LAST year I spent a lot of my spare time tidying up an old 250 Osa. You might have read the articles? It all turned out pretty well and the 250 has proved a valuable tool on estate work, where having a second machine that can run with tracks and chains while the main forwarder can be reserved for hauling timber on the road has been a major boost to production. It has also helped me maintain harmonious relations with the estate’s forestry department. No more agonising about how much it’s going to cost to repair the roads where we’ve been running on them with tracks fitted to the forwarder. Now it’s tracks in the wood and rubber on the roads.

It’s also been a bit of a surprise to rediscover just how good these old Osas must have been in their day. It climbs remarkably well and it’s pretty manoeuvrable. Now, don’t think I’m getting all misty eyed. It remains very underpowered and noisy, and the electrics are still a bit fickle. The reverse steering was a bit of a jury-rigged setup and it hasn’t been sorted just yet. I swapped all the fuses in the main board as the ancient glass fuses were a bit delicate and occasionally one would fail, simply because it had fallen apart. I found a fuse in the power coupling above the IPS boxes that had blown rather than failed through age. I replaced it only to find that the front drive switch stopped working when the crane was switched on. The new fuse blew a few seconds later and the drive worked again. After a bit of digging around with the multimeter probes, I found a diode that was touching the side of the metal box.

I straightened it up and stuck a couple of turns of insulating tape around it after checking it only passed current in one direction. I’ve since had to fit a seat switch into the crane power circuit because it now all works as it should and the drive and steering only work forward if the crane is switched off and backwards if it is switched on. It’s still too violent in operation for my liking and the steering on the cross-country stick doesn’t work, but that is a little more involved than just a shorting out diode or a blown fuse.

When I bought the 250, I had to find a headboard to replace the remnants of the one it was fitted with. It was missing the grab and rotator and the seat was beyond repair. The seat wasn’t an issue as there was one among the spares that came with it. I did have a spare grab and rotator, until someone stole the one off my forwarder one night and I had to use it to replace the one that had gone missing.

I found a good Hultdins grapple, an Indexator rotator and a headboard from an ancient Gremo that was being broken for spares. In among the bits laying in the vendor’s yard was a grapple I thought I recognised. Sure enough, I was told it had been on a Kockums that he had scrapped years before. That Kockums had been the second forwarder I ever owned, and probably the worst. I had sold it to a guy who had done some harvesting for me and, after a few more adventures, it had ended up being broken for spares, with the grapple being one of the only bits left. The trailer section was sold to a guy from Lincolnshire to replace the oft-welded and finally beyond-repair trailer on the 8335 that he used on the estate where he worked. That 8335 had also been one of mine. I sold it when I bought my first 250 Osa. It’s a small world, especially in forestry. 

The same guy turned up on one of my sites some years later to look at my Valmet 892 harvester working in some big pine. He was looking to buy an 892, but quickly realised matching an 892 with a Kockums 8335 was a recipe for trouble. He told me the little Ford four-cylinder-powered 8335 had been a great machine for him and was still running away nicely, extracting firewood and the bit of hand-felled softwood he cut in the summer. It had been a much better example than my first one, but I still wouldn’t say I’d ever look for one to restore like I did with the 250. I could write a whole book on the bogie box problems caused by a lack of maintenance but also, in part, an inherently poor design, and those brakes! Who in their right mind would fit the brakes from a saloon car onto a timber forwarder? I never managed to get my head around that one.

Forestry Journal: The lazy way to refurbish threaded holes.The lazy way to refurbish threaded holes.

