|
General Metalworking - All aspects of working with metal.
|
|
|
|
|
Posted by DoN. Nichols on May 25, 2008, 12:12 am
Please log in for more thread options
>
[ ... ]
>> > I talked to Dorian Tool yesterday. They confirmed that both the 7-71C
>> > and the 71S cutoff blade holders can be mounted upsidedown, being
>> > drilled and tapped on both top and bottom to accept the height
>> > adjustment hardware. In fact, these holders can be mounted just about
>> > any way, between their symmetry and threaded holes top and bottom.
>>
>> Sounds good!
>>
>> > I will get a 7-71C holder, SGIH 19-2 blade, and GTN-2 inserts.
>
> On order. Report to follow.
O.K. I'll wait for it.
FWIW -- I just parted off some brass stock at about 2-3/4" diameter,
running at 650 RPM using a T-profile parting blade and the
standard Aloris style holder with no drama. It was not full
radius, as it had been drilled out to 1" and then bored a bit
oversized.
[ ... ]
>> [ ... micro-drop cutting lube ... ]
>>
>> >> >> Other than making your own (which some here have done)?
>> >> >
>> >> > Hmm. Has anyone published pictures or plans?
>> >>
>> >> I think that there are some photos which were posted, but I did
>> >> not bother to save a link. If you care enough, do a Google search for
>> >> the newsgroup over the past five years I think should do it.
>> >
>> > OK. I may dimly recall the discussion.
>>
>> O.K. Next trick if finding it. :-)
>
> I found lots of postings saying that Trico Micro-Drop is the answer, and
> a few giving plans for a gravity-fed drop oiler. A lot of people use
> the Trico oil, even if they didn't have the Trico oiler. Some
> homebrewed an oiler using a retired oil burner pump.
O.K.
> I wonder how well a paint-sprayer paint-can pressure vessel would be for
> propelling oil out a nozzle. These are not cheap, though.
Well ... I got one for $2.00 at an estate sale -- but it had
been put away with aluminum paint in it, and I have yet to find the
right solvent to clean it out. :-)
[ ... ]
>> > The problem with supplied air is entanglement with the air hose.
>>
>> Overhead drop?
>
> Makes for a very short leash.
Use one of the coiled plastic compressed air hoses and you've
got a reasonable travel before it gets tight.
[ ... ]
>> > Lexan is the brand name for one manufacturer's polycarbonate resin.
>> >
>> > My worry about damage comes from observing that polycarbonate windows
>> > soon become frosted-looking. This may be more due to UV in sunlight
>> > than chemical exposure, but polycarbonate is famous for low chemical
>> > resistance, and oils are hard on many transparent plastics.
>>
>> IIRC, it is Plexiglass (acrylic) which tends to grow cracks
>> along every stress line after contact with oil.
>
> I think they all do, to one degree or another. Plastic is congealed oil.
O.K. I don't know which plastic my 180 degree cover is, but I
just had to hold it in place (wrong headstock casting -- the one with
the tapped holes for mounting the support is waiting to be faced to
allow the L-00 spindle to run in it without the lock-down ring rubbing
on the front of the casting. Anyway -- it is several years old, and all
I had to do was wipe it off with paper towels so I could see through it.
Granted, I don't use flood or mist coolant.
>> > My first attempt to turn a 1.5" diameter by 24" long 6061 bar between
>> > centers chattered badly, and I have not yet had time to figure out why.
>> > A piece of this same stock held in the 3-jaw chuck machined smoothly.
>>
>> Freedom for the workpiece and dog tail to rotate a bit within
>> the gap in the drive plate? I believe that it was common to take wet
>> rawhide strips to tie it in contact with the driving face, and wait for
>> that to dry before cutting.
>
> Hmm. Th dog *is* loose within the dog driver. Perhaps a well-placed
> wooden wedge is in order.
A wedge is likely to vibrate out, while a rawhide strip will
stay put through the hole operation.
Hmm ... also -- looking a tthe diameter vs the free length, I
think that you need a traveling steady (follower) rest to avoid
problems -- in addition to the rawhide strips.
[ ... ]
>> > I recall that the standards lab folk ran all their calibration resistors
>> > and resistance standards in stirred oil baths, precisely to control
>> > temperature effects.
>>
>> Of course, depending on the number of significant figures
>> needed, you needed to control to within a small fraction of a degree.
>
> Isn't going for tenths the same thing?
No -- unless you are going for tenths of micrometers. :-)
>> > So, if we ran the lathe in an oil bath, we could
>> > both ensure temperature uniformity and provide true flood cooling to the
>> > cutter. And, with proper design, completely eliminate splatter lines.
>>
>> But you are back to needing supplied air to run it. :-)
>
> No, no, no ... it's all electrical. Only the Amish run lathes on
> compressed air.
I'm talking about the operator needing supplied air, since his
hands would have to reach the controls of a manual machine -- so he
would have to be in the the bath too. Breathing is rather nice to
continue. :-)
Enjoy,
DoN.
