On 2011-12-30, Bob La Londe wrote:
"DoN. Nichols" wrote in message
...
On 2011-12-29, Bob La Londe wrote:
What is the best tapping oil/fluid for aluminum? The oil I am using now
is
a general purpose cutting machining oil.
Probably WD-40 or kerosene would be better for aluminum than
that.
But have you tried the TapMagic for aluminum? One thing *not*
[ ... ]
WD-40 actually works pretty good for aluminum, I don't currently use that,
but I may go back to it. I didn't mention it as an option because I am
familiar with the stock "WD sucks for everything!"
Well ... it sucks as a normal oil or a rust preventive, but it
pretty good for cleaning water off metal, and as a cutting fluid for
aluminum. (Kerosene should be just about the same, but I've not tried
it yet.)
response often seen in
this group. LOL. I'll look for TapMagic and see what it costs, and compare
tap life if I do.
O.K. I've got some of the "for aluminum" TapMagic, and a little
of the original formula (I think that there is a modern formula which is
not the "for aluminum" as well, but if I'm not tapping aluminum, I prefer
the original formula. It worked really nicely with 1/2-20 taps in 3/4"
thick mild steel in the drill press.
BTW I just got through modifying that drill press to use a 3-phase motor
and a VFD to give me slower speeds when needed (the pulleys
don't go slow enough for a 5/8" drill in steel, let alone for
hole saws in steel. :-) It was a Taiwanese made floor standing
one with a 5/8" chuck and 16 speeds. Here is the URL for the
mod:
http://www.d-and-d.com/PROJECTS/DrillPress-VFD/index.html
Oh yes -- the normal chuck on it is a Jacobs keyless -- sort of
a clone of the Albrecht -- but I'll have to swap back to the original
5/8" Jacobs clone (or a smaller Jacobs) for using left-hand drills,
because most keyless chucks release in reverse. :-)
[ ... ]
Yes, it does. And with the spiral taps which you say you use,
the best style of broken tap extractor does not work.
If I am lucky it breaks with enough of the tap sticking out the back of the
work piece to grab with pliers. Otherwise the work piece goes in the
recycle bin or gets side for personal use.
Hmm ... weld a nut onto the back of the tap to back it out?
When I replace taps I back off the clutch and then tap a hole. I'll
tighten
it a little at a time, and when the tap goes all the way through with out
slipping just barely I'll give it about 1/32 of a turn more. That seems
to
work pretty good with this head.
That sounds like what TapMatic described in their instructions,
and what I do.
I think it might have been some of your comments that led me to that setup
procedure.
O.K. And I got them from the downloadable instruction manual. :-)
[ ... ]
How do you have difficulty recognizing gun taps? Straight
flutes (usually two flutes until you get up to 3/8" or larger), with the
first few threads having an angle ground on the flutes to push the chips
ahead of the tap.
The problem is I have to "order" them, and often the descriptions just
aren't clear and some resellers even call taps by what I think is the wrong
name. If I could just walk into a local store and inspect them I wouldn't
have any problems.
O.K. If the catalog calls them either "gun taps" or "spiral
point taps", they should be what you want. Some use one name, some use
the other, and some may use both names to be sure of catching you. ;-)
And go for HSS -- just in case someone is making them in high
carbon steel. :-)
There are various coatings on the taps for different materials.
Black oxide, bright ground, TiN (not tin), and likely even Boron
Carbide. One of those is the best for the aluminum and the oxide
coating which the tap has to cut though to get to the aluminum. If you
are almost always tapping 6061-T6, call one of the good makers like
Cleveland and get what they advise -- both which particular taps, and
what tapping fluid. It may cost more per tap -- but I'll bet that they
last longer and cost less per hole.
So far I have just used bright finish. No coatings, but I may try some at
some point.
Find out what the manufacturer suggests for the aluminum you are
tapping.
You say "bar stock". Is that round which you are drilling and
tapping end on, or rectangular or square stock.
Usually X x Y x .500 flat, but sometimes X x Y x .750 or 1.00 surfaced on
one face. I doubt I am tapping through much oxide coating except maybe
where the tap exits the back of the piece. It gets milled and marked for
drilling on the mill. Then it gets drilled and tapped as soon as it comes
off.
O.K. My combination drill/tap (1/4-20) I was using in 1/2" x
3.5" 6061-T6 (or was it T651?), and I was using them with the for
aluminum TapMagic. Just make sure that there is enough clearance on the
bottom so you don't put divots in your drill press table. I was using a
lever locking drill press vise with shoulders to hold the aluminum high
enough so there was no problem -- and plenty of clearance between the
round rods that the movable jaw slides on.
In the former case, you
are tapping through virgin aluminum without oxides, but unless you part
off first, you are tapping blind holes. :-)
And -- out of curiosity -- have you tried the combination spiral
tap and drill?
I have not. I have looked at a few. They intimidate me. LOL.
Just make sure you have the clearance and the TapMagic for
aluminum and you should be fine. The TapMagic works for the drilling
too. I forget what spindle RPM I was using -- probably the fastest
available from the rear belt with the front belt on the bottom step,
which is somewhere in the middle of the speed range, I think.
O.K. I just went down and checked (after eating dinner), and it
was at 850 RPM, which is a reasonable speed for both the drill part and
the tap part. :-)
I've used them in 6061-T6 (though not as many holes as
you have since I am just doing hobby projects), but it works great with
the TapMagic for aluminum in a Tapmatic tapping head. Saves a lot of
tool changes or running the same workpiece through the machine twice. :-)
I bought a desktop 12 speed drill press that holds my tapping head as a
dedicated machine with the speed set moderately slow (750 I think). I drill
all my smaller holes (F and smaller) on my old floor drill press, and keep
the speed set fairly high. I do all my tapping on the desktop, and the
noname mill drill I picked up a while ago (last year?) gets dedicated for
larger holes. Usually with a collet in a collet chuck I leave in it.. As I
mentioned before the noname isn't a great mill, but it's a pretty good drill
press as compared to my actual drill presses. Not much in the way of
tooling changes that way. I just carry the piece(s) from one machine to the
next. I don't machine for a living so I try to make the best of the time I
have in the shop, and this actually works out pretty well.
Good Luck,
Thank you, and as always I appreciate everybody's help and perspective.
You're welcome.
And best of luck in the next year,
DoN.
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