OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers scott bonnar 45 mower

picked up a scott bonnar 45 pretty good for its age very little wear regards steve...

Looks good. Are you gonna restore this one as well? Where abouts in Aus are you just out of curiosity?

for now i will just give it a good service. sharpening corks carby oil ect to be honest its like this mower was hardly used the cylinder cutter has never been ground the cylinder drive chain tensioner has no flat spots, next to no rust, not much anyway the clutch thrust pad or pawl ithink its called is brass the spark plug is a champion C8. If i understood the the engine id numbers that could tell me the age ? any way wassbat im in nsw central coast regards steve...

servicing in progress note cylinder cutter condition which i am conparing to my other 45 which has a lot less meat ...

deviosi,

From your picture of the cylinder you have plenty of meat on the cutters.

Hi steve, this machine is in brilliant nick for it's age, is it the same model as your other machine? It would appear to be late '60's-early 70's with the Kirby Tecumseh, prior to the 2.5HP Briggs that were fitted in '74.
The cylinder reel is different also to the later Scotties, in that yours appears to be champhered up to the edge (or perhaps hollow ground?) where the later reels have a straight edge.
Plenty of meat in this one tho!!
Steve, on a good score there, mate

hi all and thanks for your intrest again all of what u deejay and bruce have said is right about the cutter reel. i think a clean up and put it back together so in keeping with the original look regards steve..

ive just noticed on the engine info/id plate that the spark plug suggested is a champion j8 which is whats in it i guess that would be called a special plug now daysbeing a full size plug

yes deejay it is the same a mark1 regards steve..

Hi Steve, thanks for posting some good pics, mate. After speaking to the gentleman re: when the Model 45 was first manufactured, he told me 1966, and the serial numbers on the first machines started from 00000 and ran sequencially. Thus with your machine, we can definately say yours was the 867th Model 45 produced!
It is a pity we don't know how many machines were made in a year, eh!

UPDATE: We now know this information was incorrect. No exact date is possible for any Scott Bonnar.

well those numbers had to mean something my other s/b 45 is 02963 going by your info she is younger than the 00867

The other thing that im not sure about is the cutter reel, and that is that the cutters are ground shaped. Im wondering if this is the original cylinder cutter, and whats the purpose of this shape. thx deejay for your source of info. If the kirby engine could be given a date /year that could tell me the age of the whole mower possibly thanks steve...

Hi Steve, yes mate, according to my info, your first SB is the baby of the family....
As for dating a Kirby Tecumseh, I haven't a clue there, Steve. I know you can date a Briggs by it's serial number, as for the Kirby....I will try and do a bit of research.

hi deejay thanks again for your reply!!! Over the weekend i couldn't help myself so i started pulling down the kirby today monday and im half way putting it back together. Head bolts were loose as was every bolt and screw. Inside the fuel tank is dried up leaded fuel and some surface rust, its not good. At the moment i have diesel and some nuts and bolts inside the tank by shaking the tank its helping clean it. I have access to new/old never used parts for kirby/tecumseh engines 40 year old new parts. Anyway heres a couple of pics regards steve....

some more pics of kirby engine pull down ...

deviosi,

It all starting to come together by the looks of it. Just make sure that you get the valve clearance right when putting it back together.

thx bruce i will make sure that i do the valve clearance


i said i would just change the corks and a sharpen but its gone way past that idea getting the inside of the fuel tank clean is a bit of a problem but im working on it handle bars cleaned up nice regards

deviosi on a fantastic job that you have done up to now. I will be looking forward to the finished product because what you have done up to now looks better than a new machine.

g day! some more pics of my rebuild ... Went to set the the cylinder cutter! to the bed knife. And its all over the shop'..... It seems the cylinder knifes are not true enough. An example of this is when, say the left side is ajusted down, and contact made with the bed knife, but the contact is 2" inch in from the left end of the bed knife. To drop it any lower, it is sitting to heavy on the bed knife. I've had both sides up down and in between, and i can't get it to cut from left to right and visa versa. I had it sharpened and a new bed knife. So to sum it up, what i am trying to achieve is a scissor like action across the face of the bed knife, but not able to. This setting was done on a very flat surface, with rear drum ajustment set square to ground and a page out of the telegraph news paper. Any advice would help before I phone the guy who did the sharpening. Thanks all....

ive had this mower three weeks . with the longer days ive realy hoed into it to get it this far in that time but the heat today has me inside for a sunday siesta anyway COUPLELA DAYZES ...

