This will probably be boringly obvious to most readers, but I'll post
it in the hope that it might be useful to a few because it worked so
well for me.

I wanted to cut some .700 dia holes in .062 aluminum. After trying
some other approaches I tried making a shop- expedient trepanning
tool.

I turned a bit of 3/4" barstock down to .700" OD, drilled it out 5/8"
and milled slots in the result. No rotary table, just V-blocks in
the vise and X-Y movements. Each slot was made so the cutting edge
thus formed was square, OD of 1/4" endmill moving radially from the
center of the workpiece. I then hand-ground a bit of relief, rake
and bevel (so it penetrates OD before ID) with a Dremel running an
abrasive cutoff disc.

Material was 12Lsomething free-machining steel. I love that stuff!

I case-hardened it with Kasenite which seems to work OK on 12Lxx,
A sharp new file skates on the hardened part. This precision
process consists of heating with an O/A torch until orange, plunging
into the can of Kasenite, heating again to a glowing glob of orange
for a couple of minutes with the garage door open so the smoke had
somewhere to go, and then plunging into a margarine tub of water.
After quenching, I poured a wee dram of Menard's finest muriatic acid
($1.98 a gallon on sale) into the margarine tub to pickle off the
oxides for a few minutes.

I don't think I spend an hour making this tool.

This quick-a-minnit tool works far better than any holesaw I've ever
used. It goes thru 1/16" al in a few seconds at 135 RPM with only
mild pull on the quill and a drop of cutting fluid on the workpiece,
cutting a nice curly chip and leaving a clean and nearly burr-free
hole. I made a slot for poking the slugs out of the center, but
wouldn't have had to. They about fall out when picked with a scribe.

Photo sent to the dropbox as "holecutter".

"Don Foreman" wrote in message
...
I don't think I spend an hour making this tool.

This quick-a-minnit tool works far better than any holesaw I've ever
used.

http://www.metalworking.com/dropbox/holecutter.jpg

Sweet. Makes me want to try at the holecutting business again
Too bad I have to find hardenable stock and file it to hell, since I don't
have a mill or Kasenit!

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

Nice report, Don! I went all the way through your explanation to the next
to last step; quenching the layer of Kasenite. I would have neglected to do
that before I read your post. It is (should have been) obvious that a final
quench will add an extra bit of "treatment" to a case hardening job. Thanks
for the information.

Bob Swinney




"Don Foreman" wrote in message
...
This will probably be boringly obvious to most readers, but I'll post
it in the hope that it might be useful to a few because it worked so
well for me.

I wanted to cut some .700 dia holes in .062 aluminum. After trying
some other approaches I tried making a shop- expedient trepanning
tool.

I turned a bit of 3/4" barstock down to .700" OD, drilled it out 5/8"
and milled slots in the result. No rotary table, just V-blocks in
the vise and X-Y movements. Each slot was made so the cutting edge
thus formed was square, OD of 1/4" endmill moving radially from the
center of the workpiece. I then hand-ground a bit of relief, rake
and bevel (so it penetrates OD before ID) with a Dremel running an
abrasive cutoff disc.

Material was 12Lsomething free-machining steel. I love that stuff!

I case-hardened it with Kasenite which seems to work OK on 12Lxx,
A sharp new file skates on the hardened part. This precision
process consists of heating with an O/A torch until orange, plunging
into the can of Kasenite, heating again to a glowing glob of orange
for a couple of minutes with the garage door open so the smoke had
somewhere to go, and then plunging into a margarine tub of water.
After quenching, I poured a wee dram of Menard's finest muriatic acid
($1.98 a gallon on sale) into the margarine tub to pickle off the
oxides for a few minutes.

I don't think I spend an hour making this tool.

This quick-a-minnit tool works far better than any holesaw I've ever
used. It goes thru 1/16" al in a few seconds at 135 RPM with only
mild pull on the quill and a drop of cutting fluid on the workpiece,
cutting a nice curly chip and leaving a clean and nearly burr-free
hole. I made a slot for poking the slugs out of the center, but
wouldn't have had to. They about fall out when picked with a scribe.

Photo sent to the dropbox as "holecutter".

I personally like using wood type spade bits-Have them up to 2" and have bored
over two inch thick material for years.Works great in sheet or solid billet.
Just hang on or clamp it down! I sometimes make a small pilot ole in thicker
material.

Get yourself one of those $50 indexers, clamp it at an upward angle in a
vertical mill, and you can cut the teeth and the relief at the same time,
with a little imagination. Index, cut, index, cut. I had always thought I
had an exclusive on these things. (pout)

RJ

"Don Foreman" wrote in message
...
This will probably be boringly obvious to most readers, but I'll post
it in the hope that it might be useful to a few because it worked so
well for me.

I wanted to cut some .700 dia holes in .062 aluminum. After trying
some other approaches I tried making a shop- expedient trepanning
tool.

