A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

I am trepanning an octagonal blank into a center disc and outer collar
to hold a thin walled tapered part, soon.

I hold my 5/16 4-flute end mills in the cross slide with a boring bar
adapter, a keyless chuck, straight shank adapter, and a sleeve. I've
trepanned Masonite, acrylic, and polypropylene with this setup.

Align the collinear end teeth radially to the rotation center
carefully so they will cut with correct rake and clearance. Alignment
to the machine axis is less critical, except when cutting steel; the
side flutes will burnish steel and harden it before they start cutting
if they're not precisely aligned. This is a Bad Thing and can ruin the
cutter. I know this will happen even though, as you read above, I
haven't trepanned steel. It's one reason I haven't. In any other
material, misalignment will only result in a little side cutting
action during feeding.

Best,

Doug

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?
--
EA



I am trepanning an octagonal blank into a center disc and outer collar
to hold a thin walled tapered part, soon.

I hold my 5/16 4-flute end mills in the cross slide with a boring bar
adapter, a keyless chuck, straight shank adapter, and a sleeve. I've
trepanned Masonite, acrylic, and polypropylene with this setup.

Align the collinear end teeth radially to the rotation center
carefully so they will cut with correct rake and clearance. Alignment
to the machine axis is less critical, except when cutting steel; the
side flutes will burnish steel and harden it before they start cutting
if they're not precisely aligned. This is a Bad Thing and can ruin the
cutter. I know this will happen even though, as you read above, I
haven't trepanned steel. It's one reason I haven't. In any other
material, misalignment will only result in a little side cutting
action during feeding.

Best,

Doug

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

I am trepanning an octagonal blank into a center disc and outer collar
to hold a thin walled tapered part, soon.

I hold my 5/16 4-flute end mills in the cross slide with a boring bar
adapter, a keyless chuck, straight shank adapter, and a sleeve. I've
trepanned Masonite, acrylic, and polypropylene with this setup.

Align the collinear end teeth radially to the rotation center
carefully so they will cut with correct rake and clearance. Alignment
to the machine axis is less critical, except when cutting steel; the
side flutes will burnish steel and harden it before they start cutting
if they're not precisely aligned. This is a Bad Thing and can ruin the
cutter. I know this will happen even though, as you read above, I
haven't trepanned steel. It's one reason I haven't. In any other
material, misalignment will only result in a little side cutting
action during feeding.

Best,

Doug

But in a lathe the patient's head would have to be spinning. I think it
would be more practical to do this on a Bridgeport or large drill press.

The Dougster wrote:
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.
Best,

Doug


A properly ground bit makes a better one .
--
Snag
Learning keeps
you young !

On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC

On Sat, 30 Jul 2011 17:31:25 -0700, wrote:

On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

Running properly with lube and chip clearance hole..several hundred at
minumum.

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc.

Perhaps if you asked them to cut you (1)..but they should be much much
cheaper if you have them do a dozen or more.

Or you need to find another shop.



Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC


Gunner

--
Maxim 12: A soft answer turneth away wrath.
Once wrath is looking the other way, shoot it in the head.

wrote in message
...
On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC

I've not had good results with hole saws - neither cheap nor expensive.
They need slow feed and flood coolant. I keep them only for non-metal use
now.
Likewise, I've cut circles in steel with a (homemade) fly-cutter. It works,
but I find it tedious and marginal in terms of speed and finish.

How about rough cutting with a fine oxy torch, rough grind off the "bulbous"
dags, clamp together (between centres) and parallel turn to size on the
lathe?
Auto-feed and auto-switch-off and very fine feed means you can indulge in a
peaceful cup of coffee, or read a magazine, while the lathe patiently does
the dirty work.
Can you drill a central hole? That'd make it much easier to clamp.

Alternatively, hold the rough shape in a 4-jaw and attack it from the face.

(sorry if I've repeated earlier advice - only just jumped in now)
--
Jeff R.

On Sat, 30 Jul 2011 17:31:25 -0700, wrote:

On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
My son could probably stamp out a few thousand per shift once the die
is set up.
Gerry :-)}
London, Canada

On 2011-07-31, wrote:
On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

[ ... ]

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

Hole saws tend to give really rough finish, and are best used in
a vertical position with a drilled hole intersecting the cut line to
drain away chips. And, given the number of cutters (teeth), and the
radius, it would probably be too much load for your fairly small lathe.

A trepanning bit for a lathe should be ground curved, so its
centerline matches the curve of the cut being made. There should be
clearance on both the inside and outside of the cut. It sort of should
look like this -- end on:

--((--

except that the curve and height of the tool should really stop at the
center of the height shown -- as indicated by the "-- --" lines.

