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possible 3D printed replacement parts for Floppy drives Specifically Shugart SA455

VERAULT

VERAULT

Veteran Member
Joined
Jan 30, 2012
Messages
8,503
Location
Connecticut, USA
Yesterday I was finishing up on my ... I dunno many many year restoration of my Commodore SFD-1001 floppy drive. For some reason that drive has very brittle plastics. While trying to use it I noiced the lever would not close the drive to read a disk. I noticed the pressure block (nylon) had a crack running through it which super glue could not repair.

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Im sure some would argue, but there are not that many drive mechs out there... Most designs are shared. So I wondered if I had something in my stash that would work. Well as it would turn out I had a Shugart SA455 which had the exact same drive mechanism.

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So I swapped the Entire lever, plastic lever, and plastic faceplate since the SFD-1001 drive plastics were brittle and cracking anyway. The only difference is the color. The commodore is dark brown the Shugart is black.

So I was able to get this drive working again but I am aware this is a stop gap. The replacement will fail in the exact same way eventually.

So is anyone aware of a 3D printed part or new part to permanently solve this?
 
No thoughts yet huh?
Well here is at least a photo of my SFD-1001 before I sell it to another vcfed member. Took too many years but I got there in the end.
IMG_20240403_152552.jpg
 
That cam repair is an easy fix. The greatest difficulty is overcoming the idea that glue alone is enough to hold together a part that is under mechanical strain.
 
Brittle and aging plastics makes me wonder how many Shugart SA-400 drives are still in operable condition. You know, the ones with the disc with the spiral groove-and-follower for positioning....
 
Chuck(G) said:
Brittle and aging plastics makes me wonder how many Shugart SA-400 drives are still in operable condition. You know, the ones with the disc with the spiral groove-and-follower for positioning....
Click to expand...
Well i know all the ones in apple disk iis are doing just fine
 
Weird, earlier today I was working on a Panasonic JU-455-7 C09 drive with the same type of failure, a cracked wedge or whatever its called, that forces the clamp action to happen. I was thinking that the plastic is Delrin and most glue won't work to repair the crack. If it is an "easy" fix I'd like to know the secret.
 
I used a little tiny zip tie on a similar type of failure. (I removed the zip tie that is on the cam lobe, it was just there while the glue dried, though I’m not sure the glue really helped, but the other zip tie it still there)

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There are glues that claim to be fine for Delrin™ or Nylon, but I wouldn't trust such a repair as far as I could pitch it. There's a reason why low-friction sliding surfaces are made of those materials--they don't stick to anything.
 
Chuck, I agree that gluing Acetal/POM or Nylon is chancy. jafir, great suggestion -- or duh, why didn't I think of leaving a zip tie on the shaft part! I was thinking of making a clamp out of metal, but a zip tie is so much easier. Thanks for the idea, now I've got to go try it out.
 
Digging into my broken Panasonic JU-455-7 floppy drive and I found that it has several (3) plastic pieces that have all failed. Not only the wedge (as above), but this drive has a "gearbox" with an offset output wedge shaft that is not part of the shaft that the front lever directly rotates. Instead, the short input shaft with the front lever rotates an internal gearbox wedge that in turn forces a secondary wedge to rotate. This secondary wedge is on the output shaft that also has the wedge that forced the mechanism down to apply pressure to the diskette and causes the diskette to spin. All three plastic wedge pieces are cracked. The two internal wedges plus the latching wedge. So moving the front lever doesn't cause the gearbox wedge to rotate, therefore the secondary output shaft wedge (also cracked) fails to rotate the secondary shaft. Since that secondary shaft doesn't rotate the locking wedge (also cracked) does nothing. So even if the gearbox was working then that final wedge would no doubt also not do it's job. Three failures all in a design just to latch up the diskette mechanism. A real rube goldberg design! Panasonic what were you thinking?

If I had to guess I think someone tried to latch the mechanism without a diskette in place and smashed the two pieces in the gearbox, that would explain why these two pieces are cracked. That plus poor engineering.

On top of that and regarding making new pieces, I believe the two shafts are round, don't have any machined flats, and so the original plastic parts were either molding in place or more likely forced on undersized to grip the round shafts. No wonder they cracked. I don't think a new 3D printed part would hold up to the process of driving them onto the two shafts. Maybe new POM or aluminum pieces could be machined at great expense?

I guess I need to find a parts donor or just scrap this drive. My only 360K drive.
 
I woudnt trash the drive. Replacement parts may become available. Your not the only one with that exact problem.
 
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