Author Topic: Repowering The Rockwell #21-100 Mill Machine  (Read 621 times)


Repowering The Rockwell #21-100 Mill Machine
« on: August 20, 2018, 06:45:07 PM »
When I bought the Rockwell milling machine, I made the transmission and installed a single phase 1/2hp, Dayton electric motor. In the normal course of operation, the motor seemed to bog down, when making a decent sized cut. After some debating, I purchased a 2hp, Smith & Jones, 1720 rpm, single phase electric motor from Harbor Freight.

This violated one of the two primary tenets, when dealing with Harbor Freight, buy nothing that uses an electric cord or uses a battery. Until the motor, over the years, Iíve broken the rule exactly 1-1/2 times. I bought on of the Central Machinery, tool bit grinder (sadly no longer available, a true gem) and a 20Ē Central Machinery floor standing drill press, that now has a Dayton electric motor and completely rewired. I did hedge by bets, when I bought the 2 year replacement warranty.

Welp, it has been a little over 2 months, since I bought the motor, to my delight (and somewhat surprise), it has been flawless, quiet, smooth, correct amp draws, even body temperatures and a some surprising (to me) amount of overall grunt. I was expecting the hp rating to be based on smaller Asian horses, that may be, but they are hard working little Asian horses.


Re: Repowering The Rockwell #21-100 Mill Machine
« Reply #1 on: August 20, 2018, 07:20:29 PM »
Glad to see this thread resurrected Jack.



Ulma Doctor

Re: Repowering The Rockwell #21-100 Mill Machine
« Reply #2 on: August 24, 2018, 05:04:52 PM »
Sweet, i'm glad you have had a good experience with the asian horses.

i have seen many electric motors over the years form the most expensive to the very cheapest.

i marvel at how the very cheap motors can last, but they seem to work as long as they are not abused or placed in high vibration environments
good luck!  8)
9 Lathes, 5 Milling Machines, 6 Welders, 2 Surface Grinders, Shop Smith & woodworking stuff too !!!


chips and more

Re: Repowering The Rockwell #21-100 Mill Machine
« Reply #3 on: September 02, 2018, 09:40:28 PM »
I own mostly good old USA iron. The 4X6 cutoff saw is not. And I canít complain. Had it for decades and itís been flawless. The guide bearings are so piled with swarf I canít make out they are bearings LOL. Iím now afraid to clean them thinking I will get crap inside the bearings. Itís like the crap on the outside is acting like a seal now LOL. The motor has not been touched. Still smooth and quit. The gear box now leaks a littleÖDave