Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "designer_craig" <cs6061@...> wrote:
>
> 
> I just finished up my CNC quill drive conversion my Bridgeport and would
> like to use it to drill boards.    I have not found a reference to what 
> speeds and feeds to use for drilling.
> 
> I am looking for the  surface feet per minute and feed per turn numbers
> for  small carbide drills in FR-4.    My 5400 RPM maximum  going to be
> well below the 30,000 to 60,000 RPM used by a real PCB drilling spindle
> but it should still work fine if  I use the correct feed rate.
> 
> Anyone got a reference for these parameters.
> 
> 
> 
> BP Quill Drive
> <http://picasaweb.google.com/lh/photo/B-uAtxYUicys82cFdd5HYg?feat=direct\
> link>
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

I uploaded two pdf files that have the information needed to calculate feeds and speeds. These files are scans of a slide rule drilling calculator that Excellon provided to their customers. Back in those days I was running three Excellon machines, two driller/routers and one drilling machine. Using those formulas, each machine was averaging a million holes per week with very few broken drills. The bits wore out before breaking so I would say those formulas worked pretty good! There is some good information on router feeds and speeds as well.