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

So -- you can figure the price of two blades. Do you have a
figure of what your time is worth? After a week or so of doing this the
arm should become accustomed to this, and the soreness of the shoulder
be reduced.

However -- I presume that the $6.00 is for cutting out a single
disc. What happens if you stack three or four sheets, so you get
multiple discs at a pass? The thicker it gets, the less precise the cut
line is I believe, but there should be some tradeoff value to determine
where to stop stacking them.

And have you checked what waterjet cutting or laser cutting
would cost instead of plasma cutting? Both of those do a cleaner cut
when stacked.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Sat, 30 Jul 2011 22:56:25 -0400, Gerald Miller
wrote:

On Sat, 30 Jul 2011 17:31:25 -0700, wrote:

On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
My son could probably stamp out a few thousand per shift once the die
is set up.
Gerry :-)}
London, Canada
He says to look for a small stamping shop and ask them for a price on
the desired quantity - you may be pleasantly surprised!
Gerry :-)}
London, Canada

On 31 Jul 2011 04:33:00 GMT, "DoN. Nichols"
wrote:

On 2011-07-31, wrote:
On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

[ ... ]

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

Hole saws tend to give really rough finish, and are best used in
a vertical position with a drilled hole intersecting the cut line to
drain away chips. And, given the number of cutters (teeth), and the
radius, it would probably be too much load for your fairly small lathe.

A trepanning bit for a lathe should be ground curved, so its
centerline matches the curve of the cut being made. There should be
clearance on both the inside and outside of the cut. It sort of should
look like this -- end on:

--((--

except that the curve and height of the tool should really stop at the
center of the height shown -- as indicated by the "-- --" lines.

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

So -- you can figure the price of two blades. Do you have a
figure of what your time is worth? After a week or so of doing this the
arm should become accustomed to this, and the soreness of the shoulder
be reduced.

However -- I presume that the $6.00 is for cutting out a single
disc. What happens if you stack three or four sheets, so you get
multiple discs at a pass? The thicker it gets, the less precise the cut
line is I believe, but there should be some tradeoff value to determine
where to stop stacking them.

And have you checked what waterjet cutting or laser cutting
would cost instead of plasma cutting? Both of those do a cleaner cut
when stacked.

Good Luck,
DoN.

And water jet would be fairly cheap.

Though..I do have a nice small plasma cutter Id sell pretty cheaply to
someone here.......its good for 1/8" and will sever 3/16" Ive cut
1/4"..but it was slow...and nasty.

But its pretty good for sheet metal

Gunner

--
Maxim 12: A soft answer turneth away wrath.
Once wrath is looking the other way, shoot it in the head.

On Sat, 30 Jul 2011 17:31:25 -0700, wrote:

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Recently had several hundred 4" diameter X 1/8" thick *galvanized* disks laser
cut. Was *way* cheaper than I could have cut them with a hole saw even if I
paid myself minimum wage.

That particular shop only had punches to 3 1/2" so I did not get to compare
prices of the different techniques.

There are also online retailers that sell plain steel disks in various sizes
and thickness. Costs were higher but lacked the minimums and lead time of the
local shop. No galvanized and the shipping was outrageous on the few I bought
to hold me until the local order was done.

http://www.wagnercompanies.com/disks_and_plates.aspx

Is the vendor I used, curiously they do not show a 2 1/2" in 3/16".
2 3/8" and 2 7/8" are both offered in 3/16" thick so perhaps it is just missing
from the list?
--
William

On Sat, 30 Jul 2011 17:31:25 -0700, mkoblic wrote:
On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:
"The Dougster" dgoncz... wrote ...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs 1
hour, 2 blades and a sore shoulder.

Do you have a (motorized) scroll saw? I can use the same blades on
mine as on my jeweler's saw. (But not vice versa -- the jeweler's saw
only takes pinless blades, the scroll saw accepts either pinned or
pinless 5" blades.) I've cut lots of wood, paper, and plastic on my
scroll saw, typically with a 15 or 20-tpi blade, and small amounts of
steel with a 40 tpi blade (0.012" x 0.022" cross section). The steel
was 1/20" sheet and I advanced it only about 1 IPM with the saw running
at about 600 strokes per minute, which gave a milled-looking cut surface.
With thicker metal, heavier blade, and higher SPM, you might be able to
race along at 2 IPM!

--
jiw

On 31 Jul 2011 04:33:00 GMT, "DoN. Nichols"
wrote:


Hole saws tend to give really rough finish, and are best used in
a vertical position with a drilled hole intersecting the cut line to
drain away chips. And, given the number of cutters (teeth), and the
radius, it would probably be too much load for your fairly small lathe.

