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Stuck Chuck (Tapered Mt.) - Now Unstuck But No Longer Smooth

cinematechnic

Cast Iron
Joined
Apr 11, 2005
Location
Walnut Creek, CA
Happy Easter fellows...

I'm hoping to again lean on the great expertise and wisdom that resides in this forum.

I've had almost all my business go away, as have many of you, and I've been dealing with the current CCP Virus situation by trying to make a batch of parts so that when business conditions improve I have some completed product in stock.

I have a Hardinge HLV-H with 4º taper nose, and a 5" 3-Jaw 30AHC chuck "Made in England". I got the chuck used and I have no idea how it was used in the past.

After turning, drilling and grooving several aluminum parts, the chuck would not come off the spindle. It was STUCK.

I'm not sure how happened, and I hope someone can suggest possible causes. Before I go any further: I ALWAYS make sure the 4º nose is clean and give it a shot of T9 or Vactra oil before mounting anything to it. And I NEVER over tighten.

I've been using this lathe for nearly 3 years and this has never happened in that time.

I have been using the method of holding one jaw near the edge with an adjustable wrench to remove the chuck. Would not budge.

I used more force than usual...Would not budge... I switched to a bigger wrench... Would not budge... I hit it with a dead blow hammer... Would not budge... Bigger dead blow hammer... Would not budge... Penetrating oil on the spindle and through the hole for the pin... Would not budge... Heated the chuck mounting plate with a torch while spinning slowly... Would not budge...

I was contemplating spending the Easter holiday pretending to take the day off all the while only being able to think about this problem.

Then I got the idea that worked: My neighbor where I have my workshop is a woodworker. I asked if he could make me some wedges. He already had some big maple shims.

I removed the pin from the back plate and carefully drove the two maple wedges in and eventually the chuck came off.

The chuck still operates but now the scroll action binds at certain points. It does not bind completely but gets much tighter at the binding point. The worst binding point seems to be at the point where the ends of the internal jaws are near the edge of the chuck.

Buying a new chuck, or even a decent used chuck is not an option right now. Need to hang on to $$ like a miser until business conditions improve.

QUESTIONS:

What could have caused the chuck mount to get stuck?

I have some suspicion that the pin (at the end of the modified set screw) was somehow a possible cause. The pin is worn and I had turned it make it near round again. But I don't have dimensions for what the size/shape of the end of that pin should be.

Was there a better method of dealing with the stuck chuck?
(I wish I had gone with the wood wedges first)

Is the chuck ruined? Or is there something I can do to repair it?

Does the binding affect accuracy?

Thanks!!!
 
way oil is going to make the chuck slip on the taper and be pulled in tighter.

I just wipe it down , perhaps with a little wd40, and snug it in place.

I have a pin spanner hole in the base of each chuck so I can easlly tap the things undone without stressing the jaws.

As to repairing your chuck, take it apart ,clean and inspect the scroll etc.remove any burrs ,its probably OK.
 
QT Billtodd:[As to repairing your chuck, take it apart ,clean and inspect the scroll etc.remove any burrs ,its probably OK.]

and might look close with your loop to see / find any bugs, bruises or stuck aluminum.
 
Thanks for the replies!

I've been thinking that some aluminum chips have have made their way into the scroll and that may be the cause of the binding. I drilled through holes in a few pieces of Al stock prior to the chuck getting stuck.

I'll take the chuck completely apart tomorrow. Last time I serviced it was in 2018. What lube would you guys recommend? Last time I used a grease from Kluber that was recommended by the makers of the Swiss scroll chucks (Maprox) for their chucks.

Thanks for the pin spanner idea Billtodd. I now have a HV-4N so I could put just the back plate on there and make a pin spanner hole. That's how I get the collet closers off.

I normally don't use Vactra on the taper, I usually use Boeshield T-9 and just give it a quick spray.

I also have a bunch of Kano Kroil and some 0W-10 racing motor oil. I've found a blend of the two works great to get sticky mechanisms (like older dial gages that are sticking) working smoothly again. Would a few drops of low viscosity oil be a good choice?
 
I'd clean the taper surfaces carefully, then examine both for signs of scuffing or fretting. If you see anything significant you might try (again, carefully) polishing it out with very fine paper or similar.

When you have the chuck apart, put the back plate on the spindle and take some indicator readings off it. If you see any signs of warpage you might take a new facing cut on it.

I'd use minimal grease during rebuild, it usually attracts chips if too much is used.
 
Your chuck should have an "England" stamp, indicating it was made by Pratt Burnerd. You can buy some authentic, but expensive PB chuck grease from Grizzly or Amazon. PBA in Kalamazoo, MI also probably sells it.

