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D1-6 Camlock Blue Check Question

ripperj

Stainless
Joined
Dec 8, 2015
Mid 80s Kerry(Namsun, South Korea) 16” gearhead Mori wannabe
D1-6 spindle in very nice condition

Brand new Bison direct mount forged steel (4000 rpm) 8” 3 jaw scroll chuck, hardened and ground scroll and pinions, balanced scroll and body.
My initial impressions of this chuck have me very pleased. Not a cheap chuck, $1600 at MSC, but can be had for $1050 shipped from Ajax Tool Supply. I have high praise for Ajax, nice people and great prices with fast shipping. I’m in Ct and the chuck shipped from Ma overnight with just UPS ground. I have only recently started using them, but will definitely be ordering more thru them.

The chuck is speced to run out less than .0015”

I spent some time adjusting the cams and mounted the chuck. The runout at the jaw tips is .0008” (Brown and Sharp .0001 test indicator), and just under .0015” measured 8” from chuck face on a 1” ground boring bar(all I really have for a test bar, I will probably make a better test bar between centers sometime), so really good run outs, but I didn’t have time to see if it’s repeatable after demounting/ remounting. I also need to do some more checks to verify it wasn’t a fluke where boring bar distortion was cancelling out the runout.
The chuck seemed to draw up pretty easy and the spindle face seems to be hard up against the chuck back, for all I know it’s not even touching the taper.
So.. if I blue the pristine chuck back and fit it up, what should I see for contact? The spindle is nice, but not perfect. What would be ideal to see for contact marks, what’s good enough?

I’m certainly not complaining about the runout results, but want ensure a proper fit to prevent damage to the spindle/chuck.

Thanks for any help you could offer

Keith





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So.. if I blue the pristine chuck back and fit it up, what should I see for contact? The spindle is nice, but not perfect. What would be ideal to see for contact marks, what’s good enough?
Fitup is well covered, right here on PM contrarian input and counters to it as well for the 'education' as to whyso.

Google should find that for you if the PM search does not.

You will want to put-by some "plastigage" as well as highspot blue.

Do not forget to try TIR at all three positions, as far as which pin goes into which hole. Record TIR at each. Scout for burrs to stone off. Repeat. Mark your best and use it if any lasting difference,
 
I should have mentioned that I did plenty of research and it was hard to determine what was the right answer. Some say that after three or so passes the face should be hard up, others say .001 gap.
All the references to blue check I found use non specific terms like “a good blue check.

My question is specific to what a good blue check would look like(actual picture would be great)
I don’t imagine that even the best spindle and chuck combo would result in 100% of the blue being removed.



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The mount should contact both the taper and the flat face. Ideally, the taper will have a very, very slight interference. Some of my chucks fall off the mounts as soon as the cams are loosened and some take a whack with a dead-blow mallet. This is for a Monarch 10EE and a Colchester Chipmaster. I don't have any noticeable problems with repeatability with any of them. I mentor in the high-school's robot shop, where they have an unmentionable green gear-head lathe. That one takes some muscle on the cams to get a nice Bison chuck to pull tight to the flat. If I had to bet, the lathe's taper is fat, rather than the chuck's bore being skinny, but I have not gauged either of them. If I had to have a gap, I would prefer the taper loose, rather than a gap at the flat. If there's a gap at the flat, the chuck could point the workpiece at an angle, whereas if there is a gap at the taper, there would just be a lateral shift leading to small runout.
 
Rk- good points , I failed to mention something probably important :)
Once the cams are released it takes a very light blow with a rawhide mallet to get the chuck off. My original thought was this certainly had to be the taper, but I’m not totally convinced that the new backplate would not “wring”(surface sticking??) due to the fine surface and slight oil film


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None of the lathes I deal with have the flat part of the D mount nice enough to wring. It's either ground too coarse from the factory, or dinged from 50 years of age. I seriously doubt a 8" chuck will wring to anything. Try wringing to the chuck and spindle flats with a gauge block or nicely-finished tooling like a v-block or grinding vise.
 
