bottom tap

bottom tap

[′bäd·əm ‚tap]
(design engineering)
A tap with a chamfer 1 to 1½ threads in length.
(metallurgy)
A hole in the bottom of a furnace for draining out the slag.
References in periodicals archive ?
A bottom tap features almost no taper at all, and is intended to cut threads almost all the way to the bottom of a blind hole.
If you want threads almost all the way to the bottom, a bottom tap would be used after a plug tap cut as many threads as it could.
Go to "Search and apps" tab, then at the bottom tap Defaults, then choose a new app for e-mail, music player, Web browsing, photos, video player and calendar.
In some cases, you have to begin by using a starting tap with a high lead on it, followed by a bottom tap, if it is a blind hole.