PFERD
By Tim Ard
timard@forestapps.com
Nov. 2010 |
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For three or four years now I have been using and promoting a unique product manufactured by Pferd, Inc. The Pferd Chain Sharp™, also sold by Husqvarna Forest & Garden under the name Sharp Force™. This tool is, in my experience, the best sharpening system for occasional and professional users for field sharpening all saw chain and chain saw brands. The reason is well illustrated by recent presentations held at the Woodsmen’s Field Days in Boonville, NY. During the presentations, I proved to the crowds, and again to myself, what a super product the Pferd tool is.
The Challenge
I had a 16" turned pine log placed in the show area for cutting demonstrations. I decided to see if a person from the audience, without a lot of promoting and training, could make the Pferd tool work on a dull saw chain. I asked for volunteers to help. The first volunteer told me that he had sharpened saw chain before but had never used the Pferd tool in his past. The challenge, for a new Husqvarna helmet system, was to beat his first cut through the log with a second cut after sharpening with the tool. I timed his first cut of 8.11 seconds through the log. Then to make it challenging, I ran the 371xp full speed and stuck the bar into the sandy ground on the way to the sharpening log. The crowd ooh’d and ahh’d, but mostly laughed. The volunteer didn’t waiver… he began sharpening. Keep in mind I had only briefly showed the tool and how to reverse the files for each side of the chain. He was on his own to figure out the rest. I then proceeded to talk with the crowd regarding techniques of directional felling. It wasn’t over 10-minute’s max. I then had him make a second cut. The time on it was a little slower 8.79 seconds but he did hit a hefty knot in the pine and bogged the saw a bit trying too hard to beat the first time. The crowd was sympathetic. Results to me were still astonishing, to the crowd and me. Considering the ground cutting and his filing experience, the chain still performed well.
I then tried it all again at a presentation on Sunday and actually had better results from a participant who had never sharpened before and really had never operated a saw. His times were 9.57 and 9.58 after a quick cut in the dirt and a quick sharpening.
The results… in both cases they were able to come close to their first times. Even with the little slower second times, I rewarded them with the new Husqvarna helmet system as the crowd cheered on.
The same Husqvarna 371xp saw and chains were used, and you can see the operator plays a big part in the cutting times. I was able to make cuts easily in the 8-second range with their sharpening -- being more familiar with the saw. The important thing in the test was their ability to produce consistent times after a good dulling. The Pferd tool works great!
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How does it work?
Naturally after showing the tool questions come. How does it work? What makes it different from other tools? I want to take you through what I feel is the difference and the mechanics of using the tool. There is a video produced that takes you through proper use and can be viewed on YouTube.
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The Concept
The Pferd tool is unique in that it sharpens the round (concave) cutting surface of the tooth with the mounted round file and sets the depth gauge in proportion to the height of the tooth with the mounted flat file. (photo 3,4,5) All is done in one pass around each side of the saw chain loop while mounted on the saw and guide bar.
Each cutter tooth works independently from other cutter teeth on the loop but yet as part of the team. The depth gauge is important to the cutter tooth function. The depth gauge sets the amount of bite or how deep the cutter will attempt to shave out a chip from the wood fiber. Too shallow and the cutter will not take a chip, too deep and the cutter and sometimes chain saw cannot handle the load. This causing the tooth to rock and vibrate out of control and increase the probability of pushback and kickback.
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The Pferd tool sets chip thickness by lowering the tool and flat file into contact of the depth gauge. (photo 4) As the tooth is sharpened, the top plate surface of the tooth declines in height. Look at any cutter tooth and you will see that the top plate goes downhill to the tail of the tooth. This tool rests on top of the tooth being filed and the back of the top of the leading tooth. As the tooth is filed back the Pferd tool drops the flat file into place and removes only necessary depth gauge material to correct the setting in proportion to the tooth height. This is important because one challenge a chain sharpener has, many depth gauge setting tools average. The heights of two to three of the teeth on the chain loop are averaged to set the depth gauge as you file across the setting tool. Utilizing this averaging system soon your saw teeth become out of consistency and the chain begins to cut toward the sharper, lower depth gauge set teeth. This usually allows circle cutting to take place. Circle cutting is when you cut through a log, the chain begins to cut to one side and then it binds in the cut about half through the log. The Pferd tool helps to minimize this effect, as the depth gauge of each tooth is really set independently from other teeth. This assuring that each tooth, no matter how long and or short the tooth is, has its depth gauge set to proper settings.
Think about it—You really do not have to count strokes on the tooth with this tool. Just make sure you file back enough to remove all damage to any tooth, keep those tooth angles correct and its ready to cut like a new chain again. Possibly, Better!
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Reversing Files
It is required that you reverse the files in both of the guide designs to sharpen left and right cutters on your saw chain. (photos 1,2) This can be done easily after understanding the files only cut in one direction and need to be placed in the guide with their cutting teeth forward. Filing work with the Pferd tool always takes place with a forward motion of the tool on the cutter tooth. Make note of the either the arrow or the top of the "Crown H" on the flat file. This will alert you of proper file direction. They should point away from you in the guide. (photos 7,8)
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Replacing Files
The files can be replaced easily. The 5/32", 3/16" or 7/32" round file is a standard 8" Pferd/Husqvarna file and can simply be replaced in the handle. (photos 9,10) The flat files last and last, but should it need to be replaced can be purchased through your dealer. The files simply (photo 11) set into the guide in their respective slots and locked in with the keeper, either wires or slide clips. (photos 8,13)
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When sharpening any saw chain, it is important to know the manufacturer’s suggested angles and depth gauge settings. In addition, the shape of the depth gauge needs to be maintained correctly. Rounded properly or kept flat as per specifications. Make sure you check these settings with your dealer or manufacturer. When you test cut with the chainsaw after sharpening make note of any aggressive behavior or vibrations. If they exist, do not use the saw chain without correcting the problem. Your safety is at stake.
Sometimes even if the chain manufacturer sells the tool you are using it is possible to have the wrong tool or gauge for the specific chain type. There are many types, sizes and designs. My recommendation is to know your chain and its specifications and then whatever tool you use to maintain the saw chain, make sure it is doing the job correctly. I try to keep the filed chain looking exactly as a new one. What I mean is, follow and keep the angles as it comes out of the box when new. No matter whether you are using a Pferd tool or a bench mounted saw chain grinder; the operator is the ultimate reason for safety and cutting results.
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The Tool(s)
There are two Pferd tool designs that are used to sharpen all popular sizes of saw chain. The first works with smaller chain such as low profile 3/8" or .325". (photo 12) This guide uses a 5/32" round file. You can recognize this version quickly as the files are clipped into the guide with wire holders.
The second version holds either a 3/16" or 7/32" file to handle the larger 3/8" tooth styles. This guide has a unique slide lock design to hold the round and flat file in place. (photos 3,13)
Availability
The Pferd tools are available through two sources. The product is sold through Pferd Dealers nationwide as the Chain Sharp™ and through Husqvarna Dealers as the Husqvarna SharpForce™. Under $25 this tool is a real asset to any chain saw operator’s toolbox. For more information please contact info@forestapps.com
Purchase the Chain Sharp Tool from the Forest Applications eStore! Follow this link to the eStore