compact 8 lathe

[krv3000]

HI all I'm having a blond moment I can not figure out the pcd for the 3 fixing screws I need this for to mack up a back plate for mi new 4 jaw chuck can any one help

 

[Jasonb]

I may still have it somewhere from when I had an Emcomat8.6, will have a look.

J

 

[mklotz]

If s is the spacing between two screws, then

PCD = s/sin(60)

 

[krv3000]

HI so 30mm from center then divided by 6 to give me the 3 fixing points is that right

 

[Jasonb]

No can't find the old backplate that I thought I had.

Take the chuck off and measure with a pair of calipers over two of the studs (unthreaded part), then take off the dia of one stud from that measurement.

This will give you the value of S to use in marv's formula.

 

[Jasonb]

I think the PCD is 63mm, working this back from marv's would put the stud ctrs at 54.56mm or distance over the two studs assuming they are 8mm would measuer 62.56mm