Brunson 771 - Page 43

39 Operation and Adjustment Manual
Forinformationonthecali‐
brationofthe190typemi‐
crometers,pleasereferto
themanualforyourspe‐
cificproduct.

2.Pointthetelescopeatanarbitrarilyplacedscale,heldatafinite
distance(werecommendabout4feetaway).Placethescaleina
horizontalorientationandchoosesomearbitrarytargetpoint,e.g.,
thethreeinchtarget.Tightenthehorizontalandverticaltangent
locks,andusethetangentscrewstosetpreciselyonthetarget.

3.Withoutdisturbingthemicrometerdrum,gentlyrotatethemi‐
crometerbodyonthetelescopebarrel180°.Nowthedétenteposi‐
tiononthebottomofthemicrometershouldbealignedwiththe
pinonthetelescopebarrel,althoughagainnotseated.

4.Nowlookthroughthetelescopetoseeifthereticleisstillcen‐
teredonthechosenscaletarget.Ifithasmoved,rotatethemi‐
crometerdrumsothatthetargetcomesbackintoregisterdirectlyin
thecenterofthereticleasitwasbefore.

5.Readthemicrometerdial.Ifithasdeviatedfromzeroineither
directionbymorethan0.001”,themicrometerisoutofadjustment
andwillintroduceerrorintothefieldchecksdescribedinthischap‐
ter.Pleaserefertothemicrometermanualforinformationregard‐
inghowtomaketheappropriateadjustments.Ontheotherhand,
ifthemicrometeriswithintheacceptable±0.001”band(indicating
anactualerrorofhalfthereading),thenyoumayproceed.


Tocheckforrangeadjustment:

1.Installandseatthemicrometeronthetelescopebarrel.Setthe
micrometerdrumtozero.

2.Pointthetransitonceagaintoanarbitrarilychosentargetloca‐
tion(linepair)onahorizontallymountedscale.Besurethatthe
scaleisnominallysquaretothetransit.

3.
Usingthemicrometeronly,shiftthereticleovertothenextadja‐
centlinepair,representingashiftofeither0.100”(Englishscale)or
2mm(metricscale).Notethemicrometerreadingatthispoint.

4.Againusingthemicrometeronly,shiftthereticleintheopposite
directionbackpastthestartingpoint,tothenextadjacentlinepair.
Notethemicrometerreadingatthispointaswell.

5.Iftheerrorineitherpositionisgreaterthan±0.0005”(English
scale)or0.01mm(metricscale),themicrometershouldbecali‐
bratedpriortouse.Pleaserefertothemicrometer
manualorreturn
tothefactoryforadjustment.
Therangeadjustmentfield
checkdescribedhereisonly
validformicrometershav‐
ingarangeof±0.100”or
±2.5mm.
Indescribingtherange
check,weareassuming
thatyouareusingametric
scaleinconjunctionwitha
metricmicrometer;orlike
‐
wise,anEnglishscalein
conjunctionwithanEng‐
lishmicrometer.