Rk- good points , I failed to mention something probably important :)
Once the cams are released it takes a very light blow with a rawhide mallet to get the chuck off. My original thought was this certainly had to be the taper, but I’m not totally convinced that the new backplate would not “wring”(surface sticking??) due to the fine surface and slight oil film


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Even if it does "wring", that's one atmosphere on a small area. The interference fit of the taper is far more "powerful".

Needs a mallet rather than just heel-of-the hand? Taper fit sounds good.

Plastigage your flat to see how it bears, you may be good to go, as-had.
 
I’ll pick up some plastigage and play. Thanks


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The chuck seemed to draw up pretty easy and the spindle face seems to be hard up against the chuck back, for all I know it’s not even touching the taper.
So.. if I blue the pristine chuck back and fit it up, what should I see for contact? The spindle is nice, but not perfect. What would be ideal to see for contact marks, what’s good enough?

I’m certainly not complaining about the runout results, but want ensure a proper fit to prevent damage to the spindle/chuck.

Thanks for any help you could offer

Keith





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The chuck MUST touch the taper all over AND be a slight interference fit with the taper i.e. you need to see a small gap of 2-3 thou with the flat of the camlock nose. This being neglected it can cause the chuck to COME OFF. If the interference is too light it'll wear the camplock nose - you can SEE this happening. Otherwise, do what Thermite says, he knows his business.
 
The chuck MUST touch the taper all over AND be a slight interference fit with the taper i.e. you need to see a small gap of 2-3 thou with the flat of the camlock nose. This being neglected it can cause the chuck to COME OFF. If the interference is too light it'll wear the camplock nose - you can SEE this happening. Otherwise, do what Thermite says, he knows his business.

All I really know is that if I ever stop paying attention and continuing to listen, research, and learn? Sumthin' nastier even than I can be will for-damned-sure be quite pleased to do me in, then gloat over it.

:)

Where ISTR we ended up was. .that yes, it will touch the flat but only when already AT a reasonably tight interference fit with the taper's body, AND NOT even close to loose nor being able to become loose.

The flat has to prevent tilt that would fret the cone on a nano-scale over macro time, or just distort it enough to loosen, momentarily, macro loading, nano time.

IOW, it is a "working" component with an important task, not "just" a reference surface.

D1, or its bolt-not-pin sibling, the same geometry "A" series short taper, are more complex than first appears. Both end up simple in use only when very, very well-executed and cleanly maintained, thereafter.

We are dealing with common metals, here. They own no such characteristic as infinite strength, nor infinite stiffness. Ultimately, ANYTHING can be moved or distorted by enough applied force.

American Standard short tapers are simply designs such that for each size, by the time that much force can be applied, a whole bunch of weaker s**t has to have failed beforehand.

Taking the otherwise heavy-legged 10EE as one example, f**k the dog on setup or use, get the stoutest QCTP or 4-Way toolholder or tool you own dead into the path of the jaw of your stoutest chuck at full gallop? Massive crash. And chuck body, jaw, compound, or some equal-opportunity committee of each will be torn right-TF off its perch and fling through "something" before a well-seated and properly camlocked D1-3 gives up its grip.

Not often one hears of a failure. D1 or A2.

Nor any other spindle nose design, to be fair.

Not a one of them as was ever planned as the weakest of several links.

This one seems good. So far. OP has been wise to seek proof of that.
 
The chuck MUST touch the taper all over AND be a slight interference fit with the taper i.e. you need to see a small gap of 2-3 thou with the flat of the camlock nose. This being neglected it can cause the chuck to COME OFF. If the interference is too light it'll wear the camplock nose - you can SEE this happening. Otherwise, do what Thermite says, he knows his business.

There should not be a gap. Think about it. If you have a gap, there will be non-repeatable angular runout of chucked stock. The runout would vary depending on who tightened which cam in what order and how much. I need to pull up the ANSI/ASME standard.
 
