" 16 times (8 each direction) before settling at zero again. (My earlier report of 9 traversals was a typo.) The initial upswing after release takes the pointer to the 4th deflection mark above zero.
I tried several more iterations of N42 magnets, and settled on "D33" N42 cylindrical 3/16 x 3/16, two on each side of the blade, with a sheet steel "tie bar" across each pair to form horseshoes. The 3/16" diameters allow them to nestle snugly in the spaces alongside the partitions, and also sit as close to the blade as the OEM magnets:
http://www.kjmagnetics.com/proddetail.asp?prod=D33
With these, the swing test yields only 6-7 traversals of "zero" before settling on zero, and the initial upswing only reaches the 2nd deflection mark above zero (i.e. half the deflection of the OEM magnets.)
Note that I packed pieces of balsa wood under and around the magnets, to position and secure them. The pieces under the magnets in the cavity on the right are 1/8" thick, to raise (toward the camera) the magnets to the center of the cavity. In the left cavity you can also see some pieces of balsa wedged in against the magnets to hold them in place. You could just use dabs of silicone sealer or whatever to secure them, but since each magnet is attracting its polar opposite across the blade gap, they tend to stay put without help, just not securely enough to keep them from falling out in handling.
Also note the polarities of the individual magnets. I marked the (arbitrary) "north" poles with a black ink dot. This arrangement makes the two "horseshoes" attract each other across the blade gap, yielding a similar force vector diagram as two parallel bar magnets (and similar to the notched OEM magnets, which act like horseshoes as well.)
I cut the sheet steel "tie bars" out of the bottom of a small soup can, they are each 1/2" x 3/16".
I'm very happy with this "improvement". I suspect the OEM magnets were stronger when they were made, but have lost some strength. It's possible this new arrangement somewhat replicates the scale's original damping action, I don't know.
-
Here are the OEM M5 magnets in place:
With these, after zeroing the scale, starting from full beam deflection against the bottom frame stop, after releasing the beam the pointer traverses "zero" 16 times (8 each direction) before settling at zero again. (My earlier report of 9 traversals was a typo.) The initial upswing after release takes the pointer to the 4th deflection mark above zero.
I tried several more iterations of N42 magnets, and settled on "D33" N42 cylindrical 3/16 x 3/16, two on each side of the blade, with a sheet steel "tie bar" across each pair to form horseshoes. The 3/16" diameters allow them to nestle snugly in the spaces alongside the partitions, and also sit as close to the blade as the OEM magnets:
http://www.kjmagnetics.com/proddetail.asp?prod=D33
With these, the swing test yields only 6-7 traversals of "zero" before settling on zero, and the initial upswing only reaches the 2nd deflection mark above zero (i.e. half the deflection of the OEM magnets.)
Note that I packed pieces of balsa wood under and around the magnets, to position and secure them. The pieces under the magnets in the cavity on the right are 1/8" thick, to raise (toward the camera) the magnets to the center of the cavity. In the left cavity you can also see some pieces of balsa wedged in against the magnets to hold them in place. You could just use dabs of silicone sealer or whatever to secure them, but since each magnet is attracting its polar opposite across the blade gap, they tend to stay put without help, just not securely enough to keep them from falling out in handling.
Also note the polarities of the individual magnets. I marked the (arbitrary) "north" poles with a black ink dot. This arrangement makes the two "horseshoes" attract each other across the blade gap, yielding a similar force vector diagram as two parallel bar magnets (and similar to the notched OEM magnets, which act like horseshoes as well.)
I cut the sheet steel "tie bars" out of the bottom of a small soup can, they are each 1/2" x 3/16".
I'm very happy with this "improvement". I suspect the OEM magnets were stronger when they were made, but have lost some strength. It's possible this new arrangement somewhat replicates the scale's original damping action, I don't know.
-
Last edited:
Mulligan
Silver $$ Contributor
Scott, I have a 5-10 RCBS/Ohaus I bought new in the early '80's.
I'm I better off having you tune this scale or buying one of your M5's?
