Intermediate pulley

[jzeke16]

I just purchased a 10 ER in excellent condition. While cleaning and oiling I started to work with an intermediate pulley carrier (between the headstock and motor) that has two pulleys, one to the motor that is fixed and a second one that seems that at one point was variable in its opening (I think) and an adjustment screw that raises and lowers the assembly. It has a cast Magna part number #131-2. Does anybody have one of these and can tell me how it works? I can post a picture if it would help.

[jzeke16]

I figured it out by reading other posts. How does it work? Is there a manual floating around the site that I can download?

[wlhayesmfs]

you can go to the Yahoo ER site and there is a manual there for the Speedchanger. If you do not find it send me a pm and I will email you one.
Good luck

[lv2wdwrk]

A manual can be downloaded from SSUG.ORG. Here is a link to the manual

http://ssug.org/index.php?option=com_do ... &Itemid=29

[jzeke16]

Excellent. Thankyou.

[jzeke16]

Ok. I read the speed changer manual. I don't understand the concept. What is the procedure for changing the speed? is it dynamic and adjusted while the motor is running? Or is the sheave adjusted when motor is of then the belts are tightened?

[mckenziedt]

The concept is: As the crank is turned, it slides the speed changer's pulley to the right or the left. This makes the driven side(motor to speed changer belt) of the pulley larger or smaller, depending on which way you turn the crank and whether you are using the speed changer in low range or high range configuration. When this happens, the driving side(speed changer to headstock belt) changes the opposite way. This changes the ratio of the driven to the driving pulley. This gives the same result as putting a smaller pulley on the motor while at the same time putting a larger pulley on the headstock to decrease the quill rpm, or vise-versa, putting a larger pulley on the motor while putting a smaller pulley on the headstock to increase quill speed, as when one was using the one longer 38" belt directly from the motor to the headstock. The direct long belt drive gives 3 different fixed speeds in 10ER stock form, or 1,2,4, or 5 fixed speeds with various after market conversions or custom made pulleys. The speed changer gives an infinite number of speeds over its 2 ranges between its minimum and maximum settings for each range. Also these 2 ranges extend over greater rpm range than the stock triple range pulleys allow.
The change of speed, done by turning the crank, is done while the motor is running. If the pulleys were not turning, the two belts would not ride up and down in their respective sides of the speed changer. If you cranked without rotational motion, you would be trying to compress one belt's width to the point where the compression force would have to exceed the friction force of the belt's sidewall on the pulley(if you lubed the belt's sidewall, it might slide up the pulley,but then you would never again get enough grip out of the belts to do any work with the 10ER). If you crank too hard with no belt motion, you would probably break the speed changer casting. That would be very expensive.
You can do searches for posts on this forum to get a lot of good information on speed changer use, lubrication and maintenance, and rebuilding.
Don

[goffoz]

Hey jzeke16
Be happy you have a speed changer, Its a very useful parts option on a 10er
...and most didn't come with it.
I've seen quite a few with broken castings, Only change speeds with the motor running.
And put a drop of oil on that center sheeve at each use.

There is also a useful tip on chips site..place a washer on the mounting bolt, between the headstock and the speedchanger.
This will make the headstock less apt to jamb when you move it.
Enjoy

[JPG]

Notice there are springs where the 'control rod' attaches to the movable collar to which the pulley shaft is located. Do not ever cause either of these springs to be fully compressed. Cranking further will cause the casting ears to break off.

Unlike the Mark 5/V, the belt squeeze occurs in both directions. It is the unresponded to belt squeeze(sheave moving) that does the damage to the parts trying to 'squeeze'.