|
Posted by DoN. Nichols on May 16, 2008, 7:10 pm
Please log in for more thread options
[ ... ]
>> >> >> Actually -- there *are* some like that. MLA (Metal Lathe
>> >> >> Associates) makes a casting for the South Bend lathes to make such a
>> >> >> cross-slide. I would have made one -- except that it is just a bit too
>> >> >> small for my machine.
>> >> >
>> >> > I must say that I'm less tempted now.
>> >>
>> >> Even with the full circle T-slot for a proper compound? All you
>> >> need to do is to talk MLA into making (and offering) a slightly larger
>> >> casting, then machine it properly.
>> >
>> > Sounds too much like work.
>>
>> Something to be proud of -- a part of the machine which you have
>> made yourself to extend its capabilities. :-)
>
> For now, the pride will have to be in machine restoration, I think.
O.K.
If I could get an MLA casting the right size for my machine
(which would be the right size for yours, too), I would dive into
machining it to make a cross-slide with the rear T-slots.
[ ... ]
>> > Well, I would not advise drinking it, or breathing too much of it, but
>> > it is used by millions of people without difficulty.
>>
>> IIRC, that was what was used in a controlled fume hood to strip
>> epoxy from potted components to allow failure analysis. Of course it
>> also pulled the epoxy out of the G-10 printed circuit board (leaving a
>> loose mat of glass fibers), and took the Bakelite and color codes off of
>> resistors. At least the transistors were in metal cans, and the diodes
>> were glass housed. :-)
>>
>> But they were *very* careful with that stripper.
>
> Oh, yes.
>
> I recall hearing of a company that used Methylene Chloride in what
> amounted to a large pressure cooker (with metal-to-metal seals for sure)
> to remove potting agents from modules, for failure analysis (and reverse
> engineering).
O.K. Failure analysis was the purpose that Transitron used back
then -- since they had few competitors to analyze anyway. :-) About the
only competitor at that time was Texas Instruments -- and while they
competed in the actual transistors and diodes, they did not seem to in
the potted assemblies.
[ ... ]
>> > I think I recall that Plaza Machinery had some tailstocks.
>>
>> Are they an eBay vendor? if not do you have the URL for their
>> website?
>
> I don't know if Plaza does eBay, but here is the URL:
><http://www.plazamachinery.com>.
>
> Their list of available stuff is a bit oddly organized, so it's best to
> download the whole pdf and then search the file locally.
O.K. I've done the download (and am thankful that they have PDF
in addition to ".DOC"), and I've now sent off an e-mail to see what he
might be able to turn up.
[ ... ]
>> > I did not get a follower rest, but I'm looking for one. The threaded
>> > holes to bolt the follower rest are there.
>> >
>> > I noticed that the left rear threaded hole kept filling up with emulsion
>> > coolant. It was in line with a perpendicular threaded hole in the back
>> > of the carriage, so I drilled a 0.125" diameter passage from one to the
>> > other, so the top hole can drain.
>>
>> Oh -- I just keep a pair of studs in mine to keep the swarf from
>> accumulating in there.
>
> I just blow it out every so often, but the little blue pool annoyed me,
> and made me worry about rusting in dark corners.
It takes a lot of picking to get the swarf out, so it is easier
to keep it from getting in in the first place. :-)
>
>> That other threaded hole may be part of the mounting for the
>> taper turning attachment.
>
> Sounds about right to me.
I was surprised to find the holes already in place and tapped
for the taper attachment on my machine.
[ ... ]
>> > There is a listing somewhere. The 5900 is gear-head as well, so perhaps
>> > they are comparable enough for the same test to apply to both.
>>
>> O.K. Just one belt to go from the motor to the gearbox, and
>> then everything else in the gearbox?
>
> One big toothed timing belt from variable speed (Reeves) drive to
> gearbox. This belt is not going to slip.
O.K. That is the one for which my metric threading gear set was
made, based on the photos in the instruction sheet.
[ ... ]
>> > Some BXA holders will accept a SGIH 26-2 blade, which will do up to 50
>> > mm diameter, but has the same groove width (2 mm).
>>
>> O.K.
