5.25 Floppy drive spindle motor screws - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 02, 2024, 03:35:54 am
content: I have to remove the rotor from a floppy drive so I can recap the speed controller. I've done this on a few mechanisms, but now I have one with mangled screw heads. I have JIS, Pozidriv, and Philips screwdrivers in various sizes that always worked so far.I was surprised because they don't look that bad really, but all I've managed to do is get some metal chips to come off and the screws don't move.Anyone have a trick to get these out? Googling gets me various woodworking or car engine repair tips.Otherwise I'm going to JB Weld some random hex key to each screw and hope to torque them out. Or does Jigaloo or Loosenut work?Anyone know the precise head name and size of these screws? McMaster doesn't go below 4mm in JIS flathead screws. I've also checked several drive manuals and if they do give a mechanical drawing, they just say "spindle motor" but not more detail.The part number is TEC (Tokyo Electric Co) CFAAK-60303 but that doesn't get me anything, I just find links to Japan's power company.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 02, 2024, 04:07:15 am
content: Usual approach is an easy out (e.g.,https://www.amazon.com/Piece-Small-Extractor-Remover-Included/dp/B00D5032RU). A small left-handed screw may work. On small sizes, e.g., 6-32 and 4-40, I have gone with a LH bottoming tap and screw. Pre-drilling usually helps to get a better bite with the easy out and is required for using a LH tap and screw. The tap itself will usually work as that is no different than an easy out, but it has a finer thread pitch and better bite.In worse cases, I drill them out with a drill about the same size as the minor diameter of the thread. That allows the head to pop off. Once all screws are out, the part is disassembled and a good pair of vise grips can grab the stub and get it out.As for size, the head diameter of anystandardflat head screw will indicate the thread size. I recently learned there can be two JIS standards for some stuff, like hydraulic fittings. The two standards are not interchangeable, and in my particular case JISM, which my machine had were very hard to find. I was surprised to find that out, and it may not apply to screws. They are obviously small, but are you sure they are JIS metric; although, that is highly likely.One concern considering how buggered those heads are is that someone used threadlocker in the past. What you see may be another attempted reparier's failed efforts. Heat is the best way to soften it.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 03, 2024, 05:27:05 pm
content: It's small, I don't see myself drilling holes into the screwheads. No drill press! Oh well, this will have to go under "rainy day"...Plus the local makerspace closed years ago, not great.Usually I'd fish out a mechanism from some other drive but these are unique, for the MSD Super Floppy Drive used on Commodore machines.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 03, 2024, 05:41:26 pm
content: I couldn't live without something like a drill press. Even in school, I had a holder for my hand drill that made it like a drill press.Might as well try the JB weld approach on that rainy day, but instead of a hex, I would use something like a flat screwdriver to get more grab on the epoxy. A piece of music wire ground flat on opposite sides and a hook at the other end might help. Heat may also help.EDIT: I forgot to mention another Phillips-like screwdriver that is much better for removing stuck screws. It's the Reed & Prince screwdriver. Looks a lot like the common Phillips but side-by-side you will see the difference. Mine is a size 2 and I suspect you would need a size 1. Inser, tap lightly, and the screw may come out. See:https://fairwindfasteners.com/blogs/news/reed-prince-frearson-drive-vs-phillips?srsltid=AfmBOoqKySlH3ajSVKrlZJ5U0j6rZLhJ7M60qry6eTWACb59xGMqBMnnPhillips are designed to "cam out," which results in the damage you see. R & P do not. If you do many such restorations, getting one might be worthwhile, even if it doesn't work in this case.EDIT2: I should have said size equivalent to the Phillips #1. Apparently R&P size numbers are a lot different.

author: BrianHG
author_rank: Super Contributor
timestamp: October 03, 2024, 10:54:25 pm
content: Purchase a jellybean cheap flat watchmans screwdriver set which you will not care about.Use a flat one which is slightly larger than a fit.Sandpaper down that flat screwdriver until is snugly grabs the remaining corners of the chosen screw and press down hard and turn. The screws should release.

author: squadchannel
author_rank: Frequent Contributor
timestamp: October 04, 2024, 12:15:56 am
content: I also removed it when cleaning the floppy on my IBM 5170. That screw is easy to break.The reason is that it has Loctite on it. It is very hard.Since it is made in Japan, I think it is a JCIS 10-70, No. 0 type 1 screw.you can use a JIS #0 screwdriver.https://www.urk.co.jp/contents/elements/element26.html(japanese website. use the translation.)I recommend screwdriver is made by Vessel.MOD:I just checked the screw on the 5170 and it looks like a #1 screwdriver.I think it's a regular JIS screw, not a JCIS screw, maybe M2.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 06, 2024, 03:33:39 pm
content: Yeah I have Vessel screwdrivers, I have a #0 jeweller's type and I bought a #0 with a handle and it didn't help.

author: MLXXXp
author_rank: Frequent Contributor
timestamp: October 06, 2024, 04:45:25 pm
content: You might be able to cut a slot in each screw using a small cuttoff disc in a Dremel type rotary tool. To get the slot deep enough, you might end up cutting into the rotor, as well, but I think the damage would be minimal. You could then grind the end of a small slotted screwdriver to match the curve and thickness of the slots in the screws. That could give you enough bite to turn the screws.

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 06, 2024, 04:45:49 pm
content: Loctite releases when heated to 250°C+, maybe heat the screw head with a soldering iron and then attempt removal while hot with a carefully fitted screwdriver?

author: helius
author_rank: Super Contributor
timestamp: October 21, 2024, 08:30:38 am
content: TheEngineercompany has tools to help with that. It looks like your screws are #0 JIS? so their DBZ-58 would be the correct removal bit.

author: amyk
author_rank: Super Contributor
timestamp: October 22, 2024, 05:04:04 am
content: My experience is mainly with larger fasteners, but would an impact driver help? I've had success with using one to loosen screws where slowly applied torque would just mangle the head.