Pork Chop Misalignment

[stew]

I have on several occasions taken my headstock completely apart for a good cleaning and inspection so I am comfortable with the process. However, this time when I put it back together I noticed that the Pork Chop-Quadrant is not aligned with the Control Sheave. In the picture you can see that the quadrant is not centered and is riding way far to the left, almost off the Control Sheave. After closer inspection I noticed the wear mark on the quadrant was not centered so I assume this has been this way a long time. Unless I am missing something my pork chop looks to be in OK condition and not bent or have unusual wear. My thought is to bend the arms to center the quadrant onto the control sheave but I fear breaking them and they don't look bent now. Any help would be appreciated.

Stew

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[charlese]

I see nothing to fix, Stew! The wear is pretty well centered. If anything - lack of lubrication has caused the wear.

In addition to the recommended 10- hour oiling, don't forget to put some grease on the teeth. Yes, the grease will pick up some sawdust, but you'll have a look-see every 10 hours to wipe clean and re-grease.

[JPG]

Sorry Chuck, I gotta disagree(sortof).

As noted, the control sheave button bearing is riding 'high' on the quadrant wear plate. Not much but quite noticeable(eventually:D).

Although the wear looks 'centered' at the far end of the quadrant gear, it is not so at the close end.

The axis of the worm gear is not centered on the quadrant gear.

The tension pin pivot is extending out the bottom leg. The top may be moved away from its normal location.

The clearance between the quadrant gear and the posts appears pretty good(not eccessive).


For starters, I would fully seat the tension pivot(it would be better to implement Bill Mayo's screw/washer/nut fix long term).

I predict that will change the alignment and cause the quadrant gear to 'rise' above its current positioning(control sheave bearing become more centered on the wear plate). It should also tend to bring the quadrant gear more centered on the worm gear axis.

That however may create a binding of the worm gear and the gear teeth(caused by the deformation of the teeth on the quadrant gear). The quadrant gear teeth deformation will need to be filed to remove the 'high' areas. It takes a veeery small interference to 'jam' things. Sighting across the quadrant gear teeth one can see the worm gear contact point(s).

The 'legs' may also need 'repositioning'(the lower one may need to be moved 'up' which will move the quadrant gear closer to being centered on the worm gear). Such 'repositioning' needs to be done veery carefully so as to not 'fracture' the leg. I recommend gradual(small movements) squeezing using a vise. The vise prevents too much movement.

Kudos on the pix. They are good, even if some are 'upside down'!:rolleyes:

[JPG]

P.S. Too rapid changes towards slow causes the type of wear shown. The worm gear pushes the quadrant gear and if the floating sheave does not have time to react, the entire mechanism is placed under stress. Belt tension is pushing the control sheave into the quadrant gear arm, and the worm gear is attempting to move it the opposite direction. When running you can feel the tension increase and diminish as you crank towards slow. Cranking towards fast is 'free wheeling'(assuming the floating sheave is free to react under spring tension).

[billmayo]

I see nothing to fix, Stew! The wear is pretty well centered. If anything - lack of lubrication has caused the wear.

In addition to the recommended 10- hour oiling, don't forget to put some grease on the teeth. Yes, the grease will pick up some sawdust, but you'll have a look-see every 10 hours to wipe clean and re-grease.

Looks like normal wear to me. I would recommend replacing the roll pin with the free bolt kit I will provide and straighten the one bent leg. Lubrication in the Control Sheave and the motor Float Sheave area is many times more important than any lubrication of the quadrant teeth and worm gear. I find the oil flushing of the Control Sheave bearing will provide any needed lubrication for this area.

[JPG]

Looks like normal wear to me. I would recommend replacing the roll pin with the free bolt kit I will provide and straighten the one bent leg. Lubrication in the Control Sheave and the motor Float Sheave area is many times more important than any lubrication of the quadrant teeth and worm gear. I find the oil flushing of the Control Sheave bearing will provide any needed lubrication for this area.