>
> I'm still thinking, but it seems to me that holders that accommodate the
> SGIH 26-x blades are a better choice, because both 19-x and 26-x will
> hold the 2mm wide inserts, and the 19-x holders are far less stiff.
>
> The main advantage of 19-x holders appears to be that one also can use
> them to hold a P-3 (0.75" high) HSS T-blade.
>
> The other issue to think about is how much one must move the blade
> holder up on the toolpost if one inserts the SGIH blade upsidedown, as
> planned to allow use in back, or in front with lathe in reverse.
Indeed. you *might* have to make an over-tall holder to deal
with that problem.
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 17, 2008, 9:27 am
Please log in for more thread options
>
> [ ... ]
>
> >> >> >> Actually -- there *are* some like that. MLA (Metal Lathe
> >> >> >> Associates) makes a casting for the South Bend lathes to make such a
> >> >> >> cross-slide. I would have made one -- except that it is just a bit
> >> >> >> too
> >> >> >> small for my machine.
> >> >> >
> >> >> > I must say that I'm less tempted now.
> >> >>
> >> >> Even with the full circle T-slot for a proper compound? All you
> >> >> need to do is to talk MLA into making (and offering) a slightly larger
> >> >> casting, then machine it properly.
> >> >
> >> > Sounds too much like work.
> >>
> >> Something to be proud of -- a part of the machine which you have
> >> made yourself to extend its capabilities. :-)
> >
> > For now, the pride will have to be in machine restoration, I think.
>
> O.K.
>
> If I could get an MLA casting the right size for my machine
> (which would be the right size for yours, too), I would dive into
> machining it to make a cross-slide with the rear T-slots.
Someday. The cross-slide is pretty much rectangular, so I suppose one
could skip the casting and start with a block of cast iron.
> [ ... ]
>
> >> > Well, I would not advise drinking it, or breathing too much of it, but
> >> > it is used by millions of people without difficulty.
> >>
> >> IIRC, that was what was used in a controlled fume hood to strip
> >> epoxy from potted components to allow failure analysis. Of course it
> >> also pulled the epoxy out of the G-10 printed circuit board (leaving a
> >> loose mat of glass fibers), and took the Bakelite and color codes off of
> >> resistors. At least the transistors were in metal cans, and the diodes
> >> were glass housed. :-)
> >>
> >> But they were *very* careful with that stripper.
> >
> > Oh, yes.
> >
> > I recall hearing of a company that used Methylene Chloride in what
> > amounted to a large pressure cooker (with metal-to-metal seals for sure)
> > to remove potting agents from modules, for failure analysis (and reverse
> > engineering).
>
> O.K. Failure analysis was the purpose that Transitron used back
> then -- since they had few competitors to analyze anyway. :-) About the
> only competitor at that time was Texas Instruments -- and while they
> competed in the actual transistors and diodes, they did not seem to in
> the potted assemblies.
I recall Transitron. There was another depotting company that
advertised their ability to strip the potting agent without dissolving
the plastic ICs, but they wouldn't say how they did this aside from
mumbling about used of heat, pressure, and a bunch of well chosen
solvents, some far too dangerous for ordinary companies to risk using,
as the story went. I think their main business was reverse engineering.
> [ ... ]
>
> >> > I think I recall that Plaza Machinery had some tailstocks.
> >>
> >> Are they an eBay vendor? if not do you have the URL for their
> >> website?
> >
> > I don't know if Plaza does eBay, but here is the URL:
> ><http://www.plazamachinery.com>.
> >
> > Their list of available stuff is a bit oddly organized, so it's best to
> > download the whole pdf and then search the file locally.
>
> O.K. I've done the download (and am thankful that they have PDF
> in addition to ".DOC"), and I've now sent off an e-mail to see what he
> might be able to turn up.
Good luck. I may drive up there this summer. It's about three hours
drive from my home. The wife would like to see the area, enough to
tolerate the resulting crate of greasy iron treasures being dragged home.
> [ ... ]
>
> >> > I did not get a follower rest, but I'm looking for one. The threaded
> >> > holes to bolt the follower rest are there.
