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IBM PC screws
- Thread starter romanon
- Start date
6-32 hex slot head I think?
I don't know an exact source of these but these look close but probably too long...
http://www.marcospecialties.com/pinball-parts/234-5000-00
I don't know an exact source of these but these look close but probably too long...
http://www.marcospecialties.com/pinball-parts/234-5000-00
Great Hierophant
Veteran Member
3/8" = .9525 cm, so those screws are probably the right length.
The originals in my 5150 are #6-32 x 3/8" securing the cards and #8-32 x 3/8" at the rear of the case. Someone posted on here before that they are stainless steel but they are frosted in appearance rather than polished like the screws found in most clones. The heads are 1/4" hex slotted. They look very much like the one in Romanon's picture. I haven't heard of anyone saying they've tracked down where to get the exact screws that IBM used.
Like most of the vintage boxes out there my 5160 has an assortment of non original screws including some self tapping sheet metal screws securing the case. :-( Not many "cherries" left out there after 30 years of people tinkering with them.
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Stone
10k Member
Interesting!
OK.... My 5150 has no missing or mismatched hardware and all of the screws are of the sizes and types I mentioned above. I probably should have also said that they are what I believe is called a hex washer head. All of the cards are original OEM stuff with the exception of an AST 6 Pack Plus. From this I think its safe to assume that the box, while 30 years old, has not been tinkered with to any significant degree.
My 5160 is another story altogether. At some point a card that had apparently been in slot 3 had been removed without the block off plate or the screw being replaced. The remaining 7 screws are all matching and the same type that's in the 5150. There were only 4 of the 5 screws securing the case when I got it, and they are of 4 different types. But they are all stainless #8 x 3/8" screws. Only one has a slotted head, two are self tapping sheet metal screws, and one is a self tapping and self drilling. I think it's pretty safe to say that the sheet metal screws are replacements. So I have no idea what kind of hardware this box would have had securing the case when it left the factory.
There's also the very real possibility that IBM didn't use the same hardware across the whole production life of the 5150/5160/5170 line. I frankly have no idea if they did or not.
This is where the experts should chime in and answer Romanon's question. ;-)
Stone
10k Member
I'll add that all the screws in both my 5150 and 5160 are the 3/32" variety. And, all the case cover screws are the same as yours -- ¼".
modem7
10k Member
The experts were in the section within IBM that either supplied screws to the factories, or told the factories what to acquire.
Screw specifics are possibly filed away in IBM archives.
In the technical manuals that IBM published for external use, there is a parts catalog in the Hardware Maintenance and Service. In those, the only mention of case/chassis screws that I can see is on page 7-7 of the IBM 5170 manual at [here].
Regarding the large case screws, an earlier thread that discussed them is [here].
Chuck(G)
25k Member
3/32" head screws? That's awfully tiny and doesn't match my recollection at all (I still probably have a couple in my hardware hellbox). Smaller than 1/4", certainly; probably 3/16", but certainly not 3/32" More or less complete description would be 6-32 3/16" hex slotted washer head x (insert your length here).
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Stone
10k Member
You're right -- they're 3/16". I'm pretty bad at reading rulers. 
Chuck(G)
25k Member
More likely spec-ed as 3/8" thread length. This is America--we don't fool with that weird commie metric stuff. :lol:
The PC business is a bit strange in that respect. Hard drives using 6-32 mountings, but floppies (being Japanese) using metric. Cases using metric for board mounting, but 6-32 and 8-32 for holding cards and lids. Rack-mount panels take either M5 or 10-32, since they're very close (but not identical and interchangeable in all cases).
The PC business is a bit strange in that respect. Hard drives using 6-32 mountings, but floppies (being Japanese) using metric. Cases using metric for board mounting, but 6-32 and 8-32 for holding cards and lids. Rack-mount panels take either M5 or 10-32, since they're very close (but not identical and interchangeable in all cases).
I double checked and you guys are correct. The #6-32 screws securing the cards and much of the other stuff inside the case have 3/16" hex heads. The #8-32 screws securing the case have 1/4" heads.
But on to the bonus question that's really the meat of the issue, are exact or "close enough" replacements available?
This appears to be quite close to the #8-32 x 3/8" case screws but the thread is from 2008.
http://www.vintage-computer.com/vcforum/showthread.php?12796-screw-thread
A line drawing in a catalog tells a lot but isn't the whole story. Have any of you perhaps seen these? Are they close enough?
But on to the bonus question that's really the meat of the issue, are exact or "close enough" replacements available?
This appears to be quite close to the #8-32 x 3/8" case screws but the thread is from 2008.
http://www.vintage-computer.com/vcforum/showthread.php?12796-screw-thread
A line drawing in a catalog tells a lot but isn't the whole story. Have any of you perhaps seen these? Are they close enough?
sergey
Veteran Member
Except when we talk about American cars
Especially if you have a powered screwdriver or a hammer, or both
Back to the topic. The official screw name is something like "#6-32 x 3/8 slotted hex flange screw". Now #6-32 hex flange screws are relatively easy to find, but with phillips (and not slotted) head, or without slot/cross at all.
Chuck(G)
25k Member
My 23-year-old made-in-Canada Ford F150 pickup uses metric all around. That didn't really sink in until I found myself under the truck replacing the front fuel pump. Fortunately, I managed to dig up a correctly-sized socket from a set of bicycle tools.
If my memory is correct, the 10-32 is about .008" smaller than the M5. So no problem for me.Especially if you have a powered screwdriver or a hammer, or both
The gotcha is that the original 5150s used 3/16" hex washer-head screws. Almost all of the ones that I've seen since then use a 1/4" head. Most would likely be happy with 3/16" hex-washer-head screws without any kind of slot.
What's odd is that the last bunch of stainless UNC-sized screws I purchased came from Scotland. Maybe there's some guy in a kilt who wants to turn out original-IBM-sized versions...
Shadow Lord
Veteran Member
Have you tried contacting lyonadmiral on this board? He used to have some matching screws (not originals).
modem7
10k Member
On eBay, there were times when it was obvious that one or more sellers had stripped down an IBM 5150/5160/5170 to sell the parts separately. Such sellers may still have the screws.I want only originals