[sebhc] hard sector substitute

Dwight K. Elvey dwight.elvey at amd.com
Mon Jul 12 11:59:49 CDT 2004

 I think you guys are getting a little carried away.
A simple manual system is all that is needed unless
you expect to go into production. One can make a simple
manual punch with a section of drill stock and something
as simple as a brass block to guide it. One can put some
holes on the pulley to use as detent stops to align the
punch on the disk. 
 When I find time, that is exactly what I intend to do.
I have all the parts and I'm just waiting for the time
to deal with it. This isn't a high tech problem.

>From: "Carroll Waddell" <CarrollWaddell at sc.rr.com>
>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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