| Topic: |
Science > Physics |
| User: |
"David Peters" |
| Date: |
09 Feb 2006 05:43:21 AM |
| Object: |
Physics: How break lead in mechanical pencil? |
I am referring to a simple mechanicalpencil like this sort of thing
http://www.abcpro.ca/images/53067-00.jpg
I was using one and I found the lead was broken. So clicked some
more lead out and after about 4mm that too was broken. A third time
showed the same. In the end I don't know how many pieces the lead
was in.
ASSUMING that someone hadn't put lots of 4mm lead fragments into the
pencil, then how can such a full-length lead get broken up.
I can't see how a lead that has entered the "user-tube" (IYSWIM) can
get broken.
Impact from dropping the pencil in-line with the vertical onto it's
lead end should not do it.
Side impact should not be a cause either.
What other things could have done this?
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| User: "PD" |
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| Title: Re: Physics: How break lead in mechanical pencil? |
10 Feb 2006 10:26:34 AM |
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David Peters wrote:
I am referring to a simple mechanicalpencil like this sort of thing
http://www.abcpro.ca/images/53067-00.jpg
I was using one and I found the lead was broken. So clicked some
more lead out and after about 4mm that too was broken. A third time
showed the same. In the end I don't know how many pieces the lead
was in.
ASSUMING that someone hadn't put lots of 4mm lead fragments into the
pencil, then how can such a full-length lead get broken up.
I can't see how a lead that has entered the "user-tube" (IYSWIM) can
get broken.
Impact from dropping the pencil in-line with the vertical onto it's
lead end should not do it.
Side impact should not be a cause either.
What other things could have done this?
It's my experience that the part of the barrel that extends from the
finger grip can get bent from excessive writing pressure. The point of
the bend in that sleeve, which is usually right at the joint with the
grip, is where stress is applied to the lead and it often breaks there.
Using a softer lead will sometimes get around this problem.
PD
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| User: "Marcelo Zimmer" |
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| Title: Re: Physics: How break lead in mechanical pencil? |
09 Feb 2006 06:26:43 AM |
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Hi David,
Have you tested if the lead was broken before you click it out of
the pencil??? I mean, I had some time ago some similar problem, and the
cause of lead breaking was that the lead I've bought was out of
patterns, or some things like this, and its diameter was bigger than
the allowed by the mechanicalpencil, so there was high pressure in the
lead, making them break easily.
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