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Drill sharpener/device for larger twist (Jan 1, 2004) |
Drilling with big drills
(Aug 12, 2004) |
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Drilling Question (Jan 21, 2004) |
Drill bit Recommendation Wanted
(Dec 24, 2004) |
| Big
drill holder for the smaller lathe's (Aug 12, 2004) |
Drilling small holes in hardened steel (Feb 22, 2005) |
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Drill sharpener/device for larger twist |
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I am using a Drill doctor for sharpening twist drills up to ? 3/4
in. Now I need to have the same for drills up to min. ? 1 5/8 in.
Those machines or devices are far too expensive for an amateur
budget. Does somebody have drawings/pictures or knows a website
where I could find such a device which I could fit to my larger
wheel grinder ? Jean-Claude (16165) |
| I
suggest that you sharpen the larger drills by the four facet method
as it is much easier to make a holder for the drills. The British
magazines Model Engineer and Model Engineers Workshop have described
various jigs for the purpose over the years (one day I'm going to
make one!). If you are not in a tearing hurry contact me off list
and I'll root through the piles and see what I can find. This site looks as if it has some useful stuff on drill point
grinding in general (but I haven't read it in detail, just a skim).
http://www.newmantools.com/machines/drillpoint.html If you
want to use a conventional, conical, point plans for the Duplex
Grinding Jig are around on the web in PDF format (I may have a set
somewhere). This is a fabricated design (no castings) for a swing
across the side of the wheel type sharpener and could be enlarged to
do your big drills. However there have been discussions as to the
efficiency of the cutting points formed by this jig. My feeling is
that its a matter of operator skill rather than any inherent
problems with the design. Lotta work tho'. In the UK there is sold
by Plasplugs an ingenious and inexpensive drill holder for their
multipurpose sharpening system. Its far too small for your purposes
but if you can get hold of one to examine it would probably not be
too difficult to make a copy for the big drills. At first glance it
this looks a much easier proposition than the Duplex Jig. The
Plasplugs take on the masonry drill sharpener is also ingenious and
simple. Every time I use it I think that the concept could make a
fine basis for a four facet sharpener. All designs would need a cup
wheel on the grinder with a face at least as wide as the longest
drill facet. Clive (16172) |
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Andy Lofquist of Metal Lathe Accessories (
http://www.statecollegecentral.com/metallathe/ ) is in the
process of prototyping a device for sharpening twist drills, end
mills, and other cutters. This will be a refinement of a version he
developed several years ago but never marketed because it was a bit
difficult to use -- though fully functional and accurate. Both the
original and the new prototype are designed to work as accessories
to standard bench grinders. If the prototype meets his expectations,
he will next work on the patterns for molds with the intention of
marketing a kit. Anyone who has bought one of Andy's kits knows that
they are top quality. I suggest emailing Andy to get on a list for
an early announcement. I suspect that he hopes to have the prototype
done before the Cabin Fever show. Kim (16175) |
| Look at
the articles stored at mwhints3 JWE (16178) |
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Drilling Question |
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I am starting a project in Feb 2003 Machinist workshop. The project
calls for drilling down thru a chuck with existing holes with a
clearance drill. That is where the confusion starts for me, does
that mean with a drill bit that will not take out the existing
threads? I realize this is probably a very dumb question, however I
did a search through the 26th machinery handbook and found a bunch
of stuff on clearance drill's but nothing that looked right for this
problem. Dee (16690) |
| The
clearance drill will completely remove the thread on a tapped hole
and enlarge it a bit more than the original screw or bolt size.