There should not be a gap. Think about it. If you have a gap, there will be non-repeatable angular runout of chucked stock. The runout would vary depending on who tightened which cam in what order and how much. I need to pull up the ANSI/ASME standard.

I did think about it. Also, I drank half a bottle of whiskey while remembering what was tested in the lathe factory I used to work for. Also, I took a drive and asked a former engineer with Group 600. And I looked on the standard. In conclusion there must be a gap due to a slight interference fit on the taper. THIS GAP ENSURES YOU ARE CENTERED. The gap is closed by the camlocks which are not tightened more or less but simply tightened. As a result, a well fitting chuck comes off with a minor "pop". Very minor.

By the way, loved the "runout would vary depending on who tightened which cam in what order and how much". Think about it :) :) :) - once the cam is tightened, the chuck is solidly against the flat of the nose and won't go past it short of breaking everything. :) Of course, imbeciles are known to forget to tighten the cams fully OR ( !!! ) do not know what "fully" means in this specific case.
 
All I really know is that if I ever stop paying attention and continuing to listen, research, and learn? Sumthin' nastier even than I can be will for-damned-sure be quite pleased to do me in, then gloat over it.

:)

Where ISTR we ended up was. .that yes, it will touch the flat but only when already AT a reasonably tight interference fit with the taper's body, AND NOT even close to loose nor being able to become loose.

The flat has to prevent tilt that would fret the cone on a nano-scale over macro time, or just distort it enough to loosen, momentarily, macro loading, nano time.

Yep, that's it.
 
Of course, imbeciles are known to forget to tighten the cams fully OR ( !!! ) do not know what "fully" means in this specific case.

Many newbies do NOT know!

The deal with cams of that shape is they can over-travel if the pins are not set deep enough in the nose-art's backplate.

If loose by but one rotation, then 6 o'clock back to 12 o'clock they are moving OUT of engagement.

Desired closure point should happen around 4:30 o'clock, must not be allowed to pass 6 o'clock.
 
Many newbies do NOT know!

The deal with cams of that shape is they can over-travel if the pins are not set deep enough in the nose-art's backplate.

If loose by but one rotation, then 6 o'clock back to 12 o'clock they are moving OUT of engagement.

Desired closure point should happen around 4:30 o'clock, must not be allowed to pass 6 o'clock.

Yep..............
 
My wife knits a lot, that looks relaxing [emoji4]
I blued the chuck taper, I need to redo it this weekend when I get more time because as best I could see there was little to no contact. The bluing was fairly heavy and now I wonder if because the taper is so gradual that blue wouldn’t be scraped off?? Wishful thinking?? I had sort of convinced myself that the blue was scraped thinner in lots of spots, but certainly not bare.

So then.... thinking that possibly there was no contact, I put 4 pieces of green plastigage taped 90 apart to the spindle nose, careful to make sure the tape was clear of the taper.
Edit: the plastigage was taped to the spindle nose where the cap screws hold the cams. The pieces were long enough so the chuck would force them along the taper and the spindle face. I verified after I removed the chuck that the chuck didn’t bottom out on the tape and plastigage.
I mounted the chuck... sort of. The plastigage seemed to provide enough interference that I didn’t feel comfortable fully tightening the cams, one didn’t want to leave 12 o’clock.

The plastigage squeezed on 4 places on the taper and 4 places on the spindle face. Roughly .0015 on the taper and 1-2 thou on the face, but the data is pretty useless as the cams were not full tight.

Need to regroup

Thanks for the continued interest


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the data is pretty useless as the cams were not full tight.
Got the "understanding" spot-on at that point, though. Not a relevant test atall if they are not tight.

NB: For the bluing contact check. The reverse. Pins have to be shed outright, initial assessment.

Much later, each position pin to different hole each go, locked and TIR tested will be on.

The good news is all this apparent monkey-motion will even only be PARTIALLY needed for each new item of nose-art as you add. D1 is fair stable so long as not dinged.
 
Thermite-I don't understand the NB: sentence, can you please explain differently?


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