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Hole Distance Measurement (Centre To Centre) : 1. Zero Positioning and Measurement Between Two Holes

1. Zero the caliper by inserting both hole distance inserts into one hole. 2. To measure the distance between evenly spaced holes on a bolt circle, multiply the constant corresponding to the number of holes by the bolt circle diameter. 3. To measure the distance between two holes at a given angle on a bolt circle, multiply the sine of half the angle by the bolt circle diameter.

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Srinu Gudala
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346 views1 page

Hole Distance Measurement (Centre To Centre) : 1. Zero Positioning and Measurement Between Two Holes

1. Zero the caliper by inserting both hole distance inserts into one hole. 2. To measure the distance between evenly spaced holes on a bolt circle, multiply the constant corresponding to the number of holes by the bolt circle diameter. 3. To measure the distance between two holes at a given angle on a bolt circle, multiply the sine of half the angle by the bolt circle diameter.

Uploaded by

Srinu Gudala
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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DK

Hole distance measurement (centre to centre)

1. Zero positioning and measurement between two holes

Assemble FMS hole


distance inserts as shown in Insert a FMS hole distance insert in
FMS holders (e.g. 10A or Insert both FMS hole distance inserts each hole - the caliper will now display
11A) on a digital caliper in one hole and zero the caliper the distance between hole centres.

2. Holes evenly spaced on a bolt circle diameter


No. of No. of
Constant Constant
holes holes
3 0,866025 14 0,222520
4 0,707106 16 0,195090
5 0,587785 18 0,173648
6 0,500000 20 0,156434
8 0,382683 24 0,130526
10 0,309017 30 0,104528
12 0,258819 36 0,087155

Hole distance = Constant x bolt circle diameter


e.g. with 3 evenly spaced holes and a bolt circle diameter of 100 the hole distance is 0,866025 x 100 = 86,60

Bolt circle diameter = Hole distance / constant


e.g. with 3 evenly spaced holes and a hole distance of 86,85 the bolt circle diameter is 86,85 / 0,866025 = 100,29

N.B. Where an even number of holes are closely spaced it might be an advantage to “jump” over a hole. i.e. 24 holes and calculate as 12 holes.

3. Two holes on a bolt circle diameter where the angle is given

Hole distance = sin (angle/2) x bolt circle diameter


O
e.g. with an angle of 70 and a bolt circle diameter of 100 the distance is
O O
sin (70 / 2) x 100 = sin 35 x 100 = 0,573576 x 100 = 57,36

Bolt circle diameter = Hole distance / (sin angle/2)


O
e.g. with a hole distance of 57,15 and an angle of 70 the bolt circle diameter is
O O
57,15 / sin (70 / 2) = 57,15 / sin 35 = 57,15 / 0,573576 = 99,64

A pair of standard FMS hole distance inserts type 63A can measure the
hole distance (centre to centre) between holes up to Ø15 mm/0.6”

Inserts for other dimensions can be made to order


– ask for a price quote and delivery time

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