Dot Punch: Difference between revisions
From DT Online
mNo edit summary |
mNo edit summary |
||
| Line 5: | Line 5: | ||
=====Description===== | =====Description===== | ||
[http://wiki.dtonline.org/index.php/File:AutoDotPunch.png '''Dot Punches'''] are similar to '''[[Centre Punch|Centre Punches]]''' but have a sharper point | [http://wiki.dtonline.org/index.php/File:AutoDotPunch.png '''Dot Punches'''] are similar to '''[[Centre Punch|Centre Punches]]''' but have a sharper point ground to an angle of 60 degrees by holding it '''[[Tangents and Normals|Tangentially]]''' to a '''[[Tool Grinder]]''' and rotating it. This tends to create grinding marks which run along the point and strengthen it rather than weakening it by going across ''(i.e. in a similar manner to a '''[[Scriber]]''')'' | ||
Revision as of 08:33, 9 February 2017
Description
Dot Punches are similar to Centre Punches but have a sharper point ground to an angle of 60 degrees by holding it Tangentially to a Tool Grinder and rotating it. This tends to create grinding marks which run along the point and strengthen it rather than weakening it by going across (i.e. in a similar manner to a Scriber)
Features and Uses
Dot Punches are held at an angle to the intersection or line to be marked and either lightly struck once with a hammer or, alternatively, Automatic Dot Punches are available, as shown, which are simply pushed down to activate.
Note:
If Dot Punches are used to mark where a large hole crosses each of its centre lines, for instance, accurate work would result in each ‘dot’ being halved across its diameter.
The lowest cost option is to use a hand-held punch with a hammer but a wide range of automatic punches are available - both Dot Punches and Centre Punches.
- In general, Dot Punches have a sharper point (i.e. 60° instead of 90°) and need only the lower ranges of impact force (e.g. 20N to 50N).
- Automatic punches are simply pushed down against the work-piece and do not need to be struck - indeed, should NOT be struck with a hammer.