You could drill a hole and put a cross hair mark on the screen and you are done.
Kim
On 6/9/11, Bruce Parham <obparham@...> wrote:
>
>> Hello Group
>>
>> I have a quick question about precision drilling of home made PCBs.
>>
>> Because of poor eyesight, I use a CCD microscope next to my Dremel
>> Model 300 drill press stand. Although this set up is a big improvement
>> over doing thing solely 'by eye', there is a parallax error introduced
>> between the location of the retracted drill tip and where it eventually
>> comes in contact with the PCB. Once I saw a milling machine where one
>> was able to sight straight down into a bulls eye. Is there a way to
>> rig mirrors to do this?
>>
>> P.S. Sincle sided boards are no problem, as I can hold them up to
>> strong light and position a hand held rotary tool with good enough
>> accuracy.
>>
>> Any suggestions would be appreciated.
>>
>> Cheers
>>
>> Chris
>>
> Hi Chris,
>
> You might try to find a metallic first surface mirror that you can
> drill a small hole into on a 45 degree angle
> and mount onto your drill stand with the drill bit going through the
> hole. Position the camera so it looks into
> the mirror from the side and down the drill via the mirror.
>
> A less elegant method is to use two point source lights (small halogen
> desk lamps) mounted 90 degrees apart
> and pointed toward the drill tip. As the drill tip approaches the board,
> the shadows will converge on the target.
>
> Bruce
>
>
>