A few weeks ago I decided to try and fix my loose muffler on a 200T myself. I was able to find an old thread here about the subject and after purchasing a drill bit, tap, and bottom tap I got it all fixed up. I put the 6mmX1.0 bolts in with lock washers. I got the drill and the tap at harbor freight and got the bottom taps on amazon and the bolts at boltdepot.com. Anyway thanks.
Thanks
- Thread starter stehansen
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MasterBlaster
Administrator Emeritus
The TreeHouse RAWKS! 
Bodean
Cali dreamer
Steve!
Magnus
TreeHouser
Make sure gasket is new. If not it will be heat issues resulting in damages to cylinder and muffler.
PCTREE
Treehouser
STEVE hows the ladies
still cutting trees?
check in once and a while
still cutting trees?
check in once and a while
Al Smith
Mac Daddy
I think that saw originally had a bellville serrated type lock washer on it .Problem being if you used torx head 6 mm I don't think there's enough room to get one in .
After the fact but a tip .Usually with a wallered out 5 mm hole if you run a spiral point tap through the damaged hole followed by a bottoming tap you don't even need a tap drill .--says the guy with a couple hundred taps lying hither and yon --
After the fact but a tip .Usually with a wallered out 5 mm hole if you run a spiral point tap through the damaged hole followed by a bottoming tap you don't even need a tap drill .--says the guy with a couple hundred taps lying hither and yon --
Al Smith
Mac Daddy
Here's the kicker .As designed those muffler bolts where M5 by 20 mm .Proper design on a threaded fastener in aluminum is 4 times the bolt diameter of tread engagement .As built it's not even close .
gf beranek
Old Schooler
Good advice, Al. Your input is gold.
Magnus
TreeHouser
I do too, in some cases. If you like I can try explain this. If not stop reading and go to next post now!
Cylinder and muffler is almost identical in material and transport heat pretty much the same. They expand extract the same in same temp. Problem is it is never same temps so they move differently. To keep the same tension on bolt and nut there must be a gasket that work as a pillow or suspension spring as well as insulator. You could think the muffler is cooled by air just as cylinder but it is not and should not get very hot, but it will be from heat transfer more than heat from fumes. This is the reason there is trouble with the bolts that often is of wrong kind and can't handle the temps either as well as washer that often is missing or replaced with wrong kind. This and heat result in inappropriate movement and tensions that very easily snap a M5,M6,M8 or stretch so tension is lost and vibration damage muffler and cylinder.
Correct bolts and washers that can handle the heat, vibrations etc + a good gasket that work as intended is a must provided surface is not damaged a must.
It is Alumium gaskets on these and thin ones that after tension will now swell up and allow re-tension as a fiber gasket. It is like washer on a plug, it is used once with correct tension, not too much and not too little.
I replace them with thin fiber gaskets of "minerit" (not sure of Eng word). This is not thicker than it will work and it insulate better from heat, vibration and tensions. I put these on the 020 that was actually a 200 just after they got out on market and they are still going without issues. I have not seen one fail yet, but likely will at some point.
Magnus
TreeHouser
What do you use as lubricant when tapping Alumium, Al?
Al Smith
Mac Daddy
"tap magic "for aluminum .If not that the inorganic coolant we run at work i
in the CNC machines .
in the CNC machines .
Al Smith
Mac Daddy
More on screws. A screw by definition is an inclined plane around the outer circumferance of a cylinder .Properly torqued it acts like an extension spring under tension .The rule of thump is in steel it needs around 1 times the diameter of the bolt for internal threads ,cast iron 2 times and aluminum 4 times to be able to take the screw to a point called yield which actually stretchs the bolt to a point it won't lossen up .
Under some conditions such as the heat from a muffler additional requirements need to be met to compensate for thermal movement such as a bellville washer more commonly used on aluminum .A standard lock washer is better than nothing though .
Much ado but that's how it works .I deal with threaded fasteners every day in my line of work.
Under some conditions such as the heat from a muffler additional requirements need to be met to compensate for thermal movement such as a bellville washer more commonly used on aluminum .A standard lock washer is better than nothing though .
Much ado but that's how it works .I deal with threaded fasteners every day in my line of work.
vharrison
Island Girl
It is gold! Hey Steve, hope all is well with you!
Magnus
TreeHouser
Is this it, AL: http://www.tapmagic.com/TMalum.pdf
I mostly use "Rödsprit" witch I think is translated to methylated spiritl.
I mostly use "Rödsprit" witch I think is translated to methylated spiritl.
Reddog
TreeHouser
A tip for the home mech, Crisco or lard work well for a tapping lube in aluminum also.
Al Smith
Mac Daddy
That's it Magnus .Actually I've used a lot of things,WD -40,hand creme,cutting oil .It's just the fact we have cans of tap magic galore at work .Cheap is good free is better .
Al Smith
Mac Daddy
Another tid bit .The original tap magic contained triclorethane which cooled by rapid evaporization which was combined with a light oil in the mixture .
It was found that tri clor was a carcinagenic in large doses so it's no longer in the mix .That aside straight tri clor is a wonderfull fluid for stainless steel .Just don't breathe the vapors or get any on you because it's skin absorbative .
Funny in a way .Tri clor was a substitute for carbon tetra chloride because of the ill effects of the later .It was only found out the tri clor was just as bad years after the fact .What's not funny is millions of us used tri clor and never knew a freakin thing about it .
It was found that tri clor was a carcinagenic in large doses so it's no longer in the mix .That aside straight tri clor is a wonderfull fluid for stainless steel .Just don't breathe the vapors or get any on you because it's skin absorbative .
Funny in a way .Tri clor was a substitute for carbon tetra chloride because of the ill effects of the later .It was only found out the tri clor was just as bad years after the fact .What's not funny is millions of us used tri clor and never knew a freakin thing about it .
Magnus
TreeHouser
Oil baced cutting liquids work if it is hard alumium but not if there is magnisium in or othef suff.
I had issues threading cylinders and cases with oil as the shavings turned it in to a pole grinder.
This left a pretty ruff surface and ruff threads we no want.
with the "rödsprit" surface got smooth and threads stronger.
I had issues threading cylinders and cases with oil as the shavings turned it in to a pole grinder.
This left a pretty ruff surface and ruff threads we no want.
with the "rödsprit" surface got smooth and threads stronger.
Magnus
TreeHouser
It is a good tip that help prevent costly repairs.
- Thread Starter Thread Starter
- #23
Al, I didn't use a torx head but a allen head which is all I could seem to find on the internet. Same difference I figure, I had to drill out the holes in the case to fit the screw head in there but they fit into the recess in the muffler just fine. I used WD-40 to lube things. I'll go to the local Stihl store here tomorrow and pick up a gasket.
Al Smith
Mac Daddy
I'm not certain you could find a short M6 torx head anyway without buying a box full .
Magnus
TreeHouser
Make sure the screws you put in can handle the temp differences as mentioned earlier.
Just use any screw will screw you over pretty good.
Just use any screw will screw you over pretty good.
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