> >> >
> >> > I noticed that the left rear threaded hole kept filling up with emulsion
> >> > coolant. It was in line with a perpendicular threaded hole in the back
> >> > of the carriage, so I drilled a 0.125" diameter passage from one to the
> >> > other, so the top hole can drain.
> >>
> >> Oh -- I just keep a pair of studs in mine to keep the swarf from
> >> accumulating in there.
> >
> > I just blow it out every so often, but the little blue pool annoyed me,
> > and made me worry about rusting in dark corners.
>
> It takes a lot of picking to get the swarf out, so it is easier
> to keep it from getting in in the first place. :-)
I don't use a pick, I use a thin needle tip on the blowoff gun.
Releasing the air from the bottom of the hole usually blows it clean.
But be careful, as it's easy to blow swarf into the eyes this way. I
loosely tie a shop towel around the gun, to intercept the flying swarf
and muck.
I've also seen people use a long thin drywall screw to pull swarf from
deep holes, and one can buy extractors that appear to be a headless
drywall screw mounted in an aluminum handle.
> [ ... ]
>
> >> > There is a listing somewhere. The 5900 is gear-head as well, so perhaps
> >> > they are comparable enough for the same test to apply to both.
> >>
> >> O.K. Just one belt to go from the motor to the gearbox, and
> >> then everything else in the gearbox?
> >
> > One big toothed timing belt from variable speed (Reeves) drive to
> > gearbox. This belt is not going to slip.
>
> O.K. That is the one for which my metric threading gear set was
> made, based on the photos in the instruction sheet.
Metric threading kit. That might be more useful than a taper
attachment. It didn't take long from me to encounter the need to make a
metric thread (the arbor nuts for the vibrating Ryobi grinder).
How often do the metric kits come up for sale, and for what kinds of
prices?
> [ ... ]
>
> >> > Some BXA holders will accept a SGIH 26-2 blade, which will do up to 50
> >> > mm diameter, but has the same groove width (2 mm).
> >>
> >> O.K.
> >
> > I'm still thinking, but it seems to me that holders that accommodate the
> > SGIH 26-x blades are a better choice, because both 19-x and 26-x will
> > hold the 2mm wide inserts, and the 19-x holders are far less stiff.
> >
> > The main advantage of 19-x holders appears to be that one also can use
> > them to hold a P-3 (0.75" high) HSS T-blade.
> >
> > The other issue to think about is how much one must move the blade
> > holder up on the toolpost if one inserts the SGIH blade upsidedown, as
> > planned to allow use in back, or in front with lathe in reverse.
>
> Indeed. You *might* have to make an over-tall holder to deal
> with that problem.
Yes. Or, make a ridged steel spacer plate to go between the lathe's
tool slide and the BXA toolpost.
Joe Gwinn
|
|
Posted by DoN. Nichols on May 17, 2008, 6:17 pm
Please log in for more thread options >
[ ... multi-T-slot-cross-slide ... ]
>> > For now, the pride will have to be in machine restoration, I think.
>>
>> O.K.
>>
>> If I could get an MLA casting the right size for my machine
>> (which would be the right size for yours, too), I would dive into
>> machining it to make a cross-slide with the rear T-slots.
>
> Someday. The cross-slide is pretty much rectangular, so I suppose one
> could skip the casting and start with a block of cast iron.
Well ... there are a pair of "hips" on mine to support the angle
plate on the compound -- and there apparently are on the MLA casting for
the South Bend as well, so I was presuming that there would be on yours
as well.
[ ... ]
>> > I recall hearing of a company that used Methylene Chloride in what
>> > amounted to a large pressure cooker (with metal-to-metal seals for sure)
>> > to remove potting agents from modules, for failure analysis (and reverse
>> > engineering).
>>
>> O.K. Failure analysis was the purpose that Transitron used back
>> then -- since they had few competitors to analyze anyway. :-) About the
>> only competitor at that time was Texas Instruments -- and while they
>> competed in the actual transistors and diodes, they did not seem to in
>> the potted assemblies.
