Ear piercing screech from bypass handle (Any lubricant?)

I have no idea what your mechanism looks like or why it’s required so keep that in mind while I play redneck mechanic online
A picture is worth a thousand words they say

So you have a solid male rod encased inside a hollow female sleeve that is obviously long enough in length that lubricant can’t make its way into the center? Sound about right? Easy to assume there’s heat involved. Can you disconnect the bypass door from the male rod and cycle it without the resistance? Would the noise stop? Has heat warped the female sleeve causing friction between the two no matter how much resistance is in the mechanism?
I would try to pry up on the female sleeve in the center while working the handle, see if there’s a sweet spot the noise disappears. If so maybe a steel wedge/shim of sorts to keep it in that position might work.
Push come to shove you might take an angle grinder with grinding wheel and grind a small hole in the top of the sleeve. Then you could dump a graphite alcohol mix down that hole to your hearts content while working the handle. Eventually the noise will stop.
Good luck with it.

Feel your pain. I had issues with my Woodstock PH bypass jamming open when the stove was hot. Cold it worked fine. It was a known problem other people had. Woodstock had a solution that involved a large hammer LOL. I didn’t like the idea of using a hammer on a part that runs through soapstone,,,,didn’t seem smart. Tried adjustments to the mechanism with no avail. Lived with it for probably five years till I figured out what was really causing it. The cast iron bypass door was expanding when hot and getting caught between the two ears it rides in. A little work with a grinder to remove some metal and add some bevels and that issue disappeared. I even called Woodstock to tell them what the issue and fix is, whether they believed me or not I don’t know LOL

 

You are correct, the solid rod slides through the sleeve (pipe). This rod, however, is welded to the mechanics that operate the bypass plate. Because of this, the rod cannot be removed and lubricated. After generously lubricating everything and having a small fire, I do have to say, I think it's a little better. Maybe some of the lubricant wormed its way down into the nooks and cranies.

 

If I thought the noise was coming from where the rod passes through the stove wall I’d pull off the bypass handle, it just slides on the keyed shaft. Then you should be able to see the gap that needs lube. Put the red tube on and Spray anything in there and then put the handle back on and work it in.

When you lube the bypass mechanism through the flue opening you have to put the lube on the places that rub. It’s not just on top but you’ve got to use your pinky to get it in there.

 

You and I were both thinking along the same track. I did exactly that last winter, and it did not get in there deep enough to help at all. It is a very tight fit where the rod passes through the pipe. The red extension nozzle tube, would not go into the gap, and even on a light spray, the graphite spray came back out towards you. I put a napkin over the nozzle and where I was spraying into the gap, but there was not enough lubricant that got into the channel that made a difference. A much better scenario, would be the bypass rod being keyed on both ends and double-nutted on the inside by the bypass door which it would allow for that rod to be completely removed in properly lubricated. I bet, if done right, it would only need to be lubricated every 2 years or so.

 

Could a tiny hole be drilled to assist getting lube to the right spot?
How about using an air compressor with a blowgun attachment to push lube back into the proper crevice(s)?

 

Thought about drilling a hole as well. Problem is, the pipe passes through the firebox.

 

So that rod passes through the firebox wall and then through the wall of the dome, the cat chamber, before it attaches to the bypass plate. I don't know if the rod rides in one long tube or if there are two separate "bearing" surfaces. It's got to be hard to pinpoint where the noise is coming from exactly and most lubes will only be temporary even if you could get it in there. Good news is that the noise only happens when you are opening or closing the bypass when you are there doing something and not some random noise at night.

If you pull off the handle and then grab onto the bypass rod with vice grips, can you pull it in and out? That might be a way to work some lube into the contact surface.

Or just operate it a million times until it smooths itself out. It's only rotates less than 180 degrees and there is no real load on it.

Blowing out the bearing surface real hard might knock out the little chunk of weld splatter or scale that is causing the screech.

 

Good point on the noise only happening when I open and close the bypass. If it was a constant thing, that would be a huge problem.