Tap Nomenclature. Key:

Transcription

1 Ta Nomenclatue Key: 1. Oveall Length 12. Chamfe Angle 2. Thead Length (Including Chamfe) 13. Rake Angle 3. Shank Length (Including Squae) 14. Width of Land 4. Chamfe Length 15. Width of Flute 5. Shank Diamete 16. Radial Thead Relief 6. Length Of Diving Squae 17. Web Diamete 7. Size Acoss Flas of Squae 18. Sial Point Rake Angle 8. Intenal Cente (Female) 19. Sial Point Angle 9. Extenal Cente 20. Sial Point Length 10. Back Tae 21. Angle of Sial 11. Point Diamete (Chamfe) (Sial Flute)

2 Basic Sizes and Toleances fo tas If tas wee manufactued to basic sizes they would have a vey shot life. The scew thead has a lus toleance and the standad allows the tas to be made within this toleance If you measue the outside diamete of a ta it will be aoximately 1% lage than the nominal size i.e. a 10mm ta will measue 10.1mm. It can be misleading to measue the outside diamete of the bolt as it will be 2% smalle. The two cannot be comaed The size of the ta cannot be judged by measuing the majo diamete LIMITS OF TOLERANCE Toleance is the amount of vaiation emitted in the manufactue of the ta and takes the fom of a futhe addition to the minimum diametes. The toleances of the majo and the mino diametes ae not given in the ta standads, but the effective diamete is egaded as the most imotant element and thus the toleance is igidly secified. Examle fo an M10 ta alying Class 2 thead toleance Basic Effective (itch) diamete = Minimum ovesize = Minimum effective diamete = Ta Toleance = Maximum Effective Diamete = Basic Majo diamete = Minimum ovesize = Minimum Majo Diamete = Maximum Majo is not secified, common actice is to leave a small flat cest and not out to a sha oint. TAPPING PRACTICE TAP DRILL SIZE In the thead chats that follow the coect taing size is given in the infomation. We also give the altenative maximum size, as with good moden dills the dilled hole can be small. On tough mateials like stainless steel we ecommend you take advantage of the exta allowance. It is esecially imotant in dee holes of 2 times diamete and geate (dill sizes fom BS1157 aendix "A")

3 TAPPING PRACTICE LUBRICANTS Fist class taing can only be done with a coious suly of oe lubicant. Use of the coect lubicants is as imotant as the decision to use it, it must be ket clean and caefully diected into the hole being taed, an amle suly is needed on the cutting edges, not only to disese heat, but to aid in the fomation and emoval of chis. SPEEDS Efficient taing has its otimum seed, see age 29 fo an initial ecommendation and guide. Exact figues cannot be given because of the vaiables such as machinability of the mateial being taed, condition of the machine, deth, itch and length of the thead, holding fixtue o taing attachment. Fom actical alication adjust ou ecommendations u o down until otimum esults ae obtained. When stating a ta do not foce o etad the ta, o a bell mouthed hole will be oduced with thin theads. Allow the ta to establish its own itch. Duing taing of a dee hole, avoid the flutes becoming clogged with chis - beakage is inevitable in these cicumstances, conside a fluteless ta fo vey dee holes. Chi disosal is a lage oblem on tas of 12mm and smalle whee flute sace is esticted see descition on sial oint and sial flute tas below. HAND TAPS Fo hand taing, the conventional set of 3 tas with staight flutes is ecommended. It is essential that the ta is esented squaely to the wok and that the tas ae coectly aligned. When tas ae used in a machine it is usual to use only the second lead. Using the bottom ta only, can cause oblems and will significantly educe the life of the tool. SERIAL FORM HAND TAPS These ae also hand tas. The oughing ta is takes out half the thead aea it is maked with a ing on the shank fo identification. The Mid-Roughe will take out to 75% of the aea of the thead, it is maked with two ings on the shank. Only the lain shanked Finish ta cuts SIZE. This fom of hand ta is ecommended fo mateials like stainless steel and lage tas ove 25mm in diamete make it ossible to hand ta ight u to 52mm Only two tas ae sulied fo fine itch theads.

