Homebrew PCBs

Hi Mike,
        Tapping a block of Delrin or PVC produces a nice
tight nut for a hobby machine. Those long joining nut have
less backlash than a small brass nut. The long joining nuts used to
be available in brass. Most joining nuts are steel. I was taught
one part should be softer. Plastic on aluminum- brass on steel.
      In the end you still have the play in your spindle. My machines 
are in the $150 range. Improving the spindle costs as much as the
machine. I am working on a PCBPal. I am looking to make a super
cheap PCBoard machine. I am using roller skate wheels-PVC-threaded
rod and MDF. I want a machine that can be built in a few hours. The
Pant O Plot was a warmup!

                                             John  








--- In Homebrew_PCBs@y..., "n4onl" <umrk@b...> wrote:
> --- In Homebrew_PCBs@y..., "crankorgan" <john@k...> wrote:
> > Hi Steve,
> >          I milled that one with a Brute. I orignally designed my
> > mills so people would have a machine to learn on. Someone asked
> > me if I could design a mill that would do circuit boards. My first
> > machines would mill, but the traces were not that good. It wasn't 
> the
> > threaded rod. It was my drive nut! The wider the drive nut the 
less
> > backlash. I now use 1/2" wide Delrin tapped with a good 1/4-20 
tap.
> > 
> >                                            John
> 
> Hi John, nice looking board!
> 
> Have you ever tried a smaller cutter and doing traces between DIP 
> pins?
> 
> I've also read that a longer nut will reduce backlash. Have you 
ever 
> tried one of the long nuts used to cnnect 2 pieces of all thread 
> togeather? Of course with a good tap in delrin your probably 
getting 
> most of the backlash out anyway. 
> 
> Another option is to split the nut in the direction of the rod (on 
> one side) and slightly pinch it to eliminate even more backlash. 
This 
> technique works better on standard threads than on Acme threads due 
> to the angle of the threads.
> 
> mike