Cutting Tool Applications Chapter 11: Reaming and Tapping

[machininglady]

Cutting Tool Applications Chapter 11: Reaming and Tapping

Twist drills do not make accurately sized or good finish holes; a reamer of some type is often used to cut the final size and finish. A reamer will not make the original hole; it will only enlarge a previously drilled or bored hole. It will cut to within +0.0005" of tool size and give finishes to 32 micro inches.
Reamers are usually made of High Speed Steel, although solid carbide and carbide tipped reamers are made in many sizes and styles. Regular chucking reamers are made in number and letter sizes, in fractional inch sizes and in millimeter sizes. They can be purchased ground to any desired diameter.

Screw threads are used for a variety of purposes and applications in the machine tool industry. They are used to hold or fasten parts together (screws, bolts and nuts), and to transmit motion (the lead screw moves the carriage on an engine lathe Screw threads are also used to control or provide accurate movement (the spindle on a micrometer), and to provide a mechanical advantage (a screw jack raises heavy loads).

When defining a screw thread, one must consider separate definitions for an external thread (screw or bolt) and an internal thread (nut).

An external thread is a cylindrical piece of material that has a uniform helical groove cut or formed around it. An internal thread is defined as a piece of material that has a helical groove around the interior of a cylindrical hole. This chapter will discuss internal threads and tapping, the operation that produces such threads.


Great article series I've been following on American Machinist...click to read on

[Cmailco]

Thanks for sharing. Informative article, seems to cover all the basics.

The only area I really took issue with was, "finishes to 32 micro inches". You'd never achieve that in cast iron for instance; which is not to nit-pick but to say that the workpiece material is a very real determining factor. Perhaps a bit overgeneralized but still a good article either way.

[nitintyagi]

for more cnc basics informations you may check following website:

http://www.futechmachines.com/cnc-section.html