Date: July 18, 2011
Jag BrushTM Less Likely than Standard Jags to Damage Rifling, Part VII: Effect of
Mass
Los Angeles, CA — since any jag can come in contact with the bore wall, it is
important to consider whether an exposed jag has the potential to cause damage. If
either cleaning element were in direct contact, a Jag BrushTM is less likely than a
standard solid metal jag to cause damage.
Each Jag BrushTM bristle is flexible and small in mass and contact area. It means
the maximum coefficient of friction created by all of its bristles if exposed against a
bore wall is unlikely to be enough to damage rifling. The obvious OK to direct contact
of a Jag BrushTM is the fact that most consumers use brushes, being exposed and
not covered by patches, to clean bores. By comparison, a standard solid jag is
inflexible, massive, and has a much larger surface area, and all of these factors in
combination result in a higher coefficient of friction spread over a larger area.
Consumers already know they never want a standard jag to make direct contact.
The table shows that the ratio of masses is 10K to 36K greater for a standard jag
than it is for a single bristle of a Jag BrushTM.
The contact area of a bristle is small, and it could seem that it creates greater
pressure, than does the larger surface of a standard jag, against a surface. But what
may seem true is not the case. Equivalent to pressure, being a force to area ratio,
would be a mass to area ratio. Ratios of mass to contact area are greater for
standard jags. Let us assume that the contact area for a jag to bore wall is a
semicircular strip of width 1 mm at the first rib of the jag. Let us assume that the
contact area for a jag brush is a circular disk at the tip of a bristle. Then the ratio for a
jag rib is over ten times greater than it is for a Jag BrushTM bristle. See calculation
below.
For example, a 22 jag might be 3.9 grams with a semi-circular shaped region of 1
mm width having area 14 square mm. The mass to area ratio is 0.28. A 22-cal Jag
BrushTM bristle extending from the twisted core is about 0.00017 grams, and it has
an area at its disk-shaped tip of about 0.0095 square mm. The mass to area ratio is
0.018. Then the fraction 0.28 / 0.018 gives 15 to 1. When we assume the jag
touches the bore not around entire circumference at one time, but along only a 60
degree arc, then press friction ratio increases to 6 times more, being 90 to 1.
PRESS CONTACTS
Shane Smith
+1 310-463-7811 (mobile)
RigelProducts@yahoo.com
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