How hard to tighten camlocks on a lathe ?
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    Default How hard to tighten camlocks on a lathe ?

    Well, pretty much what the title says.

    I'm getting long in the tooth and I have never seen a printed instruction saying how hard to tighten camlocks on a lathe spindle. Mine is a D 1-4 is that is any help and I think we have a D 1-3 around as well.
    Lots of thanks !

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    any lathe i have used it was moderate force with the supplied key, well enough you could say somewhere around 40-60 ft / lbs certainly not 80.
    There is some leverage with the t handle.

    maybe there is a specific torque but i have never needed to find out.

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    Dont have to be very tight, no cheaters!! 40/60 lbs is more than enough .....Phil

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    This is sort of like the question of how tight should a wedge tool post lever be. In my opinion about that tight....

    As for a camlock its far more important that the spindle nose and chuck mount is clean than almost anything else. Once you indicate the chuck true take a chisel or center punch and put witness marks on the spindle and chuck mount. That way when you take it off you have a reference as to how to clock it when you put it back on.

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    My understanding is that the tightness is not what holds it in place, but the way it's designed. If it has room to move, it'll come loose, but if it's solid with no room for vibrations to take effect, it'll stay.

    I'd venture to say this is true of anything with a supplied hand tightening tool (chucks, tail-stocks, etc.) If it's in OEM condition. Hand tightened, not hand "torq'd," is what you are after. IMO most bell-mouthed chucks got that way because the material wasn't clamped over a sufficient area and the answer was to over tighten, rather than get a better bite.

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    Quote Originally Posted by M.B. Naegle View Post
    My understanding is that the tightness is not what holds it in place, but the way it's designed. If it has room to move, it'll come loose, but if it's solid with no room for vibrations to take effect, it'll stay.

    I'd venture to say this is true of anything with a supplied hand tightening tool (chucks, tail-stocks, etc.) If it's in OEM condition. Hand tightened, not hand "torq'd," is what you are after. IMO most bell-mouthed chucks got that way because the material wasn't clamped over a sufficient area and the answer was to over tighten, rather than get a better bite.
    I always tighten by hand. Turn until it touches and then just a bit more. I was told LOOOONG ago that the cams will self tighten. Maybe true as I never had a cam come lose in over 40 years. But what is baffling is the absence of any written instruction.

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    I just go twice or three times around with moderate force. Its pretty easy to tell when movement stops, and when they all hit that point they're done.

    When I say 'moderate force' consider that my factory supplied wrench has a total t-bar length of about 8".

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    I thought it was until the "V" was in between the marks with moderate hand tight? Not much more then a spark plug torque. So 30-40 foot pounds. If it is less or more that stud needs to be rotated one turn at a time until it feels correct. And it should be marked so the nose and chuck are oriented the same way each time.
    Bil lD

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    Quote Originally Posted by TrueBor View Post
    Well, pretty much what the title says.

    I'm getting long in the tooth and I have never seen a printed instruction saying how hard to tighten camlocks on a lathe spindle. Mine is a D 1-4 is that is any help and I think we have a D 1-3 around as well.
    Lots of thanks !
    D-1(x) are not "tightened" at all.

    What they are is "engaged". Not the same animal.

    Optimally at 4:30 O'Clock. Never less than 3 O'clock, never more than 6 O'clock.

    ..less than 3, the camming surfaces have not fully intertwined.

    ...past 6, they have begun moving back OUT of engagement, not further into it.

    "Tight" feeling is supplied by the mating nose tapers generating an "interference" fit.

    The camming action pulls the outer taper up the inner - ever-so-slightly larger taper... which is trying to expand the outer.

    Ending-up "almost resting on" the flat at the "upper" end of the taper provides extra support if any strong-enough force trys to cock the taper at an angle and force a crash.

    Camlock studs are meant to be adjusted so that AS that interference force on the taper comes into equilibrium, the cams in the spindle WILL be close to the 4:30 O'Clock position.

    Rest of you lot of Old Farts of all ages might want to get yer eyes checked for new reading glasses?

    OP wasn't asking how to tighten the chuck JAWS. Multiple turns and torque wrenches do not apply to what he DID ask about.

    Engaging
    a D1-(x) properly..

    "I got mine" D1-3, D1-4 .. Oh.. and the reading glasses as well..


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    Nice post - on the lines of what I was trained to do. But still : no written stuff anybody knows about. Something else : must the cams be lubed or not ? This is a weird one, I must say. The reason I asked is that I am contemplating making some pins in the future and I need to get some idea what material and what treatment. I'm no expert in either - I am into repairs and maintenance. Anyway, thank you Thermite !

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    Quote Originally Posted by TrueBor View Post
    Nice post - on the lines of what I was trained to do. But still : no written stuff anybody knows about. Something else : must the cams be lubed or not ? This is a weird one, I must say. The reason I asked is that I am contemplating making some pins in the future and I need to get some idea what material and what treatment. I'm no expert in either - I am into repairs and maintenance. Anyway, thank you Thermite !
    Not worth the side-trip to make yer own & heat-treat. They last too long for there to be much of a need.