>
> I recall Transitron. There was another depotting company that
> advertised their ability to strip the potting agent without dissolving
> the plastic ICs,
ICs did not exist at this time. It was 1959 IIRC. :-)
But that was also when I discovered that silicone oil could burn. :-)
> but they wouldn't say how they did this aside from
> mumbling about used of heat, pressure, and a bunch of well chosen
> solvents, some far too dangerous for ordinary companies to risk using,
> as the story went. I think their main business was reverse engineering.
:-)
When I worked for a government lab, we had an X-ray machine the
size of a under-the-desk refrigerator for the purpose. Take two shots,
one with the object lying flat on film (4x5 Polaroid), and the second
one with one edge blocked up a little (say 1/4-1/2") and you could then
view it as a 3-D image with the right tricks. :-)
[ ... ]
>> > I don't know if Plaza does eBay, but here is the URL:
>> ><http://www.plazamachinery.com>.
>> >
>> > Their list of available stuff is a bit oddly organized, so it's best to
>> > download the whole pdf and then search the file locally.
>>
>> O.K. I've done the download (and am thankful that they have PDF
>> in addition to ".DOC"), and I've now sent off an e-mail to see what he
>> might be able to turn up.
>
> Good luck. I may drive up there this summer. It's about three hours
> drive from my home. The wife would like to see the area, enough to
> tolerate the resulting crate of greasy iron treasures being dragged home.
That is the main trick. :-)
[ ... ]
>> >> Oh -- I just keep a pair of studs in mine to keep the swarf from
>> >> accumulating in there.
>> >
>> > I just blow it out every so often, but the little blue pool annoyed me,
>> > and made me worry about rusting in dark corners.
>>
>> It takes a lot of picking to get the swarf out, so it is easier
>> to keep it from getting in in the first place. :-)
>
> I don't use a pick, I use a thin needle tip on the blowoff gun.
> Releasing the air from the bottom of the hole usually blows it clean.
The swarf that is a killer there is the tight curly stuff which
ties into knots once it falls in.
I don't have a needle tip for mine -- and I would be afraid of
what it might blow between the ways and the carriage.
> But be careful, as it's easy to blow swarf into the eyes this way. I
> loosely tie a shop towel around the gun, to intercept the flying swarf
> and muck.
O.K.
> I've also seen people use a long thin drywall screw to pull swarf from
> deep holes, and one can buy extractors that appear to be a headless
> drywall screw mounted in an aluminum handle.
I was considering a compression spring, (with the end ground
flat to get past the pre-compressed end turns) mounted in a knurled
handle which I could use to turn it and walk the chips up.
[ ... ]
>> > One big toothed timing belt from variable speed (Reeves) drive to
>> > gearbox. This belt is not going to slip.
>>
>> O.K. That is the one for which my metric threading gear set was
>> made, based on the photos in the instruction sheet.
>
> Metric threading kit. That might be more useful than a taper
> attachment. It didn't take long from me to encounter the need to make a
> metric thread (the arbor nuts for the vibrating Ryobi grinder).
>
> How often do the metric kits come up for sale, and for what kinds of
> prices?
To be honest -- I've only seen one -- because I stopped looking
after I found that one. I think that it was over $100.00 but it is far
enough in the past so I am not sure.
It came in the original packaging, with the un-used metal data
plates showing which combination of gears to use with which quick-change
settings to get which metric thread.
You know that you can't use the threading dial with the metric
gear set in place, don't you? That is why I have not (yet) used the
gears. So far -- every metric thread that I have had to cut was small
enough to fit on my little Compact-5/CNC, where I can go to metric mode
at the flip of a switch. :-)
But some of these days I will have to make something larger, and
then will be when I will need the metric gears -- and will discover
whether they truly will work on my machine. I expect them to work.
[ ... ]
>> > The main advantage of 19-x holders appears to be that one also can use
>> > them to hold a P-3 (0.75" high) HSS T-blade.
>> >
>> > The other issue to think about is how much one must move the blade
>> > holder up on the toolpost if one inserts the SGIH blade upsidedown, as
>> > planned to allow use in back, or in front with lathe in reverse.
>>
>> Indeed. You *might* have to make an over-tall holder to deal
>> with that problem.
