OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar 30" Model 65 Question

I am new to this site, and to forums in general. Not sure if this is right way to post.
I have a Scott Bonnar Mower No. 10695, Model 65030. It has an 8 HP Briggs & Stratton engine (cast iron bore). It is in working condition, but needs adjusting and sharpening. The grease nipple furtherest from the drive sprocket is missing, and the thread is stripped. I cannot see how to remove the cylinder; between the sprocket and the frame is a hole about 3/8" diameter right through the shaft. I feel that this may be for a tommy bar to undo the sprocket which could be attached by a left-hand thread. A friend thinks that this hole originally held a retaining pin which held the sprocket onto the shaft of the cylinder- if this were so then the sprocket must be rusted on. Looking at the sprocket from the end one sees a fairly featureless round recess, with no retaining nut or thread etc., and no rust. Can anyone help?

aboard to the forum MacCullum. I'm sure that we will be able to help you with your issue and here is what I would suggest you start with unless the other members have other suggestions as well.

I would suggest that you give the sprocket a good soaking of WD40 or something similar for a few hours before attempting to remove it. The if you have a brass dolly you could place it in one of the teeth and give it a hard tap (not hard enough to damage the tooth).

Then if you have a steel bar drill a couple of holes in it so that you can put two bolts in (the bar) so that they go into the tooth holes neatly. Once you have done that you should be able to undo the sprocket if it has not come loose when you tap it with the brass dolly of course.

Try this and let us know how you go.

Hi MacCullum, and a warm welcome to the forum. You will find us a friendly bunch here, as we all love to learn new things and tinker here. It's always nice to welcome another Scotty owner to the forum.

In answer to your question, your machine is a 30" Scott Bonnar Model 65.Model No:65030.

Your cutter (cylinder reel) and soleplate (bedknife and it's holder) assembly must be removed as a complete unit.
You will find that you are very lucky as well with your model, in that your cutting reel is fully reversible, thus extending the cutting life before sharpening.

The removal procedure for the Model 65 is comprehensively detailed in the operational manual contained in the Lawnmower Parts Lists and Manuals topic on the main forum. Access to this area is by subscription and is explained fully in the thread "How to Access Parts Lists and Manuals" which is the very first thread in any topic on the main forum list.This will also come in handy if you need parts as well.
Once again,MacCullum,

Thank You Bruce & Deejay!!. I am astonished to have received such prompt and useful advice. The internet sure can be a wonderful thing. I have now paid my subscription and downloaded the manual for my Scott Bonnar 65. I had not realised that the cylinder and cutter form one demountable unit. The sprocket which I was stumped by screws off with a left-hand thread, and it is obvious now that the hole I mentioned is for a tommy-bar to unscrew the sprocket. I had regarded this mower as simply a utility item, but now I see that it should be possible to almost completely restore it, and I shall look after it much more carefully in future. The bedknife is quite sharp but rusty and probably would be best replaced. I shall post again when I have got the cutting unit out and examined it more carefully. Thank you once again.
MacCullum

Hi MacCullum, no probs mate, we're glad to be of help.
Please let us know how you get on.
BTW, we all love to see pics of members projects, can you please post some as you go along?
Thanks mate.

Hi All, Have been a bit slow with the Scott Bonnar 65 because:-
1/ Spent 1 day removing one of the three cylinder gangs on a very 2nd-hand TORO Super Pro 81 (1982 manufacture) mower that I have had in the garage for some years; about 4 years ago I was starting it in order to take it for sharpeningwhen it backfired and jammed. I thought that it had broken something inside the Kohler engine, and left it as was.

Recently I started to remove the engine, and found that the drive belt had jumped and become stuck, so now the old machine is functional, though the gear box seems very worn in that the gear stick is loose and the four gears are hard to select. So I took off one gang to see if sharpening would be possible. The adjustment lowers the cylinder onto the base plate, and there is not much travel left in this adjustment. ADE Turf Equipment in Melbourne deals in large Toro mowers, and said sharpening and new base plates would be no problem.

They showed me the machine they use, and it had a Scott Bonnar mower on it at the time! This was smaller than mine, possibly a 24". The whole mower was mounted on the sharpening machine, with its base plate removed (these latter are ground by a separate machine). Thus the tool carrying the grinding wheel moves along below the mounted mower. I did not see what caused the cylinder to turn as the grinding proceeded. Having read the details about grinding these cylinders on this forum, I wondered how it would be possible to fix and position the cylinder with the accuracy apparently required with respect to its axle. I did not see this working, but will go back with the other two cutting gangs and take more notice next time.

If anyone has had the patience to read all this, what do you think, and should I be thinking of sending my Scott Bonnar cutting assembly to an engineer more like the one described by Deejay?

2/ I spent yesterday working on the drive mechanism of a Hardi 320 mini sprayer - not so mini in fact as it has 10 spray nozzles and is a vineyard sprayer, this machine was also bought 2nd hand 15 years ago and needs tlc, parts, and time. Yes we have a vineyard, very time consuming.

3/ We used the long shank of an Allen key as a tommy bar, locked this onto a handy protrusion from the frame, and then turned the cylinder using a long tyre lever working from the axle onto one of the blades beside its supporting disc. It took quite a force, but the sprocket screwed off in fine style. Had no time then for further dismantling, but the rest should be plain sailing. Will keep you posted, and upload some photos as I go.
Cheers to All, MacCullum

Hi MacCullum, The engineer in Wagga that I use, sharpens all of the bowling clubs' greens mower cylinder reels by "spin grinding" ie. just the reel in the grinding lathe, as he believes that greater accuracy is achieved....also it allows the cutter bearings to be examined and replaced if necessary.

