Montgomery Ward Drill Press Potentiometer needed

[Cecil's Maker Space]

Hi everyone, I have a Montgomery Ward THS 2437 Drill Press and need the speed control potentiometer/rheostat OR a modern solution to controlling the speed of the DC motor. The current potentiometer is stamped TKR9 1377225 and I believe it's a 220K ohm pot.
There are some old threads about this but I couldn't find anyone that was able to find a source and was wondering if anyone maybe had a non functioning drill that they were parting out maybe?
Also, I've seen where some folks have added an external speed control box and I'm curious at what the best modern solution to this would be. Some sort of PWM control?

I'd love to hear your thoughts!

 

[RTM]

Vintage Machinery says the THS series was made by Darra James for MW Searching for an appropriate DJ model might bring out a wiring diagram. Don't know enough about DJ or MW to make a translation.

Do you have a wiring diagram? Someone skilled in DC controls might be able to put it together..

Some other site talked of KB Controls, who made DC stuff in the modern era maybe having an answer. I used their stuff on fractional horse motors, and know their controller changed with the HP of the motor, so some work on that front might be your a alternative.

 

[paulsomlo]

The most cost effective solution is to get an SCR drive from KB and hook it straight to the motor.

 

[tool_scrounge]

A few more photos of different angles would probably help

I suspect it looks similar to this one

https://www.ebay.com/itm/146358726024

Also, your location would help or I usually assume you are in Siberia and I can probably not help you.

 

[Cecil's Maker Space]

The most cost effective solution is to get an SCR drive from KB and hook it straight to the motor.

I’ll look into that. I’d like to try and keep it like looking original-ish if possible but I may not be able to

 

[Cecil's Maker Space]

Vintage Machinery says the THS series was made by Darra James for MW Searching for an appropriate DJ model might bring out a wiring diagram. Don't know enough about DJ or MW to make a translation.

Do you have a wiring diagram? Someone skilled in DC controls might be able to put it together..

Some other site talked of KB Controls, who made DC stuff in the modern era maybe having an answer. I used their stuff on fractional horse motors, and know their controller changed with the HP of the motor, so some work on that front might be your an alternative.

Thanks for the info! Yes, there’s a wiring diagram in the manual but it isn’t a schematic unfortunately.

I’d really like to find out some specs on the motor but there isn’t a tag on the motor and nothing in the manual.

 

[RTM]

Thanks for the info! Yes, there’s a wiring diagram in the manual but it isn’t a schematic unfortunately.

I’d really like to find out some specs on the motor but there isn’t a tag on the motor and nothing in the manual.

Post what you have, there’s a lot of bright controls guys on here. The KB Controls stuff I’ve used is pretty small, might hide in an existing control panel easily.

 

[Beerhippie]

PWM--Pulse Width Modulation--is your friend for DC motors. A potentiometer or variable transformer varies the voltage to vary the speed. While this works, it generates heat in the motor windings at low voltages. PWM keeps the voltage constant and varies the time it's applied.

 

[alfadan]

Can you post more pics of the pot? I have a fair selection of pots with different length shafts.

 

[KFBR392]

FWIW, that pot was manufactured by CTS. The 137 number is their manufacturer code, and 7225 is 25th week of 1972.

 

[Fourwdjunky]

Any update on this? I have a Toolkraft 452 that has a bad pot.

Found this on Amazon. I think I’m just going to go ahead and order it. For the price, it’s not a big deal if it doesn’t work. The shaft is different, but the knob was missing when I bought it anyway.

 

[Fourwdjunky]

Success! A 250k potentiometer for a Fender guitar works.