Shaker Arm "Linkage" Q for Mark III Owners

I have a question for the Mark III owners (maybe Mark I & II also if they have the same set up).

My new in Nov. Mark III does not shake anymore. I let the fire die out last night and inspected it this morning. The rod from the shaker arm simply rotates in the "linkage" on the ash pan side without moving the grates at all. What I am calling the "linkage" is a bar with rounded ends that has a hole in it to receive the shaker arm rod on one side and a pin that goes into the grate lever on the other. The hole where the shaker arm rod fits has a crack which I am assuming is not correct and is why the fit is loose enough to allow it to spin in place. I do not see any evidence of it having been welded together, maybe it was missed? The Harman manual does not have an exploded parts list so I am probably not calling this "linkage" part by the official Harman name.

I have called the dealer, but they don't have one there that I could go look at and couldn't tell me if the Mark I & II had the same set up. They are supposed to call me back after checking with Harmon.

My question for other Mark owners is whether you can tell if your "linkage" is welded to the shaker arm rod, or if there is a crack on yours also?

Any chance you can photograph this part/parts and post a photo??

Greg L.

Greg was too quick......Here are some pic's which should help with my feeble explanation.....

You can see it in the first pic against the side of the stove behind the grate lever.

I looked closer at the end that has the short rod in it and it also has a crack and the rod looks to be welded in place.
I am guessing the crack is OK and the shaker arm rod is supposed to have been welded into the hole at the other end.

I have a MarkII but linkage is the same only 2 grates. The top gap is supposed to be there, looks like a friction fit. It would need to be pressed back on.

I would think that if that was a press fit, everytime the stove and grates got good and hot, the expansion of the hole would allow the shaft to spin in the hole in the lever.. If it was CUT, then I'd maybe believe it is supposed to have an 'expansion crack' but I'd say the part is broken, I certainly could be wrong, but Harman builds a pretty tough heavy duty stove, and a press fit in this location doesn't make a lot of sense to me..

Maybe press it on, then put a spot of arc-weld on it to keep it in place, If it was intended to have an expansion gap, then it should have a pinch bolt to close the gap and clamp the ring tightly onto the shaft..

I'd say it is a broken part.. untill proven wrong...

If it was mine, I'd push it back on, make sure the handle was where I wanted it, then tack-weld it in place, where I could get a 4" grinder in to grind the weld off if needed.

Greg L.

CapeCoaler....or any other Harman Mark owners.....does yours look like it is welded to the rod on the shaker arm (if you can see it well enough)?

Greg, I am leaning toward the tack weld too, the crack in the part is what has me scratching my head. It fits snugly now, but I can easily get it off and on by hand, no "press fit" is necessary. I'm wondering if I tack weld it if it will stay strong enough to withstand a vigorous shake down or if it will keep breaking. I'm thinking it might be a lot stronger if I drill a slot for a pin before welding it.

Still waiting to hear back from the dealer, or Harmon....no surprise there.

Burning some wood tonight to keep the chill off since there ain't a whole lotta shakin' goin on!

Upon further review...
Looks like we're both sorta right.
My Mark II has the same cut and the shaker is fully functional. It is pretty clean inside as the former owner's wife did not like the smell from a big backpuff just after it was installed. I am just now prepping the Mark II to replace my Vigilant wood burner. The end inside shows no grind marks and is perfectly flush.
It looks more like it was fused, as there is a discoloration from some kind of arc but no bead from a weld.

Clean hole on the link shows no weld penetration where one would expect it, the mating surface between rod and link. It would be a PIA to production weld that ring inside the ash box. Closer inspection of my Mark II shows a spot weld dimple in the middle of the 1/2" rod that comes thru the stove from the shaker rod, seems like it was more of a fusing operation. The joint looks like it was to allow the link to be placed on the rod during production but have good contact for the fusing operation.
I would drill and pin the assembly then tack the pin in place. Roll pins would also work, they stay put inside my shredder/chipper and that is a very violent place!
With the outside movable metal block squared to the welded block, the link inside the ash pit is vertical on my Mark II.

I have a SF150,the detail in question is rectangle on my stove and welded in place,yours looks like maybe in was spun/friction welded????
I feel a competent welder could weld it so as you could hang the whole stove from his weld,I cannot but know many that can.
If it were my stove........I would pay if I had to ,to get it welded right the first time.
It looks weak in you picture,sad note for Harman.Definitly fixable,said Rube Goldberg.

Hi , I have MARK III. I have the same parts as yours.With crack at top ( I think its for heat expantion).This link (small lever at bottom pic) NOT welded to big outside lever (shaker) but it's sitting very tight same as welded. It moves same as shaker only opposite direction of course, to shake grates . You can not moved by hand (may be by hammer to replace grates (when time to change). I would suggest to you to make hole by drill and insert screw to fix both of them together,or first try to use hammer to make hole at small lever(linkage) tighter and than isert by hammer on to shaker pin from inside, do not forget to hold another hammer outside of stove on flat small plate at bottom of shaker to equalize forse and do not brake or bend stove. Hope it's help.Serge.

I Just checked my stove, looks like the lever is welded on to the shaft, then ground flat. I can see the slit at the top but no indication of the 2 separate pieces. Looks like a manufacturing defect, may still be under warranty.
I can take photos of the linkage on my stove if you like, let me know.

Here's photos of the shaker linkage in my stove.

Thanks for posting those pics. From those pics and the other's descriptions the crack is supposed to be there and it looks like it was welded and then ground down. Since the grates get shaken rather vigorously my main concern was tack welding it back together would only end up failing again if the crack in the linkage wasn't supposed to be there.

Following some of the initial advise and my first thought on fixing it, I am going to try to get the rod out through the side of the stove tomorrow and drill through the linkage ring into the rod. I can insert a pin before getting it tack welded after putting it back in place. That should make it a little stronger than just tack welding it alone.

What a great resource for info this place is!

Still burning wood tonight without a shaker grate.

Sounds like a plan.
How does the Mark series do with a wood only fire? I've never burned wood in mine, except when starting it.

titleist1 wrote:I have a question for the Mark III owners (maybe Mark I & II also if they have the same set up).

My new in Nov. Mark III does not shake anymore. I let the fire die out last night and inspected it this morning. The rod from the shaker arm simply rotates in the "linkage" on the ash pan side without moving the grates at all. What I am calling the "linkage" is a bar with rounded ends that has a hole in it to receive the shaker arm rod on one side and a pin that goes into the grate lever on the other. The hole where the shaker arm rod fits has a crack which I am assuming is not correct and is why the fit is loose enough to allow it to spin in place. I do not see any evidence of it having been welded together, maybe it was missed? The Harman manual does not have an exploded parts list so I am probably not calling this "linkage" part by the official Harman name.

I have called the dealer, but they don't have one there that I could go look at and couldn't tell me if the Mark I & II had the same set up. They are supposed to call me back after checking with Harmon.

My question for other Mark owners is whether you can tell if your "linkage" is welded to the shaker arm rod, or if there is a crack on yours also?

What about the warranty? Shouldn't this be a covered item for Harman to take care of?

The warranty for defects in material and workmanship is 6 years to the original owner, can be transferred to the next owners.