On 2010-04-27, Jon Danniken wrote:
DoN. Nichols wrote:
Yes -- and get your 1" drill bit with a MT-2 shank instead of a
Silver & Demming reduced shank.
Only one choice -- MSC #01520642 -- import -- black oxide
finish, 118 degree point angle. $26.75 ea (get at least two, so if
you dull it part way through, you aren't stuck with nothing to do
until you sharpen it.
[ ... ]
Hmm ... does your new drill press have enough stroke to drill
through both sides in one setup? That would save you some trouble
with the dowel fixturing. Put some 2x4 under it so you don't drill
into the table. Mine still has no "oops" holes in the table. :-)
Hi Don, and thanks, I appreciate it. The new press has a respectable 3-3/8"
plunge, which is considerably longer than my last press, and you bring up a
Very Important Point that has an effect on the drilling operation for my
current project.
First, I may end up using 2-1/2" square steel tubing instead of 3" (for a
number of benefits), which would entail switching over to a 3/4" hole
(instead of a 1" hole).
O.K.
The new press obviously has the plunge reach to push the bit through both
sides of 2-1/2" square tube, but will that the right procedure?
I believe so. It will generate less position error than having
to start a second hole on the other side.
I will obviously spot drill one side of the tubing, and start drilling
through that side, but then if I continue on through the tubing to drill out
the other side, the bit will be starting in flat "un-spotted/un-punched"
metal.
My concern is that the bit will wander, but perhaps the size of the bit
(3/4") means it is stiff enough to resist skating. Also, perhaps the top
hole will serve as a drill bushing and keep the bit aligned all the way
through.
The "bushing effect" from the top hole will make up for a lot
with a bit that size.
The first bit in MSC of that size is #01520485 at $19.33
(Smaller gets cheaper fast.) There are 18 bits in the web page, ranging
up to $324.08 as one of the "Non Catalog Items". None of them are
described as split point, and the illustrations are not clear enough to
let me tell from them.
If you could get one with a split point, you would not have any
problems with it walking. I've even drilled a 1/16" hole in a 1/4" rod
supporting a bearing on my garage door track -- using a hand held
electric drill, and I had no problems with it walking without center
punching beforehand.
It would most certainly make my work a lot easier, more than twice as easy,
actually, and even a little more, since it would eliminate the second
spotting procedure for the other side.
I would say that you can get away with it, because the drill is
being supported less than 2-1/2" from the drill point. Even if the
quill has a lot of slop in the casting the first hole will serve as a
one-shot bushing while you start the second side hole.
Others have mentioned vises. I didn't because your original
fixture would prevent it being spun. And with that long a workpiece,
putting the side of the workpiece against the left hand side of the
column will control the spinning anyway. (It won't control the
workpiece lifting as the bit breaks through, however.) So if you can
get a lever operating drill press vise of reasonable size, and bolt
that down to the table, you should be fine. (Remember to lock the table
pivot under the table since yours, like mine, is a round table which
can spin in its mount if not clamped.)
For a nice lever-operating vise, take a look at MSC # 09145566.
There are several sizes, and this one looks as though it will
work well for your 2-1/2" square steel tubing. It has a throat depth of
1-13/16" which should be plenty. (It is similar to an old one with a
Craftsman name which I picked up at a metalworking club meeting about a
year ago and which is my favorite drill press vise. This one would be
better in that it has more choices for clamping it to the table.
The price, however, is perhaps enough to send you elsewhe
$283.94
Good Luck,
DoN.
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