Topics

Turning Troubles


jem1043 <millermohr@...>
 

I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and finish.
I have tried moving the cross slide towards the back of the lathe and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John


Allen Burr
 

--- In southbendlathe@yahoogroups.com, "jem1043" <millermohr@w...>
wrote:
I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John
John: What material are you trying to cut? Try changing the feed and
speed rate, usually the harder materials will give a cleaner cut at
slower speeds. The power feed on my 9" I only use for thread cutting.
I've found that the cleanest cuts are obtained by hand feeding the
carrage. Cutting fluid can sometimes help depending on the material.
5000 and 6000 series aluminum likes denatured alcohol steel cuts best
with water soluable oil (milk) cast iron brass and stainlessI cut dry.


John Fischer
 

John

If you are cutting in both directions it sounds to me like you are trying to
take off too much material. Especially with a rocker tool post, it will
"spring" if you are trying to slice off too much material, and when you come
back the other way, you take a bit more off as it pushes back in.

Not sure what you are trying to cut, but you may have the wrong geometry on
your tool as well. Make sure that you have clearance, and try taking a very
light cut by hand, rather than power feed.

John

----- Original Message -----
From: "jem1043" <millermohr@worldnet.att.net>
To: <southbendlathe@yahoogroups.com>
Sent: Monday, June 23, 2003 9:33 AM
Subject: [southbendlathe] Turning Troubles


I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and finish.
I have tried moving the cross slide towards the back of the lathe and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John



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terranovapress@...
 

I have a bit of trouble following what you are doing, but if you find it difficult to turn the feed screw, you have the gibs much too tight.

also, remove stock in one direction only - towards the headstock.

Your cross-feed screw probably has a bit of wear, or backlash. Bring the tool a bit closer to you, then advance it toward the stock. Note the reading when you are taking a cut. When you have finished with one pass, bring the tool back to you, move the carriage toward the tailstock end of the cylinder, advance the tool to your previous setting and add however more you want to remove. That way the backlash is not a factor. I think you were doing it backwards, which does not remove the backlash, but makes sure it is tstill there!

A lantern holder is perfectly fine - you also are probably cutting at the wrong fpm and maybe taking too big a bite. Unless the power feed is jerky (in whaich case you should fix the clutch) it should give you a smooth, even cut.

Frank

I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and finish.
I have tried moving the cross slide towards the back of the lathe and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John


jem1043 <millermohr@...>
 

--- In southbendlathe@yahoogroups.com, terranovapress@a... wrote:
I have a bit of trouble following what you are doing, but if you
find
it difficult to turn the feed screw, you have the gibs much too
tight.

also, remove stock in one direction only - towards the headstock.

Your cross-feed screw probably has a bit of wear, or backlash.
Bring
the tool a bit closer to you, then advance it toward the stock. Note
the reading when you are taking a cut. When you have finished with
one pass, bring the tool back to you, move the carriage toward the
tailstock end of the cylinder, advance the tool to your previous
setting and add however more you want to remove. That way the
backlash is not a factor. I think you were doing it backwards, which
does not remove the backlash, but makes sure it is tstill there!

A lantern holder is perfectly fine - you also are probably cutting
at
the wrong fpm and maybe taking too big a bite. Unless the power feed
is jerky (in whaich case you should fix the clutch) it should give
you a smooth, even cut.

Frank



I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John
Frank,
Thanks for the reply.
What you describe is the way I have always done it. But I tried the
opposite technique to try and find a way to keep the lathe bit from
"digging into the work".
I have the lathe turning on the middle pulley and .50 inch diameter
steel rod that I am turning. Also the longitudinal feed is being run
on the slowest (largest driven gear smallest drive gear) speed
possible.


John Fischer
 

Is there a possibility that your .5" rod is flexing? Not sure how long the
work piece is but this may be a problem.

----- Original Message -----
From: "jem1043" <millermohr@worldnet.att.net>
To: <southbendlathe@yahoogroups.com>
Sent: Monday, June 23, 2003 12:19 PM
Subject: [southbendlathe] Re: Turning Troubles


--- In southbendlathe@yahoogroups.com, terranovapress@a... wrote:
I have a bit of trouble following what you are doing, but if you
find
it difficult to turn the feed screw, you have the gibs much too
tight.

also, remove stock in one direction only - towards the headstock.