I turned a bit of 3/4" barstock down to .700" OD, drilled it out 5/8"
and milled slots in the result. No rotary table, just V-blocks in
the vise and X-Y movements. Each slot was made so the cutting edge
thus formed was square, OD of 1/4" endmill moving radially from the
center of the workpiece. I then hand-ground a bit of relief, rake
and bevel (so it penetrates OD before ID) with a Dremel running an
abrasive cutoff disc.

Material was 12Lsomething free-machining steel. I love that stuff!

I case-hardened it with Kasenite which seems to work OK on 12Lxx,
A sharp new file skates on the hardened part. This precision
process consists of heating with an O/A torch until orange, plunging
into the can of Kasenite, heating again to a glowing glob of orange
for a couple of minutes with the garage door open so the smoke had
somewhere to go, and then plunging into a margarine tub of water.
After quenching, I poured a wee dram of Menard's finest muriatic acid
($1.98 a gallon on sale) into the margarine tub to pickle off the
oxides for a few minutes.

I don't think I spend an hour making this tool.

This quick-a-minnit tool works far better than any holesaw I've ever
used. It goes thru 1/16" al in a few seconds at 135 RPM with only
mild pull on the quill and a drop of cutting fluid on the workpiece,
cutting a nice curly chip and leaving a clean and nearly burr-free
hole. I made a slot for poking the slugs out of the center, but
wouldn't have had to. They about fall out when picked with a scribe.

Photo sent to the dropbox as "holecutter".

Tim Williams wrote:

http://www.metalworking.com/dropbox/holecutter.jpg

Sweet. Makes me want to try at the holecutting business again
Too bad I have to find hardenable stock and file it to hell, since I don't
have a mill or Kasenit!

Kasenit is cheap. You could start with pipe if you can find an
appropriate size. If you don't have a forge for heating, etc., check
out Ron Reil's page. You can make one for bopkas. Once you have the
forge, used (broken) automotive coil springs are good for making many
tools where HSS or carbide isn't needed.

Do you have a lathe? If so, you can pick up an import "spin index" for
under $50 and start collecting 5C collets.

Ted

Bob Swinney wrote:

Nice report, Don! I went all the way through your explanation to the next
to last step; quenching the layer of Kasenite. I would have neglected to do
that before I read your post. It is (should have been) obvious that a final
quench will add an extra bit of "treatment" to a case hardening job. Thanks
for the information.

Absolutely necessary! Case hardening is simply diffusing carbon into
the outer regions of the steel. You now have to treat it as high carbon
steel.

Ted

Backlash wrote:

Get yourself one of those $50 indexers, clamp it at an upward angle in a
vertical mill, and you can cut the teeth and the relief at the same time,
with a little imagination. Index, cut, index, cut. I had always thought I
had an exclusive on these things. (pout)

I bought one with my 3-in-1 about ten years ago. One of the most used
accessories.

I made a block the same shape as the rectangular base of my spin index
and of such a height that the axis of the spin index is "exactly" the
same height of the table as the lathe axis. This alows me to remove the
compound from the table and mount the spin index on the block. I can
then put the cutter in the lathe chuck, orient the spin index
conveniently and use the x-y feed to do the cutting.

You can see it in use in this mode at

http://www.metalworking.com/dropbox/_2002_retired_files/Fluted_Knob3.jpg

Ted

"Ted Edwards" wrote in message
...
Kasenit is cheap.

Doubt they have it at Ace though.

You could start with pipe if you can find an appropriate size.

I've got a bit of water pipe, should make good cutters...

If you don't have a forge for heating, etc.,

Currently I'm making do with bits of firebrick and one torch or another.
I've got some refractory curing downstairs for a 3" i.d. 8" long 2" wall
forge, should work nice... I'll try 'er tomorrow...

used (broken) automotive coil springs are good for making many
tools where HSS or carbide isn't needed.

I've got a big bar, a broken torsion bar.. wonder how the hell I'll cut that
up and use it. Hehehe.

Do you have a lathe?

The start of a wood lathe, but if you want to send me 50-100lbs of aluminum
scrap and the Gingery Lathe booklet I'll get back to 'ya.

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

Ted, that's a damn good idea of using the indexer on the lathe!

RJ

"Ted Edwards" wrote in message
...
Backlash wrote:

Get yourself one of those $50 indexers, clamp it at an upward angle in a
vertical mill, and you can cut the teeth and the relief at the same
time,
with a little imagination. Index, cut, index, cut. I had always thought
I
had an exclusive on these things. (pout)

I bought one with my 3-in-1 about ten years ago. One of the most used
accessories.

I made a block the same shape as the rectangular base of my spin index
and of such a height that the axis of the spin index is "exactly" the
same height of the table as the lathe axis. This alows me to remove the
compound from the table and mount the spin index on the block. I can
then put the cutter in the lathe chuck, orient the spin index
conveniently and use the x-y feed to do the cutting.

You can see it in use in this mode at

http://www.metalworking.com/dropbox/_2002_retired_files/Fluted_Knob3.jpg

Ted

.. I can
then put the cutter in the lathe chuck, orient the spin index
conveniently and use the x-y feed to do the cutting.


