OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Victa Lawn Mower Frames 2Blade To 4 blade Conversion Hic-ups

Hi All,
Need some advice Please......
Photos below help explain.
I am in the process of converting a Victa 505SP (20" cut, 2 blade, Powertorque, self propelled, allow base) to a 4 blade cutter.
Bought the round 4 blade mulching disc to fit to it.
PROBLEM:- The shoulder on the disc boss with the pulley for the self propelled is higher than the standard disc boss (by aprox. 3mm.). The 2 plate disc that was fitted to it had a piece spot welded to the hub of it to accommodate for this.
I was thinking I could weld a disc washer to the 4 blade disc to rectify the problem.
WHICH TO DO:-
(1) I have a 3mm. thick, 22mm.I.D., 39mm.O.D disc washer that I could weld to the engine side of the disc or,
(2) I can easily get a 3mm. thick, 22mmI.D., 44mm.O.D. disc washer and weld it to the nut side of the disc.
* I am unable to get 19mm.I.D. disc washers *
Could someone please advise me as to which side would be best to attach the washer or any other ideas to fix this problem.
TIA
Cheers,
LS


Disc boss showing higher "shoulder"

Disc boss & drive pulley

Original disc showing spot welded hub

New disc-nut side

New disc center-engine side

Original disc hole showing thickness of hub and spot welded piece

New disc hole showing thickness of hub

is there any reason you couldnt drill out the spot welds on the original, and use the cup from that?

Use some plug welds to re-attach to the new disk, and bobs your uncle!

I imagine that the extra part on the 2 blade disc was added to professional grade victas as the standard discs are known to break apart in the middle. Unless it fouls on something I couldnt see why the 4 blade disc would not be fitted as-is with just the standard discwasher and nut (the dsc washer has the square notches in it)

Hi Joe,
Thanks for your reply.
The problem is that the "shoulder" on the disc boss is higher than the standard disc boss for the powertorques.
The "shoulder" height on the standard boss is aprox. 1.6mm. and the height on the boss with the drive pulley is aprox 2.4mm.
So if the 4 blade disc is fitted without any alterations to the disc the disc plate will wobble and spin freely as there is no pressure exerted on it by the nut and spring disc washer (square notched).
So the question is , which side is best to attach the extra washer to bring it to the right thickness?
Also :- can only source washers with a 22mm. i.d. hole at this stage.
Thanks again,
Cheers,
LS

I see now A washer with the exact same ID of the shoulder under the bladeplate should be enough I would not weld anything onto the metal myself, just really make sure the washer you use is very neat fitting and I would put it together in the following order: crank boss - washer - blade disc - spring washer - nut. I will look at other possibilities while outside soon, thanks Joe.

EDIT!

The "shoulder" height on the standard boss is aprox. 2.4mm. and the height on the boss with the drive pulley is aprox. 4.6mm.
Sorry my stuff-up.
LS

I would leave the disc that came off it as it is. It could be that you may have to put it back on one day.

I would assume that you are setting the mower up to do mulching.
Im not sure how the 4 blade disc will work with longer 505 blades on it instead of the high lift mulching blades that the 18" mower uses.

I would be looking for a washer/spacer to use above the blade plate.

Is my math right if i say 2.2mm thick???


I think digging in the buckets of bolts etc that i have here i found a washer that was about that, i use it for putting the PT motors back together in place of the blade plade when doing the lower nut up to get the boss to grab on the flywheel.

UPDATE:-
WILL PUT A WASHER BETWEEN THE DISC AND THE BOSS.
The only washer I could source was a disc spring washer from an early 160 (1/2 BSF, round type) and file the notches out so it was a snug fit on the shaft, but this washer is only 2mm thick, 2.2mm was needed.
As I was going to spruce-up the mower, replace drive belt etc. etc; I pulled out the engine and knocked off the boss an carefully filed 0.2mm from the shoulders (as shown in photo).

This should allow me to be able to use the original plate, if ever needed.
I am doing this conversion to (1)Get a better cut (2) Get a better cut at lower revs so I can WALK behind the mower not TROT.
I don't mind doing all this rooting around as I plan on keeping this mower forever.
Will let you know how it preforms when project is completed.
LS

I will be very interested to hear.

Ive got a 505 here and I assume by what youve said that some day I will be trotting behind it.

How did you get on???

Hi Rodeobob,
All projects on hold for a couple of weeks or so due to other commitments cropping up. Although one needs to finish this one before the spring growth kicks in with vengeance.
Will keep you posted.
LS

No worries.

Watching and waiting.

Watching the grass grow and waiting till its long enough to mow the crap out of.

I scored another 4 blade disc tody in hard rubbish. It looks good.