×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Thread Pitch of SA-194 Nuts

Thread Pitch of SA-194 Nuts

Thread Pitch of SA-194 Nuts

(OP)
Hi All,

I have a few questions regarding metric nuts according to SA-194/SA194M. For reference, I am working in the 2007 Edition of the Code (2009a Addenda).

Paragraph 8.2 states: "Unless otherwise specified, threads shall be in accordance with ANSI B 1.1 or ANSI B 1.13M, and shall be gaged in accordance with ANSI B 1.2 and ANSI B1.13M as described in 8.2.1 and 8.2.2."

Paragraph 8.2.1 states: "8.2.1 Nuts up to and including 1 in. nominal size shall be UNC Series Class 2B fit. Metric nuts up to and including M24 nominal size shall be coarse thread series tolerance 6H."

A client wants to use M20x1.5 nuts. The 1.5 pitch is listed in B1.13M. However, 1.5 mm pitch falls under the fine series. My interpretation of paragraph 8.2 and 8.2.1 is that coarse series thread must be used, i.e. 2.5 mm pitch to comply with SA-194. Am I interpreting this correctly or am I being overly strict? Is it possible to read the "Unless otherwise specified" clause in paragraph 8.2 to apply to the pitch meaning a 1.5 mm pitch is allowed.

If am being too strict, how should I interpret paragraph 7.2.1 which states: "All nuts shall be capable of withstanding the proof loads specified in Table 3 and Table 4. However, nuts manufactured to dimensions and configurations other than those covered by ANSI B 1.1, ANSI B 1.13M, ANSI B 18.2.2, and B 18.2.4.6M are not subject to the proof load test." The nuts are manufactured to B1.13M and therefore must be capable of withstanding the proof loads as specified in Table 4.

Table 4 gives the proof load for M20x2.5 nuts (not 1.5). Should the same proof load then be used for 1.5 mm pitch nuts as for 2.5 mm pitch nuts?

Thank you in advance.

RE: Thread Pitch of SA-194 Nuts

in 2019 edition also it is mentioned that M20 nut shall have coarse pitch.
It is better to use coarse pitch as mentioned in code so that there will not be doubts pertaining to proof load.

You can check with your client if they are ok with coarse pitch. You can share with them the doubts pertaining to proof load.

Do give us the feedback about client's decision.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

White Paper – Choosing the Right Spring Loaded Connector
In today’s cost-sensitive world, designers are often driven to specify the lowest cost solution for every aspect of their designs to ensure that their solution is competitively priced and their company remains profitable. However, specifying a low-cost, low-quality connector solution can result in premature failure, considerable re-work costs and damage to reputations. Download Now
eBook – Own the Lifecycle: Sustainable Business Transformation
Increasingly, product and services companies are seeking more information and control in the operational lifecycle of their products, including service and use. Better information about the operational lifecycle, and the ability to use that information, requires more than just unstructured data flowing back from products in the field. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close