OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Reel Lawn Mowers, Atco & Villiers etc. Aligning Cylinder Reel and Bottom Blade (TROUBLE)

Gentleman

Despite spending an inordinate amount of time (2.5 Hrs) attempting to get the reel and bottom blade aligned last night I gave up in disgust with a non paper cutting gap. I do not believe that Alvin the Alroh will ever be a paper cutter. I am more inclined to believe that the Tooth Fairy will arrive in the company of Mary Poppins with skyhooks and a left handed screw driver with a carton of Crownies to ease my pain......


To say this was frustrating would certainly be an understatement.


The types of issues that arose included

- The adjusting nuts (4 Off of two differing sizes)) are a size for which no socket, ring spanner or open ender has ever been manufatured.

- After getting the bottom knife just clear of the reel and tightening the upper and lower pivot bolts the blades would then move to a different position either too create a large gap or set it tight on the bed knife again

- The upper pivot is steel bar attached to the body of the blade holder is tapped to accept a bolt (another for which no spanners ever manufactured) with a spring washer and it appears the tap is now threaded

- Regardless of the tightness of the reel against the knife the paper I was using must have been indestructible as the only way to cut it was with a pair of scissors from the dressmaking cabinet. Even when the blade was only just able to move (tightish) it would still not cut paper.

- The best I managed at any stage saw the reel just touching the blade but only in the centre of the reel. If someone could explain how that happens I'd be interested to hear.

If anyone could provide an alternative strategy please let me know. In the meantime I am off the light beer and back on the heavies !!!!!

Thanks for listening


Rob

Rob,

Has the cylinder and bottom blade been sharpened?

Rob, you should think of this as your first step toward understanding Alvin at a personal, psychological level. One day you will have come to feel that you know him, but you will probably love him less because of it.
First, with regard to bolt sizes, they are probably Whitworth. Whitworth bolts and nuts are, indeed, a bit of a trial since neither A/F nor metric spanners will fit most of them (unless by luck). I junked most of my Whitworth stuff a generation ago, but had to fish around and find what remnants I could when I got my Alroh Imp edger. All of its bolts are Whitworth except those on the B&S engine, which of course are A/F.
Adjusting the bedknife is, as I've told you before, something of a black art. I can tell you how to do it, but it will take you a while to get the feel of it. Meanwhile, I think you are saying that the thread is stripped in at least one of your adjustment points. If so that will have to be repaired; the job is hard enough when the machine is working properly.
You said that even when your reel was actually touching the bedknife, it would not cut paper. It sounds as if one of three things has happened: your reel was very badly sharpened; your bedknife's cutting edge needs attention; or there is a misalignment between cylinder and bedknife so the cutting edge of the bedknife is not the part that contacts the cylinder. You can find out which by examining the edges with a magnifying glass, and looking closely at the alignment.
I think your situation is not at all unusual, and is the reason we were suggesting you form a reasonable personal rapport with your mower technician. It is likely to be a lot easier for him to show you, than for me to teach you from long distance by the use of words only. Either can be done, but the former is better if it is an available option.

Hi Bruce
It was shaprned yesterday by Gary at Woodlands Mowers here in Brisbane. He has his own lathe and told me the job went well?

what shape are the reel bearings in, does it even have reel bearing?

If these have even a millimetre of movement the you need new ones.

Also is there any reason that you cant replace the nuts and bolts with some metric or imperial counterparts.

if the reel only touched the bedknife at the center, then the bedknie needs machining

Grumpy

Arrrgggghhh

I say Good old Whitworth what fine chappy !


Unfortunately Gary (the mower tech) told me early on he would sharpen it but couldn't pull it apart or put it back together as he is booked out until Late March. What a business..


I was starting to get a feel for it later. I actually started getting the bolts turning the right way every time I tuned. It appeared to get close to the edge and then just fall into the chasm. In terms of the stripped threaded area its difficult to tell whether the bolt or the tapped area is threaded as I am not a trained mechanic, it was a little less than perfect light and to be honest both sides were the same. They hold but only just. I dont think I did anything too radical, overtightening or sideways entry stripping, so ???

I cant imagine a bloke who was recommended by a local turf expert wouldn't know how to sharpen a blade. The bedknife cutting edge seems rather sharp. Not Chefs knife but would cut your finger if you pressed and ran it down the blade. The reel also feels the same but there appears to be a jagged edge left on one side (spill).

