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Some Mods To the Belt Drive On My Mill

terry_g

terry_g

Ultra Member
I made a pulley that would fit into the top of the cone pulley on the motor to give me a slower speed
160 rpm the lowest with the factory setup was 270 rpm.

Assemble these parts.
4196325920_ba1d69f7b1_c.jpg


You will have this.
4196325924_911d156a4a_c.jpg


Slide it into the cone pulley and tighten the nut.
4196325930_302b9703d1_c.jpg


A shorter belt was required.
4196325928_f53006edfb_c.jpg


There is a wide space in the speeds in the middle between 490 rpm to 950 rpm.
By running a belt directly from the motor to the spindle pulley I was able to get 660 rpm.
4206502014_97fcb7f099_c.jpg
 
Very nice work. What did you do to align the new motor pulley groove to the existing idler top pulley?
 
The cone pulley was bored and had a key-way all the way through.
It just slid in and the expanding shaft holds it tight.
 
YYCHM said:
The motor pulley on our machines has a blind bore with keyway. Something to keep in mind here.
Click to expand...

You could always bore all the way through and extend the key way - if there is enough material on the step pulley.
 
I think @YYCHM was talking about the pulley on the typical RF30 mill. Seems there may be a difference in design.
 
Last edited:
terry_g said:
I made a pulley that would fit into the top of the cone pulley on the motor to give me a slower speed
160 rpm the lowest with the factory setup was 270 rpm.

Assemble these parts.
4196325920_ba1d69f7b1_c.jpg


You will have this.
4196325924_911d156a4a_c.jpg


Slide it into the cone pulley and tighten the nut.
4196325930_302b9703d1_c.jpg


A shorter belt was required.
4196325928_f53006edfb_c.jpg


There is a wide space in the speeds in the middle between 490 rpm to 950 rpm.
By running a belt directly from the motor to the spindle pulley I was able to get 660 rpm.
4206502014_97fcb7f099_c.jpg
Click to expand...
I'm curious...what operation did you need the slower speed for, tapping?
 
I was using a boring head with a long bar and was getting chatter because of the lack of rigidity.
 
Last edited:
My similar milling machine only has .350" of room in the cone pulley so not much room for a shaft but I guess the key takes the majority of the forces anyhow and a bit of epoxy or loctite would suffice to hold the pulleys together 20210403_124401.jpg
 
DPittman said:
My similar milling machine only has .350" of room in the cone pulley so not much room for a shaft but I guess the key takes the majority of the forces anyhow and a bit of epoxy or loctite would suffice to hold the pulleys together
Click to expand...

In that case I would suggest a shaft with key for alignment and torque load and securing the new pully to the adjacent pulley with machine screws.
 
VERY INTERESTING!! I have the exact same mill and have the same complaints with mine as well! I wish it had a few lower speeds and this looks like a great idea! Thanks for posting it.
 
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