OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Diplomat 430 bedknife issue

Hi all
I got a machinist at work to machine up my reel & put the bedknife on the mill. He's our toolmaker & he also has a very old bonner himself so I took him up on his offer.

He's wasn't shore on what angle he should grind the bedknife back so He mentioned 20 degree's & I said that will do then. He done q brilliant job it's very sharp & has a perfect clearance but I think the bedknife angle is out cause when I tryed using it the lawn looked like it had corrugations in it. Very weird?

Any idea what the angle is? It's different to the model 45 the bedknife adjusts to suit the reel. Maynot matter.. If I can't figure it out I will just take it to a mower shop..

Hi Jason, I don't mean to burst your bubble, but what I have always recommended here, is taking your cylinder reel and soleplate (complete with the bedknife attached)
to a engineer that specialises in sharpening (spin grinding) reels and lapping the knife-blade to suit.

These guys do reels as a matter of course everyday and have the "know-how" and the machinery to achieve a terrific result, which I have had every time.

My advice to you is to invest in a new bottom blade and have a recognised reel sharpener lap it to the correct angle of your existing reel, (ie) to suit the angle that your reel has been ground to.
This will solve your problem.
He may have given it a "relief" grind.

Having mates help you out and saving a few bucks is great....but with a cylinder mower...it's a different mind-set....fine tolerances and lots of moving parts.
My advice in short...leave it to the experts!!
Please let us know how you get on!!

I adjusted the reel& bed knife. When I closed the gap a bit more it turned out the reel has a some high spots. (Not turned properly!) He gave me some lapping paste & appeared to work good! When I put paper between the blades it would fold it but won't cut so I thought no contact between the reel& bed knife it would work ok then.
So I gave the old girl a go again.. It made the lawn look like smooth carpet then I started to notice fine lines in the lawn AGAIN! Gggrr 

I will have to take it to someone in my area who can do properly.. (Newcastle-maitland area) I am giving up! It's to hard lol

Lapping must be done with the reel spinning backwards, or you will round the leading edges of the blades and set yourself back rather than making much progress. Also, if your bedknife angle is wrong (which it probably is) the cutting geometry is hopeless and lapping can't fix that. I had hopes that your machinist had at least done the reel properly, but it sounds as if it was a rough job. All in all, you need to go to a specialist to get the situation put right, and get some instructions on adjustment while you are there. Proper adjustment technique is essential.

Hi Jason, I think you have made the right decision...Once the reel and the knife blade are perfectly aligned and adjusted, you will have no probs.
Please keep in touch and let us know how it goes

When I had the model 45 & the diplomat 430 pulled down the reels were identical although the diplomats reel only has a 4mm of meat on it

Both bottom plates look the same but studs are in different spots so if I can't find a replacement I may have to redrill a model 45's bedknife.
I will keep you's updated..

Just spoke to a mower mechanic who has been in the business for over 30 years he does a lot bowling clubs regrinds. I told him what type I had & he said I would have to bring the mower in. they are a lot more difficult to setup than the 45's. Theres a lot more to it than just bringing in the reel&bedknife. He said they were only in production for a couple years. (not everyone's favorite) Hard to work on etc

He qouted me $150 with a new bedknife.. I may just strip it back & repaint if I am doing that.. Will keep you's updated

For a bedknife without grinding, $150 sounds very steep to me. It's just a thin piece of spring steel. If it included grinding both knife and reel, plus showing you how to adjust them, I'd say it was a fair price. However Deejay is the man.

That's for a reel grind, new bedknife, alignment.
I am thinking maybe the front& rear rollers maybe out of alignment. Like the front roller is dropping on one side making the lines. He said something about checking them for wear. Mmm

There is a simple alignment gauge people use for checking that Jason - you can find out what it looks like and how you use it by searching old threads here. The gauge is simply a piece of half inch square rod longer than the mower, with a 5/16 inch screw going through it laterally in a tapped hole. You use the screw to measure whether the reel is the same distance above the rollers on both sides. You also need to check whether the front and rear rollers are parallel to each other in the horizontal, so the mower will sit flat on a flat surface.

With the mower sitting on the concrete it looks like there could be a 2mm drop on one Side of the front roller. I measured it off the bedknife ends. I need to make that tool. The front roller has fair of slap in it.. Dearo oh dear..

Hi Jason, as there are no bearings in the front roller set-up, both the roller end-caps and the roller axle rod wear over time....causing some alignment probs, the rod can be repaired and new end-caps are still available, if that indeed is the problem.

Here is a pic of the alignment tool;

The idea is to slide the tool back and forth, with the underside of the cup-head screw in contact with the top surface of the bedknife and the rod itself in contact with both the rear and front rollers. You will soon see if it is out of alignment.

You will notice that the screw is not placed dead centre of the tool, but closer to one end, so that it does not contact the surface beneath the rear roller. The hole in the rod itself is threaded to allow for adjustment and the nut just locks it in position.

