[sebhc] hard sector substitute

Carroll Waddell CarrollWaddell at sc.rr.com
Sun Jul 11 20:31:41 CDT 2004

Dave Dunfield wrote:

>>I've been thinking about this. What I thought about was modifying an old 
>>diskette drive to punch the holes automatically. It would have to be 
>>modified to remove part of the drive where the index sensor is located. 
>>A slideable pice could be built that contains both an index hole sensor 
>>and a hole punch. A solenoid (or whatever) could move the index sensor 
>>so that it could sense the hole in the diskette. If there were a stepper 
>>motor used to rotate the disk, a Basic Stamp could rotate the diskette 
>>until the hole is sensed. This would be the 0 degree position. The 
>>slideable punch could then be positioned over the existing hole in the 
>>diskette and the jacket. The stepper motor could then be rotated 18 
>>degrees and the first new hole punched. Next, the stepper motor could 
>>rotate the diskette 36 degrees (repeating this ten more times) to punch 
>>the remaining sector holes. A solenoid or something could be used to 
>>operate the hole punch. VIOLA!   A new hard sector diskette made from an 
>>existing soft sector diskette.
>>The difficult part would be to make the slideable index sensor / hole 
>>punch device. It would have to be thick enough and with a slot into 
>>which the diskette jacket could fit.
>>Any new thoughts?
>Hi Carroll,
>I've had similar ideas - remove the drive motor (or just don't power it
>for direct-drive drive) and implement a stepper motor which gives accurate
>positioning of the media.
>You might be able to get away without having to move the sensor and hole
>punch if you make the punch retract far enough, and sense the hole at an
>angle - I think it would be simpler to just line up the hole before
>inserting the disk in the drive - with a stepper drive, the index hole will
>NOT move as you close the drive lever. Then it's just a matter of
>'x' steps (Index to first hole distance), Punch, 'y' steps (hole to hole
>distance), Punch, repeat until at last hole.
>I'd have built one by now, but I have not been able to fashion a decent
>punch yet. Any ideas?
I measured the index hole and it appears to be .1" dia. I just found a 
hole punch on ebay that is 2.5mm (probably close enough to work).
The reason I thought about making a moveable piece was to make the lower 
part the die into which the punch would go.

I'm going to tear apart some printers, drives, or whatever else I can 
find that might have something usable. Of course the expensive way to go 
would be to machine the slide assembly from a solid block of metal.

I had a hard time going to sleep last night, thinking of about a 
millions ways to do this.

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