4 SPIRAL POINT TAPS These tas ae sometimes called GUN-Nosed, ae made with a secial leading flute gound at an angle to the ta axis. This left hand flute at the lead ushes the swaf ahead of the ta theads thus allowing the use of smalle flutes since chi cleaance is not equied. The esult is theefoe stonge tas which ae suitable fo though hole taing in most mateials. Blind hole taing should only be attemted whee thee is sufficient oom at the bottom of the hole to accommodate the swaf. SPIRAL FLUTE TAPS These tas have a continuous sial flute the same hand as the thead, thus focing the swaf u the hole. The most suitable alications ae on blind holes in ductile mateials with long continuous chis. Slowe 15 sial may be used on toughe mateials. PIPE TAPS Thee ae thee tyes of ISO comonent Pie Tas Theads 1 G seies theads (BSPF) this is a aallel fastening thead fo BS2779 whee essue tight joints ae not equied 2. Rc seies (BSPT) theads whee essue tight joints ae equied. These tas ae made to BS949 with ISO shanks and squaes. Tae eames ae an advantage on taing these theads and we stock 1:16 tae eames fo this alication. Inteuted thead tas ae also available fo stainless and othe wok hadening mateials. 3 R o BSPPl ae undesize Paallel tas fo use on BS21 gas tight alication they have taeed lugs assembled into the aallel hole and ae destuctively dy sealing. We only suly these to ode. Details ae given on age 37 AMERICAN PIPE TAPS NPS tas can be used fo NPSC & NPSM aallel theads. NPSC theads ae intenal coulings and may be used with sealant fo low essue ie wok. NPSM is used as a mechanical fastening thead. NPSF ae aallel undesize theads with tuncated cests fo dyseal use with taeed fitting NPT ae standad tae tas and can be assembled with jointing fo low essue wok. We can suly taeed ie eames to aid taing, and inteuted thead tas fo stainless and othe wok hadening mateials. NPTF simila to above but with tuncated cests to effect a dyseal. We ecommend the use of the taeed eame when taing this thead.

5 FLUTELESS ROLL (Cold Foming) TAPS Fluteless o cold foming tas can be used in a wide vaiety of mateials fom steel, aluminium, coe and soft ductile basses but will also cut stainless's and titanium and nickel mateials. As these mateials may tea athe than cut cleanly, they tend to clog the flutes of conventional tas. The fluteless ta offes an altenative foming by dislacing the mateial instead of cutting. It should be noted that the biggest change is the equiement of a lage taing dill, (see thead chats on age 30) the fluteless ta also can ta faste than a standad ta see (seed chat on age 29) Lubication is of the utmost imotance in thead foming, with an exteme essue additive is advisable in soluble oils. SOME COMMON REASONS FOR TAP FAILURES Ta Cuts Ovesize 1. Ta out of alignment with the hole o ta not unning tue 2. Feed essue on ta oducing thin o defomed theads 3. Dilled coe hole to small see thead chats 4. Incoect ta fo the mateial e.g. (a) cutting ake too geat,(b) Incoect thead elief, '(c) Chamfe lead too shot. 5. Incoect shaening e.g. chamfe elief uneven o to excessive. Ta Cutting Edges Chi 6. Ta hitting the bottom of a blind hole 7. Ta evesing with swaf taed 8. Lubication lacking o wong quality o secification. 9. Mateial too had, o abasive fo the ta tye. Raid Ta Wea 10. Seed too fast also conside items 3, 4, and 8. Poo Thead Finish 11. Ta has eached the extent of its life. Conside tye of ta used, o items 3, 4, and 8 Ta Beaks 12. Ta blocked with swaf, is it the coect tye of ta, look at items 1, 3, 4c, 5, 6, 7, 8, 9, 10, and 11.

