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Posted By: hypress A Lesson In Screws - 11/22/04 03:59 AM
Today I was hanging a front poarch light on a friends house. The screws that mount the fixture to the mounting bracket were to long so I cut them off and tried to screw them into the bracket and they would not fit. No problem I got anouther 8/32 it would not fit ether both 8/32??? WRONG.It seems that the mounting screws were 4mm. Now I have been an electrician for 30 years and this is the first time I have seen metric screws on a residential light fixture. Now I have seen european process equipment that'sto be expected but residential lighting??? I guess we are going to have to get metric screw cuters now. Has any one else run across this. THANKS HYPRESS
Posted By: e57 Re: A Lesson In Screws - 11/22/04 04:06 AM
Yep, all those high end LV hand blown glass too expensive for my house jobs. My favorite is metric mounting plates, holes are set wider than 3/0, and smaller than 4/0.
Posted By: Speedy Petey Re: A Lesson In Screws - 11/22/04 05:04 AM
I run across tham all the time. They are in many of the cheap crap Chinese fixtures sold in the big obnoxious stores.
Now I have nothing against the Chinese, or any other race, but the quality of their products is terrible.
Posted By: hbiss Re: A Lesson In Screws - 11/22/04 05:59 AM
If you can use a regular screw (it's not a fancy brass thing) just run the 8-32 part of your triple tap through the hole. Then it will be 8-32.

You do carry a triple tap don't you?

-Hal
Posted By: smokumchevy Re: A Lesson In Screws - 11/22/04 09:56 PM
Gotta luv those tripple taps.... don't leave home without one myself.

-Greg
Posted By: pauluk Re: A Lesson In Screws - 11/22/04 10:06 PM
We have a similar problem here in England.

Around 1970 the electrical industry switched to metric, adopting 3.5 mm threads on device boxes. Prior to that, device fixing screws were 4BA (BA = British Association).

The diameter and threads look pretty much the same at first glance, but are not interchangeable. As there are still plenty of 1950s/60s boxes in use, it's annoying to find the screws supplied with a modern outlet or switch don't fit the old boxes.
Posted By: DougW Re: A Lesson In Screws - 11/22/04 11:42 PM
Reminds me of "Chinese Standard Thread"

Usually 8.25 / 32 or thereabouts...
Posted By: dougwells Re: A Lesson In Screws - 11/23/04 12:50 AM
I bought some of these to supplement my Klein triple tap.
edited for spelling http://198.247.193.8/wwwroot/greenlee/detailslib.cfm?id=20125&upc=17612

[This message has been edited by dougwells (edited 11-22-2004).]
Posted By: Active 1 Re: A Lesson In Screws - 11/23/04 01:02 AM
I call those chinese 8/32. There just metric. What I hate is when you have those chinese 8/32 trim nuts. You can't tap it out cause it's not deep enough.

Maybe the rest of the world hate those american screws. They say why are they so fat?

Tom
Posted By: hbiss Re: A Lesson In Screws - 11/23/04 01:33 AM
Those are nice Doug. Solves the problem of having to have a tap drill and a tap. Everybody should have at least a 10-32 for those times you need to install a ground screw.

Gotta get them myself!

-Hal
Posted By: Steve Miller Re: A Lesson In Screws - 11/23/04 01:56 PM
I keep breaking tritap tools so I use the cordless drill. If you need to tap holes or enlarge them use your cordless with the clutch set way down. This is also great for tapping those old black enameled boxes for ground screws.
7/64 bit for 6-32; 9/64 bit for 8-32; 5/32 bit for 10-32
Posted By: NORCAL Re: A Lesson In Screws - 11/23/04 02:33 PM
If you are useing fractional drill bits to drill for 6-32,8-32,10-32 you are useing the wrong drill bit it should be a number drill, I do not have the sizes handy right now,and some dirtbag stole my Snap-On tap and die set.
Posted By: electricman2 Re: A Lesson In Screws - 11/23/04 05:58 PM
Correct drill sizes are:
6-32 No. 36
8-32 No. 29
10-32 No. 21
Posted By: Steve Miller Re: A Lesson In Screws - 11/23/04 10:08 PM
You're right ... but most guys don't have the numbered bits. The fractionals I listed are the closest to the proper number and work just fine. On the Dayton sheet they are the actual sizes listed to be used.
Posted By: Jps1006 Re: A Lesson In Screws - 11/23/04 11:05 PM
I just bought a set of these
I like them even better for those old black boxes.
Posted By: BigB Re: A Lesson In Screws - 11/24/04 02:25 AM
electricman2 are those the sizes for self tapping machine screws too? I noticed the insructions for square D grounding bar kits say to use a #26 bit for the #10 screws that are included. I bought some #26 bits and I have been using them to drill and tap for green grounding screws, they work just fine. Maybe the 26 is not much smaller than the 21? Very confusing how screws get bigger as the number goes up but drills get smaller. Just like AWG I guess.
Posted By: Hutch Re: A Lesson In Screws - 11/24/04 01:55 PM
Quote
Very confusing how screws get bigger as the number goes up but drills get smaller. Just like AWG I guess.
The BA (British Association) threads that PaulUK refers to above get smaller as their number gets bigger. The only thread of this type that might be familiar to Americans is the 2BA thread on the points and fins of darts - bigger than the old UK electrical standard of 4BA.

Check here for more information on BA threads and here for other threading trivia including those famous Whitworth threads. [Linked Image]

[This message has been edited by Hutch (edited 11-24-2004).]
Posted By: Trumpy Re: A Lesson In Screws - 11/24/04 11:04 PM
Hutch,
The old Whitworth thread is still alive and well over here!. [Linked Image]
It became common over here because of a lot of bicycles being imported here from England in the years after WWII, I think every thread on the bike was the same profile.
There is still a bicycle factory just south of here that uses the Whitworth thread on it's cycles, I have no idea why they never changed over to metric threading. [Linked Image]

{Sorry, that's WWII, not WWIII!, Oops [Linked Image]}

[This message has been edited by Trumpy (edited 11-25-2004).]
Posted By: earlydean Re: A Lesson In Screws - 11/25/04 12:14 PM
I always thought when WWIII happened we would all be gone!!!!
Posted By: NJwirenut Re: A Lesson In Screws - 11/26/04 02:50 AM
If WWIII doesn't kill us all off, then WWIV will be fought with sticks and rocks....
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