I would use the word 'typical', not normal. That wear is typical of either lack of sheave lubrication or too rapid speed lowering or turning knob without rotation of the pulley or any combinations thereof.

Glad we agree one leg is 'bent'. This one takes a sharp eye to diagnose!:p

[billmayo]

QUOTE=JPG40504]I would use the word 'typical', not normal. That wear is typical of either lack of sheave lubrication or too rapid speed lowering or turning knob without rotation of the pulley or any combinations thereof.

Glad we agree one leg is 'bent'. This one takes a sharp eye to diagnose!:p[/QUOTE]

What is the meanings of words for similar things? Yes, the wear can be from lack of lubrication or changing speeds too fast. However, I see this much or more wear on over 95% of the quadrants that I inspect. This quadrant really looks normal in the wear area and can still be used. You have curved steel worm gear teeth working againest flat alloy (aluminum like) teeth on the quadrant so there has to be a wear pattern developed over time.
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I find I have to replace the quadrant when the wear area moves to the edge of the teeth as the teeth will quickly start to give away quickly when that occurs. I find around 25% of the quadrants I inspect have worn into this area and will need to be replaced.
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This is an example of using the bolt kit and straighten the legs so the worm gear rides in the center of the quadrant teeth along side what a Speed Control Assembly looks like when I remove them.
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[JPG]

I would use the word 'typical', not normal.]

Glad we agree one leg is 'bent'. This one takes a sharp eye to diagnose!:p

What is the meanings of words for similar things? Yes, the wear can be from lack of lubrication or changing speeds too fast. However, I see this much or more wear on over 95% of the quadrants that I inspect. This quadrant really looks normal in the wear area and can still be used. You have curved steel worm gear teeth working againest flat alloy (aluminum like) teeth on the quadrant so there has to be a wear pattern developed over time.
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I find I have to replace the quadrant when the wear area moves to the edge of the teeth as the teeth will quickly start to give away quickly when that occurs. I find around 25% of the quadrants I inspect have worn into this area and will need to be replaced.
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This is an example of using the bolt kit and straighten the legs so the worm gear rides in the center of the quadrant teeth along side what a Speed Control Assembly looks like when I remove them.
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I agree with ALL you have said.

Let me explain my meaning of 'normal'.

When all the parts are new, the worm gear is as is shown in your last pix(centered on the quadrant gear). That is 'normal'(i.e. as the designers intended). Any wear will occur at the center of the quadrant gear teeth. That 'normal' wear will only occur there if the speed control knob is operated correctly(never too fast towards slow, never with the pulleys not rotating, and always with adequate lubrication on the moveable sheaves).

Alas 'normal' is not 'typical'. Typically lubrication is ignored! Typically users want to slow down quickly(like when turning on at 'S' with the band saw connected:eek:). Typically owners are aware of the 'do not adjust while not running' nono. Guests to their shop are not always so informed!

Sooo typically the combination of the back force of the control sheave towards the porkchop when adjusting towards slow too fast and the tendency of the leg to deflect(then bend) causes the porkchop to move away from the center of the worm gear and begin to wear there. But 'there' the angles are wrong and the worm gear starts to form(move/bend/displace) the material of the quadrant gear. This results in an increasing deviation from 'normal' that is typical given the above mentioned causes.

Typical/Normal can mean the same thing(what is 'usual' in the broad sense), but they have different meaning in the narrow sense.

A 'normal' driver stops for yellow lights about to become red lights, stops first then goes when turning right on red and stays to the correct(a nod to other sets of rules)" side of the road etc. A 'typical' driver (around here anyway) will run the yellow light(and the red one too if it comes on too soon), perform a 'rolling' stop when turning right on red etc.. Not a perfect analogy, but I assume y'all get the drift.

[charlese]

Thanks for the semantics lesson:D

Happy Thanksgiving - Enjoy!!

[stew]

Thanks for all the imput, I will try and bend the legs so that the quadrant is more centered on the control sheave and install Bill's bolt upgrade.

Stew