No longer about "Trepanning and Parting Off -- part 2"

    [ ... ]


    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.
    [ ... ]

    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.
    [ ... ]

    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.
    [ ... ]

    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 was surprised to find the holes already in place and tapped for the taper attachment on my machine.
    [ ... ]

    O.K. That is the one for which my metric threading gear set was made, based on the photos in the instruction sheet.
    [ ... ]

    Indeed. you *might* have to make an over-tall holder to deal with that problem.
    Enjoy,         DoN.
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Someday. The cross-slide is pretty much rectangular, so I suppose one could skip the casting and start with a block of cast iron.

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.

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 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.

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?

Yes. Or, make a ridged steel spacer plate to go between the lathe's tool slide and the BXA toolpost.
Joe Gwinn
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    [ ... multi-T-slot-cross-slide ... ]

    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.
    [ ... ]

    ICs did not exist at this time. It was 1959 IIRC. :-)
    But that was also when I discovered that silicone oil could burn. :-)

    :-)
    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. :-)
    [ ... ]

    That is the main trick. :-)
    [ ... ]

    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.

    O.K.
    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.
    [ ... ]

    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.
    [ ... ]

    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.
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I'm not visualizing this. The 5914 compound swings around a vertical pivot pin, but does not nod.

Oh, yeah. The ash is sand.
This is also why it is not a good idea to lubricate electrical contacts with silicon grease.

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.

When cleaning out a blind hole?

That could work, but the drywall screw is far stiffer.

Yeah. I would have to recompute the result of every combination, and use this as a cheat sheet.

When I outgrow the 5914, I'll be sure to have metric capability.

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 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
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    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.
    [ ... ]

    Yep! All over the place! :-)

    O.K. That I had not thought of.
    [ ... ]

    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 had no way to be sure that it was truly blind. And it was over the side slides of the carriage.

    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.
    [ ... ]

    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.

    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.
    [ ... ]

    Do that and you reduce the rigidity of the mounting of the toolpost and encourage chatter. :-)

    O.K.
    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.

    Great!
    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.
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The long delay was because Comcast's news server went down over the weekend, and was only restored late Monday.

Ahh. I think I have this too.

The word I couldn't recall was "tomography", and it was not computerized back then.
Nuclear Magnetic Resonance Imaging (NMRI) was in fact perfectly accurate. But, the ignorant will always be with us - they didn't understand that "nuclear" didn't necessarily require or imply radiation. So, the name had to change.

Certainly. But drywall screws are plentiful and cheap.

True; nothing else expected. For metric on an inch machine, one must go back up to get back to the start point without losing registration.

If you keep this up, I'll have to become frightened.

Yep. Future. First I need to do a little self-education.

Not by much, as the plate is in compression, and can be accurately machined. And, all the rigidity problems I've had so far have been associated with loose slideways.

I'm leaning to the Dorian 7-71C, which appears to be made to allow use upsidedown. I will call Dorian and ask.

Yes. I'll have to find a way to grind this feature into the blades.

Well, I'm using a heavy spray. A flood would probably end up decorating the ceiling. I've been thinking of mounting some kind of shield on the carriage. A line is already forming on wall and ceiling.
The Noga mist cooler does cause some drifting mist, which I find to cause a lot of coughing. I've taken to wearing a respirator to prevent breathing of the oil mist, but a better approach is required.
This is certainly only for roughing cuts. But speed is a good idea, even for HSMers.
Joe Gwinn
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    So -- that was why things were quiet over the weekend. :-)

    [ ... ]

    I expected so.

    Oh -- I didn't know that you were searching for the word. For some reason, I have no problem remembering that one. :-)

    Yep -- and now you can freak some of the *operators* of the devices by mentioning the full name. :-)
    [ ... ]

    Yes -- but I would expect a properly selected spring to do a better job of cleaning the hole -- then perhaps followed by the compressed air needle. (I'll have to make a snout for one of my air guns to do that.)
    [ ... ]

    O.K.
    This was for if you want to do it a *lot*. And one of the advantages of the CNC method is that it makes it easy to thread up to a shoulder with no worries at whatever speed your lathe can manage. (The Compact-5/CNC is limited to around 200 RPM because the Z-axis stepper is too slow to handle coarse threads at higher spindle RPMs. (The Z axis is parallel to the spindle -- along the bed for a lathe.

    O.K.
    [ ... ]

    The length of unsupported tool shank can be a problem even. I'm against anything which reduces the rigidity of the toolpost assembly.

    O.K. Let me know how it works out.

    Get a Dremel and a stone perhaps 1" diameter. Use a diamond to dress it to look like this: __________ <____ ____> || || || ||
and run it along the top near the tip. Or -- if you have a small surface grinder, get a thin wheel for that, and dress it as shown.
    [ ... ]

    Hmm ... I have a shield which mounts on a rod on the back of the headstock and it swivels out of the way for loading, or down to control spray towards the operator. But it only works in the vicinity of the chuck. For a carriage mounted one, you want something like the T-slotted cross slide again. :-)

    From what I have read, the micro-drop is the best thing for this.

