OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Reel movement within the frame

Hi

I have a question about the movement a reel should have (or not have). My 14in SB model 45 reel has about 5mm to 10mm of movement left/right. When I recently cleaned the chains I noticed that one of the bolt heads in the chain compartment had been worn due to the chain moving left/right and contacting with the bolt. Should there be any left/right play or am I missing some part or perhaps have something loose?

I'll post some photos when I get a chance if needed.

Thanks
Dean

Hi DeanH,
Yes, mate, photos would be good. Instructions for using the forum 'Inline Uploader' can be found HERE
The cutter bearing housings should stop any lateral movement of the cylinder reel if all is well, something may well be amiss.
Looking forward to the pics.

Hi DeanH,

I'd say that your reel cutter shafts on which the bearings are originally pressed on to are worn and as such your reel is moving laterally within the bearings. Very common scenario in the Scotty design.
This problem is generally overcome by either knurling the shaft or the cheats way is to centre punch all around the mounting area on the shaft and then press the bearings back on so that they actually rotate as any bearing is meant to opposed to the shaft rotating inside the bearing itself.

Cheers,
Bonnar_Bloke

Hi to BB and Dean H,
Good thoughts there BB, that might well be the case, I have not seen the cutter shaft worn like that personally; but it would explain the symptoms, to a tee.

The next question would be...What would cause the shaft to wear like that in the first place?

Hi Darryl,

I must admit just about every reel I've taken out has suffered shaft wear to some degree as the bearings should be a press fit and not simply slide off. This is much more of an issue on the sprocket side but it does occur on the other end as well. Why ? I still don't know, but generally most reels need to be either lightly knurled or centre popped around the bearing mounting surface. Only then can they be ground and properly mounted back into the machine.


Cheers,
M.

Hi BB,
You have raised some interesting thoughts there mate. I spoke to our forum historian, CyberJack, yesterday about this issue and to try and work out the cause. He said that as an apprentice, he found that this problem was very prevalent on many Scott Bonnar Model 45 machines he worked on.
Here we have the dilemma, was the bearing surface designed to be a 'push fit' or a 'sliding fit'.
Grumpy has suggested it is actually what is called a 'transitional fit'.
Obviously this was a design issue at the factory, and the bearing area was made so as the bearings could be put on and removed from the shaft by hand....removing the need for a bearing puller; which can only grab the outer ring of the bearing, resulting in brinelling of the bearing surfaces.
The plot thickens....

Hi all,

I think Administrator Deejay is quite right in exploring this issue.
It certainly becomes more relevant as these machines age.
Dean has raised a worthy issue for all reel mower owners.

Grumpy - ODK's resident engineer and Global Moderator - has narrowed this to
explain my experience as an apprentice. The original specification must have
been for a transitional fit:-



I had considerable experience with 45s. Even machines that were having
their first sharpen and set (after a couple of seasons) exhibited the same
reel bearing characteristics. The vast majority of reels had their bearings removed
by hand pressure alone. It was a snug fit.

It was rare to use a 2-legged or 3-legged puller. If a puller was required it was
most likely needed on the R.H. side bearing (the short shaft).

If the bearing 'fell off', this was a sign to peen the shaft and Loctite the bearing.
This was a quick and easy fix.

Note: I guess it goes without saying that the lateral movement of the reel
is caused by loose bearing fit. The other possibility is that the bearing itself
is sliding within its alloy housing. That would be a simple fix as well.

All very reel.
----------------------------------
JACK.

Hi DJ,

I'm starting to think that the original fitment was a firm slide on and not an actual interference press fit.

You'll probably find that most machinists would want the reel to sit very firmly on the inner race so as to get a very accurate result from their centrifugal grinders.

Once you have the slightest bit of movement, this will only accelerate the wear factor. I personally prefer a very firm contact with the inner race as this then allows a very fine and precise adjustment of the reel to the bed knife.

Cheers,
M

PS I was writing this post while Cyberjacks was being posted, thus my wording doesn't actually reflect what was said in his post but more so to DJ's response.
Cheers.