Chi̍t-kóa thòa-kǹg bôa-chiam
Bôa-chiam kap ko-sok chhiú-ki
Bôa-chiam ê ki-pún tô·-iūⁿ
**Bôa-chiam** (Hàn-jī: 磨針; Eng-gí: burr) sī khí-kho sú-iōng lâi siu-bôa chhùi-khí ê ke-sī, ē-sái tī thūn-chhùi-khí ê sî-chūn the̍h-lâi bôa-tû chiù-chhng ,mā ē-sái tī beh chò ké-chhùi-khí ê sî-chūn iōng-lâi siū-hêng chún-pī chhùi-khí, he̍k sú-iōng tī kî-thaⁿ ū su-iàu bôa tio̍h chhùi-khí ê to·-ha̍p. Ū-sî-chūn ē kā i kiò-chò **chǹg-á** (*drill bit*), m̄-koh chǹg-á ê hâm-ì khah e̍h-sè kan-taⁿ ū chǹg-khang ê ì-sù, bôa-chiam m̄-nā ē chǹg-khang koh ē siah ē bôa. 

Bôa-chiam ū kúi-nā-chióng, tiāⁿ-tiāⁿ khoàiⁿ--ê sī tàu tī ko-sok chhiú-ki-á (*high-speed handpiece*) ê hit-chióng. Kî-thaⁿ iáu-ū, chhin-chhiūⁿ tàu tī bān-sok oan-kak chhiú-ki (*low-speed contra-angle handpiece*) ê bôa-chiam, i ê pèⁿ ū phòa-khih, chhùn-chhioh pí chêng 1 chióng khah-tōa khah-tn̂g. Koh-ū chit-chióng sī tàu tī ban-sok ti̍t chhiú-ki (*low-speed straight handpiece*) ê bôa-chiam, i ê chhùn-chhioh koh khah-tn̂g.

Koh-iūⁿ ê bôa-chiam
-------------------

Chiàu choán-sok lâi hun:

1. bān-sok bôa-chiam (500-15,000 rpm), pèⁿ ê ti̍t-kèng 3/32 inch (2.4 mm); oan-kak chhiú-ki iōng--ê ê tn̂g-tō· tāi-iok 22 mm; ti̍t chhiú-ki ēng--ê ê tn̂g-tō· tāi-iok 5 kong-hun.
2. ko-sok bôa-chiam (100,000-800,000 rpm), pèⁿ ê ti̍t-kèng 1/16 inch (1.6 mm), tn̂g-tō· tāi-iok 2 kong-hun chó-iū, ū chhiat-siah lêng-le̍k ê pō·-ūi ê chia̍t-bīn ti̍t-kèng tāi-iok bē chhiau-kòe 3 mm.

Chiàu chit-liāu lâi hun:

1. thòaⁿ-kǹg bôa-chiam (*carbide burr*)
2. o·-kǹg bôa-chiam (*tungsten carbide burr*)
3. soān-chio̍h môa-chiam (*diamond burr*) :

Ū-ê tēng-gī kóng, môa-chiam sī kí hoán-sî-kè (couterclockwise) tńg-se̍h chiah-ū chhiat-siah ê kong-lêng ê ke-si, soān-chio̍h môa-chiam in-ūi 2 ê hong-hiòng lóng ē-sái bôa, só·-í kā lēng-gōa kiò-chò soān-chio̍h bôa-chio̍h (*diamond stone*).
Chiàu hêng-thài lâi hun:

1. îⁿ-hêng bôa-chiam (*round burr*) (1/4-10)
2. hoan-liàn-tńg îⁿ-chui-thé bôa-chiam (*inverted cone burr*) (31 1/4-44)
3. pêⁿ-bīn ti̍t-hêng lia̍t-kau bôa-chiam (*plain straight fissure burr*) (551/2-62)
4. hoâiⁿ-chhiat ti̍t-hêng lia̍t-kau bôa-chiam (*crosscut straight fissure burr*) (556-563)
5. pêⁿ-bīn îⁿ-chui-thé lia̍t-kau bôa-chiam (*plain tapered fissure burr*) (69-73)
6. hoâiⁿ-chhiat îⁿ-chui-thé lia̍t-kau bôa-chiam (*crosscut tapered fissure burr*) (699-703)
7. chhia-lián-hêng bôa-chiam (*wheel burr*) (111/2-16)
8. íⁿ-hêng bôa-chaim (*bud burr*) (441/2-51)
9. lâi-á-hêng bôa-chiam (*pear burr*) (230-232)
10. tn̂g-ko-îⁿ bôa-chiam (*oval burr*) (218-221)
11. îⁿ-chui-thé bôa-chiam (*cone burr*) (221/2-33)
12. hóe-iām-hêng bôa-chiam (*flame burr*) (242-246)

Chiàu kong-lêng lâi hun:

1. toan-chhiat bôa-chiam (*end-cutting burr*)
2. ó·-khang bôa-chiam (*excavating burr*)
3. bôa-iù bôa-chiam (*finishing burr*) mā kiò-chò thiâm-that bôa-iù bôa-chiam (*plug-finishing burr*)
4. thui-kim bôa-chiam (*polishing burr*)

hoâiⁿ-chhiat bôa-chiam (*crosscut burr*) mā kiò-chò kì-khí bôa-chiam (*dentate burr*)
ti̍t-hêng lia̍t-kau bôa-chiam (*straight fissure burr*) kap toan-chhiat bôa-chiam (*end-cutting burr*) tâng-chê mā kiò-chò îⁿ-thiāu-thé bôa-chiam (*cylinder burr*)

Chìn-chi̍t-pō· chhiáⁿ-khòaⁿ tńg-se̍h chhiat-siah kang-kū (khí-kho) (*rotary cutting instrument*).