I have to lighten a thin, 3/4inch brass tube. Wall thickness is
about 28 thou". The tube is 3" long and will be held firmly in
a milling vice on a drill press. My first thoughts are a random assortment
of 1/4"
drilled holes. Situational weakening is OK.
Any thought on the best way to drill this to have the minimum burr on the
inside of the tube?
Also drill point angles???
Thank you.

--
~d

_____________________________________________
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Turn a piece of wood to fit the ID.
Use a drill with outer spurs, like a woodworkers /sheet metal drill.

In article 7ogse.1710304$6l.1150971@pd7tw2no,
David wrote:
I have to lighten a thin, 3/4inch brass tube. Wall thickness is
about 28 thou". The tube is 3" long and will be held firmly in
a milling vice on a drill press. My first thoughts are a random assortment
of 1/4"
drilled holes. Situational weakening is OK.
Any thought on the best way to drill this to have the minimum burr on the
inside of the tube?
Also drill point angles???

Your standard drill bits will work -- but you first need to
grind on the leading edge of each flute to remove the rake. If there is
any rake, it will grab as it breaks through and will be very likely to
pull the workpiece of of the vise and start bashing it against
everything in reach. Brass is particularly nasty about this.

And if your vise will open the full 3", I would strongly suggest
that you clamp it by the ends, instead of across the diameter. The
latter will leave a lot of flex, making it easier for the drill to pull
it out of the vise.


Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Hey David,

Perfect for EDM.

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXX
On Thu, 16 Jun 2005 14:53:55 GMT, "David" wrote:

I have to lighten a thin, 3/4inch brass tube. Wall thickness is
about 28 thou". The tube is 3" long and will be held firmly in
a milling vice on a drill press. My first thoughts are a random assortment
of 1/4"
drilled holes. Situational weakening is OK.
Any thought on the best way to drill this to have the minimum burr on the
inside of the tube?
Also drill point angles???
Thank you.

Thank you very much for the advise, Don and Mr.Bamboo.
Adjusting the drill edge made all the difference and the job was 100%
successful. I am always nervous with drilling brass.
david


"DoN. Nichols" wrote in message
...
In article 7ogse.1710304$6l.1150971@pd7tw2no,
David wrote:
I have to lighten a thin, 3/4inch brass tube. Wall thickness is
about 28 thou". The tube is 3" long and will be held firmly in
a milling vice on a drill press. My first thoughts are a random assortment
of 1/4"
drilled holes. Situational weakening is OK.
Any thought on the best way to drill this to have the minimum burr on the
inside of the tube?
Also drill point angles???

Your standard drill bits will work -- but you first need to
grind on the leading edge of each flute to remove the rake. If there is
any rake, it will grab as it breaks through and will be very likely to
pull the workpiece of of the vise and start bashing it against
everything in reach. Brass is particularly nasty about this.

And if your vise will open the full 3", I would strongly suggest
that you clamp it by the ends, instead of across the diameter. The
latter will leave a lot of flex, making it easier for the drill to pull
it out of the vise.


Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Keywords:
In article puIse.1722905$Xk.1141344@pd7tw3no, "David" wrote:
Thank you very much for the advise, Don and Mr.Bamboo.
Adjusting the drill edge made all the difference and the job was 100%
successful. I am always nervous with drilling brass.

One approach no on ementioned is to use a "step drill" like a Unibit.
These are already gound with zero rake, and they cut thin metal very
nicely without grabbing.

Doug White

Thanks Doug,
I will remember that for future use,
david


"Doug White" wrote in message
...
Keywords:
In article puIse.1722905$Xk.1141344@pd7tw3no, "David"
wrote:
Thank you very much for the advise, Don and Mr.Bamboo.
Adjusting the drill edge made all the difference and the job was 100%
successful. I am always nervous with drilling brass.

One approach no on ementioned is to use a "step drill" like a Unibit.
These are already gound with zero rake, and they cut thin metal very
nicely without grabbing.

Doug White