Now, moving on to that grab. I’m not sure of the manufacturer as the plate is long gone and there’s nothing else to give much in the way of clues, although I’m sure someone out there will be able to tell me something of its origins.
It is structurally very substantially built. Weight saving obviously wasn’t an issue when this thing was designed. It isn’t a high-capacity grab, probably around the  .28 mark, but it is the same weight as a much bigger unit. The metal is all half-inch or thicker, with even the chassis plate more substantial than the Hultdins currently fitted to the 250. The issue I had with this grab all those years ago was that it overlapped the jaws if it was allowed to hit the ground when picking up produce. Small chipwood was a nightmare and posts were a non-starter. In those days it was all about getting wood onto trailers, which wasn’t the easiest job in the world. Topping out an artic trailer with chipwood using a Kockums 8335 certainly taught you crane control and how to guess where you were putting that last grab of timber, especially when the loading area wasn’t big enough to get to both sides of the trailer. I just persevered with the dodgy grab, along with the non-existent brakes, the grinding noises from the bogies and that ridiculous crane they were fitted with that always reminded me of the front legs of a Tyrannosaurus rex. Why build a crane where the second boom wasn’t as long as the first boom until the extension was all the way out? Nothing ever got fixed unless it stopped the job. 
I once worked with a cutter who was felling with a saw that had a broken front handle. I asked him how on earth he managed to work using the chain brake as a front handle and he replied: “You adapt.” And you did. It was almost the mantra of the day. It hadn’t worked well for the owners of both those 8335s.

The first one I bought out of Jas P Wilson’s yard from a finance company. I paid around £3,000 for it although there was still something in the region of £8,000 owing on it. It was in a terrible state and just how it had ever been worth even £8,000 I could never figure.

The second one came from a bankruptcy dispersal sale and cost almost exactly the same. It had been well maintained. I knew the machine and its previous owner. It still had some major issues, the worst being a water-cooled compressor that was leaking coolant into the air system that controlled the transmission. This provided lots of entertainment, particularly its habit of not dropping out of drive due to sticking valves. Great fun when it happened on the bed of a low loader and everyone around was shouting at me to stop, not realising I was trying to do just that.

Forestry Journal: It’s always a good idea to check grease gets where it’s supposed to while the pins are removed.It’s always a good idea to check grease gets where it’s supposed to while the pins are removed.

The grab had been sitting in my mate’s yard for so long that it had begun growing into the ground. There was the kind of rust on the bottom of the jaws that you generally see on warships sunk by the Kriegsmarine in the Great War. The rest of it hadn’t fared too badly. It was rusty and most of the paint had gone, but it was reasonably straight and I knew the boy I sold it to had rebushed all the pins and done some welding. He worked for me until recently and I know he has a thing about grease guns, so I was confident the pins would have been well greased while he had it. I wasn’t so confident about the other operators whose hands it had been through in the intervening years. The big issue appeared to be the pins and particularly the method of retaining and locating them. I know that sounds a bit cross-necked, as we tend to say round here, but the pins are held in in two ways for two different reasons.

Each pin has a pear-shaped plate welded on one end and a pin hole drilled at right angles to the centre line in the other. The roll pins that knock into the hole are what actually retain the pin. The bolt and spacer that go through the cutout in the plate, at the end where the grease nipple is, locate the pin. It’s not a daft design, but it is maybe a bit of an overcomplicated one. The two holes in the grab’s chassis, which is the fixed frame, don’t have bushings in them. The pin is fixed in place so it can’t rotate and this is achieved courtesy of the spacer on the bolt that fits snugly in the cutout in the pear-shaped plate. A thick washer, bigger than the spacer, helps to hold the pin in if one is fitted. At the other end of these pins, an 8 mm roll pin is deformed as it is knocked through the hole in the pin. It fits tight against the grab chassis so stopping the pin moving back into the frame. It also keeps the frame stiff and minimises flexing.

Forestry Journal: Not just a bolt, but a bolt with a spacer and the correct washer.Not just a bolt, but a bolt with a spacer and the correct washer.

Between these two securing methods, the pin is held in the frame and it is stopped from rotating. The bit that does move is the piece the middle section of the pin is inside. Take the ram that opens and closes the jaws of the grapple; it has an eye at either end which has a brass bushing in it. This effectively rotates around the pin, but, as it works against a low-friction surface which will have a good supply of lubricant applied via grease nipples, it doesn’t wear very much. All the pins on this grapple are bushed in this way and, provided they are kept greased and the pins themselves can’t rotate, they should give many hours of trouble-free service. The problems come when these bushes are allowed to dry out. With no extra lubricant, they begin to wear rapidly and, if they become so stiff they begin to exert large turning forces on the pin, they soon begin to break up. What is worse still is if the pin isn’t secured properly and it begins to turn in the frame of the grab. 

