[HBR] HBR-13 Progress

[Ejparagi at aol.com]

Hi Scott,
 
Another suggestion for holes in the 1/4 to 1/2 inch range is the use of  
brad point drills (sometimes referred to as "spur" drills), commonly used on  
wood and sheet metal.  They are also referred to as "sheet metal  drills."  
Harbor Freight and Sears have sets of these that go to  a half inch in 
diameter.  They have a very sharp point that is easily  centered on even shallow 
prick punch marks (steeper angle than a center  punch).  I have used them in 
both hand held drills and drill presses with  good results.  You might want 
to buy only two or three sizes that would  receive the most use from a 
local hardware store if you have a well stocked one  nearby.
 
Working up to a hole with successively larger conventional drills also  
works well as someone already mentioned.  You could buy a couple of  good 1/16 
inch or 3/32 inch drills for accurately locating the intended hole and  then 
use your existing larger bits to work up to the desired diameter.  Use  a 
center punch to start conventional drill bits.  I used this method for  
years, sometimes augmented by a taper reamer until I could afford step drills  
and spur drills.  By the way, I added to my tool collection over the years  by 
asking for specific tools for birthday and Christmas gifts.  Make a list  
and add to it when you think of tools that would be of use to you so you are  
prepared when someone asks for gift suggestions.
 
Sounds like you are making good progress, and that is what it's all  about.
 
73 es GL,
Ed
WB9RMA
 
 
 
 
In a message dated 4/6/2014 8:03:21 P.M. Eastern Daylight Time,  
whitebear1122 at comcast.net writes:

When  using the hand drill on the chassis I use a center punch and put a 
divit into  the aluminum and then come in with the drill at slow speeds.  The 
larger  the drill bit size the greater error I have.  You bring up a good 
point  on the sharp bits though.  I'm using my ancient bits which are likely  
contributing to the problem.  I'll buy some new bits this week.

On  my 17" x 12"x 3" chassis I put a piece of 4"x4" cedar inside the 
chassis to  drill against, then I use some Quick Grips to hold the chassis to the  
bench.  Center the drill bit on the divit and drill.  

Are  you able to get accurate location for large bits like 3/8" or 1/2"?  
The  small ones are good but I seem to get more error with the larger ones.   

73, Scott WA9WFA
On Apr 6, 2014, at 6:52 PM, Walt Hutchens  <waltah at earthlink.net>  wrote:


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