>
> Yes. Or, make a ridged steel spacer plate to go between the lathe's
> tool slide and the BXA toolpost.
Thus having to re-mount the toolpost and re-allign it when you
are done.
I would rather go with a custom tool holder for the purpose.
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 17, 2008, 8:21 pm
Please log in for more thread options
> >
>
> [ ... multi-T-slot-cross-slide ... ]
>
> >> > For now, the pride will have to be in machine restoration, I think.
> >>
> >> O.K.
> >>
> >> If I could get an MLA casting the right size for my machine
> >> (which would be the right size for yours, too), I would dive into
> >> machining it to make a cross-slide with the rear T-slots.
> >
> > Someday. The cross-slide is pretty much rectangular, so I suppose one
> > could skip the casting and start with a block of cast iron.
>
> Well ... there are a pair of "hips" on mine to support the angle
> plate on the compound -- and there apparently are on the MLA casting for
> the South Bend as well, so I was presuming that there would be on yours
> as well.
I'm not visualizing this. The 5914 compound swings around a vertical
pivot pin, but does not nod.
> [ ... ]
>
> >> > I recall hearing of a company that used Methylene Chloride in what
> >> > amounted to a large pressure cooker (with metal-to-metal seals for sure)
> >> > to remove potting agents from modules, for failure analysis (and reverse
> >> > engineering).
> >>
> >> O.K. Failure analysis was the purpose that Transitron used back
> >> then -- since they had few competitors to analyze anyway. :-) About the
> >> only competitor at that time was Texas Instruments -- and while they
> >> competed in the actual transistors and diodes, they did not seem to in
> >> the potted assemblies.
> >
> > I recall Transitron. There was another depotting company that
> > advertised their ability to strip the potting agent without dissolving
> > the plastic ICs,
>
> ICs did not exist at this time. It was 1959 IIRC. :-)
>
> But that was also when I discovered that silicone oil could burn. :-)
Oh, yeah. The ash is sand.
This is also why it is not a good idea to lubricate electrical contacts
with silicon grease.
> > but they wouldn't say how they did this aside from
> > mumbling about use of heat, pressure, and a bunch of well chosen
> > solvents, some far too dangerous for ordinary companies to risk using,
> > as the story went. I think their main business was reverse engineering.
>
> :-)
>
> When I worked for a government lab, we had an X-ray machine the
> size of a under-the-desk refrigerator for the purpose. Take two shots,
> one with the object lying flat on film (4x5 Polaroid), and the second
> one with one edge blocked up a little (say 1/4-1/2") and you could then
> view it as a 3-D image with the right tricks. :-)
It was a standard trick in the medical field as well, but I forget the
name. A related trick was to slide the film side-to-side while the
X-ray tube went side-to-side in the opposite direction. This caused all
but one plane in the subject to be blurred. CT scans replaced all that
stuff.
> [ ... ]
>
> >> >> Oh -- I just keep a pair of studs in mine to keep the swarf from
> >> >> accumulating in there.
> >> >
> >> > I just blow it out every so often, but the little blue pool annoyed me,
> >> > and made me worry about rusting in dark corners.
> >>
> >> It takes a lot of picking to get the swarf out, so it is easier
> >> to keep it from getting in in the first place. :-)
> >
> > I don't use a pick, I use a thin needle tip on the blowoff gun.
> > Releasing the air from the bottom of the hole usually blows it clean.
>
> The swarf that is a killer there is the tight curly stuff which
> ties into knots once it falls in.
>
> I don't have a needle tip for mine -- and I would be afraid of
> what it might blow between the ways and the carriage.
When cleaning out a blind hole?
> > But be careful, as it's easy to blow swarf into the eyes this way. I
> > loosely tie a shop towel around the gun, to intercept the flying swarf
> > and muck.
>
> O.K.
>
> > I've also seen people use a long thin drywall screw to pull swarf from
> > deep holes, and one can buy extractors that appear to be a headless
> > drywall screw mounted in an aluminum handle.
>
> I was considering a compression spring, (with the end ground
> flat to get past the pre-compressed end turns) mounted in a knurled
> handle which I could use to turn it and walk the chips up.
