RF-45 Downfeed Lock Knob

[henryarnold]

(06-03-2012, 07:33 AM)stevec Wrote:

(06-02-2012, 09:26 PM)Highpower Wrote: Henry,

7/8" radius? On a 3" diameter knob?

Maybe just my eyes playing tricks on me, but they don't look to be that big to me.

A 3" diameter knob has a circumference of almost 10" and those 7/8"
radius sectors (not full diameter) are probably around 3/4" across so I'd say, Ya your eyes must be playing tricks on you.
(or mine are)
Or maybe Henry meant 7/8" Diameter?
Oh, never mind

The knob has a circumference of about 9.4" ( 2 x 1.5" x 3.14). If you divide this by 12 (6 for peaks, 6 for valleys) you get 0.78". Although the boring bar radius is large, it only cuts 0.165" into the rim at 6 locations. This operation uses an interrupted cut so you must take it slow and use a nice sharp bit. I used a carbide boring bar which I had touched up with a diamond wheel.

If you have never used a boring head, I suggest you get one. They are very useful for many operations. The Chinese spin-offs are not very expensive.