--
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
|
|
Posted by Joseph Gwinn on May 25, 2008, 12:25 pm
Please log in for more thread options
> >
>
> [ ... ]
>
> >> > I talked to Dorian Tool yesterday. They confirmed that both the 7-71C
> >> > and the 71S cutoff blade holders can be mounted upsidedown, being
> >> > drilled and tapped on both top and bottom to accept the height
> >> > adjustment hardware. In fact, these holders can be mounted just about
> >> > any way, between their symmetry and threaded holes top and bottom.
> >>
> >> Sounds good!
> >>
> >> > I will get a 7-71C holder, SGIH 19-2 blade, and GTN-2 inserts.
> >
> > On order. Report to follow.
>
> O.K. I'll wait for it.
It worked just slick. I see why people use the SGIH cutoff tools.
The 7-71C holder is as advertised, seems well made, and I had no problem
configuring it for use upsidedown, with lathe running in reverse and the
upsidedown blade coming in from the front, so the cutting forces tend to
raise the cutter away from the lathe bed. This configuration is
self-unloading, not self-feeding.
All the while, the mister was spraying oil emulsion from above into the
deepening groove, with the fluid accumulating at the cutter 3/4 of a
turn later, so the cutter was really in a little flood.
The first test involved cautiously advancing the cross-feed manually,
cutting a 1.25" diameter 1018 steel bar held in a collet, and it worked
without much drama, but yielded a very rough surface. On inspection of
the cut surfaces, I could see that there had been some galling, which I
also heard. The suspicion was that I was simply pushing too hard, and
the chips were also balling up somewhat.
Next test was to use power feed, 0.001" (or is it half that?) per
revolution, at 900 rpm. This worked very calmly, and yielded shiney but
not mirror surfaces. The chips were like foil, but were not flat,
instead being folded by the shape of the chipbreaker hollow in the GTN-2
insert.
I'll have to try a more aggressive power feed. And normal rotation with
rightsideup tool. Although the complete absence of self-feeding has to
be a great help.
> FWIW -- I just parted off some brass stock at about 2-3/4" diameter,
> running at 650 RPM using a T-profile parting blade and the
> standard Aloris style holder with no drama. It was not full
> radius, as it had been drilled out to 1" and then bored a bit
> oversized.
I suspect I could do the same. I now seem to get in trouble only when
the groove is quite deep, and the chips are able to pack and wedge. I
did manage to cut a thick mild steel tube off using the T-blade in a
BXA-7 holder.
On a side note, I installed new dial clamp screws on the lathe, on the
cross-slide and compound dials. The thread length on these dial screws
is about 0.25", and it turned out that the brass slugs in the dials
between the tip of the dial screw and the sleeve upon which the dial
rotates were too short. I assume that they were replacements for the
original slugs, which were lost when the original dial screws were lost.
So, machined new brass slugs from 5/32" diameter rod (0.150" diameter by
~5/16" long). But I used a hand saw for cutoff, and finished with a
file, not having a collet that diameter.
The rod seemed a bit too thin to be cut off with a 2mm wide tool,
without causing major deflection. I suppose a thin grooving tool would
have worked.
So, now I can fix and loosen the dial screws by hand, like it's supposed
to work. And brass turns beautifully, and yields very pretty chips.
> [ ... ]
>
>
> > I wonder how well a paint-sprayer paint-can pressure vessel would be for
> > propelling oil out a nozzle. These are not cheap, though.
>
> Well ... I got one for $2.00 at an estate sale -- but it had
> been put away with aluminum paint in it, and I have yet to find the
> right solvent to clean it out. :-)
I assume that the pressure vessel is made of aluminum.
Take out all rubber seals and put them aside, dump a quart of 5f5 paint
stripper in the vessel, put cover on, and ignore for a few days. This
should soften things up nicely.
The paint stripper must be methylene chloride based, not sodium (or
potassium) hydroxide based, as alkalies will dissolve aluminum.
Alternately, if the "paint" is in fact a lacquer, soaking it in the
corresponding lacquer thinner may work.
> [ ... ]
>
> >> > The problem with supplied air is entanglement with the air hose.
> >>
> >> Overhead drop?
> >
> > Makes for a very short leash.
>
> Use one of the coiled plastic compressed air hoses and you've
> got a reasonable travel before it gets tight.
It is not a good idea to breathe compressed air from a shop source, as
the oil mist will damage the lungs, so inline oil-mist filters are also
necessary. One can probably use the same kind of filters as are used to
supply paint sprayers with oil-free air, but some research would be
required to tell.
I think I'll keep my facemask respirator.
> [ ... ]
>
> >> > Lexan is the brand name for one manufacturer's polycarbonate resin.
> >> >
> >> > My worry about damage comes from observing that polycarbonate windows
> >> > soon become frosted-looking. This may be more due to UV in sunlight
> >> > than chemical exposure, but polycarbonate is famous for low chemical
> >> > resistance, and oils are hard on many transparent plastics.
> >>
> >> IIRC, it is Plexiglass (acrylic) which tends to grow cracks
> >> along every stress line after contact with oil.