Your cross-feed screw probably has a bit of wear, or backlash.
Bring
the tool a bit closer to you, then advance it toward the stock. Note
the reading when you are taking a cut. When you have finished with
one pass, bring the tool back to you, move the carriage toward the
tailstock end of the cylinder, advance the tool to your previous
setting and add however more you want to remove. That way the
backlash is not a factor. I think you were doing it backwards, which
does not remove the backlash, but makes sure it is tstill there!

A lantern holder is perfectly fine - you also are probably cutting
at
the wrong fpm and maybe taking too big a bite. Unless the power feed
is jerky (in whaich case you should fix the clutch) it should give
you a smooth, even cut.

Frank



I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John
Frank,
Thanks for the reply.
What you describe is the way I have always done it. But I tried the
opposite technique to try and find a way to keep the lathe bit from
"digging into the work".
I have the lathe turning on the middle pulley and .50 inch diameter
steel rod that I am turning. Also the longitudinal feed is being run
on the slowest (largest driven gear smallest drive gear) speed
possible.



--
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terranovapress@...
 

Have you checked your carriage? It is flopping around any? Sumpin' is loose unless you have a most weirdly ground bit.

I don't know much about turning steel (I usually work in brass and aluminum) try lowering the cutting point of the bit very slightly below the center of the work.

Frank


Frank,
Thanks for the reply.
What you describe is the way I have always done it. But I tried the
opposite technique to try and find a way to keep the lathe bit from
"digging into the work".
I have the lathe turning on the middle pulley and .50 inch diameter
steel rod that I am turning. Also the longitudinal feed is being run
on the slowest (largest driven gear smallest drive gear) speed
possible.


Robert J. Cumming <cumming@...>
 

This is obviously a medical problem.

----- Original Message -----
From: "John Fischer" <n2nu@arrl.net>
To: <southbendlathe@yahoogroups.com>
Sent: Monday, June 23, 2003 11:56 AM
Subject: Re: [southbendlathe] Re: Turning Troubles


Is there a possibility that your .5" rod is flexing? Not sure how long
the
work piece is but this may be a problem.


----- Original Message -----
From: "jem1043" <millermohr@worldnet.att.net>
To: <southbendlathe@yahoogroups.com>
Sent: Monday, June 23, 2003 12:19 PM
Subject: [southbendlathe] Re: Turning Troubles


--- In southbendlathe@yahoogroups.com, terranovapress@a... wrote:
I have a bit of trouble following what you are doing, but if you
find
it difficult to turn the feed screw, you have the gibs much too
tight.

also, remove stock in one direction only - towards the headstock.

Your cross-feed screw probably has a bit of wear, or backlash.
Bring
the tool a bit closer to you, then advance it toward the stock. Note
the reading when you are taking a cut. When you have finished with
one pass, bring the tool back to you, move the carriage toward the
tailstock end of the cylinder, advance the tool to your previous
setting and add however more you want to remove. That way the
backlash is not a factor. I think you were doing it backwards, which
does not remove the backlash, but makes sure it is tstill there!

A lantern holder is perfectly fine - you also are probably cutting
at
the wrong fpm and maybe taking too big a bite. Unless the power feed
is jerky (in whaich case you should fix the clutch) it should give
you a smooth, even cut.

Frank



I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John
Frank,
Thanks for the reply.
What you describe is the way I have always done it. But I tried the
opposite technique to try and find a way to keep the lathe bit from
"digging into the work".
I have the lathe turning on the middle pulley and .50 inch diameter
steel rod that I am turning. Also the longitudinal feed is being run
on the slowest (largest driven gear smallest drive gear) speed
possible.



--
Web: http://groups.yahoo.com/group/southbendlathe/
More pix: http://groups.yahoo.com/group/SouthBendLathePix/
Newbie guide: http://smaa.techwood.net/SBL/Newbie.pdf
FAQ: http://groups.yahoo.com/group/sblinfo/files/SouthBendLatheFAQ.html
Post: southbendlathe@yahoogroups.com
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--
Web: http://groups.yahoo.com/group/southbendlathe/
More pix: http://groups.yahoo.com/group/SouthBendLathePix/
Newbie guide: http://smaa.techwood.net/SBL/Newbie.pdf
FAQ: http://groups.yahoo.com/group/sblinfo/files/SouthBendLatheFAQ.html
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terranovapress@...
 

