ATCO Commodore B14 restoration
Hi, I'm currently restoring a Commodore B14. I have managed to disassemble most of the mower with metric tooling but I cannot get any type of metric tool to fit the 6 bolts circled in the picture below. Shamefully, I don't do imperial, I only do metric. Are the fittings on the Commodore AF imperial fittings or are they one of the other variants of imperial?. I know it's a long shot but I was wondering if anyone here knew what imperial size I would need for these bolts?....
Parts cleaned and primed with red oxide ready to be painted ATCO green.
I would like to thank whoever uploaded the B14, B17 and B20 owners and parts manual it has been a great help. I used to digitally restore documents so I decided to restore the owners and parts manual. It's in far better condition now and it is optimized to work with mobile devices and is fully bookmarked: https://www.dropbox.com/s/widuo2ekkmmn0lo/ATCO%20COMMODORE%20B14%20B17%…
With one possible exception All the hardware on the Commodore has imperial sized Unified Fine (UNF) threads and AF (across the flats) hexagon spanner sizes. The exception is the big nut holding the traction clutch to the chassis side plate as there was some carry over from the previous models that used BSF/BSW threads and spanner sizes but that was only on very early production.
Those hex head screws ( strictly speaking bolts have nuts) holding the stiffener to the sole plate (aka bottom blade carrier) can be a right b******** to get out . If they have a few exposed threads protruding through to the cutting cylinder side it's a good plan to grind them flush so that you're not trying to drag rusted and distorted thread through the sole plate.
There are all sorts of tricks and wrinkles for dealing with stubborn and corroded threaded hardware but for a start having the correct tools for the era of machine that you're working on is a must!
As wristpin states the correct tools for the job is a must, if only to save you're knuckles from a bashing when the ill fitting ones slip off! You don't need Snap-On quality/prices. A trawl around the internet or boot fairs etc will normally yield a source of supply that does not break the bank.
Depending on rarity or otherwise, when nuts or bolts won't budge under any circumstances -- including heating them -- then I'd be inclined to drill them out/grind them off. (Others might strongly disagree.)
Can't disagree with the last post but of course the " last resort" depends greatly on what equipment you either have or can cadge the use of.
Some last resort situations can be avoided with a bit of forward planning such as I suggested in my last post, grinding off the protruding bit of a screw. At the hex end a good sharp smack with a decent sized hammer square on to the head may "crack the corrosion" and facilitate access of your favourite penetrating fluid. While on that subject, forget WD 40 ; as its initials suggest it was developed as a water dispersant and falls far short of being a decent dismantling fluid. My proprietary brew of choice is Plus Gas or if you can find it, Holt's Graphited Penetrating Oil. Even Kerosene or diesel fuel is better than WD.
The other bit of forward planning is to try not to spoil your chances too early in the procedure . For a hex head component the best weapon is the correct sized single hex socket , not the usual bi- hex ones found in socket sets. Many of the quality tool companies sell individual sockets so it need not be disastrously expensive to acquire the two or three most commonly used sizes.These are far less likely to round off the heads before you've got any where. For slot head screws, particularly counter sunk bottom blade screws, an impact driver with decent quality and fitting bits is essential. My impact driver was bought from a catalogue over forty years ago and is still going strong but I do buy Snap-On bits for it as they seem to be the only ones that put up with big countersunk screws holding gang mower bottom blades etc!
Heat. Providing that you're not melting or setting fire to anything, the more the merrier! Various domestic and plumber sized blow torches using MAPP gas or propane are better than nothing but when it comes to big lumps of heat conducting cast iron nothing beats Oxy- Acetylene but the costs of owning and operating an O/A set virtually rule it out in a domestic setting.
So if we get back to drilling out, start with a small sharp drill and take time to "find the centre" . Getting that first hole true will save time and effort and may even result in the final drill bringing the threads of the screw out leaving the "parent threads" untouched - if you're lucky!!!!
... by wristpin. There ought to be such a section on this site.