> >
> > I think they all do, to one degree or another. Plastic is congealed oil.
>
> O.K. I don't know which plastic my 180 degree cover is, but I
> just had to hold it in place (wrong headstock casting -- the one with
> the tapped holes for mounting the support is waiting to be faced to
> allow the L-00 spindle to run in it without the lock-down ring rubbing
> on the front of the casting. Anyway -- it is several years old, and all
> I had to do was wipe it off with paper towels so I could see through it.
> Granted, I don't use flood or mist coolant.
I think I will start with a simple 180-degree polycarbonate shield
attached to the carriage. This would solve ~90% of the problem.
> >> > My first attempt to turn a 1.5" diameter by 24" long 6061 bar between
> >> > centers chattered badly, and I have not yet had time to figure out why.
> >> > A piece of this same stock held in the 3-jaw chuck machined smoothly.
> >>
> >> Freedom for the workpiece and dog tail to rotate a bit within
> >> the gap in the drive plate? I believe that it was common to take wet
> >> rawhide strips to tie it in contact with the driving face, and wait for
> >> that to dry before cutting.
> >
> > Hmm. Th dog *is* loose within the dog driver. Perhaps a well-placed
> > wooden wedge is in order.
>
> A wedge is likely to vibrate out, while a rawhide strip will
> stay put through the hole operation.
>
> Hmm ... also -- looking a the diameter vs the free length, I
> think that you need a traveling steady (follower) rest to avoid
> problems -- in addition to the rawhide strips.
I didn't get the follow rest with the lathe. I did try the steady rest
in the middle of the bar, and it did help, but didn't solve the problem.
This is also when I discovered that the steady rest that came with the
lathe doesn't belong to the lathe, instead thought to be for Southbend.
Although it did kinda work on the Clausing.
> [ ... ]
>
> >> > I recall that the standards lab folk ran all their calibration resistors
> >> > and resistance standards in stirred oil baths, precisely to control
> >> > temperature effects.
> >>
> >> Of course, depending on the number of significant figures
> >> needed, you needed to control to within a small fraction of a degree.
> >
> > Isn't going for tenths the same thing?
>
> No -- unless you are going for tenths of micrometers. :-)
Opticians can do tenths of waves at 50 nm (in the deep ultraviolet, used
for making masks in IC production), which is a few nanometers. I've
never looked into how they do this, but I bet the mirrors are made of
quartz, and the final polishing steps are in effect water cooled.
> >> > So, if we ran the lathe in an oil bath, we could
> >> > both ensure temperature uniformity and provide true flood cooling to the
> >> > cutter. And, with proper design, completely eliminate splatter lines.
> >>
> >> But you are back to needing supplied air to run it. :-)
> >
> > No, no, no ... it's all electrical. Only the Amish run lathes on
> > compressed air.
>
> I'm talking about the operator needing supplied air, since his
> hands would have to reach the controls of a manual machine -- so he
> would have to be in the the bath too. Breathing is rather nice to
> continue. :-)
I was thinking a transparent wall, air on one side, oil on the other,
like a big fishtank. Another advantage is that one cannot do 20,000 rpm
spindles in an oil bath, so things will happen slow enough to actually
see what's going on.
Joe Gwinn
|
|
Posted by DoN. Nichols on May 25, 2008, 10:24 pm
Please log in for more thread options >
>> >
[ ... ]
>> >> > I will get a 7-71C holder, SGIH 19-2 blade, and GTN-2 inserts.
>> >
>> > On order. Report to follow.
>>
>> O.K. I'll wait for it.
>
> It worked just slick. I see why people use the SGIH cutoff tools.
Great!
> The 7-71C holder is as advertised, seems well made, and I had no problem
> configuring it for use upsidedown, with lathe running in reverse and the
> upsidedown blade coming in from the front, so the cutting forces tend to
> raise the cutter away from the lathe bed. This configuration is
> self-unloading, not self-feeding.
>
> All the while, the mister was spraying oil emulsion from above into the
> deepening groove, with the fluid accumulating at the cutter 3/4 of a
> turn later, so the cutter was really in a little flood.
O.K. My work on the brass was dry cutting. But then, that is
normal for brass.
> The first test involved cautiously advancing the cross-feed manually,
> cutting a 1.25" diameter 1018 steel bar held in a collet, and it worked
> without much drama, but yielded a very rough surface. On inspection of
> the cut surfaces, I could see that there had been some galling, which I
> also heard. The suspicion was that I was simply pushing too hard, and
> the chips were also balling up somewhat.
>
> Next test was to use power feed, 0.001" (or is it half that?) per
> revolution, at 900 rpm. This worked very calmly, and yielded shiney but
> not mirror surfaces. The chips were like foil, but were not flat,
> instead being folded by the shape of the chipbreaker hollow in the GTN-2
> insert.
>
> I'll have to try a more aggressive power feed. And normal rotation with
> rightsideup tool. Although the complete absence of self-feeding has to
> be a great help.
It will be interesting to see how the finish comes out with
normal operation instead of reversed.
