[Hammarlund] A Hammarlund Clock Motors and Rotors

[Roy Morgan]

Would be Clock Motor Replacers,

I located the clock motor from my Heath SB-620 station control.  I think it 
is the same sort as found in the Tymeter station clocks.

(Note: this is likely NOT the same motor as used in the Hammarlund 
Clocks.  See details below.)

This motor is as follows:

Markings:
Pennwood Numichron Co
Pittsburgh 8, PA

On the left side:
E15450
A2624A1
120V 60C
3.7W
1 RPM
19
L

and on the right side:

6436
B TP 192

LFF

The thing is pear shaped with two mounting tabs.
The shaft turns COUNTER clockwise as viewed from the shaft, and has a 
threaded end. (No gear or pinion.)  The threads appear to be 8-32 right 
hand thread.

The drum in the clock that indicates the seconds is plastic and threads 
onto the shaft, thus the one RPM. The drum has an extended part on the side 
that moves the minute drum once per revolution - once per minute.

At this link:
<http://www.atsclock.com/sys_files/other/7_Motors.pdf>
the illustration marked: "Style C: Pear Shaped with two mounting lugs" 
shows this case style.

At this link:
"http://www.cmfg.com/standard.htm"
the model 80-10 is closest to the motor I have, however it does not have 
the threaded shaft the Tymeter needs.

At this link:
"http://www.cmfg.com/lathem.htm"
we see the only threaded shaft motor they show, but it is clockwise rotation.


Thoughts on how to use the 80-10 motor:

1) Perhaps a short piece of a bolt can be drilled and soldered or epoxied 
to the shaft of the model 80-10.  Trouble is the Threads are just 1/8 inch 
in diameter.  Extending the shaft with a larger shaft reduced and threaded 
properly will mean mounting the motor away from the normal mounting surface 
to account for the extra shaft length. Quite doable if there is room.

2) The existing shaft might be able to be threaded. If it is hardened, that 
will not be possible.

3) The drum can be drilled for a lock screw.   The shaft could be given a 
flat by grinding.  Fracture of the drum hub is almost certain without a 
bushing. A metal bushing as found in good quality radio knobs would solve 
that problem if there is room for it.  The lock screw will need to 
be  installed at an angle to avoid having a hole in the face of the drum 
where the seconds markings are, unless a new seconds overlay can be made to 
be installed over the hole.

I have emailed the Colman Mfg. Co. ( cmfg.com ) asking for replacement 
motors and will report any answer I get.

Roy



- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
roy.morgan@nist.gov --