Nice posting, photo, and description...



Paul in AJ AZ

Hey Ted,

Very neat idea. When I first looked at 3.jpg, I thought that the
riser piece looked like some type of non-metallic material, and I was
a bit surprised that a "slippery" material would be used. But then I
looked at the aluminum chips in the photo, saw they were the identical
color as the riser, and assumed that the riser must also be aluminum.
Not so when I read the .txt lines! Has this been a problem at all?

I have pretty much the same generic indexer too, and I had a few times
when I either couldn't tighten the 5C enough to grip the work, or more
often could not get it to release. The knurled screw towards the back
of the housing seemed designed to just apply a tension or braking
action, rather than grip and lock the shaft firmly. The only thing
that seemed to have a large enough radius to grip was the index wheel
itself, and if you apply too much pressure, it slips too. So, I
marked the shaft from through the center of the tension screw, took it
apart and made a depression with a 3/8" drill to create a "detent"
hole which is really quite shallow, reassembled and put a brass 1/4-20
knurled head screw with rounded off end in through the tension knob.
Now, to tighten and release the 5C collet, I just rotate to that
detent and run the brass screw in. No problem now. And when the
screw is retracted a few turns, the original tension screw works
exactly as it did before, because it "runs" outboard of the detent
mark. Oh, and I did put a locate scribe mark outboard and at the
collet end so I could find it easy to do the "lock". Hmmmm... it was
a while ago I did this, so another Oh, and I made the detent in
such a position that the handle for the spindex was generally going to
rotate "down" to tighten it, so there is less chance of the whole
spindex moving when you tighten it. Of course, there is a slight
variation with different collets and the material in it, but you'll
note that most clamping occurs in a relatively close range, about 1/4
turn or less.

One other little tip, is that all around the shop I keep a whole bunch
of that "typing correction fluid" in those little bottles with the
built-in brush, or much better and handier yet, the "pen type". I
try to always carry one of those in my shirt pocket with the clip-on
screwdriver and the pencil. Great for marking and writing on dark
surfaces. Anyway, that applies to the index wheel, in that I can mark
the spaces off before-hand, and it wipes off easily with just the
slightest bit of acetone on a rag.

Take care.

Brian Lawson,
Bothwell, Ontario.

ps...convention on a lathe has it that the cross-feed is X and there
is no Y (unless you are using a milling attachment) but the carriage
feed is Z. Compound would be either not described, or called W.
Rotation of the compound in its "hole" would be I. Or is it K? I
forget. I don't know what the spindex motion would be!?! All this is
arguable of course, and a whole other thread!! VBG
XXXXXXXXXXXXXXXXXXXXXX
On Wed, 14 Jan 2004 19:01:50 -0500, "Backlash"
wrote:

Ted, that's a damn good idea of using the indexer on the lathe!

RJ

"Ted Edwards" wrote in message
...
Backlash wrote:

Get yourself one of those $50 indexers, clamp it at an upward angle in a
vertical mill, and you can cut the teeth and the relief at the same
time,
with a little imagination. Index, cut, index, cut. I had always thought
I
had an exclusive on these things. (pout)

I bought one with my 3-in-1 about ten years ago. One of the most used
accessories.

I made a block the same shape as the rectangular base of my spin index
and of such a height that the axis of the spin index is "exactly" the
same height of the table as the lathe axis. This alows me to remove the
compound from the table and mount the spin index on the block. I can
then put the cutter in the lathe chuck, orient the spin index
conveniently and use the x-y feed to do the cutting.

You can see it in use in this mode at

http://www.metalworking.com/dropbox/_2002_retired_files/Fluted_Knob3.jpg

Ted

Brian Lawson wrote:

Very neat idea. When I first looked at 3.jpg, I thought that the
riser piece looked like some type of non-metallic material, and I was
a bit surprised that a "slippery" material would be used. But then I
looked at the aluminum chips in the photo, saw they were the identical
color as the riser, and assumed that the riser must also be aluminum.
Not so when I read the .txt lines! Has this been a problem at all?

No. I had a piece of Aluminum that I could have used but it would have
taken much more work. The piece of UHMW was jaust right except for
milling the thickness down a bit. I, too, was concerned about its
slipperyness but it hasn't been a problem.

I have pretty much the same generic indexer too, and I had a few times
when I either couldn't tighten the 5C enough to grip the work, or more
often could not get it to release. The knurled screw towards the back
of the housing seemed designed to just apply a tension or braking
action, rather than grip and lock the shaft firmly.

I've never used mine except for an integer number of degrees. Then the
locking pin prevents rotation. I set the knurled screw to prevent the
collet and holder from moving in or out. It seems quite adequate for
that.

Ted

On Wed, 14 Jan 2004 15:44:47 -0600, "Tim Williams"
wrote:

"Ted Edwards" wrote in message
...
Kasenit is cheap.

Doubt they have it at Ace though.

Welding store.