That could work, but the drywall screw is far stiffer.
> [ ... ]
>
> >> > One big toothed timing belt from variable speed (Reeves) drive to
> >> > gearbox. This belt is not going to slip.
> >>
> >> O.K. That is the one for which my metric threading gear set was
> >> made, based on the photos in the instruction sheet.
> >
> > Metric threading kit. That might be more useful than a taper
> > attachment. It didn't take long from me to encounter the need to make a
> > metric thread (the arbor nuts for the vibrating Ryobi grinder).
> >
> > How often do the metric kits come up for sale, and for what kinds of
> > prices?
>
> To be honest -- I've only seen one -- because I stopped looking
> after I found that one. I think that it was over $100.00 but it is far
> enough in the past so I am not sure.
>
> It came in the original packaging, with the un-used metal data
> plates showing which combination of gears to use with which quick-change
> settings to get which metric thread.
>
> You know that you can't use the threading dial with the metric
> gear set in place, don't you? That is why I have not (yet) used the
> gears. So far -- every metric thread that I have had to cut was small
> enough to fit on my little Compact-5/CNC, where I can go to metric mode
> at the flip of a switch. :-)
Yeah. I would have to recompute the result of every combination, and
use this as a cheat sheet.
> But some of these days I will have to make something larger, and
> then will be when I will need the metric gears -- and will discover
> whether they truly will work on my machine. I expect them to work.
When I outgrow the 5914, I'll be sure to have metric capability.
> [ ... ]
>
> >> > The main advantage of 19-x holders appears to be that one also can use
> >> > them to hold a P-3 (0.75" high) HSS T-blade.
> >> >
> >> > The other issue to think about is how much one must move the blade
> >> > holder up on the toolpost if one inserts the SGIH blade upsidedown, as
> >> > planned to allow use in back, or in front with lathe in reverse.
> >>
> >> Indeed. You *might* have to make an over-tall holder to deal
> >> with that problem.
> >
> > Yes. Or, make a ridged steel spacer plate to go between the lathe's
> > tool slide and the BXA toolpost.
>
> Thus having to re-mount the toolpost and re-allign it when you
> are done.
Depends on how thick it must be. It also seems to me that it would be
an advantage to have a small gap between the bottom of the toolpost and
the top of the tool slide, so chips don't accumulate in the triangle
corners at the bottom of the toolpost dovetails.
> I would rather go with a custom tool holder for the purpose.
I won't have an opinion until I have played with this a bit more.
I tried cutting a 1" diameter 1018 steel bar off with the BXA-7 holding
a 0.125" wide T-blade, It worked pretty well, for a while, cutting a
deep groove with the lathe at ~500 rpm (not using the back gear) and
lots of emulsion coolant. No chattering, but again you could see some
toolpost motion. It eventually stalled the lathe with a bang. No
damage done, though. Aside from heart failure. I sawed the bar in two
right at the groove. What had happened was that it choked on a
wadded-up chip.
Anyway, this is progress. All that tightening up has eliminated the
chatter, even when the tool comes from the front with forward workpiece
rotation. There was some self feeding, but it was not the problem.
I also tried Clausing's chatter test, taking at least 0.125" depth by
0.002" advance per revolution on a 1.5" bar. I had a 1" bar, but was
having no problem going 0.136" deep generating chips between ).004" to
0.006" thick, with only a hissing sound. The workpiece did get hot
enough that the emulsion coolant was boiling, but one could keep doing
this so long as the coolant supply held up.
Joe Gwinn
|
|
Posted by DoN. Nichols on May 17, 2008, 10:27 pm
Please log in for more thread options >
>> >
>>
>> [ ... multi-T-slot-cross-slide ... ]
>>
>> >> > For now, the pride will have to be in machine restoration, I think.
>> >>
>> >> O.K.
>> >>
>> >> If I could get an MLA casting the right size for my machine
>> >> (which would be the right size for yours, too), I would dive into
>> >> machining it to make a cross-slide with the rear T-slots.
>> >
>> > Someday. The cross-slide is pretty much rectangular, so I suppose one
>> > could skip the casting and start with a block of cast iron.