Hi Steve, mate, I'm sorry to hear that you have had probs with setting up the cylinder reel, if it has been professionally sharpened and the reel and bottom knife blade ground and lapped together as they should have been, it should be relatively easy (with a bit of practice) to set it up.
Could you please answer the following:

(1) Does the engineering workshop that sharpened them for you do cylinder reels for Bowling Clubs or Golf greens mowers?

(2) Has the bottom blade been ground, your pics don't show the 'top' of the blade?

(3) Are the bearings true and servicable?

all you have to do is adjust each side of the blade by eye until it looks like the entire blade just brushes the bottom blade when you turn it by hand. Then get your newspaper and fine tune the adjustment untill it slices that paper the entire length

{1} he specializes in queens for bowling greens...

{2} The bottom blade has been ground and brand new

{3} New bearings have been fitted deejay and the bearing hangers/bearing cutter housings are in serviceable condition snugg fit anyway i phoned the fellow who undertook the sharpening for me and has suggested to see how it cuts and if need be come back and see him so i guess thats a fair call thanks deejay/tezza

Hi Tezza, you're correct there, in theory, that's what should happen, but as you will see, in practice, you will do the fine tuning, and all is fine.....paper is cutting nicely from one end to the other, so you then tighten the locking nuts.....
All of a sudden, the reel is too tight on the bottom blade! So you back off the locking nuts and start again!! It takes a bit of practice, but you can get it right.

That is assuming that the reel blades have been ground 'square' (ie.) the reel is placed correctly in the lathe and is spinning; and the rotating grind stone is perfectly square to it, (and in itself exactly square); as the stone moves across the face, each blade should be exactly the same height and perfectly flat (from left to right....The thing to remember here, is that the reel is a helix spiral (ie.) the blade curves around the spiral.
If for any reason the reel is not 'square'to itself or all of the blades are not exactly the same height, NO fine tuning adjustments will correct the problem.

This is what I feel has happened in Steve's case, the reel has been ground slightly "off square".
The solution; re-grind the reel and lap it to the bottom blade.

The main problem is the same one that occurs adjusting tappets on OHV engines. When you tighten the lock-nut, it pulls the central screw through the fixed nut until it is hard up against the upper side of the thread of the fixed nut. This always changes the adjustment from what seemed right when the lock-nut was loose or only slightly firm. The problem gets worse as the machine gets older, because there is more wear on the threads, resulting in more slack.

You need to understand which way the adjustment will shift when you tighten the lock-nut, and allow for it. You should also make your initial tests with the lock-nut moderately firm, and don't over-tighten it when you finish the adjustment - over-tightening accelerates the wear on the thread and makes it harder to adjust next time.

ok all thank you for your help ...

is there a chance that over time and a few ajustments to the cutter reel that it could fime tune a little better thanks again steve...

There are two issues here: first, how well the reel and the fixed blade fit each other, if perfectly aligned; and second, how well you align them. The first is a sharpening issue, and the second is an adjustment issue. You can't fix faults in one by doing additional work on the other.

In my limited experience the biggest problem in most cases is amateur adjustments that damage the blade or cylinder. Once that happens it doesn't matter how well you adjust it, the parts no longer fit each other. Hence I suggest after professional sharpening you should never run the reel under power until you have achieved a perfect result turning it by hand. A perfect result means there is almost no force required to rotate the reel, and no sound except a sort of very slight hiss as the reel blades pass the fixed blade. When you put a sheet of paper between reel and fixed blade, it should cut smoothly right across the width of the reel, and sound like using a pair of scissors to cut paper (only a bit smoother - most scissors are not very well made).

Hi Steve, if the cylinder reel is, as I suspect, slightly out of square, you will find it will wear un-evenly.

However you now have plenty of meat on your new bottom blade and plenty on the reel, so just set it through fine tuning as best you can, or better still, take the whole machine to the chap who did the sharpening for you, and get him to fine tune it....That way he can see the prob and may do a re-grind free of charge for you, if he can't set it up correctly.

Hi Grumpy, you're spot on there, mate, and good advice.
When I first started tinkering with reel mowers, I didn't have a clue on how to set the cutter clearances correctly, so I enlisted the help of the head greenskeeper at my local Bowling Club. He suggested I bring the complete machine down to his workshop, and very patiently guided me through the set-up. My SB, at that time, was very much in need of a sharpen, so he got me to remove the reel and bottom blade complete with it's holder and oganised to have it sharpened. We replaced the bearings as well and (under instruction) got me to do the final adjustments.
Grumpy, you're right about the sound, my machine just humms when it is set correctly.
The advice of that chap has been invaluable over the years, and I am indebted to him for his knowledge and patience.