OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Reel-Type Mowers Scott Bonnar 590 012 Reel Mower - Help!

"I Have a Scott Bonnar drum mower MOD 590 012 .
How do I adjust the striker plate for clearance to blades?
How do I sharpen the blades? Can I obtain a manual for this model?"

Hi hdon,

Here is a link to the parts list for the Model 590 CLICK HERE

As to a workshop manual on the mower I don't know of one but maybe one of the other members will be able to help you out with information I am sure.

Hello hdon and Bruce.

A lot has been written about the Diplomats on these great forums.

The set adjustment (reel to bedknife) is a very poor design.
It was - best guess - a result of bean-counting, rather than designers' intention.

The blades should be sharpened by a company qualified to do so.
Do not go through an agency.

Both reel and bottom blade should be sharpened.
Most probably, the bottom blade will need replacing.

On these machines, keeping the 'set' will require good habit.
Copper washers on the set bolts (4) should be in good condition,
and not work hardened through age.

The Diplomats are rewarding machines - if understood.
They won an Australian Design Award in the day.

They are greatly misunderstood!

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

Thank you Cyber Jack and Bruce for your help. I will take photographs of my mower and its cutter plate and post them early next week for your further consideration.

Appreciate your help,
H.Don

Here are the photos of my 590.

What steps do I need to take to adjust the reel to bed knife?
What extra bits do I need to get? Bolts?
What do I need to loosen before I start adjusting the bed knife? I do not want to snap or bend anything on the machine.

Hope you can guide me in this.

H Don

Hello hdon,

It is clear that the set adjusting was cheapened for the Model 430.
... But your machine - the Model 590 - had a proper adjuster.

Amazingly, ODK does not have a 590 Operator Manual!
We only have a Spare Parts List. Amazing!

I attach the required pages (see gallery).
Adjustment of reel to bottom blade would be via the
"soleplate adj screw" [No 28]... p/n 591584.

I think the soleplate pivots on [24] and [25].
You would need to loosen the set screw [27] and
then adjust [28] to close or increase the gap between the blades.

Once adjusted, the set screw [27] would be re-tightened to hold
the set in place.

However, your images are small and lack resolution.
the reel and bottom blade look blunt!
They need sharpening.

I thing a 'set' would be useless if the reel is blunt and the bottom
blade is worn beyond serviceable life.

I hope this helps. but your post has highlighted our ignorance of
the Diplomats and the differences between the 590 and 430.

Please keep us informed.

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

p.s. higher resolution images would help blade condition assessment.

Hi Jack
Thanks for keeping with me.
Here are 2 more photos for your consideration .
I would think that as well as the adjuster screw 28 I would need the Nylock nut 29 and soleplate adjusterpad 30. Are these bits readily avaliable?To my uneducated eye the sole plate looks good, no sign of wear ie. no step on it .The mower cuts quite well but the blade clearance is uneven.I will get on to the subject of back lapping the 590 after I can set the blades .
Looking forward to your thoughts .
H Don

G'day hdon
These images, again, are way-too-small.

This must be frustrating for you!
Your images are tiny. I cannot see any detail.

Now, Nylock nuts are universally available and should be replaced.
I'm not sure about the adjuster pad.

That's a clue here. It means there is serviceable life on
the bottom blade [bedknife] but the surfaces are uneven.

Again, we need clear images of an internet size.

A Note on Back-lapping: -
Back-lapping can restore a well-maintained reel and blade,
but it cannot perform miracles.

But there is another issue for the Diplomat models ...
Back-lapping requires the reel to be rotated in reverse.
Here, a Left Hand thread on the reel pulley makes this impossible.
[the pulley would unscrew].

Please keep us informed.
------------------------------------------
Jack

Hi Bruce and Jack Adjusting the drum to bed knife was just too easy on the B&S 590. After squirting the cutter blades pivot points with WD40 I slackened both end bolts off ,bolt A ,one either side of the machine .Then slackened off the locking bolt B .Note the other side does not have a locking bolt. At this stage the knife blade is quite loose and can easily be moved with the gentle use of a screw driver to the desired position.I did this first to the side where the belts are ,and tightened the pivot bolt .This locks one end.I then adjusted the other side and tightened the locking bolt B then the pivot bolt A . The 590 then cut the lawn very well .Note that by moving the plates apart the drum and blade get closer. i will look into back lapping a 590 in the new year I Have a cunning plan of how to do this.
Thank you both for all your help.
H Don

Hello hdon and Bruce
This is brilliant.
I feel you are helping advance knowledge here.

So, locking bolt on the RH side.
May I ask, is the flat washer washer copper or steel?

Your images are clear.
That final image shows an impressive finish for any domestic reel mower.

WE look forward to your 'cunning plan'.

Thanks for helping us understand the enigmatic Model 590.

------------------------
Jack

Is there some way around the drive gear problem on the 590? If not they are hardly worth the effort. I have one but I do not think it's worth worrying about.

Jeff

Hi Jeff,

I guess you've hit the nail on the head why the Diplomat style SB's became a failure from an after sales point of view.

Sadly the drive gear was the part that always failed and replacing that component of the machine was obviously painful to some folks, but when the parts issue dried up on those gears then that relegated these machines to the hard rubbish collection.

There was a short run of metal gears made which solved the issue permanently for each machine that had it fitted but they sold out in no time and were never made again.

If someone invested and had them re-manufactured I'm sure they'd make some easy money, especially in this current Scott Bonnar climate where everything with the SB name on it seems to be a must have item. The last of those metal gears sold for around $200~$300 many years ago and that made it an expensive investment to keep a mower going, thus most went to mower heaven.

Generally speaking they were quite a good concept with the catcher being behind opposed to out the front getting smacked and restricting tight movement, but the market has spoken I guess.

Cheers,
BB.

BB,
somebody was making a good quid out of selling those gears at that sort of money. Problem is now I'm guessing most of the machines with the broken gear have now been dumped so the market for a re-run of gears would be fairly limited. I'm guessing the OP here has a machine with a steel gear fitted otherwise he could be doing a lot of work only to find the gear gives up as he starts using it.

Hi Jack & Bruce.

The washer was made of steel. Will catch you next year all the best.

H Don

Hmm, I wonder,

I have never looked at the drive gear on mine. It still works, perhaps it's steel. Can you see the drive gear without dismantling the mower? I can't give this thing away. The choice is steel or plastic I think.

Just wondering
Jeff

You might have a little windfall there Jeff if you have one of the unobtainable steel gears and if not somebody might want/need the plastic one

Sadly Jeff that's the reputation that these things have.

and honestly I think they are one of the ugliest mowers ever made. Unfortunately the SB craze that's currently capturing everyone just won't extent to the Diplomat series of mowers just like the Mitsubishi Sigma won't ever get caught up in the 1970's & 80's car pricing craze.

Cheers,
BB.

Well if anyone wants it I would be happy to give it away. I have tried before but no luck. I'm not a SB fan. Was once but water restrictions mean not many can grow that type of lawn here in Brisbane

Jeff.

Change to gravel or concrete

That's about it. Or artificial grass

I'd prefer the artificial grass, but it's very pricey that's for sure