DeltaDP-SpeedReducer.txt



This Delta Drill Press is variable speed.  It goes from screeching to screaming and is good for

burning up drill bits.  It seems that every HS metal shop class has one specifically designed

to destroy bits, and frustrate both instructors and students.  I gave one of my best students

the task of modifying the press to keep the variable speed, but reduce the overall speed.  

Using a 2/7 reduction and idler shaft, we reduced the speed to where a Silver and Deming 1" bit

can be used all the way down to a 1/16" drill bit with proper speeds for both.  The original 

guard was cut in half and sheet metal bent with 1/2" lips to extend the guard.  The motor was

offset slightly to the left (as viewed from the back) to clear electrical boxes on the right 

that we could not move.  However, it helped in alligning all the extension studs.  Belt 

tightening from the variable speed pulleys was accomplished with long 1/2 x 20 threaded rod 

and nuts.  Once that was in place, the belt was calculated for the motor, then the studs were 

machined.  Actual belt tightening for the motor is accomplished by using a variable ratio 

pulley, and continually screwing it down until proper belt tension is attained.  Now we have

a usable drill press and a student with some great experience in modifying a tool.

Mike Fendley, Le Claire, Iowa    mikejanf@juno.com