In terms of the magnifying glass could you please explain the "touching" part and teh anngles at play on the edges.


Lets say

Are the edges of either blade actually cut at an angle otr are there perpindicular / square ? Bedknife particularly. I assume the cutting edge is the edge closest to the reel (front edge) and cutting edge of the reel is again the fitrst edge that comes into contact with the bed knife. Should these two just meet ??

Cheers

Hi Rob, You said in your PM, that the reel bearings were checked and found serviceable by your sharpening tech, so they should be ok. Re: the nuts and bolts, you could, as Tezza has said, replace them with equivalents in whatever spanner and socket set you possess(cheaper that going out and buying whitworth spanners) By the way, I once was given an old Qualcast that had some BA (British Association) nuts and bolts...hopeless!!

Also re the fine alignment adjusters, I also had trouble initially with my Scotty because the thread and nuts on both were worn, I replaced both...Voila!! I had success at last!
Maybe you should consider doing the same....cheaper than ruining you newly sharpened reel.

Idefinately agree with grumpy, and I said in one of my earlier posts, try to encourage the tech to show you the set up, as if the reel is uot of "true", he will re-grind and fix it for you; usually at no charge.
Best of luck with it and please let us know how you get on.

Hi Tezza and thanks

The bedknife was ground and again the tech said it was fine. I cant see how it could bend(?) after its is put back as there is no great pressure applied inwardly or outwardly?? He checked the bearings and said they were fine. I was happy to replace them.

I agree that it will be cheaper to replace the bolts. (A/F or metric ???)

Cheers

Rob

Starting with the easy point, the main potential concern with the sharpening is that burrs could have been left on the cutting edges, which has much the same effect as bluntness. On the bedknife, the edge facing the front of the mower is the cutting edge, and its front face is likely to be at right angles to the top surface (the one that has just been ground). The cutting edge is the most crucial aspect of the cutting process; it has to be sharp and burr-free. Then, the grass is swept onto the cutting edge by the many blades on the cylinder. The cylinder therefore rotates toward the bedknife cutting edge, and the leading edge of each of its blades has to be as sharp and burr-free as the bedknife. So, all of the cutting edges in play are usually right-angle edges - but some sharpeners like to "relieve" the contact area by cutting away behind the cutting edge, like the clearance angle on a drill bit. I won't get into the pro and con arguments on this, but if it is done it means the edges may not be precisely square.
The bedknife cutting edge and the cylinder blades'cutting edges are where the cutting occurs, and they need to pass extremely close to each other. This is the only point where near-contact should occur.
If your bedknife adjusting screws are made in the simple and obvious way, there is a female thread in the fixed bar the adjusting screws pass through, and a lock-nut to keep the screws from drifting out of adjustment. Most people tighten the lock-nut far too much, which mangles the threads of both the adjusting screw and the fixed bar. Over time the screw becomes loose in the fixed bar, and adjustment becomes a real pain. From what you have said, you have some pronounced but very localized damage to the threads right where they are normally engaged for correct adjustment. There are two alternative cures for that. One is to tap the fixed bar to a slightly larger size and fit matching adjusting screws. That means you end up with metric or A/F adjusting screws, which is convenient but not original. The other way to go is to helicoil the fixed bar and find some new screws of the original size. Realistically you will not be able to get screws with Whitworth heads anyway; they are obsolete.

Hi Rob, replace the bolts with whatever socket and spanner set you have.... OR whatever is the closest in tolerance to the originals, and buy some tools to fit.

Hi Darryl

I am starting to think that I might try and book an appointment with tech so that I dont do any further damage. Its unfortunate but the lawn actually needs to be mowed. I am now getting a secondary feel for the job at hand.

Look what has come out of the woodwork here. Bearing a mm out (no paper cut), Changes Fine tune Nuts (no papre cut). Look at all the reason I was getting highly stressed last night.

I also wonder how often the grind ends up being out of alignment.

Cheers

Rob

Rob,

Have you checked to see that the frame is not twisted because it will throw out all settings?

Hi and thanks Bruce


Twisting was not something I had considered.

To test for twist would it be a matter of doing some measurements bewteen sidewalls front and back and perhaps corner to corner.

