To determine the blank size for a number screw/die, multiple 0.013 x the number and add .060, i.e., #6-32 die would require a blank (6 x .013) + 0.06=0.138" To determine the tap drill size for any UN thread take the nominal size and subtract the pitch, i.e., 0.138-(1/32)=0.1068 That will give you about a 77% thread and you can usually, in low stress applications use as low as a 50% thread, especially if the threads are more than 3X the diameter though there are diminishing returns on going more than about 5 threads deep.
What are the material sizes to use with small dies?
- Thread starter Shopgeezer
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Shopgeezer, you have been given all the information you need multiple times. What is left is for you to start paying attention and start thinking.
HennieL
Well-Known Member
Cogsy
Well-Known Member
A few years ago I bought a cheap set of miniature taps and dies from Chronos in the UK. Pretty sure they're Chinese but they've worked flawlessly for me. I've tapped steel, aluminium and brass down to 0-80 and successfully cut a thread on silver steel/drill rod to that size as well, but I've mostly used the 2-56 and 4-40 stuff. It looks like too cheap a set to work but mine has been great. I've seen identical looking sets advertised in local shops for much more than I paid.
https://www.chronos.ltd.uk/product/hss-mini-imperial-tap-set-unf-unc/
Good find. Thanks. They have 00,0 and 1 sized taps. I will get all 3 and see what works with my collection of music wire. These wires are by no means precision made and vary in diameter quite a bit. I guess despite all the exactness of 3a versus 2a fits and the tolerances in the tables it boils down to what will work. If the thread on the wire fits the plastic clevis and keeps the elevator on the airplane moving it is all a good day!
Oops, my page didn’t update before I hit send. I was referring to the post about the dies from Micro Fasteners. They are a great outfit for small stuff, I have several of their cap bolt collections. The tap and die set from Chronos looks great too. That is very tempting. But those teeny taps scare me. Dies are robust even at super small sizes but I bet I could break a 00-90 tap by looking at it.
HennieL
Well-Known Member
The only imperial tap that I own (and use a lot...) is an 0-80 that I use to tap threads for liner lock folding knives - and what's really scary is tapping into titanium, free hand, using a battery powered drill - but for some reason it works
. I normally drill and tap at least 12 holes for each knife, and I've lost track of the number of knives that I've built, but have only broken one tap so far, so go ahead and try it.
Do you use tap magic or some other lube? Titanium sounds like a tough metal to tap even at larger sizes.
HennieL
Well-Known Member
I use a black tapping grease called "black magic" - this stuff can really make a mess, but works great (and it might be what you are referring to as tap magic ??)
Fortunately the liners are only 1.2mm or 1.5mm thick, but the trick is to just run the hand drill at slow speed, and to not stop until the tap is properly through - but obviously before you reach the bottom of the tap, else it will break. Then, just flip the drill into reverse and ease the tap out again.
Watch making equipment, at my age I like to be able to see what I'm making.
How about this 000-120 micro thread roller?
RonW
Well-Known Member
I'm with teeleeves. Looks like swarf to me. 4-40 or 10 BA or maybe 2mm is my minimum. The old story of the Swiss watch maker taking the smallest American screw and drilling and taping down inside of it is science fiction to me. If I can't see it it doesn't exist.
Ron W
