That's the standard way to turn an eccentric so you should not have any problems.

I usually pic a drill that is just above the small end of the pins diameter and enough so the reamer will enter the hole.

Martin

There is a table/graph in "Machinery's Handbook" that details the suggested pilot hole sizes for the various sizes and lengths of taper pins. Basically the initial hole should be the size of the small end of the pin, but if the pin is long the hole should be step drilled with two or more larger sizes especially if using a straight fluted reamer as opposed to a spiral flute one. If you don't have access to the book if you let me know the dia. of the pin at both ends and it's overall length I can tell you the appropriate drill size(s).

John

Edited By John Purdy on 24/01/2018 19:26:42

Martin

If you can't find you book let me know and I'll get you the info.  It's on page 1654 of my edition #20.

John

Edited By John Purdy on 24/01/2018 20:56:50

If you left a concentric stub on one the faces of the cam you could use a dial indicator in conjunction with your 4-jaw to set the offset from the centre-line precisely correct before facing the stub off and boring through. There'd be no need to scribe and mark up the face first. The TIR is simply twice the offset.

Of coarse if the cam is big enough to project from the jaws then there's no need to use the stub at all.

HTH

Jon

^2 means squared ie 3^2=9

^3 means cubed ie 3^3=27

yes work out E/D first then work out [E/D]^3

then work out [1 – 1/2 E/D – 3/8 [E/D]^3]

then multiply the result by 1.5*E