6 Though Blind TAPPING SPEEDS Holes Holes Staight Sial Sial Fluteless MATERIAL Flute Point Flute hadness Hb M/min M/min M/min M/Min CARBON & ALLOY STEEL Mild Steel < Low/Medium Cabon Steel < Highe Cabon Steel < Low Alloy Engineeing Steel < Alloy Steel - Heat Teated > Alloy Steel - Heat Teated > STAINLESS STEEL Fee Cutting (magnetic)feitic < Austenitic (Non Magnetic) < Matensitic/Maaging Dulex Alloys > CAST IRON Plain Gey Ion -Feitic Malleable < Plain SG Ion-Pealitic Malleable < Alloy SG Ion NiHad > ALUMINIUM Wought (soft) & Extuded < b Wought & Teated > b Cast Low Silicon 5% < b Cast High Silicon 10% > b 8-16 COPPER Pue Coe < Alha Bass (soft yellow) < Beta Bass > High Tensile Bonze < b 8-16 NICKEL Pue Nickel < Nickel, Nimonic 75 Hasteloy Alloys > Nickel, Inconel 718 Alloys < TITANIUM Pue Titanium < Titanium Alloys > b = Bight Finish Sial Point Tas available on equest Whee no seed is given in Staight Flutes, we suggest use of Seial fom Tas when hand taing Peiheal Metes/Min X 1000 Seed in RPM = (3.1416) X Diamete π NOTE fluteless tas have a secial oening dill sizes, listed in the ta and thead tables fom age 30 onwads

7 ISO METRIC COARSE Thead fom 60 ISO M / 4 / 8 Basic Rad "" = ISO METRIC FINE THREADS Thead fom as M above Height Int Thead "hn"= P Mf o M may be used fo identification, always include itch Mf4 x 0.5 hn Height Ext Thead "hs" = P Including Saklug, and Conduit. Pefeed ISO Metic Fine ae maked * Tiangula Height H = P Nom Pitch Effective Dia Max Coe Taing Cleaance hs Dia Nominal Diamete Dill Dill mm mm mm mm mm mm Mf3 * Mf Mf4 * Nom Effective Nut Max Flutless Taing Cleaance Mf Dia Pitch Coe Taing Dill Dill Mf Diam Diam Dill Size Size Size M5 (Sec mm mm mm mm mm mm mm Mf M Mf6 * M Mf M Mf M Mf8 * M Mf M Mf M Mf10S/l M Mf10 * M Mf M Mf M Mf12 * S M Mf M Mf M Mf14 S/ M Mf14 * M Mf M Mf16 *Co M Mf M Mf18 * S M Mf M Mf M Mf20 *Co M Mf M Mf22 * M Mf M Mf M Mf24 * M Mf25 Con M Mf M Mf27 * M Mf M Mf30 * M Mf32 Con M Mf M Mf40 Con Max coe given fo a 6H fit

8 Unified Coase hn / 4 UNC, NC / 8 Thead Fom Basic Rad "" = Height Int. Thead "hn"= P Height Ext Thead "hs"= p hs Tiangula Height H = P = Pitch = 1/TPI Nom Nom Basic Max Fluteless Taing Clea Size T.P.I Dia Effective Coe Taing Dill Dill Dia Diamete Dill Size Size Size Inch inch mm mm mm mm No No N No No No No No No # / / / / / / / / / " / / / / / " 4-1/ /4 4-1/ / Max coe size given fo a 2B fit

9 Unified Fine UNF, NF Thead Fom 60 = Pitch = 1/TPI Basic Rad "" = , Height Int. Thead "hn"= Height Int. Thead "hs"= , Tiangula Height "H" = / 4 / 8 hn hs Nom Nom Basic Max. Fluteless Taing Clea Size T.P.I Dia. Effective Coe Taing Dill Dill Dia Diamete Dill Size Size Size Inch inch mm mm mm mm No No # No N No No No No No No / / / / / / / / / " / / / / Max Coe size Given Fo 2B fit

