On 2009-09-25, Michael Koblic wrote:
"DoN. Nichols" wrote in message
[ ... ]
BTW -- if you want a really nice steel to machine (as long as
you don't need to harden it), look for some 12L14 (very free turning
leaded mild steel, and it produces a beautiful finish.
A quick look tells me the local supplier carries only 1.5" diameter rods in
12L14. evryone sells them in various diameters and lengths for peanuts.
Including Amazon! But nobody ships to Canada. Some more local research is
called for.
Hmm ... 1.5" diameter is probably a pretty good size for some
projects -- especially lathe ones. You'll want to get as long a rod as
you can afford/(transport home) and have some way to cut it. The
typical 4x6" horizontal/vertical bandsaw works well for this. I've got
both 1-1/2" round 12L14 and whatever the hex size is which just barely
fits through the 1-3/8" spindle bore. Grips nicely in the 3-jaw chuck.
Of course, for smaller projects, having something closer to the
desired size is helpful -- in spite of a machinist friend at work who
always used to claim "the best metal is in the middle" as he took a 3"
chuck of round brass stock to make a 1/2" diameter part. Lots of chips. :-)
[ ... ]
And who made the drill bit? If Chinese, it is a pure guess as
to how good a steel is in the drill bit. If a US manufacturer like
Cleveland, you are going to be more certain of the quality of the steel,
and if you need it, you can go to a cobalt steel which is tougher (and
more expensive).
I cannot imagine that Canadian Tire sells anything but Chinese. They look
pretty though...
Pretty as in "gold colored". This means that they have been TiN
coated (Titanium Nitride, not the metal tin). If the surface appears to
be somewhat frosted under the coating, it is likely to be a very poor
metal. If the surface appears to have been polished before the TiN
coating, it is more likely to be a good steel -- which they took the
time to work with properly when fabricating the drill bit.
I kind of gathered they were TiN. however, to my untrained eye they look
shiny. I do not have anything high quality to compare - those are covered
with black oxide.
O.K. Yes the finish varies with the intended function. Black
oxide is nice for some materials, Polished parabolic flutes nicer for
others, TiN coated for letting the chips flow out from yet others. My
usual bits (the 118 piece set of number/letter/fractional and the cobalt
steel set of number-size screw machine length bits are both polished,
though not parabolic flute. The two sets which make up my stock of
metric sizes are black oxide, and I don't use them often enough to have
an opinion for my usual materials. My metric tap-and-drill set has
everything TiN coated, but Cleveland brand bits and taps, so I know that
they are good.
The 61-80 number sized set is polished -- if I examine them in a
microscope. Otherwise, they hard enough to even see. :-)
[ ... ]
Some things can be checked by touch. For example, with one
hand, touch one finger to the vise and another to the table. This makes
it fairly easy to tell if there is motion there. A similar test can
detect motion of the workpiece in the vise -- but be careful in case the
workpiece comes loose and starts spinning.
Also -- touch one finger to the headstock casting, and another
to the side of the quill to see if that is loose.
I will pay attention next time I run this test. I hope to eliminate this
kerfaffle with a clamping jig. Sounds like clamping by the ends and leaving
1/16" inch to support the hole is probably not a thing to do.
Was the workpiece hollow or solid metal? If solid, check
whether your drill press vise has a horizontal V-groove, ideally with a
Vertical one meeting it in the fixed jaw. These give a good grip, and
the vertical V-groove gives access to the area which you want to
cross-drill. (For that matter, you can take a short piece of material the
same diameter, face off the ends and drill through the center just the
size to accept the drill bit which you intend to use, and drop it down
the vertical V-groove after inserting the workpiece in the horizontal
V-groove. Then Tighten the vise and drill guided by the existing center
hole. (If you're going to drill a lot of holes like this, make the
guide out of drill rod, and harden it after machining (facing and
drilling), so it will last longer. Probably a good idea to use a
countersink to chamfer the hole at the upper end at least -- and
probably both ends so you don't have to worry about which end is up.
[ ... ]
The experiment is to be repeated with some changes and bona fide mild
steel.
Try 12L14 if you can get some. You will find it a true pleasure
to machine.
There is a Zen-like quality to making steel wool on the Taig. When things go
badly elsewhere, I try and turn something on the Taig. Like a security
blanket. Funny, the mill does not have the same effect. I still experience a
child-like wonder when I center drill a rod and the hole is...in the center!
What you want for the Zen quality is a small shaper -- say a 7"
one. You sit there watching the ram move in and out, with the workpiece
moving sideways just a little during each backstroke. And the tool is a
simple HSS lathe bit which you can grind as you wish.
Enjoy,
DoN.
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