A trepanning bit for a lathe should be ground curved, so its
centerline matches the curve of the cut being made. There should be
clearance on both the inside and outside of the cut. It sort of should
look like this -- end on:

--((--

except that the curve and height of the tool should really stop at the
center of the height shown -- as indicated by the "-- --" lines.

The rough finish would not be a problem as the whole thing gets
finished in he lathe anyway. Cost in terms of consumables (blades) is,
as well as the duration of the procedure.

I see some people make their own trepanning tools:

http://bbs.homeshopmachinist.net/showthread.php?t=45764

Although their skill is admirable I am not sure that I want to invest
the time etc. in a single purpose tool.

I looked at what was available commercially and came across this:

http://www.kbctools.com/can/Navigati...cfm?PDFPage=52

What I found interesting was that they seem to use the same cutter
over the whole range of radii which is quite wide.

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

So -- you can figure the price of two blades. Do you have a
figure of what your time is worth? After a week or so of doing this the
arm should become accustomed to this, and the soreness of the shoulder
be reduced.

However -- I presume that the $6.00 is for cutting out a single
disc. What happens if you stack three or four sheets, so you get
multiple discs at a pass? The thicker it gets, the less precise the cut
line is I believe, but there should be some tradeoff value to determine
where to stop stacking them.

I asked for a quote on 10. $58 including the material. Looking at
other vendors on line the drop in price from 10 to 100 is not that
significant.

And have you checked what waterjet cutting or laser cutting
would cost instead of plasma cutting? Both of those do a cleaner cut
when stacked.

I would be surprised in anyone within 100 km has either of those, but
one never knows.

Michael Koblic,
Campbell River, BC

On Sun, 31 Jul 2011 12:54:12 -0400, William Bagwell
wrote:


Recently had several hundred 4" diameter X 1/8" thick *galvanized* disks laser
cut. Was *way* cheaper than I could have cut them with a hole saw even if I
paid myself minimum wage.

That particular shop only had punches to 3 1/2" so I did not get to compare
prices of the different techniques.

There are also online retailers that sell plain steel disks in various sizes
and thickness. Costs were higher but lacked the minimums and lead time of the
local shop. No galvanized and the shipping was outrageous on the few I bought
to hold me until the local order was done.

http://www.wagnercompanies.com/disks_and_plates.aspx

Is the vendor I used, curiously they do not show a 2 1/2" in 3/16".
2 3/8" and 2 7/8" are both offered in 3/16" thick so perhaps it is just missing
from the list?

Interesting, thanks. It gives me a guideline what to expect. The
prices relate well to prices of washers which is my benchmark of
expected costs (1" washer which has OD of 2.5" costs about $1.10).

The problem as you mentioned is the shipping which will be a multiple
of what you paid and the fact that they ship UPS.

Still, as Gerry suggested one should look for a stamping shop.

Michael Koblic,
Campbell River, BC

On Sun, 31 Jul 2011 21:28:21 +0000 (UTC), James Waldby
wrote:


Do you have a (motorized) scroll saw? I can use the same blades on
mine as on my jeweler's saw. (But not vice versa -- the jeweler's saw
only takes pinless blades, the scroll saw accepts either pinned or
pinless 5" blades.) I've cut lots of wood, paper, and plastic on my
scroll saw, typically with a 15 or 20-tpi blade, and small amounts of
steel with a 40 tpi blade (0.012" x 0.022" cross section). The steel
was 1/20" sheet and I advanced it only about 1 IPM with the saw running
at about 600 strokes per minute, which gave a milled-looking cut surface.
With thicker metal, heavier blade, and higher SPM, you might be able to
race along at 2 IPM!

The short answer is no. I considered buying one and asked around about
its performance on steel. The consensus was that for 3/16" plate it
was a waste of time, money and a lot of blades.

Michael Koblic,
Campbell River, BC

wrote in message
...
On Sun, 31 Jul 2011 12:54:12 -0400, William Bagwell
wrote:


Recently had several hundred 4" diameter X 1/8" thick *galvanized* disks
laser
cut. Was *way* cheaper than I could have cut them with a hole saw even if
I
paid myself minimum wage.

That particular shop only had punches to 3 1/2" so I did not get to
compare
prices of the different techniques.

There are also online retailers that sell plain steel disks in various
sizes
and thickness. Costs were higher but lacked the minimums and lead time of
the
local shop. No galvanized and the shipping was outrageous on the few I
bought
to hold me until the local order was done.

http://www.wagnercompanies.com/disks_and_plates.aspx

Is the vendor I used, curiously they do not show a 2 1/2" in 3/16".
2 3/8" and 2 7/8" are both offered in 3/16" thick so perhaps it is just
missing
from the list?

