Adding a Custom Lever to a Control Valve?

[threepiece]

I’m hoping to add 3 levers to a valve assembly. I found a few pictures of what the lever should look like but no dimensions to manufacture it correctly. I made a few measurements and came up with a drawing I thought will work.

It does not work. It looks to me like it should but there is binding in both directions. Both pins have a slip fit both in the valve body and lever hub. The binding occurs at the slotted area of the hub when the lever is moved.

I’m hoping someone has some insight on what I have done wrong here.

 

[oldnslo]

I suspect that your link is trying to push or pull the spool sideways causing the binding. I have seen what looks like a roller chain connecting link used to help with that offset movement.

 

[threepiece]

Adding another picture for clarity.

I previously made a contraption that worked well but involved several pieces and looked relatively horrendous after I happened upon a picture of the clean factory lever.

 

[threepiece]

I suspect that your link is trying to push or pull the spool sideways causing the binding.

Indeed, that appears to be precisely what is happening. The pin is free to turn when at rest, it binds when the lever is forced in either direction.
I have considered adding bronze bearings to each end of the rod where it rides in the slot.

 

[matt1roh]

I did read that you said it is binding on the spool side. However, I do see blue paint missing on the top right ear of the second post's picture, like it may be binding on the pivot side. In the 3rd picture of the 1st post, those square ears look very close to the valve body and wouldn't move much before contact.

Otherwise I would agree with @oldnslo

I would think if you polished the slots, you wouldn't need the bearing material.

Matt

 

[threepiece]

I did read that you said it is binding on the spool side. However, I do see blue paint missing on the top right ear of the second post's picture, like it may be binding on the pivot side. In the 3rd picture of the 1st post, those square ears look very close to the valve body and wouldn't move much before contact.

Otherwise I would agree with @oldnslo

I would think if you polished the slots, you wouldn't need the bearing material.

Matt

Yes well, it moves freely when the slot pin is removed. In fact it moves the spool inboard nicely with the pin removed as it bares down on the shoulder of the spool.

I noticed the pin rotates slightly before the binding occurs, indicating it wants to turn but can’t.

I will first try to reduce the thickness of the slotted ears. This may sufficiently reduce the friction and allow the interface to slide.

 

[threepiece]

Fellows, the issue had nothing to do with friction. The hub was simply binding on the shoulder on the spool. I provided clearance and it works perfectly.

I feel a bit silly now. What partially misled me was the mystery behind what I could not see in the two pictures. As I could not see the slot-pin interface, my mind wandered in the wrong direction, toward friction.

 

[oldnslo]

Thanks for letting us know the solution to your problem.