Re: [CAD_CAM_EDM_DRO] re:7 square holes

Here's another way for you:
Technically it would be called broaching but it's an adaptation of the way
we make internal cams for the bolt when building bolt action receivers from
scratch.

It requires a special adapter made to hold a standard lathe boring bar that
uses square bits. The part fits in the mill spindle and has a hole drilled
thru it so the boring bar will ride parallel to the mill table. The boring
bar is fixed in this adapter so as to prevent it's turning. the part is
then mounted on the mill table with the to be broached hole set up either
parallel to the X or Y feeds. Operating the correct feed handles will then
broach the hole for you.

If you want to do really deep holes, the boring bar can be extended all the
way thru the part and its free end supported by a special part allowing free
movement back and forth along the boring bar.

Using this method, you could concievably broach multi sided hols as well as
eliptical holes.

Smoke


-----Original Message-----
From: ballendo@... <ballendo@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Wednesday, December 13, 2000 5:04 PM
Subject: [CAD_CAM_EDM_DRO] re:7 square holes

>Brian wrote:
>Ok I've seen 4 ways to machine a square hole
>1] the swing the B'Port head trick we talked about last month
>2] broach a]thru hole broaching
> b]wobble broach for blind holes
>3] shaper or the shaper/key cutter attachment on the back of a B'Port
>4]that polygon drilling attachment that uses a 3flute drill and
>forces it to walk into the corners
>5,6,7]???
>
>Brian,
>
>Thank you for your continued efforts on my behalf...
>
>1) Drill and file. This was the longest part of the post, and the
>most interesting. In short, I knew a master machinist who could do
>AMAZING things with a file and he changed how I look at things...
>2) Make your own broach from a lathe bit.(with details) The orig
>poster wanted a 10mm sq. hole in a 25mm aluminum cube. A square
>cornered bar went thru the hole.
>3) Triangle drill (as you mentioned above).
>4) Drill and chisel w/re-ground wood chisel.
>5) Make the part from two pieces C,I shaped; U,U shaped; L,L shaped;
>which one depending on part needs. suggested aluminum pins and paint.
>6) Pay a machine shop to do it for you. (the original poster is/was a
>newbie to machining and had a sherline mill/lathe)
>7) Redesign the part to accept a thru-bar with rounded corners so it
>(the hole)could be milled.
>
>This was all I posted, but:
>
>8) EDM.
>9) water jet.
>10) Laser.
>
>I felt these weren't really options for the man asking the question,
>and besides, they are covered by "get someone to do it for you!"
>
>That makes 13 so far... using 1], 2b], and 3] above.
>
>Since I've got this post saved in notepad :-), I think I'll post it
>to the sherline list. I was so frustrated, I didn't even want to re-
>type it.
>
>Thanks again, Brian.
>
>Ballendo
>
>
>
>
>
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