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Chuck size verses Spindle / Bearing wear

Jersey John

Stainless
Joined
May 29, 2015
Location
Beccles / Suffolk, United Kingdom
Hi Folks

I'm sure when a machine manufacturer designs a lathe headstock many factors are taken into account like construction of the main spindle and it's bearings with a matched size and weight of chuck ... and obviously swing over bed clearance etc etc.

I've re-acquired a HLV-H and Hardinge's main "Standard" chucks (both 3 and 4 jaw) are 5" (125mm) diameter ... but I'd like to make my main "In use" chuck a 6" (Actually 160mm here in Europe) ...

Will I "really" be producing extra long term stress to the bearings and spindle. The machine is in great condition for it's age and it's never going to see daily industrial use.

I'm also aware of the fact that the larger the chuck diameter the lower it's maximum RPM and in the case of the 6" (160mm) it's maximum rating is still slightly higher than the HLV-H's maximum RPM

Comments welcomed before I splash out on a "larger" chuck and matching machined backplate.

Thanks in anticipation

John :typing:
 
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Spindles are usually designed for carrying quite high loads and even a fairly large chuck shouldn't be an issue. A 6" is nothing. That said, I often see pictures of clapped out old Southbends with way oversize chucks hanging out far beyond the bearings. IMO, that's a recipe for chatter and probably not as safe as a smaller chuck in daily use, when you don't need the size.

(FWIW, even my little lightweight Logan front bearing is rated at over 5000 lbs static load.)
 
Will I "really" be producing extra long term stress to the bearings and spindle. The machine is in great condition for it's age and it's never going to see daily industrial use.

I have a Hardinge-branded 6-2B 2-Jaw of about 6 1/4" @ 26.2 Avoir with tall steel 'soft' jaws mounted. The Walker magnetic is 27.6 Avoir.

Mass of the chuck - so long as motating on-center - matters very little compared to how much off-axis leverage a workpiece can put against it if you crash it 'just so'.

If you are going to 'experience' that, a 5" makes near-as-dammit as good a pry-bar as a 6".

But you won't let that happen....

Jaw hang-out if/as/when you actually USE the extreme of diameter, would be a greater concern to me.

"In theory" I can mount a 10" on the 10EE (12.5 actual swing). In practice, even the 8" is reserved for 'special needs' use. Only.

No plans to add a 10". That wants a whole 'nuther lathe, actually.


Bill
 
Working from memory and without pulling out the files, I will point out that 5 inch chucks were listed in the DV59 catalog, but 6 inch chucks were in the HLV-H catalog. Personally, I use 6 inch PBI steel body Setrite 3-jaw and 6-jaw chucks on my 1940's TR59 and flat belt drive BB 59. Both were meant to have 5 inch chucks when new.

Larry
 
Hi Conrad

I did anticipate that going from 5" to 6" should not be a "major" issue but as the HLV-H gets older and spares certainly in the UK/Europe are becoming harder to get. Also the fact that I have reason to believe that the "main" Hardinge refurbish centre will not be around too much longer I don't want to give my "lady" extra stress!

Your comments are greatly welcomed.

Kind regards

John :typing:
 
Jaw hang-out if/as/when you actually USE the extreme of diameter, would be a greater concern to me.

No plans to add a 10". That wants a whole 'nuther lathe, actually.


Bill

Hi Bill ... yep considered the jaw hang-out and another inch is not going to make a difference - good point though!

As for the 10" bit ... I wondered how long it would be before someone suggested a "BIGGER" lathe :drool5:

Had I been younger ... I may have considered that too and in one of my past workshop's I had three but there was only one favourite ;)

Thanks very much for your input ... most welcome!

John :cheers:
 
Hi Larry ...

Thanks for the comments too!

I've just had an "Amazingly good" price from PB(UK) for a 6" (160mm) Setrite 3 Jaw but the matching backplate price is pricey as it's got to come from PB(USA) ...

