Proper frame preparation is very important the park tool head tube reaming and facing set combines reaming and facing for both head tube and unthreaded bottom bracket shells park tool head tube reaming and facing set features the htr 1b combines reaming and or facing of the head tube to create a perfect fit for most sizes of headset cups the htr 1b comes complete with a 338 mm reamer and four different size pilots 298 mm 300 mm 338 mm and 368 mm the reamer is us