The quote of $150 is reasonable for the services your engineer is performing, in my opinion.
Hoping this helps,

I recently sold a model 45 that had a similar problem. It left lines like this one. It had massive wear on the end caps & shaft I didn't think it could be related to causing the mower to leave lines.. The blades were way gone on it though! I will make that tool well
Cheers

You need to replace the end caps on the front roller, Jason. Aside from making the mower cut closer on one side than the other, they cause slack between the axle and the roller, which means it may cut unevenly as it rolls along an uneven lawn. By the time you also cut alternate strips in opposite directions, it would end up with your lawn looking like the suit of motley a court jester used to wear.

Hi Jason, apart from stating the obvious, it is no good replacing the end-caps on a worn axle....the part is available but $$...I have seen a shaft built up to spec over the worn sections with weld and then reshaped by filing.

I might see what the machinist can do for me. Maybe I could get him to machine up some alloy roller ends& new shaft. He fixed my 45's clutch on the lathe.. Next time I uploads pics I will shows you's.. He done good job on that! He may tell me to rack off soon haha.. I scabbed some square tube from the scrap bin today to make tool.

An update on how my diplomat 430 is going. Well I fitted new roller end caps and it seemed to improve the firmness.. I was going to make a new shaft I had round bar ready to make it with but I found the end caps to be fairly tight.
The shaft has a bit of slap in the bracket so I made up that tool that deejay recommend but i found it hard to slide it along the bedknife cause the reel was getting in road. (have to modify the bolt to clear reel)
I gave the lawn a hit but it was to wet so i just made a horrible mess seems like if you let the lawn get away on you and you mow it its more prone to getting those lines.

I casted a pair alloy roller end caps at work I am just waiting on the machinest to finish them off. I took pics of the manufacture process for anyone who cares

Please post the pictures of the casting process you used Jason, they will make this thread more useful to others in the archive, and also people may ask you questions right away about what you have done, whether you still have the patterns, etc.

I think long wet grass does not respond all that well to reel mowers. The front roller may roll the grass flat, then it may stick to other wet grass for a while, and pop back up after it's too late for the reel to fan it onto the bedknife. Even if your reel is properly adjusted, short wet grass is one thing, but long wet grass is another. You'll be able to mow it when it's dry, unless it is quite horrendously long.

Hi to all, here is a link to a post by Steve (deviosi) re: taking the slop out of a front roller....interesting approach...
Click HERE
Hoping this may help.

The machinest tryed to machine the roller ends but he said there undersize. Alloy shinks after it has been casted so i will have to make anather set.
I am starting to think my lawn is to spongy and the mower is sinking causing the lines.. may have to give it a very cut then..

Hi all
I casted a set of rollers again but this time we made them solid so our machinest can be confident it won't flex. I am a little disappointed how the plastic ones are difficult to lubricate so i think I might get fitter in the assembly area to fit grease nipples to the roller ends.. I will keep you's updated..
Foreign orders take time

Hi Jason, good work on the castings mate, please don't forget to post some pics when you get a chance.

Newsflash! A mower bloke who sharpens reels etc wants me to get him a qoute on a alloy roller gear drive. He said he simply wants just to able to keep these diplomats going. my manager seems interested anyway see what happens.. For anyone who doesn't know the diplomats have a piss poor plastic roller gear drive that strips or slips.

Jason, the ones made out of a stack of steel stampings screwed together look quite servicable, and may be both cheaper and more durable than aluminium ones. The steel ones seem to be readily available.

Check this thread for pictures and details:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=22699&page=3

Hi Jason, as grumpy has suggested, there is a steel replacement ring gear manufactured by Turf Machinery Services in Victoria and is priced at $132.00+ freight.

Good! I will pass on the message than. I think he would have pulled out anyway, buy the time the pattern would have been made it would have blown his budget out the door : o he only wanted half dozen..
Cheers

I don't think anyone would have been happy with sand-cast gear teeth anyway, Jason. Those are rather fine teeth, and they have to run at speed. You'd have had an unhappy customer. If you were going to hob the teeth on a gear cutting machine, the cost of that alone would have pretty much eaten up the factory price he'd have wanted to pay per gear. Look at the way the steel ones are made: simple stampings, if he sources them in China the cost would be negligible. Then he sells them for $132 plus freight. Pity there aren't a lot more Diplomats around, it could be a good business.

The SB Diplomat 430/590 was not a success...unfortunately the company changed its ideas of build quality in the domestic cylinder mower market and did silly things like the nylon ring gear and belt drive in lieu of chain drive....and as for the rear catcher....sheer lunacy!!

I haven't heard from mower bloke I guess he had time to think about it. I would have got the teeth machined properly but the cost would have been out there

I like the idea of the rear catcher, All that grass in the 45's catcher, all that weight on the cheapo plastic rollers dear oh dear. Good thing that plastic ones are cheap to replace. If i see diplomat 590 POP up for sale in my area I will be temped

Hi Jason, you are placing so much importance on the plastic end caps.....mine on the SB 45 are original...and the machine is over 30 years old....and in season I mow sometimes twice a week...you are tempted by a machine that have very few spare parts available; was an absolute failure, has more bits on it made of plastic, nylon etc...has a 'V' belt drive and no cutter clutch....and a plastic rear catcher....there is more to a SB 45 than the front roller, but if that is your wish, mate....go for it!