>> FWIW -- I just parted off some brass stock at about 2-3/4" diameter,
>> running at 650 RPM using a T-profile parting blade and the
>> standard Aloris style holder with no drama. It was not full
>> radius, as it had been drilled out to 1" and then bored a bit
>> oversized.
>
> I suspect I could do the same. I now seem to get in trouble only when
> the groove is quite deep, and the chips are able to pack and wedge. I
> did manage to cut a thick mild steel tube off using the T-blade in a
> BXA-7 holder.
O.K.
>
> On a side note, I installed new dial clamp screws on the lathe, on the
> cross-slide and compound dials. The thread length on these dial screws
> is about 0.25", and it turned out that the brass slugs in the dials
> between the tip of the dial screw and the sleeve upon which the dial
> rotates were too short. I assume that they were replacements for the
> original slugs, which were lost when the original dial screws were lost.
> So, machined new brass slugs from 5/32" diameter rod (0.150" diameter by
> ~5/16" long). But I used a hand saw for cutoff, and finished with a
> file, not having a collet that diameter.
>
> The rod seemed a bit too thin to be cut off with a 2mm wide tool,
> without causing major deflection. I suppose a thin grooving tool would
> have worked.
All depends, I guess.
> So, now I can fix and loosen the dial screws by hand, like it's supposed
> to work. And brass turns beautifully, and yields very pretty chips.
Great!
>
>> [ ... ]
>>
>>
>> > I wonder how well a paint-sprayer paint-can pressure vessel would be for
>> > propelling oil out a nozzle. These are not cheap, though.
>>
>> Well ... I got one for $2.00 at an estate sale -- but it had
>> been put away with aluminum paint in it, and I have yet to find the
>> right solvent to clean it out. :-)
>
> I assume that the pressure vessel is made of aluminum.
Yep!
> Take out all rubber seals and put them aside, dump a quart of 5f5 paint
> stripper in the vessel, put cover on, and ignore for a few days. This
> should soften things up nicely.
>
> The paint stripper must be methylene chloride based, not sodium (or
> potassium) hydroxide based, as alkalies will dissolve aluminum.
O.K. I tried a mix of acetone and MEK and it didn't touch it --
even with Ultrasonics boosting.
> Alternately, if the "paint" is in fact a lacquer, soaking it in the
> corresponding lacquer thinner may work.
Hmm ... wouldn't MEK plus acetone have done that -- at least
somewhat?
>
>
>> [ ... ]
>>
>> >> > The problem with supplied air is entanglement with the air hose.
>> >>
>> >> Overhead drop?
>> >
>> > Makes for a very short leash.
>>
>> Use one of the coiled plastic compressed air hoses and you've
>> got a reasonable travel before it gets tight.
>
> It is not a good idea to breathe compressed air from a shop source, as
> the oil mist will damage the lungs, so inline oil-mist filters are also
> necessary. One can probably use the same kind of filters as are used to
> supply paint sprayers with oil-free air, but some research would be
> required to tell.
I was thinking of a rotary vane compressor, with particulate
filtration to keep the graphite and cast iron dust out of your lungs.
Certainly not an oil wetted air compressor -- and certainly the rotary
vane compressor would be run outside the shop to get mist-free air.
> I think I'll keep my facemask respirator.
O.K.
[ ... ]
>> >> IIRC, it is Plexiglass (acrylic) which tends to grow cracks
>> >> along every stress line after contact with oil.
>> >
>> > I think they all do, to one degree or another. Plastic is congealed oil.
>>
>> O.K. I don't know which plastic my 180 degree cover is, but I
>> just had to hold it in place (wrong headstock casting -- the one with
>> the tapped holes for mounting the support is waiting to be faced to
>> allow the L-00 spindle to run in it without the lock-down ring rubbing
>> on the front of the casting. Anyway -- it is several years old, and all
>> I had to do was wipe it off with paper towels so I could see through it.
>> Granted, I don't use flood or mist coolant.
>
> I think I will start with a simple 180-degree polycarbonate shield
> attached to the carriage. This would solve ~90% of the problem.
O.K. When cutting brass, you want it to come down close to the
cross-slide to keep your wrist from being sprayed with the tiny brass
swarf. At least, that makes it easier to stop the power feed when you
reach the right point. :-)
>
>> >> > My first attempt to turn a 1.5" diameter by 24" long 6061 bar between
>> >> > centers chattered badly, and I have not yet had time to figure out why.
>> >> > A piece of this same stock held in the 3-jaw chuck machined smoothly.
>> >>
>> >> Freedom for the workpiece and dog tail to rotate a bit within
>> >> the gap in the drive plate? I believe that it was common to take wet
>> >> rawhide strips to tie it in contact with the driving face, and wait for
>> >> that to dry before cutting.
>> >
>> > Hmm. Th dog *is* loose within the dog driver. Perhaps a well-placed
>> > wooden wedge is in order.
>>
>> A wedge is likely to vibrate out, while a rawhide strip will
>> stay put through the hole operation.
