[GreenKeys] M15 Synchronous (AC) Motor Lubrication - Ball Oilers

[Paul Birkel]

A great page, thank you.  Since I don’t have a grease gun the KS-7471 alternatives aren’t going to work for me – lacking experience/observations from others regarding ball oilers it seems to be that the “depress-and-drip” method is my logical choice here for applying a lubricant.

 

Given that this is a “heavy-duty” motor, a surrogate for OE 10 engine oil seems like a good choice, although there are no high temperatures around here warranting an SAE 10 (which I interpret to mean “10W-10”).  Hence a SAE 5W-20 synthetic oil seems reasonable to me, and has been mentioned in earlier GK threads (example: http://mailman.qth.net/pipermail/greenkeys/2018-May/043091.html; also earlier: http://www.qth.net/pipermail/greenkeys/2011-August/020439.html).  But I could certainly be wrong, hence my seeking practical experience for the M15 :->.

 

For the gearing where there are centrifugal forces involved I was thinking of using the red-n-tacky grease that has previously been recommended.

 

For sliding surfaces (e.g., rails) I was thinking of using white lithium grease.

 

From: Daniel Jones [mailto:djones at k6yic.com] 
Sent: Friday, January 29, 2021 11:16 AM
To: Paul Birkel
Cc: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] M15 Synchronous (AC) Motor Lubrication - Ball Oilers

 

I usually refer to this page.  It’s based on the scientific properties of the lubricants and gives you current alternatives based on those properties.  

 

http://homepage.cs.uiowa.edu/~jones/pdp8/UI-8/ks7470oil.shtml

 

Daniel

K6YIC 

http://K6YIC.com





On Jan 29, 2021, at 06:42, Paul Birkel <pbirkel at gmail.com> wrote:

All;

 

The motor on my M15 uses the “ball oiler” style of lubrication ports.  Technically they seem to be “70771 FITTING, PRESSURE”.

 

Should I just depress them with an appropriately tipped tool and then try to drip a few drops of either light machine oil or SAE 5W synthetic motor oil (that I’ve seen recommended here in the past) around the depressed ball?

 

I realize (from long ago mechanics shop) that there must be a special grease gun whose nozzle is pressed over these ports to inject grease, but I certainly don’t have one.  The armature appears to be free turning (haven’t yet applied power) so it’s not clear that I actually _need_ to lubricate the motor at the moment.  Still, one wonders!

 

In TM11-2215 (tm11-2215-teletypewriter-tt5-model-15-20pct-of600dpi-main.pdf) Section II starting on page 69 covers the topic of lubrication.  At the bottom of page 71 in the table it states “Apply grease with gun or 4 or 5 drops in each.” with lubricant “KS-7471 or KS-7470”.  The former is a grease and the latter is “Oil lubricating, Teletype Part No. 88970.*” with the footnote indicating that at “high temperatures” SAE 10 engine oil may be substituted.

 

Is KS-7470 (Teletype Part No. 88970) substitutable by light machine (e.g., sewing machine) oil?  Unless either KS-7471 grease or OE 10 engine oil is specified, KS-7470 seems to be the go-to lubricant for the M15.  I’m thinking that light machine oil is appropriate in this application.

 

What method are folks using lubricate motors equipped with this style of lubrication port?  What lubricant?

 

Thank you for your advice,

paul

 

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