• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • PLEASE SUPPORT OUR FORUM - UPGRADE YOUR ACCOUNT HERE!
[4]

Shear Pin for 816?

January Project of the Month [3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

ACHiPo

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Feb 2, 2017
Messages
589
Likes
491
#1
After crunching my quick change gear box, I'd like to add a little protection (not that I'll likely do it again!) I'm thinking of replacing the pin holding the spindle to the gear box with a shear pin. I could use aluminum or brass, and I'm wondering if I should score it so it will shear more easily, or if that will just cause premature failure when in normal operation?
 

mikey

Active User
H-M Supporter-Premium Member
Joined
Dec 20, 2012
Messages
3,869
Likes
4,096
#2
I would use aluminum, which has a pretty low shear strength. My Emco lathe uses aluminum pins between the gear train and leadscrew.
 

ACHiPo

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Feb 2, 2017
Messages
589
Likes
491
#3
Mike,
Does the pin have a notch or is it just a cylinder?
 

Superburban

Active Member
Active Member
Joined
Jan 2, 2016
Messages
363
Likes
275
#5
Trying to design a shear pin for a new application, can drive you crazy. When I made one for my PTO winch, I started on the safe side, and made them with smaller diameters at the shear points. After several tries, I realized that I can measure the shear torque by locking one side, and using a torque wrench on the other side, to see what it takes to shear them.

Then of course the other issue, is what torque do you want to strive for?
 

ACHiPo

H-M Supporter - Premium Member
H-M Supporter-Premium Member
Joined
Feb 2, 2017
Messages
589
Likes
491
#7
Trying to design a shear pin for a new application, can drive you crazy. When I made one for my PTO winch, I started on the safe side, and made them with smaller diameters at the shear points. After several tries, I realized that I can measure the shear torque by locking one side, and using a torque wrench on the other side, to see what it takes to shear them.

Then of course the other issue, is what torque do you want to strive for?
About 1 ft-lb less than my gear train will break at;)
 
[6]
[5] [7]
Top