This forum thread will track of the version history of the following download:
BOLTGRP.xls

Some details on conversion guidance between metric and inch based strength grades is given in section 3.4 of the standard SAE J1199 (Mechanical and Material Requirements for Metric Externally Threaded Steel Fasteners).

Metric fastener strength is denoted by a property class which is equivalent to a strength grade. Briefly:

Class 4.6 is approximately equivalent to SAE J429 Grade 1 and ASTM A307 Grade A

Class 5.8 is approximately equivalent to SAE J429 Grade 2

Class 8.8 is approximately equivalent to SAE J429 Grade 5 and ASTM A449

Class 9.8 is approximately 9% stronger than SAE J429 Grade 5 and ASTM A449

Class 10.9 is approximately equivalent to SAE J429 Grade 8 and ASTM A354 Grade BD

For information there is no direct inch equivalent to the metric 12.9 property class.

In the "BOLTGRP.xls" workbook and in the "Bolt Group(<=25)" worksheet off of the main calculation page on the right, I already had a facility to generate the bolt coordinates for circular bolt groups. Now, I have added similar facilities to automatically generate the bolt coordinates for bolt group patterns with 1, 2, 3 or 4 vertical rows of bolts. All the user needs to do is fill in the minimal input, copy and "Paste-Special" the coordinate values in the input data portion of the worksheet, and then input the appropriate total number of bolts. Instructions for each of the bolt group patterns are given.

It was brought to my attention in the "Bolt Group)<=25)" worksheet off of the main calculation page to the right there were a couple of text cell reference errors listed in the notes for one vertical row of bolts and 2 vertical rows of bolts.

This workbook is now version 2.8.

I recently updated the "BOLTGRP.xls" workbook, where in the calculation worksheets I added the ability for the user to select high strength bolt diameters of 1/2" and 5/8" sizes. Previous versions of this workbook limited the user to a smallest size bolt of 3/4" diameter. I made this update at the request of some folks who often use bolts smaller than 3/4" diameter in their line of work.

The version of this workbook is now 2.9.