|
Available in varied shapes to recess nuts or screw heads at or below work surface, most common are conical for flat or oval heads or cylindrical for nuts or other heads. The smaller modeller sizes may be used by hand, but cleaner holes are usually achieved with power. Some rotary tool burrs approximate them closely. 
Note: Adjust brightness and contrast for optimum viewing. |
|
|
Since many imported needle point trucks, having desirable side frames, use shorter than NMRA recommended axle lengths, replacement with standard lengths such as Athearn or Kadee, requires slightly increasing the depth of the bearings. By shortening the shanks to fit between sideframes, #1 can be used by hand to carefully deepen the bearings. Some thicker cases may require #2. Twist the bit a few turns on both sides, then mount and spin axle. Deepen with a couple more spins at a time, until wheels spin freely. Since Kadee's axles are acetal, better rolling can usually be achieved with these, but care must be taken not to blunt the ends. Using metal axles of the same length for initial trials would be safer. For model sized, flat or oval head screws, #3 very closely approximates the neck angle for countersinking flat head screws. #4 is is useful in larger metal countersink applications. To permit mounting lathe work between centers, precise countersunk holes are bored with stepped center drill bits. Designed for rigidity, they are self centering and can be used elsewhere for countersinking by using just the tip or including the step.. With a 60 ° total angle, they can be used to drill or ream truck sideframe journals for needle point or other axles by hand or machine.. 
Note: Adjust brightness and contrast for optimum viewing. #00 center DRILL BIT #4 center DRILL BIT Apparently a modified center drill bit, sold by Reboxx and others, a specialized journal countersink reamer has a 60 ° total angle and rubber ring to aid finger twirling. With one flute, cutting can be controlled easily. However it is a little long for some assembled HO trucks and will not fit narrow gauge or smaller scales. 
Note: Adjust brightness and contrast for optimum viewing. TRUCK SIDEFRAME JOURNAL REAMER For more precise work, machinist's countersinks come in various forms. Sold by screw size, conical are used for flat heads. For deeper work, pilot bits are used. These are excellent for fillister heads or other deeply sunk heads. 
Adjust brightness and contrast for optimum viewing. 5/32" FLATHEAD. 1/4" FLATHEAD. DEEP COUNTERSINK W/ PILOT #2 w/ .156" head clearance. A word of caution in selection. Although normally sold by pilot center guide, screw size with no outside diameter given, they probably will not fit pan and binder heads or washers. BACK TO COMMON DRILL BITS BACK TO DRILL COUNTERSINK BACK TO TOOLS INDEX |
| Browser -- Ibrowse V2.3 -- 2003
Text -- CygnusEd Professional V4.2 -- 1999 Drawings -- XCAD-3000 V1.1 -- 1992 Graphs -- Math-Amation V1.0d -- 1988 Rendering -- Image FX V4.1 -- 2000 Digital Camera -- Kodak DC25 -- 1998 Digital Camera 2 -- Kodak DC280 -- 2003 Scanner -- HP Scanjet 6200C -- 2000 HTML and mistakes -- BUDB -- 1931 |
