# Erector set part number P58 motor restoration



## BGHansen (Dec 25, 2018)

Another Erector set part restoration string.  First the history lesson . . .  Gilbert introduced the Erector set in 1913.  As the story goes, he saw how riders on the train from New Haven, CT to New York were fascinated by the electrification towers going up, folks commented about the daily progress of the build.  Voila, why not make a child’s building toy that does the same thing?!?  They numbered the sets to designate the size, bigger the number, the more parts included in the set.  For some unknown reason, the No. 4 set was always the smallest (from 1913 – 1947) to include an electric motor.

pieces that make up the P58 motor



As an aside, A.C. Gilbert had a well-deserved reputation for not letting the truth stand in the way of a good story . . .  Another not as widely published account is the Erector set was a copy of the popular Meccano sets developed by Frank Hornby in England in 1897.  Gilbert and John Petrie started the Mysto Manufacturing Company in 1909 and manufactured magic tricks.  Gilbert travelled to Toronto to a number of department stores showing off magic tricks and purchases a Meccano set.  He was aware of potential patent infringements so styled the girders with a trussed look instead of Meccano’s simple strip with evenly spaced holes.  Meccano did sue Gilbert but lost the case in court as the judge ruled that a toy with parts that can be assembled into other assemblies was not patentable.

The 1913 Erector set had a “build it yourself” science kit motor.  These are few and far between with maybe 10 examples known to exist.  Last one I’m aware of on eBay went for $3500.  The motor was replaced in 1914 with part No. P51 which was a preassembled motor.  Then in 1915, the P51 was dropped for the P58 motor.  This AC/DC motor was in sets from 1915 – 1947.

Whew, that’s over . . .  I’ve accumulated a stockpile of motors and parts and restore 2 or 3 each winter in our house as my shop is largely unheated.  I have a nickel-plating tank from Caswell Plating, strip the nickel parts and plate them.  I’ve picked up a few rolls of cloth covered enameled magnet wire for rewinding the armatures and field windings when needed.  Purchased carbon brushes and springs from some place on line.  Insulating disks at the terminal screws are punched in my shop.  Brush holders and field winding bushings/spacers are made from brass tubing cut to length.  The knurled nuts for tying wires to the motor are lathe turned in my shop.

one of my restored motors











One part I hadn’t “mass produced” was the commutator for the motor.  It has 3 brass contacts held on either end with a pair of fiber disks.  A hole through the center fits on the armature shaft which has a straight knurled area for retention.  Lots of these motors show up with the commutators either severely worn, or the weak fiber disks holding the contacts in place broken.

I’ve made a few commutators before by stamping out the fiber disks, screwed the blank to an arbor mounted on a rotary table and made the (laboriously) radii cuts on the mill.  I have a CNC Bridgeport now, so did the math and wrote a routine to make the cuts.

The disks are ~0.460” in diameter (see a POTD for making the punch/die).  The OD of the commutator is 5/16”, 0.300” between the two insulated disks.  I started by making a disk holding fixture for the mill.  Gilbert used two different sized motor shafts through the years:  1/8” and 5/32” diameter.  Clamp screws are a #5 and #8.  The fixture was made from a block of aluminum.  Spot drilled, tap drilled and tapped 5-40 and 8-32 holes.  Didn’t have a spiral tap for the 5-40, so tapped that with a convention wrench.  Power tapped the 8-32, still a little nervous about not backing the tap off, but with the spiral ones the chips are thrown up like a drill, so not critical to break the chips.





Punched a bunch of 0.460” fiber disks on the Roper Whitney punch press, then knocked in 1/8” and 5/32” holes for the two sizes of commutators.




The CNC routine runs quickly though my mill only has X and Y.  So I dwell to advance and retract the spindle.  I snapped off a couple of 1/16” end mills from too deep of a cut as I used the quill lever for Z.  Got smarter and used the knee adjustment for the balance of the job.








I made the brass contact in the past from brass tubing.  That required mill and slitting saw work to notch the ends for mounting in the fiber disks.  Frankly, it was pretty tedious, so decided to try making the blanks in the flat state, and mash them in a die set to put the curve on them.




Started with a slightly over 1 ¼” diameter piece of mystery steel.  Faced and turned to slightly under 1.25”.  This would be the base for the lower die which would drop into the die holder of the RW punch press.




Band sawed the round, then back to the lathe to face.  Used a spotting drill to cut a “V” groove down the middle of the base.






Next was an arbor with an OD of 5/16” to form the brass contacts over.  Chucked up a piece of 3/8” CRS and turned the middle area to 5/16”.  The width is about 0.030” over the length of the curved portion of the contacts.  Parted off on the lathe and headed to the weld bench.






