MKC TOOLSJet JMD-15 Mill/Drill ModificationsI purchased this Jet JMD-15 in 1998 from J&L Industrial. It is a Taiwan made RF-25 machine and I have been very pleased with the construction and performance over the years. It was clean, tight and ready to use out of the crate. I just finished adding a GE 1 1/4 HP TEFC 3450 rpm PM DC motor and a KBWT pwm "Whisper Drive" controller Plus one of my Trexon digital tachometers with SFM calculator (mkctools.com). This unit is very strong even at 100 rpm and super quite except for fan noise at higher speeds. The new motor has a 3/4" shaft so I turned an adapter on the lathe so I could us the original 1" bore pulley. I am very pleased with this mod. Tach Installation I was fortunate to find a perfect stand for it at a flea market for 25.00. It is a heavy 12 ga. metal bolt up stand but I welded all the joints for additional rigidity. I also added a piece of 3/8" wall angle to the bottom front and back to give it a wider base and a place to mount the adjustable feet. The top of the stand just happened (thank you Lord) to be exactly the size of the base of the mill. 
Now for the dc motor installation. I built a sheet metal (16 ga.) bracket to hold the controller and sandwiched it between the motor and mill motor mount. It's out of the way and also picks up some cooling air from the motor fan. 
I turned the head around and with my aux. wooden table in the mill vise, bolting up the motor and controller bracket was easy. The motor switch wiring, speed control pot wiring and the 9 volt power for the tachometer were routed along the path of the original switch wiring. 
The new on/off switch, control pot and SFM tachometer were mounted on a new front panel. The old panel was stuck to the inside top of the belt cover for future reference. By the way, the original pulley setting speed chart was wrong on several speeds. Shortly after I got it I got suspicious and checked it with a tach and made corrections. Thankfully I don't need that anymore. 
The original belts were upgraded to the GoodYear high efficiency cogged raw edge type. They run much smoother than the old wrapped type belts and have greater traction with less tension (easier on bearings) and won't wear aluminum pulleys like the link belts will. The fine down feed knob and feed lever lock were replaced by a steel hand wheel and aluminum palm knob respectively. Also a new Jacobs Ball Bearing drill chuck was added. I got spoiled to them a long time ago. Another addition which has proved invaluable is a Craftsman 17/19 double box end wrench that fits the draw bar and the column nuts. 
I also added a new 4" milling vice and just received my accordian way cover material which I will install soon. Other additions are the nice Z DRO (a gift from my brother) and a power Y feed almost complete. I also have the scales for the X and Y DRO. Just trying to firgure the best way to mount them. Latest addition: I've been looking for a good mill lighting solution for years. I finally made major progress in that area. Check out the pic and link below.
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