Pratt Burnerd America T23739 Chuck Lubricant | eBay

You can also get Toolmex (Bison) chuck grease for a little less money.

Toolmex TMX Chuck Lathe Grease Lubricant 16oz Tube Kitagawa South Bend Bison | eBay

I have made some of those pins. Different make chucks have different types of pin, but in all cases, I simply make the dog point fit the spindle slot with a couple thousandths clearance.

I never lubricate the spindle end, but you certainly want to clean the spindle and chuck bore.

Larry
 
The chuck still operates but now the scroll action binds at certain points. It does not bind completely but gets much tighter at the binding point. The worst binding point seems to be at the point where the ends of the internal jaws are near the edge of the chuck.
You had a wrench on ONE jaw. The jaw bears against the scroll and guide "rails" in the body. You may have raised a burr or even distorted jaw, scroll, BODY, or some combination of the above.

They are just "metal".

As to effect on accuracy? Whom, better to answer that question than he who holds physical possession of the chuck?

I cannot understand why you are ASKING remote viewers IF <<whatever>> affects the accuracy?

You should be the one TELLING US what it is ACTUALLY now doing - or failing to do.

Measure it.

If you cannot measure a problem as to accurate workholding at the sizes you USE it for? You do not HAVE a problem.. at the sizes you USE it for.

Or at least not one you can actually do much about!

:(
 
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As to effect on accuracy? Whom, better to answer that question than he who holds physical possession of the chuck?...

You should be the one TELLING US what it is ACTUALLY now doing - or failing to do.

Measure it. :(

I was asking that question from the point of view "from experience". IOW, based on my description, from your (the group's) experience, did I just screw up the chuck?

The chuck is partially apart now, and after a rare day away from the shop I will be back there today and take it apart further, before cleaning and re assembly and HOPING that it operates OK.

My plan for getting through this time depends on making a bunch of product and the hope there is still a market to sell it to once this is over. I need to have my two small machines working well and there is no money to replace any tools that get damaged.

So that was my paranoia talking. Sorry for the annoyance.
 
So that was my paranoia talking. Sorry for the annoyance.

No "annoyance" to it. It was your OWN time you were wasting. Not mine.

I'd have just chucked-up whatever it is you are trying to make, see if it was good enough, if so go Hell-hard at it.

Hardly a craftman here ain't "never" damaged a chuck. They are - hopefully - slow consumables, but eventually consumable or crashable, nonetheless.

If not? Don't "hint". Stand up and ASK!

Guys? Anybody have a chuck to get me through a rough patch?

Not one to keep score, but ISTR I've given away or traded-away at least 3 to PM members.

Some of us have "plenty", don't use the lesser ones anyway, are just as happy with sumthin' else - or even the simple pride of not OWNING a three-jaw "apprentice" chuck, lo a long lifetime .. and counting.

:D
 
Lockdown Projects

I got the chuck back together and it seems to be OK. Thanks for all the helpful posts.

Like I said I got paranoid when I realized that a replacement chuck that is worth spending the money on (6" 6-Jaw) either Buck or PBA would cost over $1550 including the correct backing plate for Hardinge taper.

If anyone knows better, please post. I will eventually want to have a 6" 6-jaw chuck.

While I had the chuck apart I did a full overhaul and reconditioning of the chuck

Clean all parts
Added a .375" hole about .400 deep for a pin spanner for future chuck removal if it gets stuck (I'm using a piece of drill rod now, it seems to be enough leverage)
Lap backing plate taper to 4º spindle nose (non-embedding lapping compound)
Lap chuck jaws to their slots
Operated chuck assembled with lapping compound on the mating parts, then disassembled and cleaned everything
Turned the index pin using the drawing provided by @JerseyJohn
Turned the bore in the chuck to enlarge it slightly to accept 40mm stock (1.575")
Put everything back together with chuck grease (Kluber Staburags NBU 4)

Results:
Smooth running through the full range
Runout of the chuck body under 0.0004"
Runout of 1" precision ground rod at 1" from jaws 0.003"

QUESTION: Should I drill some smaller holes at 180º from the .375 hole I created in the back plate to compensate for the material removal or is that too small to affect balance. I normally don't run this type of chuck above 1000 rpm, and usually well below that.
 
Runout of the chuck body under 0.0004"
Runout of 1" precision ground rod at 1" from jaws 0.003"
Seems to have turned out well. Good on yah... for being anal about it!

:D

I wouldn't tolerate ONE thou TIR at THREE inches on my El Cheapo Feurda/Gator 6-J, let alone three thou at one inch.

