0
Upcoming SlideShare
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Standard text messaging rates apply

779

Published on

1 Like
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

Views
Total Views
779
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
0
0
Likes
1
Embeds 0
No embeds

No notes for slide

### Transcript

• 1. THREAD-CUTTING TOOLS and PROCEDURES
• 2. HAND TAPS
• Taps are cutting tools used to cut internal threads.
• 3. THREAD SYSTEMS Dimensioning Code American National and Unified Screw Thread Classes of fit: 1 – lose fit 2 – medium fit 3 – tight fit
• There are five basic thread series in American National and Unified Screw Thread system. They are:
• Coarse (UNC)
• Fine (UNF)
• Extra Fine (UNEF)
• Special (UNS) National
• ISO Metric threads have a somewhat different coding system. For example a metric thread would be noted as:
• M 10 x 1.5 - 6H
• M indicates a Metric thread.
• 10 indicates a basic size of 10 millimeters.
• 1.5 is the pitch in millimeters. Note that the M 10 taps are also available as M 10 x 1.00 - 6H and 10 x 1.25 -6H.
• 6 identifies the grade of tolerance. Six (6) is commonly used and comparable with class 2 Unified American Standard.
• The grade of tolerance ranging from 3 to 5 fine, 6 medium tolerances 7-9 are coarse.
• H means that it is an internal thread with no allowance. Internal threads are defined with capitals, for example G designates a tight allowance.
• 7. TAP DRILL SIZE
• American National, or Unified Thread
• TDS = D – (1/N)
• Where: TDS = tap drill size
• D = major diameter of tap
• N = number of threads per inch
• TDS = major diameter (mm) – pitch (mm)
Cross-section of tapered hole Major Diameter Minor Diameter Pitch Depth Tap Drill Size
• 8. SET OF HAND TAPS
• Taper tap – tapered from the end approximately six threads and used to start a thread easily.
• Plug tap - tapered for approximately three threads and used to thread a hole going through a work piece.
• Bottoming tap – not tapered but chamfered at the end for one thread . Used for threading to the bottom of a blind hole.
• 9. HAND TAP WRENCH
• 10. DIFFERENT TYPES OF TAP
• 11. TAPPING A HOLE
• Before tapping the following should be determined:
• The proper tap hole has been drilled.
• The tap has the correct specifications.
• The tap hole is clean and free of all chips (particularly for blind holes).
• A suitable cutting fluid has been selected for application during the tapping process.
• If the thread is too tight, &quot;chase&quot; the threads by running the tap through again until it meets specifications.
• 12. REMOVING BROKEN TAPS
• Tap Extractor
• Made to fit all sizes of taps
• 13. PROPER CARE OF TAPS
• Care must be taken not to damage the cutting edges.
• A chipped tap must never be used. When not in use, taps should be kept clean and stored in a rack .