This HTML5 document contains 42 embedded RDF statements represented using HTML+Microdata notation.

The embedded RDF content will be recognized by any processor of HTML5 Microdata.

Namespace Prefixes

PrefixIRI
dctermshttp://purl.org/dc/terms/
yago-reshttp://yago-knowledge.org/resource/
dbohttp://dbpedia.org/ontology/
n18http://dbpedia.org/resource/File:
foafhttp://xmlns.com/foaf/0.1/
n9https://global.dbpedia.org/id/
dbthttp://dbpedia.org/resource/Template:
rdfshttp://www.w3.org/2000/01/rdf-schema#
freebasehttp://rdf.freebase.com/ns/
n16http://commons.wikimedia.org/wiki/Special:FilePath/
rdfhttp://www.w3.org/1999/02/22-rdf-syntax-ns#
owlhttp://www.w3.org/2002/07/owl#
wikipedia-enhttp://en.wikipedia.org/wiki/
dbphttp://dbpedia.org/property/
provhttp://www.w3.org/ns/prov#
dbchttp://dbpedia.org/resource/Category:
xsdhhttp://www.w3.org/2001/XMLSchema#
goldhttp://purl.org/linguistics/gold/
wikidatahttp://www.wikidata.org/entity/
dbrhttp://dbpedia.org/resource/

Statements

Subject Item
dbr:Pentalobular_screw_thread
rdfs:label
Pentalobular screw thread
rdfs:comment
A pentalobular screw thread is a form of self-forming thread used for screws. Self-forming screws are used in ductile materials, such as aluminium and plastics. Self-tapping screws are widely used for driving into sheet metal or plastics and forming their own thread. They may be either self-drilling, forming their own hole through unbroken material, or fitted into a pre-pierced hole. Self-drilling screws have some ability to cut a thread, as for a tap. Others work not by cutting, but rather by roll-forming the thread, pushing excess material out of the way by plastic deformation. This is one reason why ductile host materials, rather than brittle, are needed.
foaf:depiction
n16:Pentalobular_screwthread.png
dcterms:subject
dbc:Threading_(manufacturing) dbc:Threaded_fasteners dbc:Screws
dbo:wikiPageID
30548890
dbo:wikiPageRevisionID
1094560827
dbo:wikiPageWikiLink
dbr:Reamer dbr:Self-forming_thread dbr:Threading_(manufacturing) dbr:Ductile dbr:Tap_and_die dbr:Prime_number dbc:Threaded_fasteners dbr:Self-tapping_screw dbc:Threading_(manufacturing) dbr:Thread_profile dbr:Screw dbr:Sheet_metal dbc:Screws n18:Pentalobular_screwthread.png dbr:Aluminium dbr:Plastic dbr:Plastic_deformation
owl:sameAs
n9:2MTux freebase:m.012r5rvf yago-res:Pentalobular_screw_thread wikidata:Q25040413
dbp:wikiPageUsesTemplate
dbt:Reflist dbt:About dbt:Colorbull
dbo:thumbnail
n16:Pentalobular_screwthread.png?width=300
dbo:abstract
A pentalobular screw thread is a form of self-forming thread used for screws. Self-forming screws are used in ductile materials, such as aluminium and plastics. Self-tapping screws are widely used for driving into sheet metal or plastics and forming their own thread. They may be either self-drilling, forming their own hole through unbroken material, or fitted into a pre-pierced hole. Self-drilling screws have some ability to cut a thread, as for a tap. Others work not by cutting, but rather by roll-forming the thread, pushing excess material out of the way by plastic deformation. This is one reason why ductile host materials, rather than brittle, are needed. To form a close-fitting thread that will not be loose afterwards, roll-forming requires a lobed tool rather than a constant diameter cylindrical tool. This is particularly the case when the tool and the fastener are the same, such as for a screw. A lobed or polygonal form allows residual compressive stresses from the forming parts of the thread to be relieved in the undercut clearance between the lobes. This lobular thread has other advantages too. It allows the screw to be turned with lower torque, which also increases the 'strip-to-drive ratio' between the torques needed to drive the screw in or to damagingly strip the threads out. The proportions of the lobular thread can also change over the length of the screw, so that the tip of the screw can use greater lobulation to form the thread more aggressively and also provide a centring effect. In conjunction with a with sharp arrises, a three-lobed thread of this form is the basis of the well-known Taptite screws. The optimum number of lobes is five. Their number should be prime, to avoid the usual harmonic effects between lobes. As is already widely recognised with tapered reamers, five has better stability than three in imperfectly circular holes. More lobes than this, such as seven, would reduce the spacing for clearance between the lobes. A patent has been applied for about a thread with such an optimised pentalobular form. Such thread forms are not a new innovation. A patent for machinery to roll-form the threads of the screws was granted in 1975.
gold:hypernym
dbr:Form
prov:wasDerivedFrom
wikipedia-en:Pentalobular_screw_thread?oldid=1094560827&ns=0
dbo:wikiPageLength
3584
foaf:isPrimaryTopicOf
wikipedia-en:Pentalobular_screw_thread
Subject Item
dbr:Pentalobular_screw
dbo:wikiPageWikiLink
dbr:Pentalobular_screw_thread
dbo:wikiPageRedirects
dbr:Pentalobular_screw_thread
Subject Item
dbr:Self-tapping_screw
dbo:wikiPageWikiLink
dbr:Pentalobular_screw_thread
Subject Item
wikipedia-en:Pentalobular_screw_thread
foaf:primaryTopic
dbr:Pentalobular_screw_thread