I always hear people talking about a 2-56 or a 1-72 screw but What does it mean. Also where can one find a reasonably priced tap set for our small screww sizes.
Thanks for your help.
Jesse
2-56 , #2 is the diameter size and 56 is how many threads per inch. A 1-72 would be smaller in diameter than a #2 and have 72 threads per inch. The bigger the first number, the larger the diameter the screw.
Instead of using a ruler and counting the threads, there’s a tool called a “Pitch Gauge” used for measuring threads per inch.
Don’t go cheap with tools. Cheap ones always brake or wear out after the first use. Check out the tap sets at Micro Mark
Reasonable price is the operative words.
You can find them in you LHS usually in the RC aircraft section. I think DuBro makes them as a set or individual sizes.
Jon - Las Vegas
they are very tiny screws with very fine threads used in the hobby…you won’t find them at lowe’s or Home depot…once in awhile you can find them at Ace hardware or they can order them for you…most good LHS have them or you can order them from the internet from many of those micro tool warehouses…I get mine at a small locally owned hardware store that just happen to carry them…you’ll also need the drill bits and taps for the screws also…Kadee sells a drill and tap set for the 2-56 screw but i don’t know about the 1-76 screw…i don’t use them
What does anybody think of www.microfasteners.com their prices seem very good. Anybody know about their quality?
Jesse
Their prices seem about average. Not much variety in the tool line. Shipping is very reasonable. Don’t forget you need a tap holder too.
High speed steel taps are good. Tool steel or tungsten steel is better. Avoid carbon steel because they’re not as hard. They’ll break easier and wear out faster.
There are two different types of taps. Starter taps and plug taps (also called finish, bottom or end taps) . A starter tap is used to start the threads and it has a tappered tip. A plug / bottom / end tap is slightly tapered with a flat tip. It’s used to fini***he thread in a hole with a bottom (also called a blind hole).
For cutting plastic a plug tap will work fine. Just be sure to keep it straight when cutting threads.
Northwest Short Line, Gyros Precision Tools, K&S Engineering and Woodland Scenics also sells quality taps.
Here’s a screw chart for you…
http://www.engineersedge.com/screw_threads_chart.htm
you could ignore the minor diameter (the smallest diameter of the thread) and the pitch diameter (a theoretical diameter used in creating the thread profile).
This chart contains more info than you asked for about the screw specification, but I thought it might interest you. It gives you all of the basic outer diameters of the screw threads.
Find yourself a drill chart (just google “drill chart”) and you’ll find a list of drill sizes.
If you think screw sizes are funky, wait until you see a drill chart. We have numbered, lettered, and fractional sizes, and they mix and mingle with each other in terms of sizes (I’m an engineer, and keep a huge chart on the wall - forget trying to remember them).
And I haven’t even brought up metric screws & drills yet…
(standards in engineering stuff is as bad as knowing what scale you’re working in for the “G” scale guys!)
If you go to a store that supplies your local tool and die shops, you’ll likely find the small taps, dies, and holders. Otherwise, try Mcmaster-Carr at www.mcmaster.com. They sell a 0-80 gun tap for $9.85 each or a 19 piece set of sizes 0 to 12 for $94.35. They are not necessarily the cheapest, but they have just about everything and it generally ships that day. With locations all over the US, even when shipped ground, stuff usually arrives in a couple days.
Kadee sells a reasonably priced set for each size. The set contains the tap, a drill bit to size the hole for tapping, and a drill bit that sizes a hole that the screw will fit through without the threads engaging (clearance bit). You can get 2-56 screws of assorted lengths, nut and washers at Radio Shack. This size fits the center hole of a #5 Kadee draft gear box and is what I use on 90% of my coupler and truck applications. For tapping plastic I have cut the head off of a 2-56 screw and chucked the threaded part in a pin vise. Also if you have access to a drill press, drill the hole to be tapped and then chuck your tap in the press. Turning the tap by hand in the press starts the tap straight.
For those who remember J. L. Morris as a quality source for screws in the 1950s-60s, they’re still in business, if you think you need a gross:
http://www.morris01550.com/minsc.htm
I don’t recall seeing any of their ads recently in the model railroading magazines to which I subscribe.
Bob
NMRA Life 0543
Brownell’s, the gun people, sell taps and screws as well, for good prices. Don’t trust that “one charge” shipping; $7 I think. Whenever I get something small they send it in a small padded envelope and charge actual shipping… I think my last one was like $1.35.
Remember, when tapping steel or brass, if the tap breaks you gotta get it out. Often you can whack a carbon steel one with a center punch and shatter it. Tungsten and good luck! A broken tap tool is good insurance.
I have a pair of double-ended pin vises. There is a fine and a not-so-fine chuck. I keep one fitted with the 2-56 and 00-90 taps. The other has the pilot drills for the taps. I’ve never used a 1-72 or 0-80.
Question: is it a 4-40 or 6-32 screw in electrical boxes?
in electrical boxes …the rectangular ones that switches & recepticale go in are 6-32 the square & octaginal ones like for lighting fixtures are 8-32
Thanks, I really appreciate the answers because I can finally understand what some of my reference books have been saying. My problem is that i belong to a club where all the knowledge has literally died with its holder. I could have never gotten such good answer there. Thanks again everyone.
Jesse
I’m lucky in that there’s a hole-in-the-wall machine shop in my town where I can get those little screws in mass quantity for almost next to nothing, compared to what it would cost to mail order them. And they never even blink when you ask for the real tiny stuff…try going to True Value and asking for some 2-56 screws - they look at you like you just stepped off the flying saucer.[alien]
I used Small Parts Inc. Web page is
http://www.smallparts.com/products/descriptions/mx-fl.cfm
They were the only ones I found that had what I was looking for 1-72 1/8" These work great on coupler boxes - ConCor and Athearn. If you order anything from them, be sure to specify UPS delivery. They’ll use overnight FedExp if you don’t and it costs a lot. They deal mostly with the medical field who usually need things pretty quick.
Friendly people, easy to work with.