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 .

Chi̍t-kóa thòa-kǹg bôa-chiam
Bôa-chiam kap ko-sok chhiú-ki
Bôa-chiam ê ki-pún tô·-iūⁿ

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 siu-kái

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).