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


Pressure calculation

Pressure calculation

Pressure calculation

I'm trying to calculate the amount of pressure required for rotary broaching. I've found a few charts online, and we can see what the machine is telling us the pressure is, but I'm looking for a formula for calculating thrust lbs. in different materials, using a 1/4" hex for example. The pilot hole is already drilled, so the calculation is just for cutting the corners out of the hex hole.

RE: Pressure calculation

The minimum broach force for a round hole is calculated

Force = 3.1416 x hole dia before broaching x number of teeth engaged x rise per tooth / 2 x constant

Constant is based on material in psi

Aluminum                    200,000 - 300,000
Brass                       200,000 - 300,000
Bronze                      350,000
Cast Iron                   200,000 - 350,000
High Temp alloy steel       Up to 600,000
Lead                        60,000
Mild Steel                  450,000
Steel Casting               400,000

This calculation does not take into account other factors such as cutting fluid, chip breakers, hook/face angle, sharpness.

RE: Pressure calculation

Looks great, thanks for your help!

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!


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