Clearance drill is the drill sized to clear the OD of a screw. For a
4-40 screw (.112" OD) the tap drill is .089" and the clearance drill
is usually .125" or so. Now the question is, 'Do you want to
eliminate the existing threads'? JP (16697) |
| Big
drill holder for the smaller lathe's |
|
I picked up a bucket of #3MT drill's. I could not use them in my
10K. So I welded a handle on a 3#MT socket extension (also in the
bucket). Center drilled a hole on the tang end which I cut off. And
I push it thru with the tailstock. Run the lathe in back gear. Rest
the handle on a bar in the toolpost. Bob (20473) |
| You can
also buy an adapter, 2mt tang to 3mt socket, for around $10- 20
depending on where you look. Chris (20474) |
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Yes you can use an adaptor that's what I cut up. I was trying to get
away from the twisting motion to the tailstock ram. Some older
lathe's don't hold a taper bit very well. Bob (20475) |
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Bob, I like your idea. I'm new to machining and was wondering if the
M3 extender you used was hardened? I was under the impression that
cutting and center drilling hardened parts was very difficult. Can
you tell me how it went? I might try your idea with an M2 extender,
again to save the spindle as you mentioned. I have a few M2 drill
bits myself. Tom (20478) |
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Tom, It cut like butter center drilled just as easy. Made up a 2nd
one. I will probably put it on eBay. I have a factory made Armstrong
brand one but it has a #1MT in it. There are more pics under my
profile. Bob (20479) |
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Drilling with big drills |
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My teacher at tec. school used an SBL floor model to do a lot of
teaching. He showed the class how to drill a large hole using a dead
center, lathe dog, and a drill. In this case, it was 1 1/2".He stuck
the dead center in the tail stock, added some grease to the hole in
the arse end of the drill. Then attached the dog to the drill, and
used the compound to rest fido's tail on. He had already used a much
smaller pilot drill to get a slightly larger then web thickness hole
going. He puts it in 'grandma'. Squirts on some oil, and puts a hole
in the piece held in the chuck. Pretty simple when you think about
it. Old Cecil was a first generation wizard alright. Glad I paid
attention in class. Years later, I inherited that class, and taught
night school for 4 years before moving to New Hampshire. Some days I
wish I was back there. Ron (20476) |
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Ron, That was my 2nd day at trade school also, but I don't have any
lathe dog's yet. Just trying to make do with a box of junk. Bob
(20477) |
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Drill bit Recommendation Wanted |
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Anything USA made. I understand they are all made in a NC plant and
brand marked there. RichD (23398) |
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I use
www.ohiodrill.com quality
drills made in the US. They have a 50 dollar order. Order the
fractional, letter and number and have a nice set. Bob (23405) |
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I second that, anything USA made. I use cobalt drills for general
use but it all depends on what you are drilling. TiN (gold color)
lubricates and hardens the tool, TiCN (grey color) is harder and
lubes better but I have only found it on carbide drills and mills.
For my portable drill I like the flatted shank drills (3 flats). JP
(23409) |
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the plant in N.C. is Vermont American in Lincolnton, N.C. I
understand they make several grades. You should be able to contact
the for a catalog. Tracy (23679) |
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Drilling small holes in hardened steel |
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I am trying to drill a few #30 holes and a few #43 holes into
approximately 1/8" thick hardened steel on digital micrometer jaws.
Yes, for the digital-micrometer-to-DRO "trick" I got half way
through, and "squeek squeek squeek" My two questions are: 1 - How do
I do it right when I start the next hole? 2 - How do I finish the
probably work hardened hole I started? I cannot anneal the steel due
to the plastic and circuits of the digital micrometer. Thank you in
advance for your time Bernie (25428) |
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Bernie, The "steel" in the jaws is probably stainless and quickly
work hardens. You could use a good carbide drill to finish the first
hole and drill the rest with a SHARP drill and PLENTY of lubricant
to keep the heat down. George (25430) |
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I have no experience with micrometer jaws, but have drilled hand saw
blades and file stock. Two words: Feed Pressure. Slow the drill down
and apply a ridiculous amount of feed pressure. In my shop I use an
old blacksmith's post drill. It auto feeds and is hand cranked to
keep the foot speed low. Be sure the bit is sharp. Another thought.
The heat of the drill may spot anneal the metal. Anyone have luck
with diamond tipped drills? Mike (25433) |
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Damn, you know that I ordered some just yesterday from some Dremmel
guy on Ebay! Just 1/8" ones (what I need) by complete coincidence. I
don't know if these are very high quality. I'll try that one on the
other Digital Calipers later this week. Bernie (25435) |
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I remember reading in Brownell's "Tips and Tricks" something about
softening rifle receivers where you're going to drill for scope
mounts using a 12VDC battery and a sharpened probe to create a very
small arc and hot spot. Very localized and supposedly easy to
control. I never tried it and I don't know what it might do to the
electronics. For this kind of stuff, I've always gone with solid
carbide drills but you wind up breaking them a lot. Ed (25436) |
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Slow your drilling speed way down. Duane (25442) |
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Bernie, You would be able to burn a hole through any hardness of
metal with a home made EDM, there was an article about a cheap easy
to build one in one of The Home Shop Machinist Magazine issues a
while back. You could also try to get a solid carbide bit, or get a
few cobalt bits and force them through. To avoid work hardening use
new or very sharp bits, and don't stop until the hole is finished.
Hope this helps. I had a piece of 1/4" stainless work harden half
way through from a dull bit, I forced 2 sharp ones to finish the
hole, but i think they were pretty shot by the time I finished. Jim
(25448) |
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It was a series of articles resulting in this,
http://www.build-stuff.com/015book.htm JP (25450) |
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Bernie, Try
www.homeshopmachinist.net
you should be able to order either a back issue, or the article
itself if the back issue is gone. The article is in The Machinist's
Workshop in the October / November 2002 Issue on page 24. It's
called An Inexpensive EDM by Arnold Gregrich. There is also a sequel
to an Inexpensive EDM I think about 2 Issues after that one not sure
who was the author. They are very helpful via phone conversations
too. PS- This type of machine won't leave a precision to size hole
but it will burn through any type of metal. Jim (25451) |
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There's also a Yahoo Group Cad_Cam_EDM_DRO, strongly moderated group
but lots of useful information and links. Bernard R (25455) |
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An article in the recent February/March Model Engineer Workshop
titled 'A simplified spark erosion machine' says it avoids
electronic complexity. It says no printed circuits, no integrated
circuits, no power transistors, no stepping motor. A self
interrupting solenoid is used to give electroid movement. It says
tap water works well as as the dielectric. Walt (25461) |
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Slow speed and lots of lube. Sharpen the drill often. Don't let is
smoke at all. Getting past the section is the PITA. chances are a
carbide drill will even have a hard time getting past the section.
