I have a two variants of this type of machine. First the full plastic model and second the lower aluminum top plastic version. Since I cut in three different locations in Austria, each a few hours drive apart, I................
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https://www.arboristsite.com/community/threads/hf-chain-grinder-thread.268303/post-5092608
Although the above was posted long time ago, I yet found it quite adequate even today. Very good and direct post giving me the confidence boost I needed. I just acquired a bargain "HF" equivalent cheapo sharpener from someone who advertised on an auction type site. He apparently used it once and then rather preferred sharpening with a Dremel tool and grinding stone. My luck, as I needed something to sharpen a chain urgently.
I bought a generic China Chainsaw version model CS-4500 during Black Friday special, felled two smal trees with 200mm trunks, green softwood, and to my surprise the supplied Chinese chain, with name Alston on links, on closer inspection was badly blunted. It could not cut properly anymore. I was shocked. I could not find a replacement 18"/72 DL/325/0.058 chain locally. I then attempted sharpening the chain myself using the supplied abortion of a “file” but the bad quality cheap China file was the wrong size, it was too small and was blunt in itself by the third cutter sharpening attempt. Please note that this was my first attempt, in desperation, to sharpen a chain. I did a lot of research and watched many sharpening videos since the issue presented itself.
In the past I just had a replacement chain installed on my cheapo Chinese electrical chainsaw when the original chain was blunt, thus in total I used two chains over the span of many years before the chainsaw broke a gear.
I have quite a few trees to remove so bought Ryobi 4mm files to further attempt the sharpening, the files were better quality, much longer and the right size, etc. I tried sharpening some cutters but was not confident at all. So when I saw the advert of the available electric sharpener on the cheap, it was like I had destiny with this device. I immediately grabbed the offer and bought the device and was ever so excited at first, then I read the reviews and was disheartened some. I was very concerned indeed. I decided to first play with this sharpener device to verify all the flaws and problems I saw and read about on so many sites and only then will I attempt to do the required or recommended mods I can manage as per the videos. In the meantime it started to rain for a few days giving me more time to play eith the unit and do further research to procure a locally available chain for this saw.
I was happy when, with another stroke of luck, I found a reference about a Chainsaw supplier with a quality Oregon chain, with the correct specifications as required, repackaged under their own Chainsaw brand. I ordered online and once received gave it a test run when weather allowed. What a difference a quality brand chain makes.
Back to the chainsaw sharpener.
I have done some mods based on my newfound knowledge and also based on some of my own observations. I am considering more ideas on improving the subpar brake clamp design.
Some mods I’ve done so far:
Did not find much of a problem with the loose and unstable pitch distance control flapper but added some large washers anyway (scrounged from my scrap bin) to improve stability some more.
I found the bar/clamp unit not very straight, with a varying gauge gap right through, and thus stripped the unit to measure the sprocket thickness determining the gauge gap. I measured them as 1.54mm. I found some nylon spacers from my tinkering box with close to the exact measurements and installed one spacer between the rail plates at every screw possible holding the unit together to maintain the gauge gap at +-1.5mm throughout. Thus the chain movement using the knobs forward and backward are smoother and the chain fits snuggly and stable in the "bar".
As for the clamping plate pulling in at an angle at the bottom when using the brake, which tend to randomly lift and offsetting the cutter position during the clamping action, I placed three of the nylon +-1.54mm spacers on the bottom screw below the clamping plate. I also added additional and stronger springs on the two top screws above and towards the sides of the clamping plate. This increased the steadiness and repeatability of the clamping greatly.
Unfortunately I found the clamping, in the sharpening position, are mostly just clamping on one drive link leaving the cutter in a position that allows it to swivel upwards when touched by the grinding stone. Especially on the reversed angle when sharpening the 2nd set of cutters. To explain better; when I move the chain out of position to clamp the full width of one cutter, that means across two drive links then I cannot easily move the cutter upwards to swing. When moving the chain to the grinding position and the chain reversed tightly against the pitch stopper plate, then only one drive link are clamped and the cutter can then easily be swivelled upwards, again it’s more prominent during the 2nd set reversed angle sharpening stage. My solution is to modify the clamp block to be wider to clamp over at least 2 maybe 3 drive links at the same time.
After these changes were made, I felt much more confident and yesterday sharpened the cheap China chain "successfully?” At least back to a state to operate again.
I swopped the chains and made the China chain attack some wood. Mostly small trees and branches. I was happy with the improvement so I can only give this sharpener a thumbs up. I am feeling confident that it can only go better from here on.
Other changes I am considering;
Dump the brake and use a electrical solenoid to clamp the chain, using a wider clamp over three drive links as discussed above. The clamping action can be automated to clamp when the grinding stone head leaves the home position. A foot switch can also be considered?
I am still considering the need to reverse the motor during the 2nd reverse angle sharpening exercise?
Improve the stability of the grinding head unit using bronze bushes on the 10mm swing pin?
Improve the stability and thus reduce the flexing of the head uni,t which are causing movement of the grind position, by using an epoxy (or Plaster of Paris?) to fill the open spaces that can be seen down under when the sharpener are viewed from the bottom?
That’s it for now.
Thanks for a nice thread instilling the confidence to use this affordable sharpening unit effectively.
More photos and videos to follow as work progress, sooner than later.
Any advice or comments will be welcomed.