News:

Please read the Forum Code of Conduct   >>Click Here <<

Main Menu

small self tapping screws

Started by jerryl, May 28, 2009, 12:27:00 PM

Previous topic - Next topic

jerryl

  Before you throw those audio or video cassettes away, take some time to remove the screws that hold most of them together.  Trust me, some day you will need one or more of them.   jerry

pdlethbridge

Waste not, want not.  Good idea

OkieRick


When you go to inquire or buy these 'little screws' - all 347 gazillion required to MR - how do you tell the guy at a fastener store, "it's only about this big" as he looks at you thinking "why doesn't he want 10,000 SAE 1 inch machine bolts 6 inches long so I can make some money?"

What sizes are these little buggers, seriously!?


Okie

Invacare 2-2-2 TDX5 Tilt Recline & Elevate - 24v - ALS Head Control
God Bless Jimmie Rogers the Singing Brakeman

Yampa Bob

No, no, it's...waste not, want LOTS.
I know what I wrote, I don't need a quote
Rule Number One: It's Our Railroad.  Rule Number Two: Refer to Rule Number One.

Jim Banner

To tell the size of screws, you need three things - a digital caliper to measure diameter, a thread gauge to measure pitch and a table of thread sizes to figure out what you have.

Metric machine screws are usually a bit smaller than their nominal size, for example an M4 or 4 mm machine screw is typically about 3.8 mm in diameter.  Their pitch is given as the number of mm between adjacent threads.  For example, an M4x0.7 is a metric machine screw nominally 4 mm in diameter with the threads .7 mm apart.

In the imperial system, machine screws are designated by a number related to diameter and a pitch expressed as threads per inch.  Some examples are #2-56, #4-40, #6-32, #8-32 and #10-32.  The diameter in inches is .06 plus .013 times the number.  For example, a #6-32 is .06 + .013 * 6 = .138 inches in diameter.

Some metric machine screws look similar to imperial machine screws.  For example, an M5x0.8 is virtually indistinguishable by the naked eye from an imperial #10-32, but they are not interchangeable.

Self tapping machine screws are generally specified only by diameter in metric or # in imperial measure.  They are similar in size to wood screws but not identical.  In addition, wood screws are tapered, self tapping screws may be straight or slightly tapered at the lead end.

But if you really want to buy screws, then you also need to specify head style, slot type, material and finish.  It really is not a simple subject.

Jim
Growing older is mandatory but growing up is optional.

Yampa Bob

#5
2-56 phillips machine screws for trucks/couplers, low as 59 cents per 100.

http://tinyurl.com/kjmcdu
I know what I wrote, I don't need a quote
Rule Number One: It's Our Railroad.  Rule Number Two: Refer to Rule Number One.

ALCOS4EVER

Try Micro Fasteners - (800) 892-6917

Jhanecker2

Jim Banner is right, it is not a simple subject. Whenever I need more screws to finish a repair,  I usually "mike " the screw in Imperial and metric units and then look it up in the Machinery Handbook.  Works OK for machine screws , but it does not work for woodscrews
Fastener Manufacturers have their reference Manuals  for many of their products. I usually end up going down the aisles of Ace , Menards , Home Depot , Woodcraft or industrial Supply stores on a quest .  Sometimes I Think the "Grail  Quest " is easier. John II

mudzuks

I love this thread, I made my wife read it so she understands I am not a nut and why I stop and pick up every discarded boom box, vcr and dvd player and then spend an hour disassembling these things, they have a great amount of tiny nuts bolts screws pulleys belts arms sprockets springs and motors which I use to animate stuff and model.

Jeff

OkieRick


As usual, great info from all 'cept me.  It's bookmarked as . . .


                      HOW TO SCREW - BY THE PROs


Okie

Invacare 2-2-2 TDX5 Tilt Recline & Elevate - 24v - ALS Head Control
God Bless Jimmie Rogers the Singing Brakeman

ALCOS4EVER

Go to "boltdepot.com". They have charts and tables to identify what you are looking for. All you will need is a set of calipers.