Ohaus 3100 beam rubs magnetic dampener

[pjh421]

Any idea why the dampener magnets would pull the beam toward the rear of the magnet mounts? The beam looks pretty straight. This misalignment interferes with the beam travel.

Paul

[cwtebay]

Not an expert on this scale, but I can guarantee that any tweaks like appears in the second photo will cause wonkiness in its behaviour.

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[beemer]

I have an Ohaus 3100, I got it out and took a good look. The tab that goes between the magnets is not straight with the beam or the slot between the magnets. It looks to have been slightly bent towards the front of the scale. The arm with the pointer is spaced like yours.

The dampening tab is not magnetic so it will not pull the beam, only creates current when the beam is moving.

The only set I have seen is the one I have so I can't tell you if it is right or not. All I can say is that I have checked my scales with a set of Lyman weights and the weights that came with a Pact scale. It agrees with any or all the check weight I have.

Hope you figure it out.
Dave

[pjh421]

Its wonky alright. The bearings aren't seated in this position, lol.

Dave, thanks for dragging yours out! I thought I'd just add a magnet to counter the pull but like you said, it's not magnetic.

Paul

[beemer]

The tab is held in place by screws, I wonder if there is a small adjustment slot under them. If there isn't any I would try to bend it slightly. It might be bad advice but it is useless as is. If I did I would check it against a known scale or with check weights.

I don't know how much you know about scales so a friendly word of warning, be very careful. Check everything before doing anything. Check for damage and binding around the pivot bearings and hangers. Don't remove any metal as it will affect balance. Parts are not available for these scales unless you find a junk set. I have no idea if anyone repairs them. I hope someone with more experience will check in.

I am NO expert but like to tinker and have fixed a few RCBS beam scales that were giving problems, most work about the same. I hope you figure it out as that is a nice set. Have you just recently acquired them or owned them for a while?

Dave

[1hole]

Ideally, the magnetic damping vane will be more or less centered in its gap, not for accuracy but to prevent accidental contact with the frame during use. Bend the vane so it runs right and move on, it's not critical.

The thing that IS critical with a balanced beam scale is that you can start by precisely adjusting the beam to "zero". After the beam is balanced and zeroed correctly, the scale's absolute accuracy is totally determined by the beam's detents and sliding weights; they don't change unless physically damaged by misuse. If the beam is damaged it can't be hidden so you can see it. I know of no easy way to fix a damaged beam at home.

I'll emphasise again that the beam itself should be precisely zeroed, absolutely free swinging and more or less level for use but, unlike cranky digital scales, it isn't necessary to precisely level a beam scale's frame; if the thing is zeroed and looks level it is plenty level enough.

You have one of the finest reloading scales ever sold. Keep the "V" blocks and knife edges clean and free from cobwebs.

[1066]

These old "Dial O Grain" scales are really well made. It look to me as if the beam has taken a sideways knock at some point. The damper blade is made of fairly soft thin aluminium plate and can easily be bent back into shape. First off, I would remove the damper blade completely, just the two little cross head screws hold it in place, then see if see if the beam is free and working as it should, of course it won't zero without the weight of the damper but you should easily be able to just slide the small poise along until it does, also expect it to take an age to settle without the damper.

So, if you can get it to balance and it's swinging free, just bend the damper blade flat and replace it. If the beam fails to swing free once the blade is removed you have a deeper problem. You can inspect the outer bearing block and knife edge without too much trouble by sliding the dust cover off but I wouldn't attempt the inner one unless you feel quite confident with this type of work.

[BCB]

These old "Dial O Grain" scales are really well made. It look to me as if the beam has taken a sideways knock at some point. The damper blade is made of fairly soft thin aluminium plate and can easily be bent back into shape. First off, I would remove the damper blade completely, just the two little cross head screws hold it in place, then see if see if the beam is free and working as it should, of course it won't zero without the weight of the damper but you should easily be able to just slide the small poise along until it does, also expect it to take an age to settle without the damper.

So, if you can get it to balance and it's swinging free, just bend the damper blade flat and replace it. If the beam fails to swing free once the blade is removed you have a deeper problem. You can inspect the outer bearing block and knife edge without too much trouble by sliding the dust cover off but I wouldn't attempt the inner one unless you feel quite confident with this type of work.

I agree with this.

I have a 304 which is the earlier model of this type of scale--it has been excellent.

In behind the dial, if you can look at the pivots by removing the metal dust cover. I didn't try to remove mine, but it might be worth a look see. Don't force anything--this is a precision instrument! Maybe something is under one of the knives, that will cause the bar to shift one way or the other. But, I really can't think something could get in there. Likely the damper blade is bent. Worth a try what 1066 says...

Good-luck...BCB

[pjh421]

Yeah, I'm no expert either. Started out with a Lyman D-7 that some druggies stole out of my storage area in the basement of an apartment I was renting. I wanted to kill them. All I could afford to replace it with at the time was the Lee Powder Scale at $16. Not even in the same league. Things got better over the years and I began accumulating some 505s, 502s, digital stuff too. The 304 was what I wanted but by the time I could afford one they were out of print. Long story short, the Letgo app notified me a few weeks ago that a Dial-O-Matic was available...FOR 50 BUCKS! The guy still had it but kept having to go out of town for a few days to a week at a time. I eventually got it for $107 delivered. Someone even built a box around it. The guy wasn't super talkative about the scale even after I told him what I wanted it for. I suspect it was a family member's and he somehow wound up with it. Turns out it was a 3100. It lacks the trickler stand that the 304 has. Anyway, it dragged from the moment I removed the wadded up protective paper. No biggie. I think we'll get her up and running soon. I just didn't want to proceed without asking the experts first. I could easily see myself permanently buggering it up because I thought I knew what I was doing. I removed the outer dust cover. They're soft and bend open easily. Underneath that is a black stop plate that will fall free. Its there to keep the pivot bar centered in the bearings. Yep, the inner one will be more challenging so I'll make sure our other options don't work before risking that. I think I would first tape the spring to prevent movement (uncoiling) and then disconnect the spring from the beam before attempting to remove the inner bearing dust cover. Thanks for all the suggestions! They are truly appreciated.

Paul

[1066]

Here's one I turned into an auto-trickler a while ago.

https://www.youtube.com/watch?v=0eGThfOYsrA

[NyFirefighter357]

I can pull mine out if you need another view.