CW
bobinpa
Gold $$ Contributor
Many shooters ask me questions about scales, beam scales in particular. I thought it might be useful to address some of those questions here.
Q: What is the accuracy that I can expect?
A: One half of one tenth or 1/20th of a grain for absolute accuracy in normal loading weights.
Q: What is the level of precision achievable with a beam scale.
A: I have a customer in Denton TX who has quantified this with SD of less than .02grains.
In general, I say plus or minus a kernel.
Q: What do you do to them?
A: I make them better
Q: What scale do you use?
A: I use a tuned Redding that is in too poor of shape to sell to anyone.
Q: What scale do you recommend?
A: An M5 if you have the scratch, a Redding or a D5 or older 502 if you are on a budget, all need tuning and calibrating.
Q: Can you tune an RCBS 505?
A: No, sorry that middle poise just doesn't allow for repeatability. It is a major design flaw. Two poise 505s work up wonderfully however.
Q: How long will it take?
A: it varies greatly. I'm one man, this is a side hobby that demands perfect focus. I'm never bugged by customers calling me. I know what it is like to wait for good stuff.
Q: Can you tune my 10-10 scale?
A: if it is American made, most likely, yes. If made elsewhere(Mexico,China) no!
Q: Will one of your scales reduce my ES and SD?
A: in most cases, yes. However, the chronograph and other loading practices must be up to the task.
In other words, dont expect my scale to make up for using mixed headstamp brass, etc.
Q: What do you think of the Dandy Auto Trickler?
A: I love mine and can't imagine how I lived without it. With it, one of my scales and a Lee powder measure($20) you have a very cost effective, high precision charging system
Scott Parker
Single Kernel Scales
VLD223@yahoo.com
661 364 1199
Hi Scott. Can an RCBS 304 be tuned?
danny
Silver $$ Contributor
Scott,
Let me see if I understand that statement above correctly. It might be helpful to others as well. If you have tuned a scale and then would check it with a 20 gr. weight repeatedly, does this mean that you would expect, and find it reasonable that you would get weighing results for as much as 20.05 gr., as low as 19.95, and results in between?
Thanks,
Danny
BoydAllen
Gold $$ Contributor
One thing that I have done to my self tuned 40 year old 10-10 is to pad the beam swing stopping points with some very inexpensive, self adhesive foam weatherstripping. I stacked two pieces on the bottom, and one on the top. The material is of the lowest density, quarter inch thick... the cheap stuff. I bought a roll for a project and had the leftover material sitting around. It has worked very well, improving the scale's performance. The swing has a shorter arc, and comes to a stop rather quickly because there is less momentum (mass times speed) to overcome. Shorter arc = less speed and the foam acts to cushion the beam.
sparker
Silver $$ Contributor
No, it means that when testing against known values, the scale will be within .05 grains of that value. From one reading to another at the same value, it should be plus or minus a kernel.
danny
Silver $$ Contributor
Thanks Scott,
I guess, quantifying that more properly, a known 20 gr. value could then resolve out at 20.025 on the high side, or 19.975 gr. on the low side (or inbetween) , if weighed repetitively, on a tuned scale?
Thanks,
Danny
sparker
Silver $$ Contributor
Accuracy and precision are different things. The accuracy level is within .05 grains. So, a 50 grain check weight could weigh 49.95 on the scale. It should weigh 49.95 plus or minus a kernel each time.
danny
Silver $$ Contributor
danny
Silver $$ Contributor
I found (after trying a Redding Model 2) that I much more prefer an Ohaus/RCBS scale, M5, 10•10, etc., but that's just me.
Danny
sparker
Silver $$ Contributor
These are hydraulically dampened model 1s.
They dampen out like lightning and are sensitive to a single kernel of IMR 8208. They are absolutely amazing when I’m finished with them.
I put this in front to make the graduations easier to read:
They dampen out like lightning and are sensitive to a single kernel of IMR 8208. They are absolutely amazing when I’m finished with them.
I put this in front to make the graduations easier to read:
Murray Brook
Silver $$ Contributor
sparker
Silver $$ Contributor
N
No sir.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.