if you have a Dremmel and can grind the bottom of the hole, you can
do that. If you can drill from behind, that should work. be careful,
keep the part COLD, and well lubed. maybe HSS or Cobalt to get past
the death zone. Chances are it will break your carbide drills. The
EDM reference is probably one possibility, but home-brew EDM is a
far cry from a good shop tool. It has a VERY slooow cut rate, and is
only good for thin sheets. your 1/8" is near the max for depth. I
Think a bunch of us have our own EDM's so you may be able to get a
favor for the few holes you need. Dave (25462) |
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Walt, Do you have a copy of the article? Could you put a copy in in
SouthbendLathePix file section for everyone to see? JP(25463) |
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There is an old gunsmithing trick that will probably work for you.
Take an electric soldering iron and hold the tip to the location
that you want to drill the hole and hold it there for about 30-60
seconds. Then let it cool slowly. Drill a little ways till you feel
the bit start to stop cutting and repeat the soldering iron
application drilling. Continue this until you drill all the way
through. Basically you are spot annealing the hardened steel. Chris
(25464) |
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Sounds simple enough. The whole reason for circuit boards is to
drive the stepper. if you can vibrate the tip then it reduces the
need for hand feeds. a small manual screw feed adjustment would keep
it in range. I use brass tubing as the cutter and siphon water into
that. works fine or thin stuff. probably need a solid core something
as thick as 1/4" or even 1/8 inch. Dave (25473) |
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Jim, I presume that you're talking about this particular machine,
not EDM in general. The high end boys are doing some incredible
stuff as can be seen from this extract: "And, when combined with the
latest Nano Interpolation development giving NC commands to the
machine servodrives with an ultra-fine pitch of 0.001mm, high speed
cutting up to 330mm2/min using 0.3mm brass wire can be performed
with a high precision capability such as holding roundness to within
1.2 microns on a 30mm diameter hole to a surface finish of 0.7
microns." (Extract from Fanuc Robocut Alpha-iC series of wire
electro-discharge machines press release). (25476) |
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EDM can but High end stuff is incredible. Incredibly fast (for edm)
and incredibly accurate. The come circuit is nothing more than an RC
(resistor capacitor) oscillator of huge size. The resistor allows
the capacitor to fill, and once it reached a voltage level, it jumps
the gap. when it jumps, the very thin outer layer of metal is flaked
(blasted) off. This repeats thousands of times a second. For home
brew the first problem is positioning accurately. Just reversing the
screw often makes the whole machine twist. What one learns very fast
in trying to do longer holes, is that the cutter cuts so close to
the part that any movement will allow the cutter to touch the hole
and that causes problems. These can be handled rather simply by any
number of methods. but are almost non-existent on thin sheets. Also,
the shape of the electrical arc on home-brew is basically the high
initial spike followed by the very rapid decrease. In the high end
stuff, the include an oscilloscope and offer controls to actually
shape the arc increasing or decreasing in points and such. As a
weekend toy project to remove a busted tap, it is fun. As a tool to
remove a 1/2-13 tap broken an inch deep, the challenge is to get it
to go that deep. And that requires precision guides and a steady
part. and that is where the automation part comes in. Dave (25486) |
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I have a related question to this. I am trying to make a cheap dro
for my mini mill using calipers. I bought a couple of the 6" ones
from HF for $15 each. Why couldn't I salvage just the electronics
portion and make my own 'ruler' for it to slide on out of steel or
aluminum? Then I could cheaply turn my 6" caliper into a 12" or
whatever I need for my Z axis. Is there any reason this wouldn't
work? I ask because I found that the ruler portion is really hard. I
could easily hacksaw the jaws off of the lower piece but I ended up
using an angle grinder to get them off of the main section - and as
far as drilling the mounting holes goes - same deal. Could I anneal
this stuff to make it softer? The electronics have all been removed
so the most damage I could do is to melt the little plastic ruler
strip off. Kevin 26068) |
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An axle flange of a truck drive axle and the drill bit wouldn't get
started cutting until the edge curled up on the drill bit. I took
the axle shaft to a machine shop and asked if the machinist could do
the job. Yep, he could. He clamped it on to a drill press table and,
using a very slow drill speed and turpentine, got the job done for
me and I learned something in the process. Henry (26073) |