>>
>> Hmm ... also -- looking a the diameter vs the free length, I
>> think that you need a traveling steady (follower) rest to avoid
>> problems -- in addition to the rawhide strips.
>
> I didn't get the follow rest with the lathe. I did try the steady rest
> in the middle of the bar, and it did help, but didn't solve the problem.
I didn't get either the steady or the follower with the lathe.
The steady came from eBay, as did the first traveling steady (which I
prefer to use for most things), which I needed to make shoe soles for to
get it to just the right height. The second one came from a flea market
at the local metalworking club, IIRC. It is the right size, but not as
easy to adjust.
> This is also when I discovered that the steady rest that came with the
> lathe doesn't belong to the lathe, instead thought to be for Southbend.
> Although it did kinda work on the Clausing.
Yep -- that happens.
>
>> [ ... ]
>>
>> >> > I recall that the standards lab folk ran all their calibration resistors
>> >> > and resistance standards in stirred oil baths, precisely to control
>> >> > temperature effects.
>> >>
>> >> Of course, depending on the number of significant figures
>> >> needed, you needed to control to within a small fraction of a degree.
>> >
>> > Isn't going for tenths the same thing?
>>
>> No -- unless you are going for tenths of micrometers. :-)
>
> Opticians can do tenths of waves at 50 nm (in the deep ultraviolet, used
> for making masks in IC production), which is a few nanometers. I've
> never looked into how they do this, but I bet the mirrors are made of
> quartz, and the final polishing steps are in effect water cooled.
Yes -- but that is not the same as serious metal removal rate
with a lathe.
>> >> > So, if we ran the lathe in an oil bath, we could
>> >> > both ensure temperature uniformity and provide true flood cooling to the
>> >> > cutter. And, with proper design, completely eliminate splatter lines.
>> >>
>> >> But you are back to needing supplied air to run it. :-)
>> >
>> > No, no, no ... it's all electrical. Only the Amish run lathes on
>> > compressed air.
>>
>> I'm talking about the operator needing supplied air, since his
>> hands would have to reach the controls of a manual machine -- so he
>> would have to be in the the bath too. Breathing is rather nice to
>> continue. :-)
>
> I was thinking a transparent wall, air on one side, oil on the other,
But if it is a manual lathe, how do you keep access to the
controls while the lathe is running in oil? Remoting all of those
controls would be difficult.
> like a big fishtank. Another advantage is that one cannot do 20,000 rpm
> spindles in an oil bath, so things will happen slow enough to actually
> see what's going on.
:-)
Enjoy,
DoN.
--
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
|
|
Posted by Joseph Gwinn on May 25, 2008, 11:26 pm
Please log in for more thread options
> >
> >> >
>
> [ ... ]
>
> > The first test involved cautiously advancing the cross-feed manually,
> > cutting a 1.25" diameter 1018 steel bar held in a collet, and it worked
> > without much drama, but yielded a very rough surface. On inspection of
> > the cut surfaces, I could see that there had been some galling, which I
> > also heard. The suspicion was that I was simply pushing too hard, and
> > the chips were also balling up somewhat.
> >
> > Next test was to use power feed, 0.001" (or is it half that?) per
> > revolution, at 900 rpm. This worked very calmly, and yielded shiney but
> > not mirror surfaces. The chips were like foil, but were not flat,
> > instead being folded by the shape of the chipbreaker hollow in the GTN-2
> > insert.
> >
> > I'll have to try a more aggressive power feed. And normal rotation with
> > rightsideup tool. Although the complete absence of self-feeding has to
> > be a great help.
>
> It will be interesting to see how the finish comes out with
> normal operation instead of reversed.
Yes. Worse, I suppose, as chip removal is better upsidedown.
Kennametal recommends upsidedown, with two coolant streams, above and
below the cutting point. There is a picture on page 754 of the J&L
catalog (#74), where the Kennametal "Separator Cut-Off System" is
described. Interestingly, they recommend putting the tool 0.005" to
0.015" above the center of the workpiece. In their setup, the workpiece
surface is moving upward.
Kennametal also recommends increasing the rotation rate and decreasing
the feed (epecially near the center) for better finish.
> >> [ ... ]
> >>
> >>
> >> > I wonder how well a paint-sprayer paint-can pressure vessel would be for
> >> > propelling oil out a nozzle. These are not cheap, though.
> >>
> >> Well ... I got one for $2.00 at an estate sale -- but it had
> >> been put away with aluminum paint in it, and I have yet to find the
> >> right solvent to clean it out. :-)
> >
> > I assume that the pressure vessel is made of aluminum.
>
> Yep!
>
> > Take out all rubber seals and put them aside, dump a quart of 5f5 paint
> > stripper in the vessel, put cover on, and ignore for a few days. This
> > should soften things up nicely.
> >
> > The paint stripper must be methylene chloride based, not sodium (or
> > potassium) hydroxide based, as alkalies will dissolve aluminum.
>
> O.K. I tried a mix of acetone and MEK and it didn't touch it --
> even with Ultrasonics boosting.
