Harman MK I Latch Adjustment???

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rberq
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Post by rberq » Fri. Jan. 23, 2009 9:19 pm

I want to adjust the loading-door latch on my Harman Mk I, so it will pull the door a little tighter. The hinge side is snug, but the latch side is loose; there is no tension at all on the latch mechanism.

The only way I can see to adjust it, is to bend the curved piece that is bolted to the stove body. It is very thick steel and does not look like it would be easy to bend. If I put a wrench or vise-grips to it, will I damage or break the bolt? Is there some other simple way to do this that I am entirely overlooking?

 
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Uglysquirrel
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Post by Uglysquirrel » Fri. Jan. 23, 2009 9:42 pm

The compression of the door and the latch friction works in parallel with the compression of the rope that goes around the inside of the door, if your rope is more that 2-3 years, think about replacing the rope with a similar size. Other than that you could bend the steel strip, it's likely 1030 carbon and will bend pretty easily in a vice. I would however remove the strip by bolt removal since rapping the strip with a hammer or some sort of impact while the strip was attached to the stove could (unlikely) cause the bolt to partially crack in a place you may not see since the bolt nut & threads are exposed to coal corrosion. With thermal expansion/contraction the bolt could fracture later when you least expect it. I also would replace the bolt. That's just conservative me with some limited design metalurgy experience and failure experience on airplane enjuns.

Of course removing the strip would cause you to use two matches this season !!!

 
rberq
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Post by rberq » Sat. Jan. 24, 2009 8:58 am

Thanks, squirrel. I think conservative is good when it comes to airplane engines.
I already used my second match this year when I shut down to replace the door gasket.
You were right, the strip bent fairly easily. I was able to do it in place, by slipping a crescent wrench over the end and levering it toward the stove body. I only had to move it a tiny bit and now there is no red glow visible between gasket and stove body.


 
Joe in NH
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Post by Joe in NH » Sat. Jan. 24, 2009 9:18 am

I do not know if the latch mechanism on your MK I is the same as on my Harman SF 260 but it sure sounds the same. I have a similar problem and first thought of whacking the metal catch with a hammer but had visions of the bolt head flying across the floor. I then thought of removing the catch and grinding a little metal off the back where it attaches to the stove. Bending with a crescent wrench is the way to go. Thanks.

 
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coaledsweat
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Post by coaledsweat » Sat. Jan. 24, 2009 10:23 am

Break the bolt? I don't think so unless it is smaller than 1/4-20, one smack with a hammer ought to tighten it up. Make sure your door gasket is up to snuff before making any adjustments.

 
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coalkirk
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Post by coalkirk » Sat. Jan. 24, 2009 11:11 am

coaledsweat wrote:one smack with a hammer ought to tighten it up. Make sure your door gasket is up to snuff before making any adjustments.
BINGO! Never underestimate the usefullness of a good 'ol hammer.


 
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Cap
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Post by Cap » Sat. Jan. 24, 2009 11:47 am

Just use a 10" or 12" adjustable wrench, close the jaws and use as a pry. More prcision than a BFH.
A pry is one of your 7 basic tools!

 
rberq
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Post by rberq » Sat. Jan. 24, 2009 2:34 pm

Yeah, I was considering the hammer, too, but the wrench turned out to be easier to control. If I hit it too hard with a hammer, then I would have to un-hit it to adjust it back outwards a bit, and I don't know how to un-hit something.

 
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Uglysquirrel
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Post by Uglysquirrel » Sat. Jan. 24, 2009 4:30 pm

My mind is in rocket science, I gotta pull it away sometimes, cresent wrench it is.

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