The Old Lawnmower Club
Collection, Preservation and Display of Old Lawn Mowers
X

Setting a fine turf mower ‘on cut’

Enter a word or two to search the forum section and click the Search Forum button.
Will Sun, 22/05/2022

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

https://youtu.be/1bz5RrCjFVg
 

cheers all,

Will

 

Forums

Mower1 Wed, 14/12/2022

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. 

wristpin Sun, 18/12/2022

“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 .