>>
>> Well ... there are a pair of "hips" on mine to support the angle
>> plate on the compound -- and there apparently are on the MLA casting for
>> the South Bend as well, so I was presuming that there would be on yours
>> as well.
>
> I'm not visualizing this. The 5914 compound swings around a vertical
> pivot pin, but does not nod.
The "angle plate" to which I was referring was the thick disc at
the bottom of the compound pivot which carries the angle scale engraved
in it. The "hips" provide a possible place to scribe an index mark for
the scale, since the disc is wider than the cross-slide at other
locations.
[ ... ]
>> > I recall Transitron. There was another depotting company that
>> > advertised their ability to strip the potting agent without dissolving
>> > the plastic ICs,
>>
>> ICs did not exist at this time. It was 1959 IIRC. :-)
>>
>> But that was also when I discovered that silicone oil could burn. :-)
>
> Oh, yeah. The ash is sand.
Yep! All over the place! :-)
> This is also why it is not a good idea to lubricate electrical contacts
> with silicon grease.
O.K. That I had not thought of.
[ ... ]
>> When I worked for a government lab, we had an X-ray machine the
>> size of a under-the-desk refrigerator for the purpose. Take two shots,
>> one with the object lying flat on film (4x5 Polaroid), and the second
>> one with one edge blocked up a little (say 1/4-1/2") and you could then
>> view it as a 3-D image with the right tricks. :-)
>
> It was a standard trick in the medical field as well, but I forget the
> name. A related trick was to slide the film side-to-side while the
> X-ray tube went side-to-side in the opposite direction. This caused all
> but one plane in the subject to be blurred. CT scans replaced all that
> stuff.
Yep -- if you can afford it. Granted, I saw the shell of one at
a hamfest some years ago -- back when they were still called "CAT"
scans, and "MRIs" were "NMRIs" before people started freaking at the 'N'
word. :-)
[ ... ]
>> > I don't use a pick, I use a thin needle tip on the blowoff gun.
>> > Releasing the air from the bottom of the hole usually blows it clean.
>>
>> The swarf that is a killer there is the tight curly stuff which
>> ties into knots once it falls in.
>>
>> I don't have a needle tip for mine -- and I would be afraid of
>> what it might blow between the ways and the carriage.
>
> When cleaning out a blind hole?
I had no way to be sure that it was truly blind. And it was
over the side slides of the carriage.
>> > But be careful, as it's easy to blow swarf into the eyes this way. I
>> > loosely tie a shop towel around the gun, to intercept the flying swarf
>> > and muck.
>>
>> O.K.
>>
>> > I've also seen people use a long thin drywall screw to pull swarf from
>> > deep holes, and one can buy extractors that appear to be a headless
>> > drywall screw mounted in an aluminum handle.
>>
>> I was considering a compression spring, (with the end ground
>> flat to get past the pre-compressed end turns) mounted in a knurled
>> handle which I could use to turn it and walk the chips up.
>
> That could work, but the drywall screw is far stiffer.
A stiff spring which would just fit into the tapped hole (say it
had wire about 1/3 the clearance diameter of the hole allowing for two
wires and a through hold of the same size should be stiff enough.
[ ... ]
>> > How often do the metric kits come up for sale, and for what kinds of
>> > prices?
>>
>> To be honest -- I've only seen one -- because I stopped looking
>> after I found that one. I think that it was over $100.00 but it is far
>> enough in the past so I am not sure.
>>
>> It came in the original packaging, with the un-used metal data
>> plates showing which combination of gears to use with which quick-change
>> settings to get which metric thread.
>>
>> You know that you can't use the threading dial with the metric
>> gear set in place, don't you? That is why I have not (yet) used the
>> gears. So far -- every metric thread that I have had to cut was small
>> enough to fit on my little Compact-5/CNC, where I can go to metric mode
>> at the flip of a switch. :-)
>
> Yeah. I would have to recompute the result of every combination, and
> use this as a cheat sheet.