I do not understand the comment about it being a "medical problem" Can you elaborate?

Frank

This is obviously a medical problem.

----- Original Message -----
From: "John Fischer" <n2nu@arrl.net>
To: <southbendlathe@yahoogroups.com>
Sent: Monday, June 23, 2003 11:56 AM
Subject: Re: [southbendlathe] Re: Turning Troubles


Is there a possibility that your .5" rod is flexing? Not sure how long
the
> work piece is but this may be a problem.
>


Jeff Groom <jeffgroom@...>
 

Frank, I believe the comment was directed towards the previous
comment which stated:
"Is there a possibility that your .5" rod is flexing? Not sure how
long the work piece is but this may be a problem."
I believe that the length and flexibility of a mans workpiece should
be a private matter ;-)

...And now for something completely different.

It sounds like the tool profile is a little off or the tool is
sitting a bit high. I use a lot of scrap rod (mostly cold rolled)
and it is very difficult to keep from gouging. A round nosed tool
with little or no rake seems to leave the best finish. As to the
previous silliness, I use a tailstock center as much as possible to
prevent any flex in the work. Cold rolled steel is a real pain to
work with, but the price is usually right.

Have fun

Jeff

--- In southbendlathe@yahoogroups.com, terranovapress@a... wrote:
I do not understand the comment about it being a "medical problem"
Can you elaborate?

Frank


jem1043 <millermohr@...>
 

--- In southbendlathe@yahoogroups.com, "jem1043" <millermohr@w...>
wrote:
I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John

All:
Thanks for all the comments.
I was turning a .5 inch diameter steel rod that was about 5 inches
long. One end was in a 3 jaw chuck with the other by a "dead center"
in the tail stock.
The tool might have been at the wrong height, but it was aligned
by eye with the "dead center" which had been aligned with a center in
the head stock. One of the tools I was using was a brand new
indexable
carbide with a 7 degree clearance angle. Another was the "diamond
tool", which gave better results.
Which case would cause the tool bit to "dig in" more. The tool above
center or below?


Thomas G Brandl
 

Basically neither is good. I would say tool below center line is the lesser
of two evils. The tool above would cause more problems of the tool digging
in. The aligning with the dead center should be correct tool height.
Smaller diameter work pieces are more critical of tool hieght, but 1/2
diameter isn't too finicky. I don't know if it was mentioned before, but
check tool over hang. I think you are using a rocker type tool holder. Keep
the length of the holder as short as posible. ie closer as possible from
the cutting tip to the tool post. The rocker post is a bit more flexable or
less ridgid than other toolholders, still it is a good idea to keep this in
mind with other setups. With a rocker type, you are rotating the rocker up
or down to achieve center hiegth. This affects the tool clearance angles.
If to great, you need to shim up the tool holder to keep the tool
angle/geometry correct.
As too 1/2 stock, what type of steel is being cut? Check the spindle
play or clearance in the headstock. It is adjustable. Check this in the
tailstock. I don't know if you are turning between centers or with a chuck
and center. Not any real difference though. Are you using a diamond tipped
(CBN) insert or some brand called 'Diamond'?
Another thing to look at is the tool nose radius and depth of cut.
Different materials are better or worst for finish. You depth of cut should
be over twice the tool nose radius. This keep even load on the tool. Just
some thoughts. Hard to give good advice without seeing whats going on.
Tom




jem1043 <millermohr@worldnet.att.net> on 06/24/2003 08:20:25 AM

Please respond to southbendlathe@yahoogroups.com

To: southbendlathe@yahoogroups.com
cc:
Subject: [southbendlathe] Re: Turning Troubles


--- In southbendlathe@yahoogroups.com, "jem1043" <millermohr@w...>
wrote:
I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John

All:
Thanks for all the comments.
I was turning a .5 inch diameter steel rod that was about 5 inches
long. One end was in a 3 jaw chuck with the other by a "dead center"
in the tail stock.
The tool might have been at the wrong height, but it was aligned
by eye with the "dead center" which had been aligned with a center in
the head stock. One of the tools I was using was a brand new
indexable
carbide with a 7 degree clearance angle. Another was the "diamond
tool", which gave better results.
Which case would cause the tool bit to "dig in" more. The tool above
center or below?



