CNC Software CNC Software

Giveaway!

CNCCookbook Giveaway

Click the Giveaway photo for details!

Subscribe

 

Categories

Spindle Orientation, Drive Dogs, and Repeatable Runout

Mar 15, 2012   //   by Bob Warfield   //   Blog, Techniques  //  1 Comment

Every CNC machinist has seen the ubiquitous “drive dogs” found on many tapers:

Spindle Drive Dogs

Spindle Drive Dogs…

They’re the two little “ears” that engage notches in the toolholder.  Not every taper has them, but many do.  Getting the drive dogs positioned to line up with the toolholder in the changer carousel before a toolchange can happen is called “spindle orientation” or sometimes “spindle positioning”.

You might think spindle orientation is only about lining up the drive dogs with toolholder notches, but I recently learned differently.  Dave Decaussin, one of the original founders of Fadal, recently remarked on a video I was watching that spindle orientation is also essential to maintaining tolerances while machining.  The reason is runout.  When you maintain the same spindle position relationship to the toolholder, you ensure that whatever runout there is will at least be consistent–either consistently good or consistently bad.  Consistency is the main thing, because if it is consistent, we can compensate for it.  If you think about it, the runout just makes the endmill act like it is a slightly larger diameter as it wobbles in the cut.  If that effective diameter changes every toolchange, the CNC machinist will have a tough time maintaining tolerance.  But if it is consistent, there is hope.  You can use your wear offsets to just enter the effective diameter of the tool and cut accurately despite that runout.

It’s good to learn at least one new thing every day!

 

Like what you read on CNCCookbook?

Join 30,000+ Machinists, Designers, Engineers, and Hobbyists!  Get our latest blog posts delivered straight to your email inbox once a week for free. Just enter your email address below:

 

100% Privacy: We will never Spam you!

1 Comment

  • Spindle orientation is also very useful for things like auto loading lathes. You probably already know that but think iPod this as completeness.

Leave a comment

Home

Software

  GW Calculator

  GW Editor

  Gearotic

  Conversational

  Deals and Steals

CNC Blog

  Software

  Techniques

  Beginner

  Cool

  Projects

 

Cookbooks

     Feeds and Speeds

     G-Code Tutorial

     CNC Machining & Manufacturing

     DIY CNC Cookbook

     CNC Dictionary

CNC Projects

Resources

     Machinist's Search

     Videos

     Online Groups

     Individuals

     Reference Data

     Books

     CNC Dictionary

     Suppliers

     Tool Brands

Workshop

     Hall of Fame

     Organization: Soon!

 

About

     Customers

     Partners

     Our History

     Privacy Policy

 
All material © 2010-2014, CNCCookbook, Inc.