Beam scale probems, Help?

[XnotedgeanymoreX]

I have an old Lyman D-7 which I believe to have been made by Ohaus that I picked up used. It's a 505gn capacity scale with the large poise being 5gn increments up to 500gn and the small poise being in tenths of a grain, up to 5.0gn. For the record I do not have a set of check weights and consequently have not used this scale to load anything with because of my concern.

The problem is that the small poise does not agree with the large poise. If I set the large poise to 175gn and place a 175gn projectile in the pan it reads spot on. If I set the large poise to 170gn and the small one to 5gn the pan comes up light. It does this consistently and repeatably. Seems like it was only off by about half a grain, but it's enough that I don't trust it as I am loading small volume handgun cases. I don't recall the exact amount, but I will set it up and check it tonight if I have time.

Edit:My mistake, the pan comes up heavy, not light. Consistently what this scale thinks is 0.7gn heavy, whatever thats worth...


The scale is immaculately clean and appears to have seen very little use. The knife edges on the bearing are sharp. They are also clean and dry, as are the agates. There are no obvious signs of damage, wear or missing/misaligned parts. The beam moves freely and does not contact any part of the scale other than the pivot point.

Has anyone ever had a similar issue with a beam scale? I have read horror stories about lyman not being any help with these as its discontinued and wasn't made by them in the first place. I read that Ohaus has a repair facility in AL, but have yet to contact them. Is there anyone local that might be able to shed some light on this?

Any advice, suggestions or experiences are much appreciated! Thanks in advance -Josh

 

[Snow Bird]

Just me but I would say forget it and get an elec one. Not being smart about it but elect are so much faster and are within 1/10 0f a grain.

 

[M.O.A.]

I'm going out on a limb here but 2 questions.
1) does it zero correctly
2) are you using it on a verified level surface ?

 

[XnotedgeanymoreX]

Yes, zeroes easily and holds zero well if not moved. When I noticed this condition I built a leveling plate out of a 1x12 and machine screws to set the scale up on. I level it out both ways with a torpedo level prior to zeroing the scale.

I set it up last night and verified the condition. If any quantity of powder is weighed with the large poise only (say 10gn), then altered to make it level out with both poises (5gn+5gn) 0.7gn consistently have to be removed from the pan to get back to zero. (Well, whatever this scale considers to be 0.7gn anyway...) This weight is consistent all the way from 10gn to 200gn, but thats as far as I went.

SnowBird: You might well be right, I may end up with one before this is over with!

 

[M.O.A.]

Only 2 things I know to check besides that. First is the weigt of the pan and counterweight under the pan. ( yeah it sounds dumb but if its not the right pan for that scale they don't weigh right ) second is the way the pan hanger is attached. If its backwards that will mess them up also. Other than that I'm clueless.

 

[XnotedgeanymoreX]

Pan looks original, just like the one in the picture on the box, but that is no guarantee. Hanger is oriented like the picture and the instructions depict, and zeroes out near the middle of adjustment, making me think the counterweight is ok. All parts fit in the original box like they grew there.

I'm stumped too, thinking contacting Ohaus is about the only option other than replacement. Thanks for the input! -Josh

 

[XnotedgeanymoreX]

MOA: I think you're on to something about the counterweight. I opened it and removed a single *tiny* piece of shot and put it back together. The difference changed to 0.8gn consistently. I replaced it and it went back to a difference of 0.7gn so I suspect the screw was loose at some point and some shot fell out. I bet if I had 7 more pieces of shot like the one I removed to place in the counterweight the difference would be gone...

Don't know if I will try to find some ballast or just source a replacement pan holder/counterweight, but I think I have figured out the problem. Many thanks! -Josh

 

[M.O.A.]

Fishing sinker and a pocketknife.. or #7.5 bird shot has served me well. Good luck.

 

[XnotedgeanymoreX]

I filed down a screw to 0.7gn and zeroed the scale out with it in the pan. The adjustment screw was almost all the way out, and the inaccuracy was exactly the same as without it. Seems I was wrong in suspecting the counterweight as the problem. With no clue what else to do I think I'll just look into replacing the scale. Thanks for everyone's input, especially MOA! -Josh

 

[M.O.A.]

Bring me the scale n I will fix and calibrate it for you or at least check it against my digitals and cal weights.

 

[XnotedgeanymoreX]

Bring me the scale n I will fix and calibrate it for you or at least check it against my digitals and cal weights.

Thats an extremely nice offer! I'll send you a PM to work out the details. MOA, you have been one of the most helpful people I've talked with on here! Thanks for all the help, as well as the dies! -Josh

 

[M.O.A.]

OK. Here's what I found. At some point the amount of ballast was changed in the scale platform. Probably because the pan was lost or damaged and replaced. Corrected the ballast issue and the scale checks against my cal weights within .01 gr. That being said I would not use these for weighing small charges without verification.

 

[XnotedgeanymoreX]

Cool, many thanks John! I'll shoot you a PM to work out the details. Thanks again! -Josh