>
> > Alternately, if the "paint" is in fact a lacquer, soaking it in the
> > corresponding lacquer thinner may work.
>
> Hmm ... wouldn't MEK plus acetone have done that -- at least
> somewhat?
Probably, if it was really lacquer, which dries by solvent evaporation.
If the paint is something that dries by chemical reaction, acetone and
MEK are unlikely to have much effect.
> >> [ ... ]
> >>
> >> >> > The problem with supplied air is entanglement with the air hose.
> >> >>
> >> >> Overhead drop?
> >> >
> >> > Makes for a very short leash.
> >>
> >> Use one of the coiled plastic compressed air hoses and you've
> >> got a reasonable travel before it gets tight.
> >
> > It is not a good idea to breathe compressed air from a shop source, as
> > the oil mist will damage the lungs, so inline oil-mist filters are also
> > necessary. One can probably use the same kind of filters as are used to
> > supply paint sprayers with oil-free air, but some research would be
> > required to tell.
>
> I was thinking of a rotary vane compressor, with particulate
> filtration to keep the graphite and cast iron dust out of your lungs.
> Certainly not an oil wetted air compressor -- and certainly the rotary
> vane compressor would be run outside the shop to get mist-free air.
I would ask around in the scuba diver forums, as this has been worked
out in great detail by the diving community.
> >> >> IIRC, it is Plexiglass (acrylic) which tends to grow cracks
> >> >> along every stress line after contact with oil.
> >> >
> >> > I think they all do, to one degree or another. Plastic is congealed
> >> > oil.
> >>
> >> O.K. I don't know which plastic my 180 degree cover is, but I
> >> just had to hold it in place (wrong headstock casting -- the one with
> >> the tapped holes for mounting the support is waiting to be faced to
> >> allow the L-00 spindle to run in it without the lock-down ring rubbing
> >> on the front of the casting. Anyway -- it is several years old, and all
> >> I had to do was wipe it off with paper towels so I could see through it.
> >> Granted, I don't use flood or mist coolant.
> >
> > I think I will start with a simple 180-degree polycarbonate shield
> > attached to the carriage. This would solve ~90% of the problem.
>
> O.K. When cutting brass, you want it to come down close to the
> cross-slide to keep your wrist from being sprayed with the tiny brass
> swarf. At least, that makes it easier to stop the power feed when you
> reach the right point. :-)
I haven't managed smoking blue brass chips just yet -- didn't know it
was possible.
> >> >> > My first attempt to turn a 1.5" diameter by 24" long 6061 bar between
> >> >> > centers chattered badly, and I have not yet had time to figure out
> >> >> > why.
> >> >> > A piece of this same stock held in the 3-jaw chuck machined smoothly.
> >> >>
> >> >> Freedom for the workpiece and dog tail to rotate a bit within
> >> >> the gap in the drive plate? I believe that it was common to take wet
> >> >> rawhide strips to tie it in contact with the driving face, and wait for
> >> >> that to dry before cutting.
> >> >
> >> > Hmm. Th dog *is* loose within the dog driver. Perhaps a well-placed
> >> > wooden wedge is in order.
> >>
> >> A wedge is likely to vibrate out, while a rawhide strip will
> >> stay put through the hole operation.
> >>
> >> Hmm ... also -- looking a the diameter vs the free length, I
> >> think that you need a traveling steady (follower) rest to avoid
> >> problems -- in addition to the rawhide strips.
> >
> > I didn't get the follow rest with the lathe. I did try the steady rest
> > in the middle of the bar, and it did help, but didn't solve the problem.
>
> I didn't get either the steady or the follower with the lathe.
> The steady came from eBay, as did the first traveling steady (which I
> prefer to use for most things), which I needed to make shoe soles for to
> get it to just the right height. The second one came from a flea market
> at the local metalworking club, IIRC. It is the right size, but not as
> easy to adjust.
I'll be chasing the rests for a while, I expect.
> >> [ ... ]
> >>
> >> >> > I recall that the standards lab folk ran all their calibration
> >> >> > resistors
> >> >> > and resistance standards in stirred oil baths, precisely to control
> >> >> > temperature effects.
> >> >>
> >> >> Of course, depending on the number of significant figures
> >> >> needed, you needed to control to within a small fraction of a degree.
> >> >
> >> > Isn't going for tenths the same thing?
> >>
> >> No -- unless you are going for tenths of micrometers. :-)
> >
> > Opticians can do tenths of waves at 50 nm (in the deep ultraviolet, used
> > for making masks in IC production), which is a few nanometers. I've
> > never looked into how they do this, but I bet the mirrors are made of
> > quartz, and the final polishing steps are in effect water cooled.
>
> Yes -- but that is not the same as serious metal removal rate
> with a lathe.
Well, there are diamond-tipped machines for generating an optical
surface, at least in the IR, where the wavelengths are long enough that
the machine-marks are not a problem.
> >> >> > So, if we ran the lathe in an oil bath, we could
> >> >> > both ensure temperature uniformity and provide true flood cooling to
> >> >> > the cutter. And, with proper design, completely eliminate splatter
> >> >> > lines.
