Hi Fishbreath,
Ok, I've purchased a couple of taps and dies, but haven't a
clue as how to use them. Do I drill a hole and then insert the tap
(small, threaded part) to make the threads? I am pretty sure that
the die is the larger part into which I can put wire and get threads
on the wire by turning the die.
There are several different screw thread systems & I don’t know which
you have. Here’s the info for the ‘preferred’ sizes of screws made to
the ‘Uniform Miniature Screw Standard’. It’s taken from the ‘Tapping’
section of Machinery’s Handbook. The screw sizes are defined by 3
numbers followed by the letters UNM. For simplicity, I’ll omit the
UNM.
Because the thickness of the metal being drilled has an affect on the
required hole size, 3 sets of minimum & maximum hole sizes are
listed. The 1st set is for material up to 2/3 the thickness of the
screw diameter (2/3D). Set 2 is for material 2/3 - 1 1 /2D. Set 3 is
for 1 1/2 - 3D.
Column 1 is the screw number, Col 2 & 3, set 1; col 4 & 5, set 2;
col 5 & 6, set 3. The numbers in columns 2 thru 6 are listed in mm.
0.30 .226-.240 .236-.254 .245-.264 0.40 .307-.324
.318-.340 .329-.351 0.50 .383-.402 .396-.422 .409-.435
0.60 .459-.482 .474-.504 .489-.519 0.80 .611-.640
.630-.668 .649-.687 1.00 .763-.798 .786-.832 .809-.855
1.20 .963-.998 .986-1.032 1.009-1.055
The standard drill numbers for these sizes are listed in the
following table. The sizes listed fall between the minimum & maximum
size. In 2 cases, 1 size drill is used for 2 holes.
0.30 #89 #88 #87 0.40 #82 #81 #80 0.50 1/64
#78 #78 0.60 #77 #77 #76 0,80 #73 #72
#71 1.00 #68 #67 #66 1.20 #62 #61 #59
When drilling holes of theses sizes, it’s best to use a drill press
(unless you’ve got a very steady hand) and very high speed.
Taps should be lubricated before beginning tapping. Use your burr
lub. Because taps are very hard steel or carbide, it’s brittle. Any
side to side bending motion is apt to break the tap. As a result it’s
best to mount the tap in a drill press or a tapping machine. Turn the
drill press by hand.
Dave