Two types of jaws for key cutter

[pcm81]

Not trying to spam with threads, Just trying to keep them on a subject.

In my Hudson 598B machine the key holding jaws have 2 sides to them. One side looks like a Z shaped and the other like a trapezoid.

Here is an example image: http://g02.a.alicdn.com/kf/HTB1f0XSKFXX ... hine-b.jpg

My question is: for which key types do i use which jaw? There bound to be an intended application for each... So far no luck googling user manual for the machine, mine came off ebay...

Thanks ahead

[billdeserthills]

Keys like most house keys, that are only cut on one side used the 'stepped jaw', that jaw has a flat bottom, where the bottom of the key sits.
Keys that are double sided, like most car keys, are cut on the other side, where they are held by a milling often found in the center
of the key.

The stepped jaw is the one to the right side of the jaw shown on the left

[pcm81]

Keys like most house keys, that are only cut on one side used the 'stepped jaw', that jaw has a flat bottom, where the bottom of the key sits.
Keys that are double sided, like most car keys, are cut on the other side, where they are held by a milling often found in the center
of the key.

The stepped jaw is the one to the right side of the jaw shown on the left

Thanks. I forgot that the car keys are cut on both sides and have a groove in the middle. My car key is a wafer key, but both sides are flat and the milling is only on the faces...