I still think the 1-8 plate was a design error and discovered early on and changed. How many of those plates has any one seen? I think I remember seeing one on eBay years ago.JPG wrote:I am gonna crawl out on a limb and 'guess' the manual with the 1-8 plate was created after the step was added, but the pix with the plate did not make it into the manual at that time.jsburger wrote:That was my initial thought also. However, after looking at both manuals I am not sure that is true. The picture above looks like it has a 1-8 plate. The (Illustrated Parts BreakoutJPG wrote:The floating sheave acquired the step at the bottom at the same time.
The early SC did not have that step, and 'bottoming out' was all the way to the shaft.
That was not a good thing so the step(stop) was added and the 6,7,8 removed from the scale.
I am curious if the speed chart in the '1-8' manual agrees with the later '1-5' manual and if the speed range was greater.) IPB page from that manual clearly shows the center sheave with the flanges. The second manual does also.
The manual with the crank on the right and what looks like a 1-8 plate has a speed chart. Curiously the other manual with the crank on the left (1-5 plate???) has no speed chart.
I wonder if the 1-8 plate was an error caught early on. Assuming the sheaves and the belts are the same on both versions you can't go past 5. At 5 one belt is riding at the top and the other one is all but bottomed out.
I really would like to know what speeds were 'published' with the original SC. The range had to be greater.
As for the belt positions at the 1-5 settings being maxed out, that is reasonable with the step limiting the travel. Without the step, the belt travel is greater. The travel of both belts is greater.
I assume from your comment that the speed chart in the '1-8' manual does not list speeds for 6,7,8?
I do totally agree with you that the early manual that appears to have a 1-8 plate but a stepped pulley is the result of the manual not getting updated properly. Of course no normal person would notice anyway.
As far as the belt bottoming out on the shaft I don't see a problem. I talked to Skip one time about it and he said the SC's without the flange show wear to the shaft caused by the belt bottoming out and allowing the floating sheave to rotate on the shaft. I said how can that be? The entire assembly turns in unison. The fixed sheaves and the shaft are one, the belt rides on the fixed sheave and the floating sheave causing the floating sheave to rotate in unison with the rest of the assembly. I think the wear was caused by not a large enough bearing surface between the floating sheave and the shaft. When you are at either extreme of the range one or the other belt is putting side pressure on the outer edge of the floating sheave. Adding the flanges gave added support and eliminated the wear. But, adding the flange causes the belt at minimum diameter riding on the flange to put pressure on the sheave into the shaft at the same time the belt at maximum diameter is doing the same thing in the same direction. Hmm... Maybe they changed material at the same time.
As far as the flange limiting travel, that is true. However, the flange is only 1/16" thick. See the pictures. When set on 0 the belt is maxed out at the outer edge of the sheave. When you go to 3, the equivalent of going from 5 to 8, the belt moves 1/2" on the sheave. The limiting factor is the minor diameter and removing that 1/16" will not allow a 3 increment travel on the scale. Plus you are already maxed out at the major diameter.
Yes the speed chart in what appears to be the 1-8 manual with the crank on the head stock side is only 1-5. The other manual with the crank on the left has no mention of speed other than high and low belt settings. No mention of actual RPM's.