If the bearings are worn, you will not be able to set up the correct clearance between the bedknife and cutter, resulting in uneven wear on the components.

Thanks Deejay, I suspected you were going to say that. I will have to try to find someone like your engineer in Melbourne.
MacCullum.

MacCullum, your description of how the cylinder reel is aligned in the sharpening machine is not detailed enough to indicate whether the result will be good or bad. It would be a bad idea if the mower frame is being used as the blade alignment jig, because the key relationship is between the reel and the bedknife, not the reel and the frame. The traditional solution is to make the reel true to its axle after sharpening, rather than true to the mower frame. Sharpening the reel true to the frame could result in the reel being tapered along its length, which might work in the short term, but could cost you a lot of blade material if the next time you sharpen it, you go back to a traditional method and grind off a whole lot more of the blades to bring it back to parallel. In addition to this there is Deejay's point: if the reel is sharpened while mounted on loose or worn bearings, you will end up with a lot of irreplaceable blade material ground off but a reel that is worse than it was before sharpening.

Hi MacCullum, just contact your nearest local bowling club and speak to the greens-keeper. They are usually friendly guys,and will point you in the right direction as to where they get their sharpening done.

Hi All, I have now got the cutting assembly separated. Will try to post pictures. The bearings seem OK, but the thread for the grease nipple on one of the bearing housings is stripped. Much worse, the left hand (looking from front) bearing housing is cracked where it is held by the "cutter bearing housing pivot". This pivot unscrews with an Allen key, but I have not attempted to undo it, as turning it will almost certainly complete the fracture in the housing. A new cutter bearing housing would be the best answer but I have no idea whether this would be available - part number 651268. The pivot also looks a bit moth-eaten - part number 651284. I also feel that a new bottom blade should be fitted - part number 652746. Could one of you please tell me whether these parts can be found, and how I should go about it. Hopefully, I attach illustrative photos. MacCullum

It looks to me as if it is the rust that is holding it together, so removing the Allen cap screw probably would result in it falling apart, as you say. In the old days it might have been repaired by cleaning out the radial cracks with a saw blade and welding them up before dismantling it, then welding it up more elaborately and dressing the welds where necessary. A new part is a tidier and more controlled solution, if the part is available. Personally I'd try to weld it, just because I'm an old guy and accustomed to working on old stuff for which new parts are either unavailable or too expensive. However I've made a lot of work for myself at times by following that approach.

Hi MacCullum, I hate to be the bearer of bad news.

I have made some inquiries for you regarding the availability of spare parts for the Scotty Model 65. Bruce has indicated that the online store cannot help here. I have been told by an acquaintance of mine, that parts for this model are really scarce and those parts that are available, are very expensive.

I contacted another business that deals in Scott Bonnar parts and you can get the cutter bearing housings...but at a price...are you sitting down....$240.00 each...
The "cam action bearing housing moving" (you call it the "cutter bearing housing pivot" is also available at...you better sit down again...$160.00...Ouch!!

Bruce and I discussed the condition of your cylinder reel, and we both agree that it will be good for possibly 2 maybe 3 regrinds before it will need to be replaced. Bruce may be able to help out here when the time comes. Used reels in good condition are available, depending on how many blades you require; 8 or 10.
Sorry I could not have better news for you,

Overcoming the stripped thread for the grease nipple should not be much of an issue. My system is to keep a jar of miscellaneous grease nipples and when one breaks I just replace it. If the mounting thread is stripped, I just tap the hole to suit one of the larger types. From memory the largest standard type is 1/8" BSP (also known as 1/8" Gas). You can probably gather a supply of mixed-thread-size grease nipples from really old equipment lying around or in farm clearing sales. Many old grease nipples are of limited use because the ball the grease gun fits to is worn, and there is excessive leakage when you apply high pressure, but if no great pressure is required this will not be a problem.

thats bad news on the parts cost holy crap.

looks like you may have to break out the welder and do a patch job.

it does look to be aluminium tho. in which case your rooted

Hi Tezza, you are right there, mate, the part is aluminium alloy, as is the "cam action bearing housing moving", as well.
However, second hand parts may be available, which would get MacCullum out of trouble...
Here's hoping,

You should be able to MIG weld it, using argon, if you can clean it well enough. Second-hand parts may not help all that much, since the main problem seems to have been electrolytic corrosion between the aluminium flat part and the steel Allen screw. The corrosion deposits built up in the gap between the flat and the screw, which eventually caused a tensile failure of the aluminium flat in two places. Unless it has been kept dry, a second-hand one is likely to have much the same problem. Unfortunately the hole is now much larger than it was originally, so if you repair it by welding, it will have to be bushed back to the original size before you can re-use it. Might be a good idea to keep it dry in future, and use a stainless steel cap screw to keep the electrolytic reaction to a minimum.

Thank you Deejay. It is good to know that those parts are available, though I did have to sit down after seeing the price. Are the parts you quote new? I wonder why the "cutter bearing housing pivot" as it is called in the parts manual, has morphed into a "cam action bearing housing moving"? How much would I need to pay for a cutter reel (mine is 8 blade) in good condition?
As a first move I have taken the cutter assembly to an aluminium welder who has a very good reputation. He seemed unfazed by the request to weld the part; I suspect that it will need rebushing. I do not know what the "bearing housing pivot" looks like when removed; is it just a simple pivot rod, or does it also prevent the bearing housing from moving laterally?
Thank you Grumpy for your advice which, as you see, I have followed.
Is a suitable bottom blade available?

Hi Again, Welding now done; seemed to go without a hitch.

Can anyone tell me if I can get a bottom blade for my 30" Scott Bonnar 65? The current one has 10 holes.
MacCullum