[time-nuts] time-nuts Digest, Vol 157, Issue 11

Joseph Gwinn joegwinn at comcast.net
Mon Aug 7 18:51:32 UTC 2017 

On Mon, 07 Aug 2017 12:00:01 -0400, time-nuts-request at febo.com wrote:
> ------------------------------
> 
> Message: 2
> Date: Sun, 6 Aug 2017 15:56:33 -0500
> From: Chris Waldrup <kd4pbj at gmail.com>
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Subject: Re: [time-nuts] Thunderbolt question
> Message-ID: <EEB049F8-A72A-4A24-AED2-38646D501DD5 at gmail.com>
> Content-Type: text/plain;	charset=utf-8
> 
> Thanks everyone. This has given me a lot of things to check as I 
> further investigate over the next few evenings. I'll let you know 
> what I find. 
> 
> Chris 
> 
>> On Aug 5, 2017, at 3:07 PM, Charles Steinmetz 
>> <csteinmetz at yandex.com> wrote:
>> 
>> Arthur wrote:
>> 
>>> I’d say it would be an MMIC amp similar to this device  [Avago MGA-87563]
>> 
>> If a chip similar to the Avago part Arthur referenced is what is 
>> installed, which seems plausible, the 0.749v on the RF input (Pin 3) 
>> is a fault and is caused by an external source of voltage (3.417v) 
>> imposed on the RF output (Pin 6) through the internal feedback 
>> resistor to Pin 3, attenuated by the gate resistor.
>> 
>> Avago says this particular chip needs to have 0vDC at Pins 3 and 6, 
>> so if the connected parts would impose any DC voltage on those pins, 
>> external blocking capacitors must be used on Pins 3 and 6.  You 
>> might check to see if there are blocking caps (at least at Pin 6), 
>> and if they are good.  (Alternatively, the internal output capacitor 
>> from Pin 6 back to the output FET source may be bad.)
>> 
>> Of course, don't expect a bad external cap to be the only other 
>> problem -- if it is bad, the 6-pin amp may well be bad, as well as 
>> whatever is connected to the other side of the cap.
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
>> <Avago_MGA-87563_equiv_circ.png>
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> 
> 
> ---------------------------------
> 
> Message: 4
> Date: Mon, 7 Aug 2017 10:57:10 -0400
> From: Scott McGrath <scmcgrath at gmail.com>
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Subject: Re: [time-nuts] Machining some aluminum help!
> Message-ID: <22552004-20B8-4C3C-AA2D-4D3C4C57D53A at gmail.com>
> Content-Type: text/plain;	charset=us-ascii
> 
> I don't want to start a flame war here but I tend to take the 
> recommendations in Machinery's Handbook as the basis for process 
> decisions.    
> 
> for the last 75 years Machinery's Handbook recommend Kerosene as a 
> tapping fluid for Aluminum even for forming taps

I'm not finding this.  I'm looking at the 27th edition (2004), and on 
page 1147 they talk of tapping (by cutting) aluminum with various heavy 
oils or greases, and not kerosene.  On page 1939, on cold-forming of 
threads, they say that one should use a good lubricating oil, versus a 
cutting fluid.

Is there somewhere else I should look?

 
> Btw if anyone here has a machinists tool box that odd rectangular 
> drawer is for your copy of Machinery's Handbook
> 
> 
http://new.industrialpress.com/machinery-s-handbook-30th-edition-toolbox.html
> 
> WD40 should not be used in any machining operation  

WD-40 is largely kerosene, with a bit of oil.  It is widely used for 
machining aluminum, such a drilling with a hand drill, but not much as 
a circulating cutting fluid.

 
> it was initially created for the USAF to remove water (WATER 
> DISPLACER formula 40) from missile parts which had gotten wet and to 
> leave behind a dry lubricant to prevent corrosion and force out water 
> via capillary action
> 
> Thats why it works on seized fasteners the capillary action gets the 
> lube into the corrosion cells allowing fasteners to move
 
All true.  WD-40 is also good for softening self-stick labels that have 
become hard and brittle.