> >> >>
> >> >> But you are back to needing supplied air to run it. :-)
> >> >
> >> > No, no, no ... it's all electrical. Only the Amish run lathes on
> >> > compressed air.
> >>
> >> I'm talking about the operator needing supplied air, since his
> >> hands would have to reach the controls of a manual machine -- so he
> >> would have to be in the the bath too. Breathing is rather nice to
> >> continue. :-)
> >
> > I was thinking a transparent wall, air on one side, oil on the other,
>
> But if it is a manual lathe, how do you keep access to the
> controls while the lathe is running in oil? Remoting all of those
> controls would be difficult.
>
> > like a big fishtank. Another advantage is that one cannot do 20,000 rpm
> > spindles in an oil bath, so things will happen slow enough to actually
> > see what's going on.
Gloveboxes, clearly.
Joe Gwinn
|
|
Posted by DoN. Nichols on May 26, 2008, 8:51 pm
Please log in for more thread options >
[ ... ]
>> > I'll have to try a more aggressive power feed. And normal rotation with
>> > rightsideup tool. Although the complete absence of self-feeding has to
>> > be a great help.
>>
>> It will be interesting to see how the finish comes out with
>> normal operation instead of reversed.
>
> Yes. Worse, I suppose, as chip removal is better upsidedown.
Depending on the material. Brass makes tiny chips which fall
out rather quickly, even with forward/rightside-up operation.
> Kennametal recommends upsidedown, with two coolant streams, above and
> below the cutting point. There is a picture on page 754 of the J&L
> catalog (#74), where the Kennametal "Separator Cut-Off System" is
> described. Interestingly, they recommend putting the tool 0.005" to
> 0.015" above the center of the workpiece. In their setup, the workpiece
> surface is moving upward.
Interesting.
> Kennametal also recommends increasing the rotation rate and decreasing
> the feed (especially near the center) for better finish.
Yes -- easier to do with a machine with continuously variable
speed -- or with a VFD on the machine. Not sure what we would do for
the cross-feed without a CNC machine. :-)
[ ... ]
>> >> Well ... I got one for $2.00 at an estate sale -- but it had
>> >> been put away with aluminum paint in it, and I have yet to find the
>> >> right solvent to clean it out. :-)
>> >
>> > I assume that the pressure vessel is made of aluminum.
>>
>> Yep!
>>
>> > Take out all rubber seals and put them aside, dump a quart of 5f5 paint
>> > stripper in the vessel, put cover on, and ignore for a few days. This
>> > should soften things up nicely.
>> >
>> > The paint stripper must be methylene chloride based, not sodium (or
>> > potassium) hydroxide based, as alkalies will dissolve aluminum.
>>
>> O.K. I tried a mix of acetone and MEK and it didn't touch it --
>> even with Ultrasonics boosting.
>>
>> > Alternately, if the "paint" is in fact a lacquer, soaking it in the
>> > corresponding lacquer thinner may work.
>>
>> Hmm ... wouldn't MEK plus acetone have done that -- at least
>> somewhat?
>
> Probably, if it was really lacquer, which dries by solvent evaporation.
> If the paint is something that dries by chemical reaction, acetone and
> MEK are unlikely to have much effect.
O.K. So the 5f5 paint striper may do the job. What about
inside the spray head?
>
>> >> [ ... ]
>> >>
>> >> >> > The problem with supplied air is entanglement with the air hose.
>> >> >>
>> >> >> Overhead drop?
>> >> >
>> >> > Makes for a very short leash.
>> >>
>> >> Use one of the coiled plastic compressed air hoses and you've
>> >> got a reasonable travel before it gets tight.
>> >
>> > It is not a good idea to breathe compressed air from a shop source, as
>> > the oil mist will damage the lungs, so inline oil-mist filters are also
>> > necessary. One can probably use the same kind of filters as are used to
>> > supply paint sprayers with oil-free air, but some research would be
>> > required to tell.
>>
>> I was thinking of a rotary vane compressor, with particulate
>> filtration to keep the graphite and cast iron dust out of your lungs.
>> Certainly not an oil wetted air compressor -- and certainly the rotary
>> vane compressor would be run outside the shop to get mist-free air.
>
> I would ask around in the scuba diver forums, as this has been worked
> out in great detail by the diving community.
They would have good information -- for highly compressed air.
I was thinking more along the lines of 10 PSIG at a maximum. Fairly
large aperture, not much back pressure on the rotary vane pump.
[ ... ]
>> > I think I will start with a simple 180-degree polycarbonate shield
>> > attached to the carriage. This would solve ~90% of the problem.
>>
>> O.K. When cutting brass, you want it to come down close to the
>> cross-slide to keep your wrist from being sprayed with the tiny brass
>> swarf. At least, that makes it easier to stop the power feed when you
>> reach the right point. :-)
>
> I haven't managed smoking blue brass chips just yet -- didn't know it
> was possible.
