[NTLK] eMate 300 Repair Question - Washers vs New Spring?

[DXH]

> On May 11, 2021, at 3:40 PM, Doug <ispinn at gmail.com> wrote:
> 
>> 
>>   (3) Replacing with a
>> continuous spring is best to
>> eliminate the problem.
> 
> I disagree.

That is your right.

> Any manufacturing-physics experts correct me, but the precision
> needed for a single, solid piece spring would be too difficult to achieve.

Except that I can make them all day long with ease…

> The high tensions involved make it even harder.

With the right tools it is not that difficult.

https://youtu.be/Xy_1QohiEwU


> The two spring pieces, as is, interact individually along key planes,
> independent of each other, and have some wiggle room, when lubricated
> properly, to work correctly.

So do the ends of a continuous spring. The ends are still free to move independently of each other, it’s just that any axial movement is greatly reduced because the each end is pulling against the other.


> Making them one piece, confining and eliminating some of that previously
> mentioned wiggle room--and adding significant, additional
> restrictions--would make the engineering requirements too exacting, too
> precise, and too hard to maintain their tolerances during the manufacturing
> process. The single part becomes too impossible to make, although it's the
> best *in theory.*

Springs, by their very nature, are compliant systems. 
Again, I see a lot of hand waving about engineering requirements but, if I can make them in my humble workshop and they work, a 2T dollar company should have no problem with making them.

> Apple IMHO, thought this through.

Did they? 
Or perhaps the spring manufacturer was already tooled-up for a particular spring and said ok Apple, I can give you a great deal on a bazillion single-loop springs? Just a thought. Not saying that’s what happened but I have worked in engineering for long enough to know that deals like that are made every day.

> Two piece springs is best.

I don’t have a dog in this hunt. I am not providing any one-piece spring repair other than providing instructions on how to do it yourself. 

I understand you do provide the two piece spring repair service…

> They just
> didn't put enough thought into how to keep them from walking, or that
> they'd eventually walk at all.

Or that the machine would still be used 24 years later…


PCBman