The Craftmans Shop > New from Old
Thwaites 2 Ton Two Cylinder Dumper Running On One Cylinder
awemawson:
So today's task was to make the spherical bearing holders, as the retaining circlips had turned up.
First I bored the full length of that bar to 1.625", being careful towards the end to 'wash the heat out' with suds. Bearings were a nice snug fit (phew :thumbup:
Then a slightly hairy experience cutting circlip grooves 'blind by numbers'. Went round the houses a bit as my first grooving tool rubbed (not enough front clearance) and I managed to work harden (*) that bit of the bore :bang: - careful application at low speed of the next grooving tool that I ground got me past the hard bit, then it was a case of parting off and repeating.
Clearing the burrs raised by the grooving operation was a bit of a pain - ended up using a very fine 'half round' file. Then it was just a case of drilling, spot facing and tapping for the grease nipples.
I decided to fit a locating 'roll pin' in the housing to aid in location when they are being welded. When I chop the end off the rod I'll mount it up in the lathe using lead slips to protect it, and drill a hole to receive the pin. The one in the cylinder I'll probably have to do by hand. The idea being that it's only too easy for thing to move when you start welding, especially when you can't clamp them very satisfactorily.
Note that the orientation of the grease nipples is different between the two holders to allow access.
(*) which proves my suspicion that this is more than mild steel, or it would not have work harderned
awemawson:
Television was particularly boring this evening, so I escaped to the workshop for 45 minutes :ddb:
I decided to remove the old bearing eye from the piston rod and prepare it for welding. First job, unjam the jam nut that holds the piston assembly onto the rod, then remove all the components, sliding them onto a long ty-wrap to preserve their assembly order.
Then off to the cold saw to saw off the old bearing eye, protecting the rod in sheet lead so that the vice doesn't do damage. I deliberately cut through the old eye to make sure that I don't shorten the rod.
Then mount up in the lathe, again using sheet lead as a cushion, and turn off the old weld, put a 45 degree chamfer on it to enhance weld penetration, and drill the end 1/8" to accept the roll pin for centring. Cleaning it up, the bit of the old eye neatly fell away exposing virgin rod on the end surface, so no rod shortening :thumbup:
(I will of course be dismantling the bearing assembly before welding)
awemawson:
So cut off the cylinder eye then welding today - but first I had to go and pick up 250 kG's of Sow Nuts from the feed store and hump it into it's storage bin :bugeye:
Set up the cylinder in the cold saw ready for chopping - problem is that being hollow you daren't tighten the vice or it will distort, hence the packing under the eye. Chopped off the old eye, cleaned up the raw end and marked it for a hole for the location dowel pin. Can't go in far as the end wall is only 5 mm by my measurements, so just a dimple really.
Clamped up and welded the new rod eye and cylinder eye. It would have been so nice if I could have 'rolled' the rod on the welding bench to run a neat bead round it, but obviously the surface of the rod would have suffered from the arcs from the bench contact. Had to do it in fits and starts, protecting the chrome with wet cloth (which steamed up my welding mask :bang: )
awemawson:
Then it was just a case of putting the piston assembly back together with new seals and a bit of a clean up.
awemawson:
Then I got a bit enthusiastic and decided to give it a coat of paint. Quick clean and degrease using IPA, mask it up then a coat of etch primer, which was given an accelerated drying time by using a heat gun.
Followed the etch primer with a aerosol can of satin black that covers a multitude of sins - matt black is even better but I'd run out :lol:
Bit of a cook with the hot air gun, take off the masking tape and put it back on the machine, giving everything a good grease up. I hate grease guns - they always run out just as you want to use them, then putting in the new cartridge, which should be so easy, always seems to end up with grease everywhere :bugeye:
Never mind - ram is back on and pivot pins and bearings greased up, hydraulic fluid bled though, and woo-hay - she works :ddb: Steering is so much more positive, less jerky AND there are no leaks from the ram. It won't last for ever, as there are a few dings on the rod - if I'd realised I'd have made a new one as it's only 1" hard chromed rod stock with a shoulder and thread at one end.
Still - I'm a happy bunny. Just need to ponder whether I can be bothered to sort out the centre articulation bearings - looks like at least two skinned knuckles if I do :lol:
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