Backlapping cylinder mower cutters...

[Nick]

Anyone done this? We have several mowers, but the final finish is generally done by an Allen National 68 triple mower....

Last time I had this beast serviced, it cost several hundred quid , mainly due to having the three sets of cutters backlapped.

Looking at YouTube, it seems I can do this myself using 80-grade grit paste and a power drill in a jig... I know that the cutters have to be run in reverse at about 60rpm...

Thoughts welcome!

[AlanBeckett]

I thought the idea was to run the Cylinder between Centres and run a Grinder along it. I think there are special Machines which do it.
I think the Fixed Blade should be Ground as well.
I don't see why it should be particularly expensive, but ......

Alan

[AlanBeckett]

How about http://www.oldlawnmowers.co.uk/ol-blades.php

Alan

[Nick]

The point about backlapping in situ is that both blades and the bedknife are done together without dismantling the whole cutter...

Interesting link. They charge the same for 300ml of paste as I paid for 2.5kg on eBay (free delivery too). The kit seems to be paste plus instructions, which are available for free on YouTube.

[AlanBeckett]

So what's the problem?
If you have the Paste and Instructions, and you can run the Cylinders backwards, why not just do it?

Alan

[Nick]

Real question is what grit to use? 120 or 80?

[AlanBeckett]

Ah, so.
I suppose the usual Engineering answer would be start with 80, then 120, then .... until you get to the Finish you want, or at least one that works.

Alan

[singlepentode69]

They used to sell an attachment that clipped on the cutting plate and you ran in reverse .they we're sold in the garden magazines I had several when I had a collection of atco cylinder mowers.
Regards
Robin