Setting a fine turf mower ‘on cut’
Afternoon,
Hope everyone’s enjoying the weekend..
I’ve always had a bit of a thing about the amount of contact between cylinder and bottom blade. I’m very much a lawn enthusiast as well as a mower enthusiast, so the quality of cut is paramount to me.
Just recently I’ve been experimenting. I’ve sharpened up a Ransomes Ajax - with the original lipped bottom blade I can get it to pass the paper test with zero contact. I put it on the lawn, mowing in virtual silence and it was … nothing more than OK…. I wound it on a bit to achieve a medium contact and, my goodness, so much better!
A sharp Greens Zephyr Deluxe and a Certes I can only get to pass the paper test with a medium heavy contact. I’ve been using the Certes, its a tough push but what a finish! Just superb.
So my question is, on the manual fine turf mowers (or perhaps any push mower) - is it reasonable to expect them to be set on quite hard in order to achieve the best possible finish?
in this vid, which I like a lot, you can hear the type of contact I’m talking about circa 2:50
cheers all,
Will
Forums
“is it reasonable to expect…
“is it reasonable to expect them to be set on quite hard in order to achieve the best possible finish?”
In an ideal world - No. Quite hard implies metal to metal contact and that implies heating and expansion; at which point heavy contact becomes too heavy. With professional equipment the current vogue is for “ contactless cutting” . That assumes cylinder bearings in A1 condition and cylinder blades precision ground , perhaps with some relief and a bottom blade ground to a similar standard on both the top and front faces . Nothing but proper grinding will achieve that but for the “ hobby “ mower owner, probably, the best that can be achieved is a one time properly ground cylinder and blade , maintained by back lapping. No disrespect, but I’d suggest that dressing with a stone is unlikely to give satisfactory results in the long term. Regrinding can be expensive and every time it’s done metal is being lost , eventually leading to the need for a new cylinder or the machine being relegated to an exhibit.
Going back to the original question , the quality of the cut relies on the blades of grass being cleanly cut and not bruised between a mismatched cylinder and bottom blade; a hard set is unlikely to achieve that . My take on the “ cut paper test” is a dry 80gm copy paper strip folded. If the top layer is cut and the bottom bruised , it is often the best that can be achieved without winding down the adjusters. However, when I grind a cylinder and bottom blade I would expect a clean cut of a single piece of paper with the blades barely touching .
Hello - I have always…
Hello - I have always sharpened the bottom blade and cutting cylinder with a stone placing a single strip of A4 paper to test the cutting performance across the entire width of the blade. It's a bit hit and miss at times as to whether it cuts the paper or not. I usually place the mower on its side on the bench and as I rotate the cutting cylinder to sharpen the next blade the sound does change which indicates that I'm making some progress. There is a fine line between too much and not enough contact between the bottom blade and the cutting cylinder of course.