what's the spindle knob for?

[Jkroofer]

Question... on the back side of the plate with the letters, there’s a groove that a springy thing at the top runs in but it doesn’t correlate with the min / max letters. I get from A to half way between S and T and that’s as far as she’ll go. Is this common?

[Jkroofer]

BC0C2987-3DBA-424C-98AC-61D0B0EBE500.jpeg (105.46 KiB) Viewed 3450 times

[DLB]

I'm not sure if we have a standard name for that, I think of it as a detent spring. It should not stop you from going faster, just give you a change in the feel when you are going into the higher speed or extreme low speed range. I'd first try removing the speed control and dial for visual inspection (and pic) of the spring and I would wax and buff the back of the speed dial. And it'd be a good idea to start a new thread under Maintenance for this problem if it persists so it will be under a relevant title that others can find later.

The hard stops for fast and slow do not (normally) have anything to do with the speed dial. It is possible that you are hitting the high speed stop, which is a long set screw in the speed control. In this case your high speed adjustment is incorrect. With the speed control handle removed the dial should rotate independently of change in speed. If your high speed adjustment is incorrect go ahead and perform one.

- David

[DLB]

...One thing is for sure, the original collar is too short to apply any pressure against the inner race of the two bearing quill.

Perhaps those with more experience will chime in and educate us all.

I don't have more experience but I have two different examples of two-bearing quills. I have no way to confirm that either is original to its headstock, but I'm going to call them a '91 and a '01. I removed the '01 from its headstock when I did the PP upgrade earlier this year, and it appears to be identical to the one I installed from the kit. The '91 has a smaller bore and thicker walls, smaller OD bearings. The bearing at the business end is much closer to the end, and the spindle knob is short. Visually, the knob looks the same as jkroofer's and the single bearing example in JPG's picture. Because the bearing is mounted closer to the end of the bore in the '91 the short knob is in contact with the bearing's inner race.

The '91 is so similar to jkroofer's that it was even very hard to remove. In my case, one of those danged POs had tightened the set screw with it rotated and left a burr on the shaft. This whole headstock needs work.

An aside: Both the '01 and PP quills have a rubber-sealed outer bearing, the '91 is shielded. As far as I can tell this is the only rubber-sealed bearing in the PP headstock. (No attempt to look at the ones in the motor.) As a generalization, per my local bearing guy, RS bearings offer a better seal for dirty environments while shielded ("Z," usually double shielded "ZZ") are preferred for higher RPMs.

- David

[JPG]

Question... on the back side of the plate with the letters, there’s a groove that a springy thing at the top runs in but it doesn’t correlate with the min / max letters. I get from A to half way between S and T and that’s as far as she’ll go. Is this common?

Look closely at that groove at the fast end. At about the border between "saw/joint" and "rout" the groove should 'end'. Original "A" casting greenies had an abrupt stop at the end of the groove. A pin on a movable plate ran in the groove. At the end of the groove, the pin needs to be pushed out of the groove so speed can be increased above that setting. A plate(that that pin is mounted) is held in place by the power switch mounting nut. The casting has a hole that allows the plate to extend behind the groovey dial. The intent was to prevent inadvertent excessive speed setting without an extra step taken(pushing on the plate to disengage the pin out of the groove).

"B" and later headstock castings used that spring as an anti rattle device, but it also modified the ring so the end of the groove has a short ramp that the spring rides on up out of the groove. This provides a small increase in resisting increasing speed beyond that point. IMO too small to be effective. So it is commonly referred to as an anti-rattle spring.

So which version ring do you have?

[rpd]

"B" and later headstock castings used that spring as an anti rattle device, but it also modified the ring so the end of the groove has a short ramp that the spring rides on up out of the groove. This provides a small increase in resisting increasing speed beyond that point. IMO too small to be effective. So it is commonly referred to as an anti-rattle spring.

So which version ring do you have?

I had some handy to take a picture,
unramped on left, ramped on right.

speed dials.jpg (312.45 KiB) Viewed 3358 times

[JPG]

GOOD BOY!!!!!!