I have new bolts / washers for the tapped area and it will determine whether a new tap will be required there. I'll eliminate that this arvo.

I had advice that I should have some "tension" on the pivot bolt and I certainly couldnt move the bottom bed at all by hand. Should the "tune" movement be relatively easy. I guess the more tension on everything the more likely the tapped area could be stressed. Once the lower pivot bolt is tightened I cant inmagine it would be easy to shift. Its a very large bolt and nut.

Thanks Guys


Rob

If you've got a piece of very flat concrete about 2 feet square (checked across both diagonals with a reliable straightedge) you can park the mower on it and see if front and rear rollers are both in contact with it at both ends. If they are not, it can be twisted back into alignment but you want to have it sit very flat indeed, without prestress. If it is prestressed it will creep back into a twisted state sooner or later. Use a feeler gauge or something similar to check that all four corners are touching. Remember, that piece of concrete has to be as flat as surface-ground metal.

Grumpy,

I have used in the past a straight edge with a bolt and a nut welded to it. What I did was put the straight edge on the rear roller and front roller and then adjust the bolt until it was just touching th bottom blade on one side.

Then I would move it across to the other side to see it had any difference and if you did you knew that the frame was either twisted or the bottom blade was bent or the height adjustment was out.

Bruce, I'd like to know I have a straight frame before I check for localised distortion or bad things having happened to the bedknife mount. In particular, I'd like to check the frame before modifying the bedknife mount. I'd hate to have people filing the bedknife mounting holes oval when what was really wrong, was someone had twisted the frame (with a bit of home welding, for example).

Hi Bruce, grumpy and Rob,
Bruce, your quite correct there mate, I bought this alignment tool a couple of years ago on the advice of my local greenskeeper, to enable me to set-up my Scotty correctly.
It's made of 1/2" square hard chromed steel, 18 1/2" long, and has a cup head screw that is screwed into a tapped hole with a locking nut on the underside. The screw is located in an offset position being exactly 8 1/2" from the left-hand end.

As Bruce has said, you place the rod on the front and rear rollers, and adjust the screw so the underside lip sits on the topside edge of the bedknife blade. You then slide it across the bedknife from one side to the other to see if the alignment is correct.



Hoping this is of help.

Hi Darryl and thanks guys for your responses. I had another crack at the alignment yesterday with the assistance of a panel beater (!!) and we were unable to get it any closer despite changing out the loose pivot bolt holding the adjusting bolt in the bed knife body arm.It firmed up nicely.

I see what you are getting at with the bar but wonder how you "run" the bar along the bedknife and the rollers. Is the mower suspended and/or upside down and/or just sliding the whole machine along it in standard position? I guess the other question is that if the blade is only out by the proverbial bees wilbur how can you tell with your bar and nut?

I had another thought and wonder whether its possible to sharpen the blade to the incorrect rotation. (ie back to front and what impact that might have). Darryl what side is the sprocket on the Scotty's on as you face the mower from the front. The Alroh drive is on the right as you look from the front of the machine. I wonder if anyone knows whether its possible this is the problem. The sharpener did not ask and thinking about it there is no way you could tell.

Thanks again guys for all your suggestions

Hi Grumpy

No home welding attempted

"YET"

Cheers

Rob

Hi Rob, My sprocket is on the right, looking from the front....as are all cylinder mowers as far as I know.

Re: checking with the straight edge, the machine is laid straight back to the ground, resting on it's handlebars, to expose the rear roller, bedknife assembly and front roller. Rob, caution here, as with a petrol engine, the oil will run in areas it's not supposed to....this procedure is best carried out during an oil change, so the oil is not a problem.

This issue seems to be really getting technical, when it should be a relatively easy (once practised) job to do.
Here are my thoughts:

Alroh is a very well made Australian mower that is very strong in construction. I very much doubt that the frame is twisted.
It was owned by a member of your family and, from what you have said, other than exposure to a little salt air, most probably treated very well.

The tech that did the grind for you is a professional; and the lathe would be set up to accept reels correctly and ground in the right direction.

As the tech did the grind, he is the person most qualified to address the issues that you are having.
Without us being physically able to see the machine, it is almost impossible to correctly diagnose your problem.
A bit like going to the Doctor, over the phone!
I know that you are anxious to get your dwarf lawn mowed, and advice from your tech would be my best advice.