OTOH, it has the fine adjustable backplate mount, and was bought brand-new and "virgin", has not yet been crashed, nor even worked the least bit hard, as it is for thinwall use here ONLY.

The several 4-J (or collets), are used for most other work, the 2-J and the magnetic, still settin' "waiting" for some years already for a task as actually NEEDS either one of them.

You should buy an adjustable hook-type pin spanner - or make one during these days with spare time - rather than piss about with a stub of drill rod as can hurt you and/or wallow-out the hole.

Your "balance" effect from one hole is insignificant, even at far higher RPM than you run it.
 
"QUESTION: Should I drill some smaller holes at 180º from the .375 hole I created in the back plate to compensate for the material removal or is that too small to affect balance."

Back in the day you would tap that hole, put a setscrew in it, and stamp "OIL" alongside it....
 
"QUESTION: Should I drill some smaller holes at 180º from the .375 hole I created in the back plate to compensate for the material removal or is that too small to affect balance."

Back in the day you would tap that hole, put a setscrew in it, and stamp "OIL" alongside it....

Yazzzz.. then some LAZY bugger, next owner, would pull the setscrew and replace it with an Alemite "Zerk" fitting.

Next owner would be posting on PM.

Asking what grade of grease to use...

Whatever ELSE yah do to that hole?

Please.. don't install artificial hair around it!

You'd hafta know Machinacycsts..?

The rule is de-pill if not "natural".

:(
 
I wouldn't tolerate ONE thou TIR at THREE inches on my El Cheapo Feurda/Gator 6-J, let alone three thou at one inch.

I don't have a way of checking that "precision ground" 1" rod to see how "precision" it is. It's from McMaster and lately they have been sourcing precision steel from China and the tolerances have left something to be desired...

When I did the same test, with the same rod, on my $2500 (bought for WAY less in the good 'ol days of fleaBay) Swiss-Made 3ZF chuck mounted on a custom 5C arbor, turned on the same lathe, the results were not that much better. The 3ZF chucks are rated at 0.01mm runout (.0004").

So perhaps I'm reading a combination of the chuck runout and the rod runout. I'll try testing again with various rods to see if I can detect a pattern.

Also, I remember reading in some book about machining that indicators would read double the error, but I don't recall the cause being explained. The number I gave are the total indicator reading "TIR".
 
I don't have a way of checking that "precision ground" 1" rod to see how "precision" it is. It's from McMaster and lately they have been sourcing precision steel from China and the tolerances have left something to be desired...

When I did the same test, with the same rod, on my $2500 (bought for WAY less in the good 'ol days of fleaBay) Swiss-Made 3ZF chuck mounted on a custom 5C arbor, turned on the same lathe, the results were not that much better. The 3ZF chucks are rated at 0.01mm runout (.0004").

So perhaps I'm reading a combination of the chuck runout and the rod runout. I'll try testing again with various rods to see if I can detect a pattern.

Also, I remember reading in some book about machining that indicators would read double the error, but I don't recall the cause being explained. The number I gave are the total indicator reading "TIR".

Can't remember buying much "precision ground rod" of late. Wot I do is buy high-grade dowel pins and even better drill blanks sets - two at a go makes measuirng stuff easier 'coz yah have pairs. Cheap enough yah can take an abrasive chop saw to 'em if yah need short shapes.

OTOH, I DO have the ability to vet them. Uber mics, insane DI's, and a tiny 9" X 12" "AA" grade DoAll black granite plate.

Also two, not one, of PM member Brian Miller's superbly executed test bars, A 12 jarno for the 10EE's, a 5 MT for the Cazeneuve HBX-360-BC, and another for 5 MT, made in India that ain't half bad, actually. Given it was only about $90 US with shipping included?

Yah can chase yer own butt hairs for an age if your metrology goods aren't good enuf' for what you THINK you are measuring.

First, you have to "vet" the metrology goods THEMSELVES .. and keep notes of their shortcomings for later corrections or at least "level of confidence" common-sense expectations.

Same again, taking only one or a few readings of whatever is under investigation. Not good enough. Take "many" readings and write them down.

Either way, yah need to build a "dataset", then toss-out the outliers as .... ta da... usually "pilot error".

The same guy who has been drinking yer beer, shagging yer wife and grinnin' back atcha outta the bathrom mirror as he uses yer toothbrush being the "pilot" who makes those errors, if yah hadn't twigged to that...

:)
 
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OTOH, I DO have the ability to vet them. Uber mics, insane DI's, and a tiny 9" X 12" "AA" grade DoAll black granite plate.