--
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More pix: http://groups.yahoo.com/group/SouthBendLathePix/
Newbie guide: http://smaa.techwood.net/SBL/Newbie.pdf
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gorvil
 

John,

I have sometimes had the work piece try to "climb" the tool when it
is mounted below center line. In effect the tool pulls the workpiece
into itself. This is more pronounced when there is a lot of overhang
as in a rocker style toolpost.

The angle of the tool to the work should be set up so that the forces
tend to push the tool away from the work, rather than pulling it in.
I think there is a discussion of this in How To Run a Lathe.


Glen Reeser



--- In southbendlathe@yahoogroups.com, "jem1043" <millermohr@w...>
wrote:
--- In southbendlathe@yahoogroups.com, "jem1043" <millermohr@w...>
wrote:
I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting
tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that
seems
to
be the best. But what a pain to find a place to get the tool
closer
to
the turning center line and then move it back to the setting I
need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I
would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John

All:
Thanks for all the comments.
I was turning a .5 inch diameter steel rod that was about 5 inches
long. One end was in a 3 jaw chuck with the other by a "dead
center"
in the tail stock.
The tool might have been at the wrong height, but it was aligned
by eye with the "dead center" which had been aligned with a center
in
the head stock. One of the tools I was using was a brand new
indexable
carbide with a 7 degree clearance angle. Another was the "diamond
tool", which gave better results.
Which case would cause the tool bit to "dig in" more. The tool
above
center or below?


terranovapress@...
 

Unless you take very small cuts, the stock may indeed flex and you might try a follower rest. First try taking a cut of maybe .005 and using a good sulfated cutting oil and see what happens. also make certain you have lubed the dead center.

Frank


All:
Thanks for all the comments.
I was turning a .5 inch diameter steel rod that was about 5 inches
long. One end was in a 3 jaw chuck with the other by a "dead center"
in the tail stock.
The tool might have been at the wrong height, but it was aligned
by eye with the "dead center" which had been aligned with a center in
the head stock. One of the tools I was using was a brand new
indexable
carbide with a 7 degree clearance angle. Another was the "diamond
tool", which gave better results.
Which case would cause the tool bit to "dig in" more. The tool above
center or below?


JC Johnson <two-jays@...>
 

Date: Mon, 23 Jun 2003 14:12:38 -0000
From: "Allen Burr" <aburr@notes.tcs.treas.gov>
Subject: Re: Turning Troubles

--- In southbendlathe@yahoogroups.com, "jem1043" <millermohr@w...>
wrote:
I am not very experienced at machining and I have a problem with
turning a outside diameter with my South Bend 9" lathe.
I have turned the gibs so tight that it is not easy to turn the
dials
but I still get gouges in a cylinder that I am trying to get to a
specific diameter.
Also, if I power feed towards the headstock and then power feed
toward
the tail stock the cutter removes material in both directions?
I generally use the rocker tool mount and I have used cutting tools
that are HSS, the "tangential tool" and carbide tipped tools. The
tangential cutting tool seems to give me the best control and
finish.
I have tried moving the cross slide towards the back of the lathe
and
then towards me to remove as much "play" as possible and that seems
to
be the best. But what a pain to find a place to get the tool closer
to
the turning center line and then move it back to the setting I need
to
turn.
Maybe this lathe is just worn out. I don't use it much but I would
like to be able to use it when I need it.
Any suggestions would be greatly appreciated.
John
John: What material are you trying to cut? Try changing the feed and
speed rate, usually the harder materials will give a cleaner cut at
slower speeds. The power feed on my 9" I only use for thread cutting.
I've found that the cleanest cuts are obtained by hand feeding the
carrage. Cutting fluid can sometimes help depending on the material.
5000 and 6000 series aluminum likes denatured alcohol steel cuts best
with water soluable oil (milk) cast iron brass and stainlessI cut dry.
Allen, denatured alcohol gives me an enormous headache, but have found
kerosene to give me good results cutting aluminum.

Johnny