Clausing 5914 - Test Report Requirements

I talked to Clausing today. One question I had was how much of a cut the lathe ought to be able to handle without chattering. The guy I
talked to didn't recall such a spec. Later, I asked if there was spec on spindle runout et al, and he said that there was a sheet that gave that information, which he was happy to fax to me, and did.
It turned out to be the "Clausing Test Report, 5900-series Lathe", a one-page form that was filled out and provided to the purchaser of each lathe. There are 15 tests listed. Most are for various kinds of alignment and runout, and are all less than 0.001" both near the headstock or tailstock as appropriate, and also at the end of a 12" bar held in one or the other.
As for runout, on hearing my long sad chatter stories, Clausing suggested tightening the spindle bearing take-up nut by 1/4 turn, even though the spindle passes the spein-spindle-by-hand test.
The next to last test, the "Running test for smooth operation", is the answer to my original question. The test specifies that the lathe must be able to cut a 1.5" diameter bar of CRS with 5" protruding from the 3-jaw chuck (and no tailstock use), running at "high speed" while taking a 0.125" depth of cut (0.25" diameter reduction) and feeding 0.0026" per turn, without chatter.
What is "high speed"? If their tools were HSS, the surface speed should be in the range 80-120 fpm for optimum performance. To achieve 120 fpm in a 1.5" round bar, one must spin the bar at 306 rpm, which is above the fastest backgear speed and below the slowest normal speed, so this seems unlikely.
If the tools were instead carbide, the optimum speeds are a factor of 5 faster, which puts one at 1,528 rpm, which is at the upper end of the 5914's range (the max being 1900 rpm), which makes sense. This sounds like smoking blue chip territory for sure. But I will try it. While standing well to one side.
Also of interest is the cross feed screw backlash, 0.004" max. It was 0.025" on receipt of the lathe, and is now 0.010" after replacement of the T-Nut (the original screw being retained). The compound slide backlash also meets this 0.004", after replacement of both screw and bronze nut; it had been about 0.050".
Actually, what is the claimed speed range of the 5914? This must have been published in a brochure or catalog page somewhere. The scale on the variable speed control wheel appears to be wider than the actual range. For one thing, the scale goes to 2000 rpm, but one hits a mechanical stop at 1900 rpm. Probably the same control wheel assembly was used on multiple lathe models, each with slightly different gear/pulley ratios, with limit stops adjusted to match.
Joe Gwinn
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Clausing claimed 52-280 rpm in back gear and 360-2000 in direct drive for the 5900-series lathes. This from a Clausing brochure I have of unknown vintage.
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[snip]
That agrees with the scales on the control wheel, but there is a hard stop at 1900 rpm. Thus my question.
Joe Gwinn
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I've not delved into the speed control much, but if memory serves there is a roll pin that acts as the hard stop. Can the speed control hub be rotated to adjust the setting at which the stop becomes effective?
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Probably, but Clausing probably had a good reason to put the hard stop where they put it. I'm trying to figure this out before T try to circumvent it.
Joe Gwinn
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No, I meant that the position of the hard stop may *need* to be adjusted. I'm not at all certain of that though, so just consider it a thought.
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OK.
Joe Gwinn
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Joe,
Don't believe that dial...
When I rebuilt mine I checked the speeds with a tach... In direct drive I got 300 not the 360 listed on the dial. And at the top end I got 2150 not the 2000 listed on the dial. Not many of the speeds on the dial matched EXACTLY what the tach said, but in truth it's plenty close for the "4 x D calc in your mind" numbers.
Sorry to hear you have chatter on heavy cuts, I was just blasting through some 4 inch cast iron wheels in back gear taking nice 0.100 cuts, and yeah I know that aint CRS but...
I also did a couple of axels out of some .750 drill rod I had kicking around and a fine finish cut of .005 at the slowest longitidunal speed came out like glass.. :-)))
--.- Dave
.

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I don't. The Clausing manual suggests using a rpm meter to set the speeds (by adjusting the cone nut on the lower VS pulley). If no meter, just set it so the belt comes to the top of the flange. This is what I have been doing.
The reason to ask is to know what range I should be able to achieve, to know when I have achieved what the machine was designed to achieve.

Yep.
Heavy cuts per se don't seem to be the problem, but cutting off is.
It's an old machine, and every discovery seems to yield substantial improvement, but eventually diminishing returns will set in.

I bet cast iron would not be a problem, based on how brass worked.

This I can probably do already, as I have gotten some mirror finishes.
Joe

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I haven't had any issues with cutoff work.
What's your tool post?
What kind of cutoff tool?
Have you tried a test with the cutoff tool mounted directly to the cross slid and not on the compound, that's what I had to do on the "import"...
--.- Dave

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Aloris BXA bolted (5/8-20) to the the T-slot in the standard-issue compound.

BXA-7 and also SGIH 19-2 blade held in a Dorian BXA 7-71C.
I get chatter even when the SGIH blade et al are mounted upsidedown and the lather run in reverse, which eliminates self-feeding as a cause.
Oddly, the upsidedown SGIH works fine when the work is held in a collet, but chatters if the work is in a 3-jaw chuck. The chuck does not appear to be worn, but its length implies that the cutting point is an added 5" or 6" farther from the spindle bearings.