I do have a decent set of metrology tools for a one-man shop, but I don't have a matched pair of V-blocks. The indicator I used to check the runout was a Compac Geneva 0.0001" reading.

Also two, not one, of PM member Brian Miller's superbly executed test bars, A 12 jarno for the 10EE's, a 5 MT for the Cazeneuve HBX-360-BC, and another for 5 MT, made in India that ain't half bad, actually. Given it was only about $90 US with shipping included?

That sound like another one of those "He don't do that anymore, you missed out" deals. I'm sure Hardinge would offer to sell me a test bar if I ask real nice but the price would probably be in the "if you have to ask" range.

IMHO, if you found a GOOD Indian supplier, you should let the members here know. If they make good stuff they deserve to make money.

Most of the tools I've seen coming out of India nowadays look like the Chinese tools did in 1990.

I WISH India could get its act together (they have the worst bureaucratic class in the world) and take the economic fight to China. Just like I wish Mexico could get corruption under control so we could have the low value stuff made there instead of China.

In both cases, the problem is endemic, self-serving and self-perpetuating. I've never spoken to an Indian or Mexican that thought there was any hope of the situation changing...

And YES I am 100% in favor of US manufacturing (and I am one, though tiny), but we need to follow the German model and make high quality stuff so that we can pay decent wages and still be competitive.
 
I do have a decent set of metrology tools for a one-man shop, but I don't have a matched pair of V-blocks. The indicator I used to check the runout was a Compac Geneva 0.0001" reading.
Compac, Tesa, Interapid, and the B&S re-branding of.. et al make decent "half tenths" indicators as well, and I have several.

The "other half" are Hamilton, Dorsey - who bought the Hamilton tooling and hired the staff when Hamilton exited - also Pratt & Whitney-branded Dorsey's.

"ABS" house here. "Anything BUT Starrett", so lots of those, plus Mitutoyo, Etalon, Mahr, B&S, B&S-Hexagon, Scherr, even Lufkin.

:)

That sound like another one of those "He don't do that anymore, you missed out" deals.
One had to contact Brian and ask. Then wait a while. He has other bizness, sorta does 'em in batches when he has enuf' ordered to justify setting up for a run. Not unusual for small/medium shops, that. Price wasn't "trivial", but I considered it a good deal.

IMHO, if you found a GOOD Indian supplier, you should let the members here know. If they make good stuff they deserve to make money.

Did so. With a link, even. But not a match for Brian's work.

Most of the tools I've seen coming out of India nowadays look like the Chinese tools did in 1990.

I WISH India could get its act together (they have the worst bureaucratic class in the world) and take the economic fight to China.
If it involves Cast Iron, I submit they ain't half bad. Rotabs and such for example. Yah - I WANT a Moore or P&W. In due course. But they won't be new.

Meanwhile a 10" made in India ELSE Taiwan and go do the work.

Just like I wish Mexico could get corruption under control so we could have the low value stuff made there instead of China.

In both cases, the problem is endemic, self-serving and self-perpetuating. I've never spoken to an Indian or Mexican that thought there was any hope of the situation changing...
Was involved in a Mexican Presidential election forever ago. There's no hope, nor ever will be.

See also Philippines.
 
Guess ya didn't win.

Our guy surely DID win.

Jose Lopez Portillo.

My part was setting up his PRI Ministerio de Prensa y Propaganda with auto-feed "Autopen" signature machines coupled with IBM "MTST" automated typewriters that solicited a short TON of contributions to his election campaign - all apparently "signed in person". Which is what Autopen's were all about.

That he was to be "anointed" rather than meaningfully "elected"..

You'd have to know "PRI"?

... wasn't the issue.

A Mexican President serves a six-year term to a standard economic pattern:

- Two years, what they steal goes to pay-back the party that put them in office.

- Two years more years, what they steal goes into his own pocket and that of his family. Buying Villas and income property, etc.

- Last two years, he has to steal enough to be able to employ a minor army of bodyguards that keep him alive in his retirement.

Mexican citizens don't actually LIKE being f**ked, y'see.

Or so explained my minder, Head of Ministerio de Prensa y Propaganda.

No surprise he was elected. Less surprise, yet, that he wasn't remembered as a very good President. Wiki has a page if yah give a damn.

But the IBM's and the Autopens worked as they were meant to do, and he raised plenty of money. Unfortunately, late in his term, their currency became worth a great deal LESS than it was worth when first he had acquired it!

Even so, he died old, and of natural causes, not from a "Mexican voting machine" AKA rusty revolver.

You'd have to know Mexico's history?

:(
 








 
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