UNF for the machine
What takes two tools by hand, one tool does in a single pass on the machine. VÖLKEL makes 104 machine taps for the American fine thread UNF, from UNF No. 4 x 48 to UNF 1.1/2 x 12: to DIN 371, DIN 376 and JIS B-4430 in HSSE and to ISO 529 in HSS-G, each in form B and form C.
Form B or form C
Form B has a spiral point lead of four to five threads and carries the chips forward, which only works in a through hole. Form C with a 35° spiral flute lifts them out to the rear and is made for blind holes. Each of the four standard series comes in both forms.
DIN, JIS or ISO
The standards set the shank and overall length, not the thread. DIN 371 and DIN 376 are the European dimensions, JIS B-4430 the Japanese, and ISO 529 describes the shorter international design. Which series fits depends on the holder on the machine and the depth of the thread.
HSSE or HSS-G
HSSE with added cobalt withstands the higher hot hardness that alloyed and stainless steels demand. HSS-G is ground high speed steel and is sufficient for unalloyed steels and many non-ferrous metals. The differences are explained in the article HSS, HSSE and HSSE-PM explained.
The tap drill gets tight
The finer the pitch, the smaller the gap between tap drill and nominal diameter, and the more sensitive the thread is to a wrong size. The calculation is in the article calculate tap drill size.
Hand tools under UNF hand taps, the even finer series under UNEF, other thread types among the machine taps, gauges among the thread plug gauges.
All sizes at a glance
104 articles in 4 series. The article number links straight to the tool.
Series: Machine Tap JIS B-4430 HSSE · Machine Tap ISO 529 HSS-G · Machine Tap DIN 376 HSSE · Machine Tap DIN 371 HSSE
Machine Tap JIS B-4430 HSSE
| Threadnominal size | Tapping drillØ in mm | Form B | Form C 35° Spiral Flute |
|---|---|---|---|
| UNF No. 4 x 48 | 2.4 | 93554 | 93754 |
| UNF No. 5 x 44 | 2.7 | 93555 | 93755 |
| UNF No. 6 x 40 | 3 | 93556 | 93756 |
| UNF No. 8 x 36 | 3.5 | 93558 | 93758 |
| UNF No. 10 x 32 | 4.1 | 93559 | 93759 |
| UNF No. 12 x 28 | 4.7 | 93560 | 93760 |
| UNF 1/8 x 44 | – | 93561 | 93761 |
| UNF 5/32 x 36 | – | 93562 | 93762 |
| UNF 3/16 x 32 | – | 93563 | 93763 |
| UNF 1/4 x 28 | 5.5 | 93564 | 93764 |
| UNF 5/16 x 24 | 6.9 | 93565 | 93765 |
| UNF 3/8 x 24 | 8.5 | 93566 | 93766 |
| UNF 7/16 x 20 | 9.9 | 93567 | 93767 |
| UNF 1/2 x 20 | 11.5 | 93568 | 93768 |
| UNF 9/16 x 18 | 12.9 | 93569 | 93769 |
| UNF 5/8 x 18 | 14.5 | 93570 | 93770 |
| UNF 3/4 x 16 | 17.5 | 93572 | 93772 |
| UNF 7/8 x 14 | 20.25 | 93574 | 93774 |
| UNF 1" x 12 | 23.25 | 93576 | 93776 |
Machine Tap ISO 529 HSS-G
| Threadnominal size | Tapping drillØ in mm | Form B | Form C 35° Spiral Flute |
|---|---|---|---|
| UNF 1/4 x 28 | 5.5 | 83514 | 83714 |
| UNF 5/16 x 24 | 6.9 | 83516 | 83716 |
| UNF 3/8 x 24 | 8.5 | 83518 | 83718 |
| UNF 7/16 x 20 | 9.9 | 83520 | 83720 |
| UNF 1/2 x 20 | 11.5 | 83522 | 83722 |
| UNF 9/16 x 18 | 12.9 | 83524 | 83724 |
| UNF 5/8 x 18 | 14.5 | 83526 | 83726 |
| UNF 3/4 x 16 | 17.5 | 83530 | 83730 |
| UNF 7/8 x 14 | 20.25 | 83534 | 83734 |
| UNF 1" x 12 | 23.25 | 83538 | 83738 |
| UNF 1.1/8 x 12 | 26.5 | 83540 | 83740 |
| UNF 1.1/4 x 12 | 29.5 | 83542 | 83742 |
| UNF 1.3/8 x 12 | 32.5 | 83544 | 83744 |
| UNF 1.1/2 x 12 | 36 | 83546 | 83746 |
Machine Tap DIN 376 HSSE
| Threadnominal size | Tapping drillØ in mm | Form B | Form C 35° Spiral Flute |
|---|---|---|---|
| UNF 7/16 x 20 | 9.9 | 77520 | 77720 |
| UNF 1/2 x 20 | 11.5 | 77522 | 77722 |
| UNF 9/16 x 18 | 12.9 | 77524 | 77724 |
| UNF 5/8 x 18 | 14.5 | 77526 | 77726 |
| UNF 3/4 x 16 | 17.5 | 77530 | 77730 |
| UNF 7/8 x 14 | 20.25 | 77534 | 77734 |
| UNF 1" x 12 | 23.25 | 77538 | 77738 |
| UNF 1" x 14 | – | 77540 | 77740 |
| UNF 1.1/4 x 12 | 29.5 | 77546 | 77746 |
| UNF 1.1/2 x 12 | 36 | 77554 | 77754 |
Machine Tap DIN 371 HSSE
| Threadnominal size | Tapping drillØ in mm | Form B | Form C 35° Spiral Flute |
|---|---|---|---|
| UNF No. 4 x 48 | 2.4 | 76504 | 76704 |
| UNF No. 5 x 44 | 2.7 | 76505 | 76705 |
| UNF No. 6 x 40 | 3 | 76506 | 76706 |
| UNF No. 8 x 36 | 3.5 | 76508 | 76708 |
| UNF No. 10 x 32 | 4.1 | 76510 | 76710 |
| UNF No. 12 x 28 | 4.7 | 76512 | 76712 |
| UNF 1/4 x 28 | 5.5 | 76514 | 76714 |
| UNF 5/16 x 24 | 6.9 | 76516 | 76716 |
| UNF 3/8 x 24 | 8.5 | 76518 | 76718 |
Tapping drill: drill diameter recommended by VÖLKEL (Technical Information “Tapping drill sizes”).
