OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Rover Model 45 (or SB45) Cutter Adjustment

Hello Everyone,
My mower does not appear to be cutting the grass properly as it is leaving some strain of grass and have to run it a few times to cut the left over. I'm in the process of checking the cutter to see if it just needs adjustment before attempting to get it sharpened.
Attached are some photos if this would help.

Hello Shannon!

This is a very common issue, and it requires a procedure to be done to
determine the condition of the bottom blade. The reel itself looks to be
recoverable by back-lapping, rather than grinding. The bottom blade presents
as being of servicable thickness.

But ... if the bottom blade is not recoverable, both reel sharpening and a new
bottom blade (also sharpened)will be necessary.

The Administrator, Deejay, is back from leave now, and Bonnar Bloke has
dealt with your clutch 'issues'. I think they have their own unique method of setting
reel mowers, so I won't interfere with that advice as my focus here is history.

I hope this helps.
----------------------------------
JACK.

Hi Jack,
Sorry for my ignorance but what does it mean by back-lapping ?
Also, if I need to sharpen the reel and the bottom blade, do you have a place that you can recommend for sharpening around these suburbs - Baulkham Hills, Castle Hills, Blacktown, Seven Hills ? Also, would you have an idea on how much will this cost ?

Hello Shannon,

That's a great question for many reasons ...

It appears to me that the dramatic decline in reel mower sales has resulted
in a concomitant decline in the knowledge base about the maintenance of them.

Backlapping is an excellent (and cheap) procedure whereby the reel is
spun backward (usually manually with a crank handle) in combination with a
grinding paste, to refresh the cutting edge of the reel and the bottom blade.
After a complete flush of the paste, paper is used as a 'sharpness test' to
determine the condition of the cutting surfaces. Here, paper is not used as
a 'thickness gauge', as though it had similar properties to grass.

The procedure is greatly underutilised and certainly misunderstood nowadays.

Recommendations:
This is another great question. It appears to me to be insufficient just
to refer-on reel maintenance to an 'engineer' - a mower sharpening service.

I hope an ODK member or visitor can recommend a service in your area.
Falling short of that, you must take control in asserting consumer awareness.

Here is my check list:
- Is the service an agency, or do they sharpen reel and bottom blade themselves?
- Do they have 'the knowledge'? Example: do they understand required relief angles?
- Do they have purpose-built equipment?
- Do they grind both the reel and bottom blade?
- What is the price differential between delivering a complete machine, or just components?

I hope this helps.
-----------------------------------
JACK.

Hi Shannon,

I think Jack has said it all and there's not much else I could add apart from going to see your local bowls club and ask them who they use as they don't muck around with amateurs, nor can they afford to. Generally whoever is the greenskeeper will be only too happy to chat to you, especially if you show a keen interest in what he's saying.

All the bowling greens send their blades and reels off on a regular basis to the same engineer all the time as they are normally satisfied with him and won't just change because of pricing. If you use the same as they do I'm sure you'll be happy.

Many small lawnmower shops don't have the equipment nor the expertise and normally will use the same engineer as many of the bowling clubs do, so to cut out the middle man charge just go to the bowling club who will inturn send you direct to the engineer where you'll save on middle man costs.

Cheers,
BB

PS.

Just looking at your photos of your reel and bed knife they look to be rather good and probably just require very fine adjustment.
DeeJay has a very good video on adjusting the reel to the bed knife and if you follow that you can't go wrong. If you want to go into back lapping then that would be an added advantage giving you an even better end result.

CJ, there is indeed some truth in your statement, but there's a 'play it safe' aspect to this advice too.

Along with the decline in reel mower maintenance technique knowledge, there has been a general steep decline in mechanical repair experience/ability among the populace as a whole. And an even more severe decline in the number of folk who can 'nut out' repair issues, by visualising how something mechanical should work, if all is well with it. The latter has largely become a 'bush mechanic' attribute, these days!

That's why, with reel mowers in particular, there's a reluctance to blithely advise novices to 'have a crack' at some tasks. Particularly those that are best done using special tools and fixtures [e.g. rusted in bedknife screw removal].

While we may have been able to make some estimate of an enquirer's workbench facilities and abilities with respect to a given task, and reply accordingly, there's another potential issue.

That is, that these discussion threads become a persistent record. And they will be read by the clueless, at some time. Thus the possible issue of a reader, by their efforts, causing expensive or even irreparable damage [even to irreplaceable components] is very real, I feel. No reflection on any poster to this thread here is intended, by the way.

Very good checklist there, CJ.

To 'return to our muttons' on reel/bedknife grinding, it seems that there are only three main makers of this specialised equipment in the world. FOLEY in the US, and HUNTER and BERNHARD in the UK.

A look around those makers' websites will give one an idea of the high-tech automated equipment that is the state of the art for these tasks. And maybe the setup costs involved in offering these services, at a high quality!

Thank you guys for all your comments. It certainly help and gave me ideas. First, I'd like to try doing the adjustment first if I can.

BB,
Are you able to point me where I can find Deejay's video ? I want to try doing the back-lapping as well but not sure where to get the grinding paste.
Is there a particular brand I should be looking for ?
Is there also a video on how to do back-lapping process ?

Thanks

Hi Shannon,

Just firstly watch this and see how you go before any back lapping.

https://www.outdoorking.com.au/forum/ubbthreads.php?ubb=showflat&Number=32207#Post32207

Cheers,
BB

Thanks BB. I watched this video and was quite informative. I'll start making little adjustment and see how it goes next time I cut the grass.

Hi Shannon,

I would simply adjust it until it touches evenly on both sides and then very finely back it off until it just doesn't make contact anymore and then see if you get the desired result on your lawn.

Cheers,
BB

Hi Again Shannon,

If after this you want to go down the back lapping road then I would do that as your reel looks to be in really good nick.

Cheers,
BB