Re: [CAD_CAM_EDM_DRO] Re: Stuck collet

Guys, There is no standard way to lubricate bolts. Each is specified by
the manufacturer. I worked at an auto plant till a couple of years ago and
those bolts were all unlubricated. In fact they were specified for a
particular torque for only the first tightening.

If they had to be disassembled for any reason after their torquing, they
were assumed to be stretched the proper amount and within their strength
specs. To avoid exceeding their tension specs if they needed to be
disassembled, they were discarded and new bolts (including studs) were used
so they were not stretched a second time. Of course, the buyer doesn't do
this when he must disassemble and reassemble.

At 08:02 AM 5/8/01 -0400, you wrote:

>Ballendo: Where do you come up with this stuff? I have been building

engines for about 35 years. Automobile engines both racing and

>street engines. Domestic and exotic foreign

(Ferrari,Maserati,Jaguar.Alfa,Porsche etc.). Torque ratings are specified
with lubricant

>for uniformity. Some bolt companies even supply the proper lubricant for

their product. A stud set will come with a tube of

>lubricant. I don't know what kind of engines that you are referring to

,but it is general practice to lubricate fasteners that

>require critical torque. Chromoly fasteners generally require a

molydisulfide based lubricant to prevent galling. Titanium is also

>prone to galling. You may have encountered a situation that called for no

lube but please don't call that a general practice because

>it ISN'T.
>
>ballendo@... wrote:
>
>> Buck,
>>
>> You can use a piano tuners "trick" with the long wrench. Hold it
>> loosely in the hand and apply pressure with only one or two fingers.
>> Use your weaker fingers and you won't be able to apply as much force.
>> Also adjust your hand position on the wrench. (There's no reason to
>> use/make a short wrench if you are only applying force near
>> the 'turning' point)
>> In fact, you can probably do a better job of lightly closing the
>> collet , with the longer wrench! (long wrench, LIGHT force EQUALS
>> short wrench, heavy force.)
>>
>> The spindle should not be scoring the collet! I have heard that the
>> taig collets are not always deburred well (don't want to single out
>> Taig, this is true of MANY tools purchased nowadays)
>> Have you checked the collets to see if THEY are smoothly finished and
>> deburred. Break any sharp corners, and have an experienced machinist
>> have a look, if you are new to this stuff. (It might even make for a
>> good friendship, if you remember he is probably busy, and show
>> respect for his time.)
>>
>> You asked about "migrating" lubrication:
>>
>> The lubrication you put on the OUTSIDE of the collet/inside of the
>> spindle/ threads of the nut does NOT often stay there! It moves, due
>> to vibration, the action of your fingers, or while you think you
>> are "cleaning" the assembly or parts...
>>
>> Silicone is especially BAD, and I was surprised to hear Jan R (Troll)
>> recommending it!
>>
>> Once it gets to the inside of the collet, tools start to slip...
>> So you tighten down harder to compensate... Cycle continues, and it's
>> not a good thing!
>>
>> Lubing the threads of the nut will also allow you to turn the nut
>> more easily, and therefore achieve more than the designed/desired
>> holding force. Again, NOT a good thing! (This is the same as re-
>> building an engine in an automobile or aircraft. We are warned NOT to
>> lube the studs or nuts, because the torque values will be incorrect.)
>>
>> Nearly every machine tool manufacturer WILL request that you CLEAN
>> the spindle bore, and collet surface(s)(at every tool change), but
>> will NOT recommend lubrication. Some old timers do use "hair oil"
>> (run your fingers through your hair, then on the threads), but you
>> can gather that this is a minimal application of oil, hopefully :-)
>>
>> Hope this helps.
>>
>> Ballendo
>>
>> --- In CAD_CAM_EDM_DRO@y..., yahoo@a... wrote:
>> > Hello Ballendo,
>> >
>> > Interesting opinion you have.
>> <snip>
>> > I should probably mill a 1/8 thick inch, steel stubby wrench
>>
>> > Next, the spindle scores the collet, since the collet is such a
>> > sharp angle.
>>
>> > Last can you explain the lubrication problem? And what does this
>> mean
>> > ... "lube "migrates" to the tool holding surface"?
>> >
>> > Thanks,
>> > Buck
>>