Changing pulleys?

[DPittman]

Would changing pulleys on my milling machine to a 4 groove pulley like the one seen on the drill press be of any advantage? The slowest speed I can do now is 230 rpm and a 4 groove motor pulley would offer another lower range.

 

[YYCHM]

What mill do you have and what's the current pulley configuration? If it's not variable speed I can't picture how you're getting by for speed changes currently?

 

[DPittman]

Its a 6x26 mini knee milling machine. Speed changes are done with belt/pulley changes like most any other machine without variable speed. The second picture is the milling machine.

 

[YYCHM]

Hold on here...…. Is this a legitimate setup?

With this arrangement the belt is misaligned with the sheaves????

 

[DPittman]

Hold on here...…. Is this a legitimate setup?

With this arrangement the belt is misaligned with the sheaves????

No i don't think there is anything illegitimate about it...it just doesn't have a four groove pulley on the motor side and therefore I can not make use of all the combinations of the four grooves on the other pulleys. The belt has to be in line on all grooves no matter the combination.

 

[DPittman]

Oh ya know what...i bet that if I ran a four groove pulley on the motor that would be either redundant of another combo or of little use because then I couldn't use the belt in position "A" in the picture. But it should give me a lower speed if I could run the belt in position "D" and the smallest new groove of the proposed pulley?

 

[Janger]

What's the minimum diameter pulley that belt can use? Position D1 looks pretty small already.

 

[YYCHM]

Seems to me, if you installed a 4 sheave on the motor you could gain on the low end to the spectrum and fill in some gaps. If you're just looking for slower, moving your three sheave motor pulley up to let you catch the top pully of the idler would slow it down.

I have 4 sheave pulleys on all three (spindle, idler, motor) and range from 120-2500 RPM.



The crude guestimate is just ratios of pulley diameters, you could use that to see if it would benefit.

What make/model mill is this thing? A three sheave pulley on the motor seems odd?

My 230 RPM is 4-6 which is your I-D which are the same sheave positions. Interesting.

Hmmm..... my image copy and paste in post #4 didn't work? I wonder why.

…… I cut and paste that's why. Daaaaa.