When I look at small eye bolt threads (not wood screw, machine screw)
I see thread sizes like 1/8"-32 and 3/32"-32 and 3/16"-24 in the
(e.g. McMaster-Carr page 1465.)
Is it possible that these are really 6-32, 8-32, and 10-24 threads,
just called something weird out of the deep eyebolt tradition? Or are
there truly funky threads with matching funky nuts only used on
I remember stove bolts coming in similar small fractional funky sizes
too but don't see them much anymore.
A 10-24 nut fits the 3/16-24s from Home Depot just fine. Can't say for
sure about the other two sizes.
We use them to hold mold-in inserts at my work, so I keep a small supply
as well as a box of extra nuts. Each "insert holder" needs two nuts and
I can tell no difference between the nut that comes with the eyebolt or
the ones from the box.
(Catalog page actually has 5/32"-32, not 3/32"-32)
While 5/32"-32 and 3/16"-24 match up with #8-32 and #10-24,
the diameter of 1/8"-32 would be like #5 (0.1250" basic diameter)
rather than #6 (0.1380" basic diameter). Of course #5-32 isn't a
standard thread, unlike #5-40 and 44.
I've seen #10-24 referred to as 3/16"-24, eg on boxes of stove
bolts, but don't recall seeing 5/32"-32 before.
Well... using the formula for diameter for number screws, I find
Katana:dnichols 22:57:27 > number-screw 5 32
For a #5-32.000 screw:
Clearance diameter: 0.125
Tap drill diameter: 0.094
So -- it is a number screw, but an uncommon one.
As for 3/32-32: (0.093" diameter)
Katana:dnichols 22:57:32 > number-screw 3 32
For a #3-32.000 screw:
Clearance diameter: 0.099
Tap drill diameter: 0.068
Katana:dnichols 22:59:19 > number-screw 2 32
For a #2-32.000 screw:
Clearance diameter: 0.086
Tap drill diameter: 0.055
Neither of these match the diameter of the fractional size.
Same lack of match for a 3/16-24: (0.1875")
Katana:dnichols 23:01:41 > number-screw 10 24
For a #10-24.000 screw:
Clearance diameter: 0.190
Tap drill diameter: 0.148
Katana:dnichols 23:01:47 > number-screw 9 24
For a #9-24.000 screw:
Clearance diameter: 0.177
Tap drill diameter: 0.135
It calculates to be just a bit loose.
Thank you James.
I went to the local hardware store, bought some screw eyes of the
various small sizes, and indeed 6-32, 8-32, and 10-24 seem to fit just
Looking at my old machining books, I note that the nomenclature used
for the screw eyes (3/16"-24, 5/32"-32, 1/8"-32) exactly matches the
nomenclature for standard BSW and BSF threads. I think that's mostly
coincidence, and I can tell by looking that these screw eyes were not
cut with Whitworth thread forms. (Maybe not entirely coincidence
because maybe our UNC/UNF threads were by design semi-compatible with
BSW and BSF thread in parameters if not profile.)
Actually a lot loose! Grabbed one today and immediately noticed it is a
rolled thread. Thought "ah-ha" and reached for my calipers, the
un-threaded part of the eye bolt is only .158. Way under sized for 3/16
in my book.
Even the crests are a bit under 3/16 and the blame thing tapers five
thou! .176 close to the tip to .181 near the eye. Apparently the root
does not taper (nothing to measure it with here) as a nut is just as
floppy at either end.
Bag of two eye bolts with two nuts and the plastic 'box' of 100 nuts are
both distributed by Crown Bolt. No surprise why they fit the same... Nor
was the country of origin;-)