plead for 3 jaw chuck knowledge

Casca 92 I hope the light is still on and you're healing. Arrange your chuck jaws as RJ's #20 post and watch this from around the 17 minute mark.

[/
 
Wreck™Wreck said:
On a 3 jaw scroll chuck the threads on the jaws are offset 1/3 of the scroll thread lead from the part holding surfaces. In the case of a .125" lead .041xxxxx", it does not matter which slot the master jaws are in so long as all three are in the same thread in the correct order. To simplify jaw changes it is useful to number the slots and jaws but is not required, as seen below.

Turn the scroll until you see the beginning of the thread and install jaw #1, rotate the scroll until the start appears in the next slot and install jaw #2 and so on. The relationship lies between the threads of the scroll and master jaws. Keeping each jaw in the same slot helps with repeatability as any error remains in the same place, if indeed the OEM finish ground the hard jaws in place then slot placement is important as the error in radial slot location either advances or retards the work holding surfaces.

Many chucks that I have used have the slots numbered inside the groove where they are not easily seen much like the jaws are numbered down in the slot which can not be seen until removed.

I do not know why this is done but surmise that it makes for a cleaner looking product, high end products often have the numbers laser/chemical etched where they may be seen. Also take into consideration that the employees at the chuck factory need to know where the parts belong in a given assembly.

Buy yourself a set of number stamps and mark it for your own use, you will not be able to to do so on the hard jaws however.
Click to expand...

Good info especially the thread lead offset. I was flying by the seat of my pants when I stated the jaws would have fewer threads based on the sequence they were inserted. I was basing this on the #1 moving towards the center without thinking the movement may not be a full thread width when the scroll end reached the next slot. Thanks, -Russ
 
You must log in or register to reply here.
Back
Top