Stiff doorknob on wood-burning stove

I've recently moved house and inherited a wood-burning stove. The doorknob is unusably stiff. I've put on some WD40 equivalent (as advised) and worked it back and forth. It seemed to get worse the more I worked it. I then tried engine oil - it also got worse the more I worked it. In neither case did I light the fire. It's now practically seized.
This behaviour defies common sense (well, mine anyway).
The knob consists of a threaded rod which goes through the door, one end of which has some rod welded at right angles, the other end has the handle screwed onto it. The thread seems in good condition.
Any suggestions?
Another Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I wonder if what is happening is that the high level oils you are trying to lubricate with are dissolving the low level tars that have probably got onto the thread from the wood and are effectively smearing the softened tar over the threads.
Is it possible to get the door off and put the area with the handle into some paraffin with the aim of dissolving out the muck in the thread ?
Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What about "Coppaslip" or is it Copperslip. The stuff used to lubricate car brakes - and to smear onto sparkplug threads.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Another Dave wrote:

That's cast iron for you. Graphite IIRC is the appropriate lubricant. Sharpen a pencil in the vicinity..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 12 Dec 2007 09:55:38 +0000, Another Dave wrote:

Handle tightening up on rod? Hold the inner latch unscrew handle (might have a locking nut) remove bits and clean. Don't bother with any normal lubricant as it will burn off the first time you light a fire. Graphite should survive...
--
Cheers snipped-for-privacy@howhill.com
Dave. pam is missing e-mail
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Another Dave wrote:

Thanks for all the suggestions.
Eventually I tried brute force and ignorance and with much grunting and swearing just forced the threaded rod to unscrew all the way out.
This revealed the source of the problem - the thread was knackered. Judicious use of a hacksaw on the bits of the thread normally resident inside the door has made the door usable though it's far from ideal.
I've no idea how it got into such a state :-(
Another Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.