Huh? The threading dial (to the right of the carriage) does not
work at all for metric threading with an imperial thread leadscrew. If
you want to do metric threading a lot -- replace the leadscrew with a
metric one, change the QC gearbox to give the right ratios, and replace
the threading dial with one which has four different gear tooth counts
on a sliding spline so you can select the one which works for the thread
in question. (That is one of the places where metric is less
convenient, at least the standard set of metric threads is.) Inch
threads can all be done with a single threading dial, but not metric
threads. (Of course with a CNC machine there is no threading dial at
all, and the leadscrew is not geared to the spindle rotation, but rather
driven by a stepper or servo motor. The spindle has an encoder disc with
two circles of holes -- one has one hole, so every thread pass starts at
the same point, and the other has some large number of holes -- at a
guess I would say perhaps 32 holes -- and every time another hole
appears the stepper motor moves a pre-calculated number of steps -- or
the servo motor checks that it has move at constant speed the right
distance, and corrects itself if necessary.
>> But some of these days I will have to make something larger, and
>> then will be when I will need the metric gears -- and will discover
>> whether they truly will work on my machine. I expect them to work.
>
> When I outgrow the 5914, I'll be sure to have metric capability.
The right way to do it is to get a machine with three shafts --
one keyed to drive the power feeds in the apron, and the other two being
leadscrews with imperial and metric pitches -- with matching half-nuts
in the apron. And -- you need two threading dials as well.
[ ... ]
>> >> Indeed. You *might* have to make an over-tall holder to deal
>> >> with that problem.
>> >
>> > Yes. Or, make a ridged steel spacer plate to go between the lathe's
>> > tool slide and the BXA toolpost.
>>
>> Thus having to re-mount the toolpost and re-align it when you
>> are done.
>
> Depends on how thick it must be. It also seems to me that it would be
> an advantage to have a small gap between the bottom of the toolpost and
> the top of the tool slide, so chips don't accumulate in the triangle
> corners at the bottom of the toolpost dovetails.
Do that and you reduce the rigidity of the mounting of the
toolpost and encourage chatter. :-)
>> I would rather go with a custom tool holder for the purpose.
>
> I won't have an opinion until I have played with this a bit more.
O.K.
> I tried cutting a 1" diameter 1018 steel bar off with the BXA-7 holding
> a 0.125" wide T-blade, It worked pretty well, for a while, cutting a
> deep groove with the lathe at ~500 rpm (not using the back gear) and
> lots of emulsion coolant. No chattering, but again you could see some
> toolpost motion. It eventually stalled the lathe with a bang. No
> damage done, though. Aside from heart failure. I sawed the bar in two
> right at the groove. What had happened was that it choked on a
> wadded-up chip.
Ah yes -- the reason for a shallow 'V' groove in the top of the
parting tool to pinch the chip a bit narrower and reduce the chances of
this happening.
> Anyway, this is progress. All that tightening up has eliminated the
> chatter, even when the tool comes from the front with forward workpiece
> rotation. There was some self feeding, but it was not the problem.
Great!
> I also tried Clausing's chatter test, taking at least 0.125" depth by
> 0.002" advance per revolution on a 1.5" bar. I had a 1" bar, but was
> having no problem going 0.136" deep generating chips between ).004" to
> 0.006" thick, with only a hissing sound. The workpiece did get hot
> enough that the emulsion coolant was boiling, but one could keep doing
> this so long as the coolant supply held up.
Sounds pretty good. Beware when you are running that hot to not
let the flow of coolant to a carbide insert get interrupted. This can
cause cooling fractures in the insert. Either work hot, or have good
flood cooling. (And if you are working as hot as you described, go away
and do something else to let it cool way down before measuring prior to
a finish cut. :-)
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 ---
|
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>> >> >> Associates) makes a casting for the South Bend lathes to make such a
>> >> >> cross-slide. I would have made one -- except that it is just a bit too
>> >> >> small for my machine.
>> >> >
>> >> > I must say that I'm less tempted now.
>> >>
>> >> Even with the full circle T-slot for a proper compound? All you
>> >> need to do is to talk MLA into making (and offering) a slightly larger
>> >> casting, then machine it properly.
>> >
>> > Sounds too much like work.