Just picked up a 4-40 tap from the local hardware supply.
Looks like good quality made by Vermont American:

http://www.vermontamerican.com/Products

I have a bunch of those also:

http://www.vermontamerican.com/Products/productdetail.html?CID=4086


VA's quality is so much better than it was 30-40 years ago.

 

As promised - a small sample of supplies for technical credo, or " bragging rights " ...

The large object needless to say is a pin-vice... really the only tool I will recommend for taps this tiny, to give enough tactile torque control for the job.

These taps were originally obtained through the Camera repair school, circa 1976 - I don't know if the Yamawa brand is still available.
Matching dies for these, are really hard to find, but I imagine are available through something like a jewelers, or a watchmaker supply house...

P.S. I googled ' yamawa tools ' they are still there, and the Alibaba websit lists them as both Japan, and China Mainland... FWIW

 

As promised - a small sample of supplies for technical credo, or " bragging rights " ...

The large object needless to say is a pin-vice... really the only tool I will recommend for taps this tiny, to give enough tactile torque control for the job.

These taps were originally obtained through the Camera repair school, circa 1976 - I don't know if the Yamawa brand is still available.
Matching dies for these, are really hard to find, but I imagine are available through something like a jewelers, or a watchmaker supply house...

P.S. I googled ' yamawa tools ' they are still there, and the Alibaba websit lists them as both Japan, and China Mainland... FWIW

I have the same tap holder (small cylinder with collets on each end) on the lower right of the photo. I was just looking at it last week and I couldn't remember what it was for - it wasn't with my micro-taps. I haven't used it in 20 years to tap a hole. Thanks for the extra effort of including a photo, PackratKing. Your timing was perfect.

 

Meandering back to the motor matter, if anyone still cares, and though I think seals should be a bigger concern, take a look at Mabuchi:

http://www.mabuchi-motor.co.jp/en_US/product/p_0300.html

http://www.skycraftsurplus.com/smallflathobbymotor6-24vdc.aspx?gclid=CND6uKPfiLsCFQh1QgodS2cAWg