Joe Gwinn



> 
> Content by Scott
> Typos by Siri
>> On Aug 7, 2017, at 10:36 AM, Joseph Gwinn <joegwinn at comcast.net> wrote:
>> 
>>> On Sat, 29 Jul 2017 22:49:10 -0400, time-nuts-request at febo.com wrote:
>>> 
>>> ------------------------------
>>> 
>>> Message: 2
>>> Date: Sat, 29 Jul 2017 20:57:56 -0400
>>> From: Scott McGrath <scmcgrath at gmail.com>
>>> To: Discussion of precise time and frequency measurement
>>>    <time-nuts at febo.com>
>>> Subject: Re: [time-nuts] Machining some aluminum help!
>>> Message-ID: <F4DD2BEC-D51D-43B2-93F3-28A57CD6E8B4 at gmail.com>
>>> Content-Type: text/plain;    charset=us-ascii
>>> 
>>> Kerosine is a better tap lube for Aluminum as it is more persistent 
>>> and less flammable
>> 
>> NO.  Kerosene is *not* a good lubricant for _forming_ taps.
>> 
>> Kerosene (WD-40) and alcohol are good lubricants for _cutting_.
>> 
>> For _forming_, one needs something very viscous, something that 
>> lubricates at very high pressures, at the yield strength of the 
>> material being formed.
>> 
>> Joe Gwinn
>> 
>> 
>> 
>>> Content by Scott
>>> Typos by Siri
>>> 
>>>>> On Jul 29, 2017, at 6:41 PM, Joseph Gwinn <joegwinn at comcast.net> wrote:
>>>>> 
>>>>> On Sat, 29 Jul 2017 12:00:02 -0400, time-nuts-request at febo.com wrote:
>>>>> Send time-nuts mailing list submissions to
>>>>>   time-nuts at febo.com
>>>>> 
>>>>> Message: 7
>>>>> Date: Fri, 28 Jul 2017 14:11:09 -0700
>>>>> From: "Gary E. Miller" <gem at rellim.com>
>>>>> To: Discussion of precise time and frequency measurement
>>>>>   <time-nuts at febo.com>
>>>>> Subject: Re: [time-nuts] Machining some aluminum help!
>>>>> Message-ID: <20170728141109.71aad750 at spidey.rellim.com>
>>>>> Content-Type: text/plain; charset="utf-8"
>>>>> 
>>>>> Yo cdelect at juno.com!
>>>>> 
>>>>> On Fri, 28 Jul 2017 12:46:30 -0700
>>>>> <cdelect at juno.com> wrote:
>>>>> 
>>>>>> After mounting the tap in the drill
>>>>>> press and putting a dab of Crisco on the tap I was able to tap each
>>>>>> hole to a depth of 7/16" as fast as I could turn the handwheel!
>>>>> 
>>>>> 
>>>>> Cool!
>>>>> 
>>>>> I suggest you get some real cutting fluid.  The threads will be 
>>>>> smoother.
>>>> 
>>>> I second that.  What I use is a lubricant wax made by Lenox, the saw 
>>>> maker.  It's intended for metal-cutting band saws, but works just 
>>>> splendid for form taps.  There are many equivalents.
>>>> 
>>>> By the way, when drilling aluminum, use denatured alcohol as the 
>>>> cutting fluid.  This will prevent aluminum gumming up the cutting edge 
>>>> of the drill.
>>>> 
>>>> And, as others have mentioned, one does not use the same size drill for 
>>>> forming taps as for cutting taps.  The diameter accuracy required can 
>>>> only be achieved by using the correct number (versus fractional) drill 
>>>> bit size.  Do not use Chinese drill bits - steel not good enough.  US, 
>>>> Japan, Germany et al are OK.
>>>> 
>>>> Joe Gwinn
>>>> 
>>>> 
>>>>> RGDS
>>>>> GARY
>>>>> 
>> ---------------------------------------------------------------------------
>> 
>>> 
>>> End of time-nuts Digest, Vol 156, Issue 38
>>> ******************************************
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> 
> 
> ------------------------------
> 
> Message: 5
> Date: Mon, 7 Aug 2017 11:35:34 -0400
> From: Charles Steinmetz <csteinmetz at yandex.com>
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Machining some aluminum help!
> Message-ID: <598888C6.1000507 at yandex.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> Joseph wrote:
> 
>> For _forming_, one needs something very viscous, something that
>> lubricates at very high pressures, at the yield strength of the
>> material being formed.
> 
> I've had excellent results with STP oil treatment, by itself or with 
> added Tungsten disulfide.  I frequently tap under power at 20-150 rpm, 
> using Tapmatic self-reversing tapping heads.

I've heard of the STP approach - it's all high-pressure lubricant, to 
make a clanky old engine sound young long enough for the sale to go 
through.  I was once offered an old SAAB for sale by owner.  The 
giveaway was when I checked the oil with a dipstick - the oil dripping 
off the dipstick, left a long trail in the wind, like a spider trailing 
a silk line.  I passed on this find offer.

Another traditional high-pressure lubricant is Castor Oil - used when 
pressing steel things together.

Joe Gwinn


> 
> End of time-nuts Digest, Vol 157, Issue 11
> ******************************************

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