    And patience after roughing to let it cool enough. I try to set things up so I just finish the roughing before being called to dinner, that way I have something to be doing while the workpiece cools. :-)
    Enjoy,         DoN.
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I haven't tried that. Yet.

I found an air needle set that was threaded to fit into the snout of a real Schrader blowoff nozzle that I've had for years, long before I had a compressor to run it.

Ahh. Now it becomes clear -- buy a CNC lathe. To go one better, it must weigh at least 3000#. Got to have sufficient rigidity.

I'm thinking a plate ~0.1" thick.

I called today, but have not yet talked to a human. Form their catalog, it appears that their 7-71C is intended to be used upsidedown, which would be perfect. It uses SGIH 19-2 blades, which are slightly larger than the 11/16" blades the Aloris BXA-7 uses, but one cal also get Dorian 7-71S holders, which accept SGIH 26-x blades, which are a good bit stouter.
The Aloris BXA-71 uses a very stout blade, 1.5" high, but does not appear to be reversible - it has a one-sided bevel.

This is doable, except for the surface grinder part.

Or drill and thread some mounting holes in the cast-iron cross-slide screw cover, which I've been considering.

So I've heard, but they are quite expensive. What alternatives are there?
Maybe the solution is flood cooling plus a cover to catch what's flung off the workpiece. The cover need not be transparent, as even transparent covers will soon become opaque from the accumulated emulsion and crud.
With Rustlick WS-5050 emulsion, the baby blue milky fluid, decoration of nearby surfaces isn't a disaster, but will eventually stain the surfaces. A carriage-mounted shield should cut this down a lot.

I haven't been at the point where this would matter, at least not yet. But it will soon enough become something I need to worry about.
Joe Gwinn
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wrote:

I do have about 100lbs of 4x5x2 well seasoned cast iron blocks from a lathe manufacturer.
Gunner
Political Correctness is a doctrine fostered by a delusional, illogical liberal minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
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    Hmm ... interesting sounding. I will have to check the overall length of the cross-slide casting -- but I think that it is well over 6", so the would not work. Sigh! Same for Joe, I believe. While there are differences between our machines, I would expect those dimensions to be pretty much the same.
    Enjoy,         DoN.
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On my 5914, the tool slide is 6.5" x 3" by 1.25" or so, so 4x5x2 would not work, sadly.
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    Are you talking about the compound slide again? This is supposed to be be cross-slide -- first thing up from the carriage, and mine is 8-3/4" long, so there is no way that it would work.
    Good Luck,         DoN.
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"Tool slide" is Clausing's name for it, being the topmost slide with a single large T-slot to which the toolpost is clamped, and which swings about a vertical pivot pin.
The cross-slide outer dimensions are about 8.75" x 4" x 1.25", about the same as yours it seems.
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    And *that* is the one which is supposed to be made with extra T-slots, not the compound slide (or tool slide depending on the phase of the moon.)
    Enjoy,         DoN.
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On Tue, 20 May 2008 22:23:17 -0400, Joseph Gwinn

Ill check this coming weekend when Im back home again.
Sadly..I passed on the 1000lbs of larger cast iron blocks
I snagged these for making KDK type holders.
The rest was scrapped....sigh
Gunner
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    [ ... ]

    [ ... ]

    He has lost track of what we were talking about. It needs to be a replacement for the cross-slide, not the tool slide (compound slide). So the figures which I just posted are what he will need, just as they are what I will need. 9"x4-1/2"x1-3/4" should be large enough to work as needed.

    Hmm ... how small were the smallest of those? Obviously, a 1000 lb block would be more than I need -- and more than I can do much with, too.

    O.K.
    Sigh, indeed.
    Enjoy,         DoN.
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wrote:

Ive got some larger bits. Email me with the max dimensions you need.
Gunner
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    [ ... ]

    I'll have to skip the e-mail until I have a different address for you. I checked to see whether I had the domain (corrected by removing the obvious) blocked, and at the moment my nameserver can't look up your IP address, which means both that I can't reach you, and that a reply from you could not get back to me.
    I remember other e-mail conversations which just sort of died, I suspect from similar problems..
    The absolute minimum size (with nothing for clean-up passes) would be 8-3/4 x 4-1/4" x 1-1/4", and the last really should be 1-3/4" to allow for greater thickness were I add the T-slots at the back. So, desired would be 9x4-1/2x2" to make it easy to clean up in all dimensions.
    If all else fails, the phone number in my .sig below is valid. Please don't call until the afternoon or evening, since I live a shifted time schedule.
    Enjoy,         DoN.
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