    Pay Mac-Its prices for the best, US threaded stud.
    Shars is "good enough" for the Metric kit as is weaker by a hair off the threads being less optimal.

    The usual metric handicap applies.

    Whole Metrifuckated sytem was designed by chair-setting clerks on theory-paper, not selectively evolved off the back of hard experience in the metal as US sizes are. Surviving WINNERS of ever so many real-world pass/fail encounters.

    US sizes are not all nice, neat and logically spaced and orderly to the tiny mind of a clerk?

    Well..F**k that for a game o' sojers!

    That's because the world and the alloys they have to fasten s**t in was never nice, neat, and orderly EITHER! They HAD to cheat and DID cheat to win!

    Arrogant clerks. God must have loved them or she would never have invented looting sandalistas and their alleged "governments", metrifuckated or otherwsie.


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    Not trying to hijack this thread, but on a related note, how tight should I tighten an ER-32 collet in my mill?

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    Quote Originally Posted by steve45 View Post
    Not trying to hijack this thread, but on a related note, how tight should I tighten an ER-32 collet in my mill?
    The entire ER (and TG, and SK, and, and .. etc) families were MEANT to be tightened precisely, and with torque wrenches. Their makers publish the specs.

    "Above my pay grade" to even guess how many folk actually DO it, as whilst I have the wrenches, I just cannot be bothered ..so long as "feels about right" keeps the f**kers from spinning. NB; endmills don't go in collets. That's what side-locks are made for.

    CNC gurus preseting tooling off-machine to load toolchanger magazines for running balls to the walls where every bit of performance and please-no-pull-out for crashes has life-cycle MONEY involved are far the better source, but even so?

    Use of torque wrenches probably still a distinct minority among even CNC users, yah?

    We are a complacent, if not also lazy lot, and usually pressed for time, are we not?

    End of the day? Torque is like sex. Your tooling. Your preferences.

    Whatever don't hurt too much, break the budget, yet still puts a smile on yer face.

    The other sod can find his own comfort-level.

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    Fasteners have torque values because in a too loose situation they back out. In a too tight situation they break off. Sometimes that window can be like threading a needle.

    Lathe chuck camlocks on the other hand, I wouldn't be surprised if "too tight" was >100x the value of "too loose". Good design there with the caveat that you have to make the tapers correctly and keep them clean.
    It is a valid question, but one which likely hasn't gotten much thought because it doesn't need it.
    Upper limit is likely somewhere around the point at which you shear the square off of the drive key or split the female side. Might also be able to fail the stud thread in tension, but we're talking an awfully high force at that point over center or not. Lower limit since they are probably over center with a shallow engagement angle is probably very near zero.
    Next time someone is about to sell a lathe to the scrapper it might be fun to put a torque wrench on it and see what it'll take. Could do the same with a sprung chuck about to be turned into tin cans with a nut and small cylinder on the back end of the pull stud.

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    Quote Originally Posted by jccaclimber View Post
    Fasteners have torque values because in a too loose situation they back out. In a too tight situation they break off. Sometimes that window can be like threading a needle.

    Lathe chuck camlocks on the other hand, I wouldn't be surprised if "too tight" was >100x the value of "too loose". Good design there with the caveat that you have to make the tapers correctly and keep them clean.
    It is a valid question, but one which likely hasn't gotten much thought because it doesn't need it.
    Upper limit is likely somewhere around the point at which you shear the square off of the drive key or split the female side. Might also be able to fail the stud thread in tension, but we're talking an awfully high force at that point over center or not. Lower limit since they are probably over center with a shallow engagement angle is probably very near zero.
    Next time someone is about to sell a lathe to the scrapper it might be fun to put a torque wrench on it and see what it'll take. Could do the same with a sprung chuck about to be turned into tin cans with a nut and small cylinder on the back end of the pull stud.
    D1? Yer playin' wit' yerself. Weakest section is the wall of the stud where NOT cut away. Meant to be there, as the studs are the least cost parts and fastest to replace. Cams in the spindle last ages longer.

    Whomever patented it back in the '30's (a Pratt & Whitney genius IIRC? ) had cleverly worked it out so that one stud-anchor turn too tight, you couldn't get to 3 o'clock, one turn too lose, you were past 6 O'clock.

    When gone wishy-washy the stud cam cutout was worn otta spec and yah needed new studs.

    Ham-fist a D1 yah needed a new line of work.

    There's a coil drag spring in there to provide the friction so it don't work loose. No need to Bubba-f**k on it.

    All based on the coarser US threads. Of course.

    Metrifuckated's too-fine threads will be less obviously firm as to only ONE proper position. Why are we not surprised!



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