OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Rover 45 Reel Sharpening

Hi, I just want to get some views and opinions on sharpening reel blades. I have seen some videos on making use of a lapping compound in sharpening reels and not really sure if this one really work or recommended before I go ahead and buy the material.
Also, I've seen different types of grits - 80 (Course), 120 (Medium), 180 and 220 (Fine) and not sure which one should I go for.
Any advice is much appreciated.

Thru the growing season I back lap once a month this of course depends on the size of you block and how many times a week you mow , 120 grit is all I use , I also put a relief grind on the back side of my reel , I get mine professionally ground once a year but this would also depend on how often you mow . Hope this helps you a little

Hi all,

Honestly Backlapping on a Model 45 is just snake oil. The reel used in a 45 is not reverse able and as such is a one way reel.

Back lapping paste on these is simply a money making scam by all the sellers trying to sell you snake oil.

Speak to any honest operator of a machine shop and he'll soon give you "the good oil" on this practice.

This practice has been highly spread like the Corona Virus on the FB pages as most of these pages are run by sellers on eBay and other parts of this Cottage Industry.

Cheers,
BB.

Yes BB seems like snake oil is out there with the Corona virus as well. I have just done the maths (have not been able to find the recovered figures anywhere) but Victorias figure climbs daily and is now at 1329 cases. I have just found a figure and it tells me that there is 130 active cases in Victoria. That tells me 1199 have obviously recovered or died

and rubbery figures as well Norm.

Hmmm one positive note and the rest negative. I'm now having a 2nd thought of doing this. I haven't really sharpened my reel since I bought it and I thought of doing this as I can see the lawn is not cut cleanly. I sometime have to go thru the grass more than once.
I might look at having it done by a machine. Any shop you can suggest around Sydney possibly around West, Northwest ?

I’m far from an expert , just bought another mower adjusted reel would only fold paper , gave it a good back lap , it put a decent edge back on bed knife , re adjusted reel now cutting same paper as was only folding before , maybe ring a couple of grinding shops ask there opinions, as the shop I used recommend putting a relief grind on reel and also to back lap , now I’m s as Leo a bit confused

I've never back lapped mine. It can certainly be done, but a grind and set is better. Think of it as extending the inevitable.

I wouldn't worry at all about a relief grind on a domestic mower.

Ok had a chat to a fellow that made my grooming reel , he runs a cylinder grinding shop in SE Qld , he is a professional that has been in the game for many many years , he also recommended back lapping as a good maintenance tool to do In between grinds , so I will continue to back lap as I have been doing below is the conversation . Hope this clears up the confusion

G'day Shannon, Troy, BB, Norm, and Mystyler
I was apprenticed to a State Ransomes Distributor.
I became a tradesman there.

For me, back lapping is a brilliant procedure between grinds.

In fact, it extends the life of reels between grinds.
For domestic use, a mid-season back-lap makes complete sense.

Think of back-lapping as like the honing of a knife.
It keeps the edges sharp before re-grinding is necessary.

In Australia, ignorance the the main inhibitor to back-lapping.

Hope this helps.
--------------------------------
Jack

p.s. a warning on back-lapping
It will not restore reels that are beyond redemption.
It should be used as a procedure after a regrind,
and not as an excuse to save regrinding.

Hello Troy and Jack,

Thanks for posting that up Troy. I wasn't very clear with my answer, sorry. It's like a leather strop for a razor. A back lap will take away all the tiny imperfections, but you will still have to grind eventually. Sorry if I muddied the waters! And the bloke is deadset right about the bedknife buddies. Cheap and awesome from Reel Solutions in QLD.

And to belatedly answer your question, 120-180 should suffice. Most of the people I know who regularly back lap seem to use 120. You can use valve grinding paste in a pinch, but beware the clean up. It's not water based! Don't really recommend but it is an option if you're truly stuck.

Jack, where do you stand on relief grinding a domestic cylinder?

Hi Mystyler
If you owned a hydraulic or electric gang mower I would say -
not too relevant.

Domestic reel mowers - with smaller diameter reels - can take
advantage of relief grinds - even when the benefit is shorter lived.

There is still a benefit.

Cheers
Jack.

p.s. Many thanks for your thoughtful, and helpful, contributions
to these great forums. All members benefit.

You're too kind Jack, I'm one who appreciates seasoned knowledge! I like trying to give back to the forum that has helped out myself, a keen back yard hack.

Regarding the the relief grind - would the main tangible benefit for the homeowner be the cleaner cut? Everything else I've known about the relief grind is that it reduces wear and has greater efficiency for the petrol motor as the cylinder contact area is absolutely minimised. Less wear, less fuel, less stress, less dollars?

Thanks guys for the great information and explanation, appreciate it

G'day Mystyler, Troy and all
No, relief grinds will not produce 'cleaner cuts'.

But - theoretically - should reduce wear because of efficiency gains.

There is a tendency for inexperienced folks to 'over-set' reels - meaning that
the reel to bedknife contact is too tight.

Relief grinds - by definition - reduce contact area and ... friction.

I have seen over-sets where the reel has overheated to the extent that
motors start to labour [without any grass cutting].

I once witnessed this on a Ransomes 5/7 hydraulic.



An apprentice had over-set the reels and the machine was
in distress when the reels were raised. Fine when cutting
grass [because grass was cooling the reels].

Cheers
--------------------
Jack

p.s. I think that apprentice might have been me ...

Jack the old apprentice trick hey lol , geez that machine pictured would take some setting up