Well ... brass does not turn blue from the heat -- and with no
coolant (normally not used/desired on brass) smoking is also a good
trick, but the spray of hot fine chips makes it hard to reach for the
power feed control.
[ ... ]
>> >> > Hmm. Th dog *is* loose within the dog driver. Perhaps a well-placed
>> >> > wooden wedge is in order.
>> >>
>> >> A wedge is likely to vibrate out, while a rawhide strip will
>> >> stay put through the hole operation.
>> >>
>> >> Hmm ... also -- looking a the diameter vs the free length, I
>> >> think that you need a traveling steady (follower) rest to avoid
>> >> problems -- in addition to the rawhide strips.
>> >
>> > I didn't get the follow rest with the lathe. I did try the steady rest
>> > in the middle of the bar, and it did help, but didn't solve the problem.
>>
>> I didn't get either the steady or the follower with the lathe.
>> The steady came from eBay, as did the first traveling steady (which I
>> prefer to use for most things), which I needed to make shoe soles for to
>> get it to just the right height. The second one came from a flea market
>> at the local metalworking club, IIRC. It is the right size, but not as
>> easy to adjust.
>
> I'll be chasing the rests for a while, I expect.
Well ... I just went to eBay for a check, and found the
following which has a good photo of the multi-T-slot cross feed (with
the toolpost removed from it, and no compound) and a bed turret much
like mine. So -- you could get both of those with the lathe offered in
auction #260243352639 (currently at $444.00) It is a model 5509. It
also has the lever style collet closer.
Or -- this one (#370054502968) gets you a steady rest and a
telescoping taper attachment -- currently at $676.00. I think that this
one is pretty close to what you have.
[ ... ]
>> >> >> Of course, depending on the number of significant figures
>> >> >> needed, you needed to control to within a small fraction of a degree.
>> >> >
>> >> > Isn't going for tenths the same thing?
>> >>
>> >> No -- unless you are going for tenths of micrometers. :-)
>> >
>> > Opticians can do tenths of waves at 50 nm (in the deep ultraviolet, used
>> > for making masks in IC production), which is a few nanometers. I've
>> > never looked into how they do this, but I bet the mirrors are made of
>> > quartz, and the final polishing steps are in effect water cooled.
>>
>> Yes -- but that is not the same as serious metal removal rate
>> with a lathe.
>
> Well, there are diamond-tipped machines for generating an optical
> surface, at least in the IR, where the wavelengths are long enough that
> the machine-marks are not a problem.
Yep. I've got a couple of PCD inserts -- but not the holder for
them yet. Nice for working aluminum.
And yes, I am familiar with how good a mirror plain aluminum
makes in the IR -- especially the far IR. (There are two primary bands
below the visible in which there is sufficient atmospheric transparency
to be worth while using. :-) I can't remember the actual wavelengths,
but I used to work with imagers in both ranges.
[ ... ]
>> >> > No, no, no ... it's all electrical. Only the Amish run lathes on
>> >> > compressed air.
>> >>
>> >> I'm talking about the operator needing supplied air, since his
>> >> hands would have to reach the controls of a manual machine -- so he
>> >> would have to be in the the bath too. Breathing is rather nice to
>> >> continue. :-)
>> >
>> > I was thinking a transparent wall, air on one side, oil on the other,
>>
>> But if it is a manual lathe, how do you keep access to the
>> controls while the lathe is running in oil? Remoting all of those
>> controls would be difficult.
>>
>> > like a big fishtank. Another advantage is that one cannot do 20,000 rpm
>> > spindles in an oil bath, so things will happen slow enough to actually
>> > see what's going on.
>
> Gloveboxes, clearly.
Have you experienced trying to shove your hand in a glove into
just plain water from the top -- and the amazing pressure you feel
(which you don't without the glove)?
And aside from that -- using gloves around a machine tool is a
good way to reduce your ability to count to ten on your fingers. :-)
Enjoy,
DoN.
--
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
|
| Similar Threads | Posted | | Continuing lathe chatter (from people now, not the lathe. :-) | May 21, 2008, 1:19 am |
| Re: Continuing lathe chatter (from people now, not the lathe. :-) | June 1, 2008, 11:51 am |
| Re: Continuing lathe chatter (from people now, not the lathe. :-) | June 2, 2008, 10:13 pm |
| Re: Continuing lathe chatter (from people now, not the lathe. :-) | June 9, 2008, 9:48 pm |
| wear in cross-slide nut contribute to lathe chatter? | March 12, 2006, 9:04 am |
| Re: HELP Designing lathe spindle, bearings questions, WTB: Lathe headstocks | July 2, 2006, 9:53 pm |
| OT - The continuing Wolfowitz saga | May 3, 2007, 9:11 am |
| the trades, consequences, and committees are all continuing and fond | August 12, 2007, 10:57 pm |
| for Abbas the pine's continuing, in charge of me it's moral, whereas via you it's advertising profound | August 12, 2007, 4:54 pm |
| i was continuing complaints to vulnerable Kareem, who's taxing apart from the despair's sunshine | August 12, 2007, 7:37 pm |
|
|
|
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap