What tolerance must be applied to a hole when the shoulder bolt is H9?
Hello, I'm not a mecanichal enginneer and I'm unable to find out what tolerances must be applied to a shoulder screw with a h8 tolerances.
The shoulder bolt serve as a hinge, the part with the hole must move freely but with less gap as possible.
I went for H8 (same as the bolt!) but not sure that's the rules to follow in mechanic.
As per the Diam 16/H9, this is for a locking bolt to be welded. Here again I applied the same tolerance beetween the part and the hole. Again not sure about
I will be glad to understand better what tolerance to applied to hole when we purchased standard part, and the reverse to, manuafcturing a bolt when we purchased standar part with holes.
And also make sure that the tolerances I applied for this project are good.
Thanks for your help.
Accepted answer
for a tight tolerance, the hole diameter that rotates on the shoulder screw should be the H8 largest diameter tolerance plus 0.013mm minus 0.000
The basic rule is to always take the largest/smaller tolerance and add your tolerance plus/minus according to your requirements.
By the way, see the image attached. It should the proper way to secure a shoulder screw for the purpose of accuracy and resistance.
Could not understand why you would want to weld the shoulder screw, it is not advisable, you may need to replace the worn shoulder screw or the linkage at a later date.
If you are going to weld it, why not just use a straight pin?
To make it simple and interchangeable, use a pin secured with retaining rings.
4 Other answers
It depends upon the application. Generally the hole diameter would be the same or greater tolerance. H8 or greater. That doesn’t mean the tolerance stays in the “H” classification. Because a shoulder bolt is a purchased item destined for a whole host of applications, some of which require close running fits, it has a rather tight tolerance of h8.
For a pivot constructed of steel or stainless steel a H8 tolerance on the hole may lead to galling and binding. A much looser tolerance may be necessary. Plus you must consider the tolerance of other related components that allow for alignment of the pivot. There is no predefined single answer for you. You must consider the application and determine the tolerance yourself.
I went for H12 as the connector will be welded to tubes and deformation will occur for sure, unless there is a way to avoid the deformation.
Since you have to cap it, you could take this simpler approach.
Press fit the pin in the inner part, and let it rotate on the outer holes.
Cap press fit plugs with inner permanent lubrification.
This is an interesting guideline: https://www.sandvik.coromant.com/fr-fr/knowledge/drilling/drilling-tips