10 BRITISH STANDARD WHITWORTH BSW h 55 Thead Fom 55 = Basic Radius = P h = Basic deth of thead = P P = Pitch = 1/ti Nom. Nominal Basic Max Fluteless Taing Size T.P.I. Dia Effective Coe Taing Dill Dia Diamete Dill Size Size Inch inch mm mm mm 1/ / / / / / / / / / / / / / / / " / / / / / " 4½ / / Maximum coe diamete given fo Medium Fit

11 BRITISH STANDARD FINE BSF h 55 Thead Fom 55 = Basic Radius = P h = Basic deth of thead = P P = Pitch = 1/ti Nom nom Basic Max Fluteless Taing Size T.P.I Dia Effective Coe Taing Dill Dia Dia Dill Size Size Inch inch mm mm mm 3/ / / / / / / / / / / / " / / / / / " / / Max Coe diamete given fo medium fit

12 BRITISH ASSOCIATION Thead Fom B A 47½ thead angle = Basic adius = h = basic deth of thead = 0.6 = itch h B.A. Nom Effective Max Fluteless Taing Numbe Dia Diamete Coe Taing Dill Pitch Nominal Diamete Dill Size Size mm mm mm mm mm mm B.A. Theads ae basically a metic thead based on 6mm With the diamete educing by aox. 88% on each ste and the itch educing by 90% to give a useful ste to the next size fo instument, watch and clock use

13 h 55 Thead Fom 55 ( Whitwoth) = Basic Radius = P h = Basic deth of thead = P P = Pitch = 1/ti BRITISH STANDARD PIPE FASTENER "G" seies, BSPF, BSP (Medium Class) Nom Majo Effective Max Fluteless Taing Size T.P.I Basic Dia Coe Taing Dill Dia. Nominal Dia Dill Size Size mm mm mm mm mm 1/ / / / / / / / " / / / " / / R (BSP Pl) educed effective diamete fo BS 21 Gas fittings Nom Majo Secial Effective Max Taing Size T.P.I MINIMUM Tae Gauge Coe Dill Dia Nom tuns of diamete Size mm mm gauge mm mm 1/ ±1¼ / ±1¼ / ±1¼ / ±1¼ / ±1¼ " ±1¼ / ±1¼ / ±1¼ " ±1¼ Tas fo R ae sulied only to secial ode. these ae made to a negative toleance on the Nominal Paallel taed hole - use taeed notch gauge

14 BRITISH STANDARD PIPE TAPER Rc (BSPT) Thead Fom 55, Tae 1 in 16 on Diamete, Basic R adius "" = , Basic Deth of thead "h" = , "" = 1/TPI Axis h Majo Basic Diamete 90 Gauge Plane Basic Effective Diamete Reame (R) Nom Majo Effective Position Ream Taing Dill Size Size T.P.I Basic Dia. At of gauge Dia. (R) with without Dia. Gauge P. "L" on ta at "L" Reame Reame mm mm mm mm mm mm 1/ / / / / / " / / " / Position of gauge lane "L" is ± one thead on the ta. We stongly ecommend the use of the eame fo Rc Theads 1:16 tae ie eames ae available in the eame section of the catalogue Length fowad of gauge lane (L)

15 NPT National Pie Tae (API, ANPT, Biggs tae) Thead fom 60, Tae 1 in 16 on diamete, Basic deth of thead "h" = 0.8, Pitch "" = 1/TPI h Axis Majo Basic Diamete 90 Basic Effective Diamete Length fowad of guage lane (L) Guage Plane Reame Diamete (R) Nom Outside Effective Position Ream Taing Dill Size Size T.P.I Pie Dia at of gauge Dia. (R) with without Dia. Gauge Plane "L" on ta at "L" Reame Reame Inch inch inch* inch mm mm 1/ / / / / / " 11½ /4 11½ /2 11½ " 11½ * u to 3 /4 ± 1/16", 1" and ove ± 3/32" We stongly ecommend the use of the eame fo NPT Theads 1:16 tae ie eames ae available in the eame section of the catalogue