Friday, April 9, 2010

Tough Brakes...


Tough Brakes….


By Tim Ard, Forest Applications Training, Inc.



Innovation takes time to be tried, tested and perfected. New ideas taken from concept to commonplace often take decades.



The chain brake has been readily available on chain saws since the early 1980’s. It was designed and available as an accessory to certain chain saws a


few years prior. The chain brake has proven its worth in saw safety and has become standard equipment on most chain saws for close to thirty years. In my opinion it is one of the most significant developments in safety of the chain saw operator to ever be offered to date.



Today a couple manufactures are competing to make the chain brake system even more user friendly and better fit the applications of current chainsaw operators. Retaining operator productivity and offering new designs for improved brake operations has challenged manufacturers.



In my training I emphasize awareness of the reactive forces of the cha


in saw and discuss the chain brake working to stop the chain rotation giving the operator greater reaction time. I also discuss the important technique of using the brake system as a parking brake. When you take a hand off the saw the chain brake can go on to remove some chance of the spinning chain coming in contact with the operator. Applying the brake before removing a hand and then release the brake to begin work removes a lot of incident potential.



Two manufacturers, I am aware of, have added new innovations in chain brake designs to a couple saw models. Stihl(R) and Husqvarna(R) are reviving the Battle of


the Brakes.



I requested a Husqvarna(R) saw with a TrioBrake(TM) for evaluation to compare to the Stihl(R) C-Q Brake. I was hoping to compare side-by-side but to date they haven’t sent the saw. So I am going to complete the comparison, evaluating the TrioBrake(TM) saw at a later date. I have included my findings on the Stihl(R) unit. So enjoy!



In the following review I have written the evaluation of the machine basically right out of the box. I reviewed a fresh unit with the open mind of an operator and/or a chainsaw mechanic… Here are my findings.










Stihl(R) MS 362 C-Q



First Impressions: CES Rating* – 5



Unpacked the saw from the box, filled it with bar oil and 50Fuel (Your Stihl(R) dealer will do the set up for you). The engine started (from dry) in 4 pulls with compression release on. Compression seems good on the unit right out of the box. I’ve had problems starting some new saws in the past using the compression release before the engine is broken in. Saws are usually a little hard to start until the compression gets seated. The MS 362 starter system is smooth with or without the compression release engaged and the recoil rope didn’t attempt to snatch my fingers (some light weight, high compression saws will jerk at your fingers when you pull the rope, this one did not at all).




The chain oiler primed quickly and was ready for use in less than a minute with sufficient oil all around the bar surface.




I warmed the saw up and ran it up to top rpm. High speed had a good flutter. It seems like there may be a governor system in the saw but the tachometer didn’t show any change in reading so, I assume the compensator designed air box is managing the situation and not electronics. The high speed no load is said to be 14000 rpm in the owner manual. I left the adjustments a little rich on the high screw for a couple tanks of fuel, just to get everything seated and broken in a bit. I have since turned it up to just under the 14k (maximum) since I have several tanks through it now. Carburetor adjustment is easily set and is very consistent on this engine. The fuel economy (gas mileage) is much better at the proper setting and runs out well with little smoke from the exhaust. Good deal!




The air filter element is a two-stage design and is fed with pre-cleaned air pulled (or pushed up) from the flywheel area creating a three-stage air cleaning system. The two cleanable elements however are a little tricky to reinstall, you have to take your time and get them seated correctly. I will practice a bit on it and see if it’s me or design. Right now it’s easy to distort the element shape and you have to really be particular that the filter seals to its mount. Sawdust gets around the top edge of the pre-filter element easily if not. The total (three stage) filter system seems to stop all particles however with the primary element the last stop before the carburetor throat. Tapping out the secondary pre-filter occasionally throughout the workday keeps the primary element virtually clean as new.



Checking the fasteners right out of the box, I found the screws slightly loose on polymer parts but all others were tight on the crankcase, carburetor area and starter housings. After running it for several tanks all the screws are still snug. Top covers on saws are notorious for screws that vibrate loose. The MS 362 has twist locking style fasteners (similar to Dzus®) on the top cover that hold it down securely and are ready for 200mph plus. This type of fastener has been used in racing applications in the auto and motorcycle industries for years, glad to see them used here. They are quick and they work!




The new chain brake system on this MS 362 is much improved. The first Q-C units I observed and ran in the field with the two-position chain brake activation, I had difficulties performing carburetor adjustments, chain sharpening and chain tensioning because of the rear brake activation lever. It was a two-person task, as someone had to work the two brake controls. It seemed in the earlier versions, the brake levers were somehow tied together and it was hard to work independently with these areas, performing adjustments. On the new version the system now works like a usual brake lever in front with the added rear release lever activating the brake if your hand is removed from the rear handle. When your hand is removed from the rear handle the brake is applied. If the front brake handle/guard is engaged forward, the brake is applied. It engages in two ways to tighten the brake band to the clutch drum during work applications. Stopping the rotating saw chain quickly.



The brake system also engages with a push or kick of substantial force. It is designed to be inertia activated. I found it to take a fairly strong inertia force to trigger the front brake. I couldn’t get it to trigger in a fairly strong kick on the tip. I had to drop the saw bar hard into a wedge (without it running) to trigger it. So the inertia feature is working but shouldn’t trigger without reason and if the saw operator actually lost control and the saw left their hands, the release of the grip on the rear handle would immediately activate the brake because of the rear activation feature. In all - the new system works super for reactive force situations as well as loss of control scenarios such as slips and falls. That is a great feature!




Fit and finish of the MS 362 C-Q is very precise and the see through fuel tank is a great feature. You can observe fuel volume quickly during operations without opening the tank cap. The fuel cap and the oil cap take some added attention to make sure you start the twist locking action in the right place. If you don’t start the twist in the right position, when you flip over the twist lock, the cap will leak around the seal. With a little practice it’s not really a problem, unless you do not start it right.



I haven’t put this much run time on a StihlÒ saw in several years. I found it to be a pleasurable experience. Especially since the AV system is now spring mounted- it’s firm but has very little vibration felt at the handles. The two-position chain brake activation is the reason I wanted to run the saw and I am glad I did. It’s a new system that has great potential of reducing loss of control lacerations and reactive force incidents of chain saw operation.



I have used the MS 362 C-Q in several training classes now and feel very confident it can offer added safety to operators who for some reason have a habit of removing a hand from the rear handle to grab or move an object or brush. It’s a great innovation in chainsaw safety advancement. I endorse this innovative unit and highly recommend it for your chain saw applications.



For more info on the MS 362 go to http://www.stihlusa.com/chainsaws/MS362CQ.html











* To define the ChainPoint Endorsement System (CES Rating) use the following 1 through 5 rating.





  • 1- 1 Not impressed at all– back to the design bench


  • 2- 2 Could have limited applications


  • 3- 3 Suggest closer evaluation


  • 4- 4 Recommend it


  • 5- 5 Endorse - Highly Recommend it







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