Interesting, thanks. It gives me a guideline what to expect. The
prices relate well to prices of washers which is my benchmark of
expected costs (1" washer which has OD of 2.5" costs about $1.10).

The problem as you mentioned is the shipping which will be a multiple
of what you paid and the fact that they ship UPS.

Still, as Gerry suggested one should look for a stamping shop.

Michael Koblic,
Campbell River, BC

You're around Van Couver, above Washington State? Oh, I see, yer on that
big island.....
Man, you must be in paradise, over there, altho mebbe not machine-shop wise.

How is industry over there, in general? How bout in places like Van Couver,
or Surrey?

I see from Victoria, you could proly row-boat to Seattle, eh??
--
EA

On Sat, 30 Jul 2011 17:31:25 -0700, wrote:

On Fri, 29 Jul 2011 13:50:15 -0400, "Existential Angst"
wrote:

"The Dougster" wrote in message
...
A 2- or 4- flute end mill makes a fine trepanning tool on the lathe.

Trepanning of a square blank held on an expaning arbor through a
smallish center hole leaves a square with a round hole, and a disc
with the smallish hole. If what one wants is the disc, trepanning
saves the wear, tear, and irritation of the interrupted cut, and save
turning all those square points into chips.

Assuming the blank is 1/2" thick, idnat why God invented hole saws?

I am struggling to find a good way of cutting out 2.5" disks out of
3/16" steel plate. I have not tried trepanning but it is on the list.

Would a hole saw be useful for this application? How many disks would
one be able to get out of one saw bit?

BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
Greetings Michael,
Trepanning the steel would work well if you have a rigid setup and a
slow enough speed. Hole saws don't have much room for chip evacuation,
so you need to keep pulling the saw out of the hole to clear chips.
3/16 isn't that thick so maybe not too much trouble. A high speed
steel trepanning tool would need to be spun pretty slow but if ground
properly can take a pretty good chip load. A carbide tool needs more
rigidity but will cut much faster. If you can tolerate the noise it's
possible to run the carbide fast with a light chip load if you use the
right grade of carbide. You might be able to unsolder a tooth from a
circular saw blade and use that. Anyway, with a light chip load and
spinning fast the carbide will chatter and the chips will come out as
flakes. Using spraymist with plenty of air pressure will blow the
chips out of the groove so you will be able to make a continuous cut
clean through the the steel. Grind the end of any tool you use at an
angle so that the tool will break through first at the inside diameter
of the groove if it's the discs that you want. Stop feeding the tool
when it is just shy of breaking through. Then use a hammer to knock
the disc out of the plate. There will be a slight burr that is easily
removed with a file or sander. If you cut all the way through there is
a good chance that the disc will shift and pinch the tool which will
probably break the tool. I must reiterate that using carbide in the
above manner will be VERY noisy. Use hearing and eye protection.
Cheers,
Eric

On Mon, 1 Aug 2011 17:03:56 +0000 (UTC), wrote:


BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
Greetings Michael,
Trepanning the steel would work well if you have a rigid setup and a
slow enough speed. Hole saws don't have much room for chip evacuation,
so you need to keep pulling the saw out of the hole to clear chips.

Set your saw and turn it on, lowering it to the work. Now you have a
scratch of the diameter of the saw.

Now take a drill motor and drill a hole in that scratch. This hole now
lets the chips fall through as the saw turns and cuts away the metal.

If you measure the radius..you can drill the chip hole and the pilot
hole at the same time and do this as many times as necessary for all the
holes you are making.

It helps tremendiously to save the saw, to make the cutting go faster
and so forth.

Gunner

--
"The danger to America is not Barack Obama but a citizenry
capable of entrusting a man like him with the Presidency.
It will be far easier to limit and undo the follies of an
Obama presidency than to restore the necessary common sense
and good judgment to a depraved electorate willing to have
such a man for their? president.. Blaming the prince of the
fools should not blind anyone to the vast confederacy of
fools that made him their prince".

"Gunner Asch" wrote in message
...
On Mon, 1 Aug 2011 17:03:56 +0000 (UTC), wrote:


BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
Greetings Michael,
Trepanning the steel would work well if you have a rigid setup and a
slow enough speed. Hole saws don't have much room for chip evacuation,
so you need to keep pulling the saw out of the hole to clear chips.

Set your saw and turn it on, lowering it to the work. Now you have a
scratch of the diameter of the saw.

Now take a drill motor and drill a hole in that scratch. This hole now
lets the chips fall through as the saw turns and cuts away the metal.

