[TheForge] drilling question

[Andrew Vida]

You a couple of choices - a drill guide or an endmill.  The latter is 
generally not too practical.

The guide can be made any of several ways such as adjustable or non-. 
If you are drilling a lot of holes at the same angle, get yourself a 
piece of 4140, drill a hole in it perhaps 0.010 wider than the drill you 
will be using.  Cut one end off at the right angle and fashion a means 
of clamping it TIGHTLY to the work.  I must emphasize the importance of 
this for safety reasons, as well as the sake of not buggering up your 
work... which will always happen when you are drilling the 474th of 475 
holes in a single piece of costly material, necessitating a restart from 
scratch.  You may want to add a witness mark on the outside to indicate 
the centerline so you can line it up with a mark on the work to be 
drilled.  Another way is to have another bit on hand and use the tip to 
find your punch mark.  Clamp in place and go from there.

Heat treat to C50-55 and you should be good to go.  You can also regrind 
your drills so that the point bites before the ends of the lips do. 
This will GREATLY ease wander.  I would also deeply punch the center 
mark - at least a good 1/8" diameter or more  THis will further help the 
bit from wandering off center.  One other thing you can do, and this 
really isn't necessary - you can stone the flute edges so they will not 
cut into the bore of the guide.  This *may* be worth doing if you're 
going to have to drill, say, 1000 holes and are not in the mood to make 
another guide.

Another way to pilot your holes, and this only works with relatively 
thin work materials, particularly in relation to the diameter of the 
drill - drill a cross hole 1/4 or 1/2 way at the punch mark.  E.g., if 
you have to make 7/16 holes at 30* in 1/2" x 2 for a railing, you can 
punch the centers and then drill, say, 1/8" diameter pilots 1/8 or 3/16 
deep and normal to the surface.  Then use your guide and acutely ground 
drill bit.  The point will stay right there at home in the 1/8" peck and 
establish itself nicely.  You can also use a center drill (lathe tool) 
for marking centers.  They are very short and stout and will make you 
happy in this regard. :)

Also, and this can be important in some cases - use the SHORTEST drill 
bit that will do the job.   If all you have are longer bits, make the 
guide as long as will allow the hole to be drilled to the depth you need.

Guide can look like this:

                      ________________       _____
                     /                |     |     |
    Witness mark--> /----             |     |  0  |  Drill from sq. end
                   /__________________|     |_____|


Andy Gladish wrote:
> Here's one for the list:
> Looking at an upcoming railing job, I realize that I've never really  
> learned how to drill angled holes- anyone have pointers, or links to a  
> site that tells best practices for that?
> A few Google searches didn't really turn up what's needed.
> 
> Thanks!
> Andy G.
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-- 

     -Andy Vida

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