Makes you wonder why you'd ever want to buy "Second-hand" or off eBay as the price difference is minimal

All the best

John :typing:
 
When I bought a new HLV-EM in the 90's, I specified a collet set and 3 and 4 jaw chucks. The chucks were both 6 inch. I have a nice new 6 1/2 inch 6 jaw I would like to use, but afraid of the long overhang. Chuck is quite thick.
 
Hi Davis ...

Thanks for the comments on the 6" 3 and 4 Jaws.

So I guess you're actually having the "Same" concerns about your 6 1/2" 6 Jaw as I'm asking ???

If you purchased the new machine from Hardinge did they not comment on your purchase request?

John :typing:
 
When I bought a new HLV-EM in the 90's, I specified a collet set and 3 and 4 jaw chucks. The chucks were both 6 inch. I have a nice new 6 1/2 inch 6 jaw I would like to use, but afraid of the long overhang. Chuck is quite thick.

C'mon lads.... anyone here as never expects to put a WORKPIECE in these bare-nekked chucks we are fretting over?

Far more important, the difference from one to another of those can be. Ga-ron-tee I'm paying a good deal more attention to how well I can clamp, rather that what the chuck weighs.


Bill
 
Far more important, the difference from one to another of those can be. Ga-ron-tee I'm paying a good deal more attention to how well I can clamp, rather that what the chuck weighs.

Bill

Bill just in case something is being lost in translation as it crosses the Atlantic ... by "Clamping" are you talking "Workpiece" in Jaws or "Chuck to Spindle"?

IMHO ... both matter

John
 
Bill just in case something is being lost in translation as it crosses the Atlantic ... by "Clamping" are you talking "Workpiece" in Jaws or "Chuck to Spindle"?

IMHO ... both matter

John

Chuck to work.

'Usually' one tears the work OUT of the chuck before stress reaches the point that it could bend the spindle or even Brinell the bearings. Chuck may be trashed - sprung t-rails in the body. Or not. Spindle usually survives.

Lathe designers have had a lot of years and tears back of them 'in combat' to work their design choices into that sort of pragmatic balance point.

Mind - the other matters, too, but only a few of the mounts present much chance of getting it wrong.

Ever on one's mind with a thee-pin-only D1 nose, where the studs must be 'tuned' such that the camlocks tighten-up at the wanted 'O'clock' position, and on the whole lot, not just a few. D1-3 in my case.

OTOH .. D1 is why it is practical to have 'many' chucks.

Fred-Hardinge taper & key may be faster yet. I've never had to change one.

Every Hardinge I ever had my mitts on was running collet work, and in take-no-prisoners volume production.

For me, NOW, it is handier to have some 4-J with the jaws already reversed, swap chucks, rather than to have to unbolt 2-pc jaws or crank the solid ones clear out and turn them around.

My 6-Jaw has 2-piece, and no 'mirror image twin'. Yet. But .. I expect to seldom work rings or tubing. Even were I to do, ID or OD clamping is much the same. Less likely to have need to rotate them. Two-piece jaw choice was really more so I could use bespoke top-jaws for more challenging holding needs.

Ditto the 2-J and 2-piece jaws.

The Walker magnetic is more specialized yet. A potential problem-solver that I hope to not HAVE TO use.


Bill
 
Thanks for making the clamping clearer Bill ...

Quote "Ever on one's mind with a D1 nose, where the studs must be 'tuned' such that the camlocks tighten-up at the wanted 'O'clock' position, and on the whole lot, not just a few. D1-3 in my case"

Another very interesting point and much welcomed! ... something to REALLY think about on my Boxford 280TR (D1-3) when I'm running it at 3000 RPM :eek:

John :typing:
 
Thanks for making the clamping clearer Bill ...

Quote "Ever on one's mind with a D1 nose, where the studs must be 'tuned' such that the camlocks tighten-up at the wanted 'O'clock' position, and on the whole lot, not just a few. D1-3 in my case"

Another very interesting point and much welcomed! ... something to REALLY think about on my Boxford 280TR (D1-3) when I'm running it at 3000 RPM :eek:

John :typing:

Y' know... D1 has a damned good track record.... and yet... I look at how MUCH of each stud is cut-away... visualize the tiny cross-section that leaves, 'understand' - theoretically - that the taper and face are meant to take the loads...

