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10 E/R pulley/speed combinations.

Posted: Sat Feb 25, 2017 8:45 pm
by JPG
On another thread the posts deviated from the original subject due to a video showing an unusual pulley combination using a speed changer.

The standard pulleys are a 2/3/4 inch pulley on both the headstock and the motor.

'Standard' combinations are 2:4, 3:3, and 4:2.

With a 1750 rpm motor, the quill shaft speeds possible are 825, 1750, and 3500.

By shifting the motor, the following combinations are possible.

2:3, 3:4, 3:2, and 4:3 which yields 1167, 1312, 2625, and 2333.

One could consider the speeds possible by including the speed changer, but the speed changer is dimensioned properly for the belts to be on the 2" and 4" pulleys only(the movable sheave requires the space between). Only by skewing the belts could the speed changer be used with combinations other than 4:2 and 2:4.

Re: 10 E/R pulley/speed combinations.

Posted: Sat Feb 25, 2017 9:10 pm
by jsburger
JPG wrote:On another thread the posts deviated from the original subject due to a video showing an unusual pulley combination using a speed changer.

The standard pulleys are a 2/3/4 inch pulley on both the headstock and the motor.

'Standard' combinations are 2:4, 3:3, and 4:2.

With a 1750 rpm motor, the quill shaft speeds possible are 825, 1750, and 3500.

By shifting the motor, the following combinations are possible.

2:3, 3:4, 3:2, and 4:3 which yields 1167, 1312, 2625, and 2333.

One could consider the speeds possible by including the speed changer, but the speed changer is dimensioned properly for the belts to be on the 2" and 4" pulleys only(the movable sheave requires the space between). Only by skewing the belts could the speed changer be used with combinations other than 4:2 and 2:4.
Or by different length belts for the non standard configurations.

Thanks James!

Re: 10 E/R pulley/speed combinations.

Posted: Sat Feb 25, 2017 9:21 pm
by JPG
I was assuming adjusting the motor mounts to accommodate the 'non-standard' combinations(Both in/out and up/down).

Re: 10 E/R pulley/speed combinations.

Posted: Sat Feb 25, 2017 9:25 pm
by jsburger
JPG wrote:I was assuming adjusting the motor mounts to accommodate the 'non-standard' combinations(Both in/out and up/down).

I agree.