What is the tolerance for locating pins?

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In this episode of Engineer to Engineer, Locating Pins edition, we’ll take a look at mounting methods with different shank types. If you’re new to the series, check out the previous episodes to learn more about locating pin head types, and the basics to workholding concepts.

Before diving into mounting methods, it’s important to grasp fit tolerances when working with locating pins. There are 3 basic types of tolerance fits: interference, clearance and transition.

Interference: This tolerance type creates an extremely tight fit by using a slightly oversized shank within a slightly undersized hole.

Clearance: On the opposite end of the spectrum, a clearance fit allows a small amount of space between a slightly undersized shank and an oversized hole.

Transition: The final tolerance type, transition, provides a near-exact match between the shank and hole, with slightly overlapping tolerance ranges.

Watch the video below to learn more about mounting methods. Subscribe to our YouTube Channel at http://www.youtube.com/MisumiUSA to be the first to know when we post new content.

 

 

 

Dowel Pin Installation Design Tolerance Table Chart

Hardware ANSI Menu
Mechanical Tolerance Standards Charts
Dowel Pin Size Chart Machined ASME ANSI

Design for press and slip fit of dowel pins used for alignment of mating parts utilizing GD&T tolerancing methods.

Review your design to determine if you have similar application requirements.  Should these design guideline be inadequate, reference the charts given within the Hole - Shaft tolerance pages.

General

• Typical material is 6061-T651, per QQ-A-250/11 or similar aluminum alloy for the base mating components.
• Dowel Pin - are stainless steel 304, 306, 18-8 etc .. or similar.
• Application - These fits are for location or alignment applications between two components.  Some shear load is acceptable, designer should determine acceptable stress limits for their particular application.

General

These fits are not line-to-line .  Fixed fastener calculations will show minimal interference between dowel pins and slip fit holes.  Dowel pins should be installed into press fit holes after finishing processes and not removed there after.  After the mating components are assembled the first time, one should note assembly orientation for repeat assembly of mating dowel pins.  It is optimal to design for one configuration assembly (fool - proof).

See bottom of page for application  illustrations.

Dowel Pin 
"D"
Diameter

Press Fit Hole

Slip Fit Hole

Hole Depth
"MD" MIN.

Pin Engagement
"E"

.031

Dia .0305 +/-.0005
V Dia .040 MAX. X 90°

Dia .0320 +/-.0005
V Dia .040 MAX. X 90°

.055 +/-.010

.025 +/-.010

.062

Dia .0620 +/-.0005
V Dia .080 MAX. X 90°

Dia .0635 +/-.0005
V Dia .080 MAX. X 90°

.070 +/-.010

.040 +/-.010

.094

Dia .0935 +/-.0005
V Dia .120 MAX. X 90°

Dia .0955 +/-.0005
V Dia .120 MAX. X 90°

.095 +/-.010

.060 +/-.015

.125

Dia .1245 +/-.0005
V Dia .160 MAX. X 90°

Dia .1265 +/-.0005
V Dia .160 MAX. X 90°

.110 +/-.010

.075 +/-.015

.187

Dia .1870 +/-.0005
V Dia .240 MAX. X 90°

Dia .1895 +/-.0005
V Dia .240 MAX. X 90°

.145 +/-.010

.110 +/-.015

.250

Dia .2495 +/-.0005
V Dia .315 MAX. X 90°

Dia .2520 +/-.0005
V Dia .315 MAX. X 90°

.175 +/-.010

.140 +/-.015

• These illustrations are toleranced per ASME Y14.5M - 1994 and ASME Y14.5-2009
• Units are in Inches
  
  Dowel Pin Installation Design

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Slip Fit Hole Design

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