This I have not tried, and would require some fabrication. An alternative would be to over-tighten the gibs of the compound. But, the lathe ought to be able to make such cutoffs without bypassing the compound, which is why I have kept on trying.
Gunnar suggested locking the lower gibs and using only the compound to advance the blade. I did this some time ago and it had no effect, but it may be time to repeat the exercise.
My suspicion is focused on the cross-slide slideway and gibs, as when I put a 5-foot long 1" bar in the boring bar holder perpendicular to the bed ways and tug up and down on the bar, which is centered in the holder so the bar's own weight balances out. I feel motion only in the cross-slide gap when I tug on the bar.
The problem is that this is a very severe test, and I don't know how much motion is to be expected for a lathe of this size and heft, even if it were new.
Clausing has also suggested that I tighten the spindle adjustment nut by 1/4 turn. This is today's project. I may have to fabricate a radial-pin spanner wrench to do this.
Joe Gwinn
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Jeez,
I use the same (well mines a knock off but..) tool post and blades...
RE: Crossslide only, Understood that it "should" work on the compound, since mine "does" work... Just trying to come up with a simple test to eliminate things...
Clausing might be right, time to try the spindle nut test.
Keep us.. "posted".. :-)
--.- ave
wrote:

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I just tightened the spindle bearing adjustment nut. It made a huge difference. Now that I think about it, the headstock never got warm after running a while, and it's supposed to get warm but not too hot to touch.
Joe Gwinn

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Could you scan that and email it to me?
wess ignorethis At ignorethisalso Wess.mdns.org
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Not easily at present (no scanner), but Clausing will fax it to you on request. Their phone number is 574-533-0371.
I can also extract and summarize the relevant text. What's lost are the little diagrams showing what is being measured, so I've added some clarifying words.
1. Bed Level, transverse direction: all readings (across bed) to be within 0.0005" in 12 inches.
2. Bed Level, longitudinal direction: Maximum reading along bed of 0.001" in 12 inches.
3. Spindle Center Runout: zero to 0.0008" total indicator runout, with indicator resting on a dead center mounted in the spindle.
4. Spindle Nose Runout: 0 to 0.0003" on the spindle's L-00 taper.
5. Spindle Taper Runout: Total indicator runout in two places, right at the spindle nose, and at the end of a 12" test bar: 0 to 0.0003" and 0 to 0.0006" respectively. The test bar appears to have a MT 4.5 taper in one end, as there is no mention of using the MT3 spindle sleeve.
6. Headstock Alignment, vertical: Max height deviation at end of 12" bar is 0 to +0.0005". Probably uses same test bar as test #5.
7. Tailstock Alignment, vertical: Max height deviation at end of 12" bar with spindle fully extended is 0 to +0.0008". Test bar will need a MT3 taper.
8. Headstock Alignment, horizontal: At the end of a 12" test bar, 0 to +/- 0.0003".
9. Tailstock Spindle Alignment, horizontal: At the end of the fully extended spindle, 0 to 0.0005", measured from the front of the lathe.
10. Tailstock Taper Alignment, horizontal: At the end of a 12" test bar, 0 to +/- 0.0005". Spindle shown as fully retracted, and perhaps it's clamped as well.
11. Tailstock Taper Alignment, vertical: High at the end of a 12" test bar, 0 to +0.001". Spindle shown as fully retracted, and perhaps it's clamped as well.
12. Cross Slide Alignment: This is a combined test. Apparently, one first faces off (machines) the faceplate, and then does some indicator tests. The faceplate is allowed to be concave only, and the deviation from flat cannot exceed 0 to 0.0005" when the cross slide is moved, scanning the indicator along a diameter. The runout due to rotation of the faceplate also cannot exceed 0 to 0.0005".
13. Lathe Must Turn Round With Work Mounted in Chuck: Turn a test piece, and measure diameter with a micrometer. No pair of measured diameters can differ by more than 0.0003". Actually, it's possible to pass this test and yet not be round. A better test is to turn something, and then measure it between a V-block and a dial indicator. But the multiple-diameters test will catch most of the irregular shapes a lathe is likely to make.
14. Running test for smooth operation: The test specifies that the lathe must be able to cut a 1.5" diameter bar of CRS with 5" protruding from the 3-jaw chuck (and no tailstock use), running at "high speed" while taking a 0.125" depth of cut (0.25" diameter reduction) and feeding 0.0026" per turn, without chatter. High speed is not defined, but surely precludes use of the back gear for this test.
15. Back Lash on Cross Feed Screw: 0.004" max.
Joe Gwinn
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The Leblond at work has about 0.001 backlash. I like the feel of that machine. :)
Wes
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Errr. May I ask, what does this lathe weigh?
Joe Gwinn
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Joseph Gwinn wrote:

Aha! Well, the test is a darn serious cut, except for the feed per turn. That can cause work hardening, so you need some REALLY mild steel to prevent problems there. I'd use the slowest direct-drive speed, and maybe cut the depth of cut down to .1" or so. 5" work overhang with no support is really pushing it, it is something you'd rarely do in normal practice, but it will tell you if there is something loose! I'd make especially sure the tool is well supported, the overhang from the toolpost should be an absolute minimum, and the compound should be in the center of it's travel for the best support.

This is not the cause of chatter, and is expected on a used machine.
Jon
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I've been using the BXA-16N holder, which is massive.
In any event, I could not cut a 1" steel (1018) bar without chatter at any direct drive speed at that depth of cut, with the bar (3" sticking out, not 5") in the 3-jaw chuck.
I did test for bell-mouth of the chuck jaws, by the ball-bearing test and by chucking a 0.5" drill blank and probing with a 0.001 feeler. No go.
As discussed in other postings, I think it's time to take Clausing's advice and tighten the spindle bearing adjustment nut.

Yep.
Joe Gwinn
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