TIG welded the die spool to the 1 ¼” diameter base.  Then moved to the mill.  Trammed in the die surface with a DTI so the surface was parallel to the X-axis.  Then cut a couple of notches in the ends of the lower die.  The brass contacts have a rounded surface with areas that drop into the fiber disks.  A narrow tab protrudes through the ends of the fiber disks which is bent over to hold the commutator together.  The two tabs will drop in the notches in the lower die to orient/hold the contact blank (later photos show what’s going on).








Next was the upper die.  Cut off a length of ½” drill rod, then faced and chamfered on the lathe.




Mounted the die in a square collet block and flatted either end to about 0.020” narrower than the distance between the larger diameter areas on the lower die.




Then milled in a 5/16” diameter curve on the end of the upper die.  Flipped the ½” round and milled in a couple of anti-rotation notches for securing the upper die in an adapter used in the punch press.






Mounted and aligned the dies in the Roper Whitney #218 punch press.  In use, the brass contact sets on the lower die and is mashed with the upper.  The brass is pretty soft so I didn’t harden the dies.






The prototype formed really nicely, so time to make a bunch of contacts.  I did the layout work with 5 dial calipers set to specific dimensions and scribed the surface of the brass.  Did the cutting with a notching tool.  Then set the brass blanks in the lower die and mashed down with the upper.








Hit the photo limit of 30, so the rest is on the next message.

Thanks for looking,

Bruce


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## BGHansen (Dec 25, 2018)

bunch of contacts



For assembly, I made a holding tool out of a piece of CRS.  Didn’t photograph it, but turned the surface down to the ID of the commutator contacts with a 1/8” and 5/32” pin left on the ends.  One tool for both sized armature shafts.  Slip a fiber disk on the tool, set a contact in place, slide it home and bend the tab over on the end.  Repeat twice, remove from the tool and set the opposite side disk in place.  Bend those tabs over, set a steel round on top and give a light tab with a hammer to bend the tabs down tightly.  Oh, one end has longer tabs that the other for soldering the motor rotor wires in place.














Looks like I’ll be stripping and fixing a few motors this winter.

Thanks for looking,

Bruce


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## mikey (Dec 25, 2018)

Awesome write up, Bruce! I loved your attention to detail and inventiveness in creating the brass contacts. Thanks for sharing.


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## john.oliver35 (Dec 25, 2018)

Thank you for posting Bruce.  Your work is very authentic!


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## cathead (Dec 26, 2018)

Looks like you found your niche!  Nice work I must say, Bruce.


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## cathead (Dec 26, 2018)

Bruce, 

Your post inspired me to take a look at an old electric motor called an "Ajax".  It's about the same size
as your erector set motors and has a three contact commutator similar to what you are working with.  
Is this part of an Erector Set or possibly something older?  The frame is cast iron.  I ran it a couple years ago and
it runs on two D dry cells quite nicely.   The output shaft looks to be about 1/8 inch or so...


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## BGHansen (Dec 26, 2018)

cathead said:


> Bruce,
> 
> Your post inspired me to take a look at an old electric motor called an "Ajax".  It's about the same size
> as your erector set motors and has a three contact commutator similar to what you are working with.
> ...


Cathead,

I've seen them on eBay.  Knapp was another company who made toy electric motors at the time.  Here are a few YouTube links to your motor.

Best regards, Bruce














https://picclick.com/Antique-Electric-Motor -AJAX-1910-Rare-283083404055.html
https://www.worthpoint.com/worthopedia/antique-ajax-electric-motor-toy-steam-533184774
https://www.antiquesnavigator.com/d...re-ajax-electric-motor-engine-perfect-nr.html


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## cathead (Dec 26, 2018)

BGHansen said:


> Cathead,
> 
> I've seen them on eBay.  Knapp was another company who made toy electric motors at the time.  Here are a few YouTube links to your motor.
> 
> ...


Bruce,

Thanks for taking the time to post the You Tube links.  I watched all three videos.  I hadn't given the old motor much thought
as it sat for years on the shelf collecting dust.


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## C-Bag (Dec 27, 2018)

Facinating stuff Bruce. Is there any pic's of the old factory? It does make you wonder how did they make those parts like the special fiber washers? It would seem that had to be fairly expensive to make that motor because of all the small parts.  But I guess with the right fixture and machine it was possible. 

The husband of my wife's best friend who lives on the east coast got together in October. We only see them once in a blue moon. We got to talking and it turned out his dad had a stamping business from the 40's till the late 60's and he told me about working in his dad's shop. Talk about a lost art. I'm hoping next time I see him he can find some pictures. He said when they closed because the world had changed and his brother couldn't keep it going they sold all the machinery for scrap. Some of the machines were 12' square and weighed tons.


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