[R-390] The R-390 gear train issue

[rbethman]

> On Mar 3, 2014, at 10:01 PM, Chris Farley<kc9ieq at yahoo.com>  wrote:
>
>> I was looking through the drawings to see how that shaft is supposed to be pressed/crimped into place.  It appears there may be a drawing missing from the set (SM-D-178900 missing, as referenced to on SM-B-178901), but here is info gleamed from drawings of the shaft, the RF gear train assembly front plate, and the gear train assembly:
>>
>> The pressed-in portion of the shaft is .219" +.001" -.000" by .040" deep.  That end also has a hole drilled into it, which strangely is shown without specs, aside from being 1/4" deep and tapped at 8-32.
>>
>> The hole in that front plate is complicated.  .2187" +.0005" -.0000" hole.  Countersunk at 82° ±3° to .343" on the front, and countersunk at 82° ±3° to .248" on the rear.
>>
>> Now I'm no machinist, but that sure seems like it must be a temporary "hold it in place" plan given the approx .0001" press-fitand overlapping tolerances, and then probably flared out from the rear for a more solid fit.
>> Question is, why does the shaft drawing show the rear hole to be threaded??  Is there actually the possibility of using a screw to hold that shaft in place?  One is not shown on any of the drawings I have seen thus far.
>> BUT if it IS indeed threaded and they aren't messed up from whatever pressing or staking took place, or the ID is such that you COULD drill/tap it, sticking a truss head screw (or a screw with a <shudder> FLAT WASHER) in there would seemingly be a pretty easy fix, assuming there is clearance behind the plate.
>>
>> ????
>>
>> Regards,
>> Chris


Chris,

The 82 degree of countersink IS a standard for said application and 
falls into what you can find easily at either one of the Home 
Improvement stores.  They will have them in packages.

TIP #1 - If you go there, write the specific description on paper and 
take it along with you.

TIP #2 - In lieu of purchasing a package that would cost a bit more, and 
leave you with extra ones lying around, look for the SAE/METRIC 
drawers.  They are in the hardware dept.

This allows you to buy only the number that YOU decide.  You have to 
make the decision whether the package of some number like either ten or 
twelve is appropriate, or to go for buying smaller numbers.

My specific experience has been going to Lowe's.

TIP # 3 - Do NOT go with the "staking"!  The single screw of the correct 
size will do.

_To resolve the loosening possibility.  Do as I posted regarding the 
Blue Loctite.

_Just a little dab will do.  A HobbyTown would most likely carry the 
smallest size and better fit the wallet.

The larger sizes are at automotive parts emporiums.  The difference is 
VERY dramatic!  The larger containers *will* be at least 3 times more in 
cost.  At least that, as I haven't bought one of these in close to 10 
years now.  I expect this has also gone up in price, as well as all else 
has.

I "husband" these things with great care.  I always have to ensure that 
I put them away as the XYL may indeed throw out what I wish to keep.  I 
won't go into this in any detail.  It is very simple. She has no 
inclination for things mechanical, electrical, electronic, and the 
digital realm.

I was called home from work when "she" decided to put up a new ceiling 
fan all by herself.

Oh dear, she was doing it the way that I do.  I leave the circuit live.  
I've been taught well, and I always either tape the lines, or place wire 
nuts on them during this process.

She had no idea or comprehension in this regard.  She shorted things out 
and popped the breaker.

I came home and dealt with finishing the task.  In this entire process I 
failed to notice one single black conductor that was tuck up inside the 
4 x 4 ceiling box.  I had had one fan installed there previously.  This 
one conductor came back to haunt me for weeks.  I had lost the feed to 
the adjacent bedroom.

I had to take down the new fan, after much tracing and testing, to 
finally figure out that this single conductor was NOT connected any longer.

The reworking of the new fan included finding the errant conductor and 
placing it back where it *had* been, and using the proper size wire nut.

I am well aware of this series of issues.  We have come to an 
agreement.  NO more electrical for her!

That falls into my realm of household "Honey-Dos".

To all besides Chris:  Yes I indeed do have the NEC book on the shelf as 
published by the NFPA!  I am no fool, I know how memory is.  I refer to 
it as I need to ensuring that the proper conductors are being sized 
correctly and installed correctly.

The one I have is NOT current.  I have dealt with GFCI issues.  I have 
discovered that the NEW hair dryers now have one as part and parcel to 
the plug.

I will openly state:  These items, GFCIs, do NOT play well in series!  
Experience has demonstrated this, and a different list we held this 
topic for discussion.  My experience was validated.  I do not take such 
lightly.

She plugs it into the very close bedroom receptacle now.  This still 
provides proper protection since the device being used has the built-in one.

This is simply extra info for all!

Back to Chris again. _Use the __Blue Loctite!_  It will serve well.  It 
doesn't really take a lot, extra will NOT hurt!  Just wipe any excess 
away when doing this fix!

This should resolve your problem.

Regards,
Bob Bethman
N0DGN