And yet...deep-down just cannot quite bring meself to TRUST the buggers as much as a long 'L' nose on a fifty-inch, fifty horsepower machine hauling a locomotive axle to-be against 300+ lbs of direct-on-the-cross 4-way with 3/4" Cobalt blanks shimmed into its 2" slots.

In time, I may get there... if only 'coz I don't ever again expect to have to Doo that. Certainly not for 'Union Scale' of $3.34/hr + shift-differential, anyway!

:)

Bill

PS: I do envy TRboatworks the D1-FOUR spindle on his Hendey T&G. Same pin count. Larger taper. Larger pins. And even though he has less swing as well.

Just seems more 'right' than the D1-3 on the 10EE.
 
Y' know... D1 has a damned good track record.... and yet... I look at how MUCH of each stud is cut-away... visualize the tiny cross-section that leaves, 'understand' - theoretically - that the taper and face are meant to take the loads...

:)

Bill

Hmmmm ... So where does this chuck security conversation end??

My HLV-H has the 4° Taper nose and just ONE tiny pin is holding a "Huge" lump of iron in place, to say nothing of what's in the jaws too!

Not sure I'll sleep tonight :sleepy:

John
 
Hmmmm ... So where does this chuck security conversation end??

My HLV-H has the 4° Taper nose and just ONE tiny pin is holding a "Huge" lump of iron in place, to say nothing of what's in the jaws too!

Not sure I'll sleep tonight :sleepy:

John

'Anecdotal evidence' has it that Fred Hardinge tried HARD to 'sell' that concept to other makers. Sure bragged on it enough.

It is strong, less-costly to make than first appears, and has proven dead-nuts-accurate and rock-reliable.

Just didn't get the take-up he had wanted. Didn't stop Hardinge for long. They just went and sold more lathes than most others. So there.

Be grateful it isn't one of lebenty-three different bore, thread-count, and final-shoulder 'designs' that plague even the under 14" market alone. Some are also mildly tapered, to boot. Cue 'Cerrocast' just to figure out whatcha GOT.

Bill

PS: The Hardinge THREADED nose? 'In theory'.. I could mount the 2-Jaw on the threaded-closer adapter for the reg'lar and 'extra deep' Hardinge 5C step-chucks I have been accumulating and not alter it to a D1-3 back.

In practice'? That WOULD be an obscene amount of hang-out for a heavier-than-average-anyway chuck.

Not happening. Most especially not on a 10EE with a max of 20" of daylight, c-to-c. Horizontal mills exist that could 'turn' longer stock, even as 'Tee' lathes...

Bill
 
I have had a 12" on my 16" SB for about 20 years with no apparent ill effects.

Different set of operating parameters, I suspect.

I bid and 'won' on several 4-Jaw's off the 'bay that had been on SB tens from the backplates they had on 'em. Marked as one or some combination of Cushman-Skinner-Horton or Union.

Wear aside, all save one Cushman proved too light and too low in max RPM for serious use on a 10EE.

They've been asided for DH and fixturing use, whilst gradually being replaced with brand-new Japanese and even Chinese goods (Gator/Fuerda). Bison went to the wall a while back, was reorganized, fell off my radar due to some reports of inconsistent QC. And/or 'offshoring'. Steel-body / high-RPM Bison are pricey when one DOES find 'em.

In 6" or so, Schunk no longer even lists a MANUAL 4-jaw independent amongst their pricey 'Rota Classic' line. Nor Roehm. Nor ToS. Nor the Swedes.

Down to Taiwan or PRC now for NEW goods under 8 or 10 inches. Even the Japanese 4-J chuck was a forgotten NOS shelf-queen.

Ever' body has gone over to making power chucks for CNC, ELSE BIG 'Oil Country' size manuals.

Where the money is, IOW.

Whether you mount it right away or no... a GOOD 6" 4-J 'manual' has become an investment.

Bill
 








 
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