If you measure the radius..you can drill the chip hole and the pilot
hole at the same time and do this as many times as necessary for all the
holes you are making.

It helps tremendiously to save the saw, to make the cutting go faster
and so forth.

Perty ingenious.....

Now, iffin only yer politics could follow suit....

Still, ahm gonna move in with you, in a year or so....
--
EA





Gunner

--
"The danger to America is not Barack Obama but a citizenry
capable of entrusting a man like him with the Presidency.
It will be far easier to limit and undo the follies of an
Obama presidency than to restore the necessary common sense
and good judgment to a depraved electorate willing to have
such a man for their? president.. Blaming the prince of the
fools should not blind anyone to the vast confederacy of
fools that made him their prince".

On Mon, 1 Aug 2011 18:46:33 -0400, "Existential Angst"
wrote:

"Gunner Asch" wrote in message
.. .
On Mon, 1 Aug 2011 17:03:56 +0000 (UTC), wrote:


BTW if I farmed this out to a local shop for plasma cutting it would
cost me $6 per disc. Cutting the same disc with a jeweler's saw costs
1 hour, 2 blades and a sore shoulder.

Michael Koblic,
Campbell River, BC
Greetings Michael,
Trepanning the steel would work well if you have a rigid setup and a
slow enough speed. Hole saws don't have much room for chip evacuation,
so you need to keep pulling the saw out of the hole to clear chips.

Set your saw and turn it on, lowering it to the work. Now you have a
scratch of the diameter of the saw.

Now take a drill motor and drill a hole in that scratch. This hole now
lets the chips fall through as the saw turns and cuts away the metal.

If you measure the radius..you can drill the chip hole and the pilot
hole at the same time and do this as many times as necessary for all the
holes you are making.

It helps tremendiously to save the saw, to make the cutting go faster
and so forth.

Perty ingenious.....

Now, iffin only yer politics could follow suit....

Still, ahm gonna move in with you, in a year or so....

Ill set up a tent for you in my empty lot next door. Just dont bother
the neighbors pit bulls. They tend to keep me awake and keep my dogs
running from window to window trying to see what the pits are barking
at.

As for my politics...shrug...Im not a leftwinger...and I own my own
place free and clear...and a few toys of this and that nature...and can
support my family. What else is there not to love?

Gunner

--
"The danger to America is not Barack Obama but a citizenry
capable of entrusting a man like him with the Presidency.
It will be far easier to limit and undo the follies of an
Obama presidency than to restore the necessary common sense
and good judgment to a depraved electorate willing to have
such a man for their? president.. Blaming the prince of the
fools should not blind anyone to the vast confederacy of
fools that made him their prince".

Gunner Asch wrote:

I'll set up a tent for you in my empty lot next door. Just don't bother
the neighbors pit bulls. They tend to keep me awake and keep my dogs
running from window to window trying to see what the pits are barking
at.

As for my politics...shrug...Im not a leftwinger...and I own my own
place free and clear...and a few toys of this and that nature...and can
support my family. What else is there not to love?


Democrats!!!


--
It's easy to think outside the box, when you have a cutting torch.

On Mon, 1 Aug 2011 12:30:20 -0400, "Existential Angst"
wrote:

You're around Van Couver, above Washington State? Oh, I see, yer on that
big island.....
Man, you must be in paradise, over there, altho mebbe not machine-shop wise.


It's great if you like rain.

How is industry over there, in general?

There is some. Not a lot. Small machine shops etc.

How bout in places like Van Couver,
or Surrey?

I suspect there is industry there. Bit out of the way to investigate
first hand.

I see from Victoria, you could proly row-boat to Seattle, eh??

But why would I want to?

Michael Koblic,
Campbell River, BC

wrote in message
...
On Mon, 1 Aug 2011 12:30:20 -0400, "Existential Angst"
wrote:

You're around Van Couver, above Washington State? Oh, I see, yer on that
big island.....
Man, you must be in paradise, over there, altho mebbe not machine-shop
wise.


It's great if you like rain.

More rain than Seattle?

Ito actual downfall, NYC actually get LOTS more actual inches than Seattle.
Seattle is just foggier/cloudier.


How is industry over there, in general?

There is some. Not a lot. Small machine shops etc.

How bout in places like Van Couver,
or Surrey?

I suspect there is industry there. Bit out of the way to investigate
first hand.

I see from Victoria, you could proly row-boat to Seattle, eh??

But why would I want to?

Why, to shoot paint balls/BBs at all the Microsoft/Google assholes, of
course!
--
EA



Michael Koblic,
Campbell River, BC