These parts don’t get grease directly as the drillings in the pins direct grease from the grease nipple into the middle of the pin where the bushings are. A pin that begins to rotate in the frame wears both elements very quickly as steel against steel isn’t a good idea, and every time the grab is parked overnight the newly polished surfaces in these plain steel assemblies will rust incredibly quickly.

Forestry Journal: A motley collection of fasteners, none of them actually suitable.A motley collection of fasteners, none of them actually suitable.

I removed any of the pins that looked like they’d had a particularly hard time and checked the bushings in the ram, the link rod and the jaw pivots. They were all worn but not enough to invest in another set of bushes. All the locating plates were bashed back and I replaced nearly all the bolts. None of them had spacers on them, so all the pins had been moving slightly and most of the bolts were either bent or had worn with a distinct narrow ‘neck’ just below the bolt head. These spacers can be easily knocked up using pieces of steel hydraulic pipe. I cut 5-mm rings off a length of thick wall pipe that generally replaces a half-inch BSP hose on the long runs down a forwarder crane. A 12-mm bolt fits nicely through the spacer and, with a decent washer under the bolt head, that’s job done. 

One thing that’s a good idea is to run a 12-mm plug tap through each threaded hole. Even if there’s no damage it makes it a lot easier spinning the bolts in.
The other end of each pin either had nothing in it or a variety of split pins, nails, bolts and bits of wire. I knocked the ends off all of them with either a cutting disc on an angle grinder or (my favourite) a good sharp chisel and Mr Lumpy. I resisted the urge to clean these holes out other than by using a 10-mm drill to deburr the ends of the holes. Seven new 8-mm roll pins at around 40p each knocked in using a large flat-ended punch completed the job, almost.

The only other issue was that one pin was held in solely by a large split pin. On closer inspection, I saw it had been put in the wrong way round, so the tab had no bolt hole in the frame to line up with. I knocked the pin out and tried to put it back in only to discover why it had been put in arse-first. The frame where the pin was supposed to slide in had been built up with weld and the plate on the pin wouldn’t go past it, so I ground the welding back until it was a nice smooth curve, then I took a few millimetres of one section off the plate on the pin. It was just enough to slide the pin home and rotate it slightly to get the bolt to line up.

I had spent a good while the day before degreasing and powerwashing the whole assembly so now it was time for an angle grinder with a flap disc on to knock off a few bits of scabby welding and to smooth out some deep gouges and obvious dings. That was followed by a wire cup brush on another grinder, a blow-off with the airline and finally a wipe down with some thinners, or ‘gun wash’ as they now call it. I then gave all the bare metal a light coat of etch primer to get the paint to stick, although painting timber grapples is a bit of a fool’s errand. They generally look really good until you start using them.
I had in my cupboard a tin of Takeuchi grey that I bought to use on the Viking head we rebuilt last year. It turned out to be too pale, so the Viking ended up being painted Massey Ferguson TE 20 grey, which was a much closer match. The frame, ram and link rod were done with non-reflective black and the rest of it got several coats of the grey.

Finally, it got a good run round with a grease gun and, as it had never left the trailer, it was shipped back to site on the Monday morning.

Forestry Journal: Ain’t she pretty?Ain’t she pretty?

It will be lounging about in the estate yard (not sat directly on the ground though) as a spare in case of issues arising with the grapples currently in use, but it is my intention to fit it to the 250 as it will be up for sale quite soon given that I have made the decision that, after more than 30 years in the business, I’ve finally had enough. I can no longer  put up with being told how to do my job by people who don’t know a chisel chain from a cheese roll. I decided enough was enough when it became clear welfare units would become compulsory and I, as a contractor, would have to pay for them. If this bear can’t s**t in the woods anymore, then this bear’s going to retire.

I’ll still be writing for FJ though, so long as they want me to, and I guess there’ll be some old forest machines in the free classifieds over the next few months.