On 5 Jan 2005 08:45:59 -0800, "Too_Many_Tools"
wrote:
This summer after building a number of items using I-beams and heavy
plate, I finally figured out that having a mag drill would be very,
very nice.
After pricing them new and noting that in the used market they seem to
retain their value, I have to ask myself "Why not build one?"
Considering that we have some very good magnets on the surplus market
these days and an Asian morse taper bench drill presses are available,
has someone undertaken this task in the past?
One problem is the fact that any of the smaller drill presses which
are light enough for this type work don't have a low enough speed and
the spindle is to small for large drills. I guess if you're only
drilling smaller holes that might be alright but the big reason for a
mag drill is drilling larger holes (at least for me).
Next is the problem of permanent magnets for a base. I actually have
a mag drill with a permanent magnet base. It's also got a air motor
for the drill head. I believe it is a home made type affair though who
ever built it did a very nice job. Even though they used aluminum
through out the construction it's still way to heavy for easy use.
Also the permanent magnet is no where near strong enough to do the job
properly. It looks like a standard plate lifting magnet with a cam for
release but even once I manage to clean it and the work piece well it
doesn't have 1/4th the strength of my old Milwaukee mag drill I got
off ebay. Speaking of cleaning that's another sore spot for permanent
magnets. You make a lot of shavings while drilling and with no way of
turning off and demagnetizing (yes the base on a proper mag drill goes
through a demag cycle when turned off) the base you'll forever be
trying to clean the shavings off. Then there's the problem of
positioning. It can be hard enough to get a electromagnet base in the
right position before energizing. With the permanent magnet this job
becomes several times harder.
Now I'm not saying that it can't be done but you should keep in mind
the pitfalls I've mentioned above.
If it was me I'd go another route for cheap portable hole drilling.
It turns out that I've also got the method of drilling large holes in
a portable situation that came before mag drills. It's in the form of
two air drills that I have. I don't think I've got a picture of the
larger drill online right now but I do have some pictures of the
smaller one.
http://www.metalworking.com/DropBox/...xtension07.jpg
This picture shows my smaller air drill which happens to be a right
angle drill. It's got a #2 morse taper socket in the head. What you
can't really see in that shot is the jack screw which is on the other
end of the head. By turning the jack screw I can force the drill into
the work. That's a 5/8" bit in the drill right now and I drilled about
240 holes in that frame with it. Some of them through the extension
which when totaled up was 1 1/8" thick. I firmly believe that this
method is even easier to use than the heavy mag drill which I now
have.
Now drills with jack screws aren't real common in this day and age
but a similar setup with the screw in the dead man with the proper
(read heavy duty) drill would do the same thing.
Another method which I've considered in the past before getting my
mag drill was to take one of those small lightweight frames that are
made to hold a portable drill. If you'll make another base for it
which straddles the hole being drilled and use C-clamps to hold in
down you could have a easily made portable drill press. You could make
different bases for different types of work as well. If you get the
right drill to mount in the base you could easily drill larger holes
than the average import drill press can handle. In fact I have a
friend who used one those drill presses for his larger holes up until
recently because his bench top drill press couldn't handle the larger
bits. He's just now finished rebuilding and modifying a old bench top
drill press I gave him so he can drill larger holes with it.
Wow. Hopefully this longer than intended outburst will prove useful
to you in some way.
Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook