towing: hitch ball mount tapered seats

[zorobabel]

The hitch ball mount I have has a tapered seat from about 13/16" to 3/4". I just bought a 3/4" diam shaft ball, and the shaft is not tapered.
I know nothing of towing yet, is this a safe combination?
Ball is obviously inserted backwards in the photos, for illustration purposes.

 

[ragtoplvr]

They punch that hole, not drill. Characteristic of punching is a taper hole. Ball should be so tight that it can not move, held by friction.

Rod

 

[ABN_CBT_ENGR]

Originally Posted by zorobabel
The hitch ball mount I have has a tapered seat from about 13/16" to 3/4". I just bought a 3/4" diam shaft ball, and the shaft is not tapered.
I know nothing of towing yet, is this a safe combination?

Ball is obviously inserted backwards in the photos, for illustration purposes.


You are perfectly fine. That's normal for punched holes that thick.

That's punch taper ( where at the start of a punch, external metal gets drawn into the die due to ductility and other factors) Technically its not a true taper, its not a true chamfer or countersink- its more like the collapsed ring around a crater.

 

[zorobabel]

Thanks a lot!

So off topic here: to clarify the punching, is the exit "wound" the larger diam?

 

[ABN_CBT_ENGR]

So off topic here: to clarify the punching, is the exit "wound" the larger diam?

Shouldn't be but a lot of that has to do with the press and die settings and power.

Remember, a stamped hole is basically "more round than less round" and should never be counted on to be dimensional unless drilled, reamed or other finish is applied.

 

[A_Spruce]

Thanks a lot!

So off topic here: to clarify the punching, is the exit "wound" the larger diam?

As the others have said, punched hole, typical of ball mounts. Ball mounts can be used in either direction, meaning, they do not have a top or a bottom. I suspect the small diameter is the exit wound, but you can usually tell by the shape of the hole. The entrance side will be rolled slightly into the hole, the exit side will flat with a very sharp edge.

Take a look at a leather belt, you'll see the same thing, rounded entry hole, flat and sharp edged exit hole. Same principle.

Oh, and you can file or drill the hole out to fit the shank of the ball.

 

[zorobabel]

Thanks for the explanation!
Can't really feel any edge on my mount, as it was touched up.

 

[A_Spruce]

Can't really feel any edge on my mount, as it was touched up.

If it's touched up on only one side, that would be the exit wound side.

A better example that just came to me is a flat washer, these are punched out by the millions. The entry side is all nice and smooth and rounded, the exit side has sharp edges on the inner and outer diameters. Your hitch should show the same kind of marks.

 

[zorobabel]

If it's touched up on only one side, that would be the exit wound side.

A better example that just came to me is a flat washer, these are punched out by the millions. The entry side is all nice and smooth and rounded, the exit side has sharp edges on the inner and outer diameters. Your hitch should show the same kind of marks.

Ah yes, good example with the washer. If I were to pick one, the smaller diameter is the sharper one.

 

[A_Spruce]

I knew we'd get to the bottom of it sooner or later!