Saturday, 31 August 2013

Matrix clutch on a Colchester Chipmaster lathe

I've been setting up my colchester chipmaster at last. It was an absolute dream to run, except the clutch. Pulling the handle engaged it, but as soon as I let go it disengaged. There was no clunk, click or anything to suggest any sort of locking mechanism locking in place, and I was getting pretty fed up. There was no indication of anything thant would keep pressure on the plates, either physically or in the parts book.
I joined the colchester lathes Yahoo group, and immediately found a document that explained how it works. This collar fits on the end of a shaft, and is pulled in and out by the clutch lever. Note the 3 internal lugs:

When you pull the lever, these lugs are supposed to go over these rollers, 3 off, in the ring.

This squeezes the rollers in toward the centre of the shaft, and up the ramps, which forces the two plates apart and puts pressure on the clutch.
However, you can just see there are two splined shafts, one inside the other. The collar fits on the smaller of these, which you can just see poking out in the picture above, and the clutch assembly on the larger. These splines have a different number of teeth!

So, my lathe looked like this. Look closely, and you can see that the lug in the collar is only half over the roller. So, instead of going over the roller and squeezing it in, it just presses against the plate-so the lathe starts, then immediately disengages.

You need to turn both the collar assembly and the collar on their splines (i.e. take off, advance one spline, try it), until the lugs line up with the collars like this. The rollers have been removed for clarity, since they fall out at any opportunity it is easier to line it up before you refit them.

There is a knurled adjusting collar that adjusts the slack in the clutch. You should be able to pull the collar over the rollers with a clunk-if it won't go, back off, if it doesn't clunk, tighten up.

This was one of those utter arsehole problems that seem impossible to solve, so feel free to spread this post about-I might save someone else days of stress and a headstock strip!

Thursday, 25 July 2013

BEV 551-Livery and details

I've been having a good look at that one remaining photo of a working BEV 551. I even bought a copy of Industrial Narrow Gauge Railways of Britain, hoping for a slightly better version.
Here it is again:

First, note A and B. A is a cable running into the battery box, repeated at the other end. No clue as to what for (other than "to carry electricity"), but handy to know it was there.
B is some sort of data plate-maybe the works plate, maybe battery data, could be anything cos I can't read it! Hopefully a better copy of the original would show it up, if I ever find it.

C and D are more useful now though. Note how in oval D, the back of the bufferbeam and part of the frames is just distinguishable in the shadow. It seems to be a lighter colour than the black middle section, which isn't in shadow.
C shows how the buffer beam looks a lighter colour, but with the edges in a darker shade. For reference, here is it built up:

Obviously a junior SGLR member was used to recreate (ish) the other photo!

At first glance, BEV seems to be pure rust, but there are still flecks of paint. Even better,
removing the wheels has exposed areas that are inaccessible to someone giving it a quick tart up, and protected by grease. A quick clean up revealed...

The red in the top right isn't actually the colour I'm looking for. Initially I thought this was it, hence BEV was painted red when I did the top half. I now think it is actually red oxide primer, presumably the result of a quick tart up by a previous owner.
Instead, look at the vague arc going bottom right to top left. That is where the wheel was, and where the mystery painter couldn't reach. The black is old grease, and in the middle...the original Grey! The darker flecks are bare metal.

Further investigation found this grey patch on top of the frame:

So thats the lighter colour probably settled. For me, the patch behind the wheels seals it. Theres no more paint behind or on top of it, I doubt industrial owners would take off wheels for a repaint-if they ever painted it-and I reckon if anyone in preservation took a wheel off to paint behind, it'd either have had a more obvious start made or been left in a million bits until scrapped.

The buffer beam edge that shows dark in the photo threw up this:


Again, red is most likely red oxide.The black in the middle seems to be paint, the small flecks of grey beneath are bare metal. At least, the black flicks off with a knife blade leaving the grey flecks behind.

Finally, the wheels:

In the scraped away patch: Silver seems to be a tart up, with thick layer(s) of black beneath, then grey, then red oxide. Why they originally put primer on the wheels yet none apparently on the frames is a mystery, maybe they couldn't be bothered?

So, it looks like light grey (probably battleship grey) and black may be the colours shown in the old photo. Ironically, I've often said we should paint it grey and black because the picture is in grey and black! Besides, it should look very smart like that.

Tuesday, 16 July 2013

BEV 551 Part 2

We had another BEV day on monday.

First up, we fetched the remaining wheels off. This was much easier than the first, probably because we knew how hard to hit them!
Here is the extractor. There are two threaded holes in the wheel bosses. I used a plate, two bolts and some soft packing. In this case I used aluminium billet, but any softer metal, or even hardwood, should do. The packing protects the axle end.

Jack and support the loco clear of the rail/floor by an inch or two. Put some plywood under the wheel you're about to attack, in case it needs a soft landing. Assemble as shown, then wind the bolts in to get some tension, making sure they don't bottom out in the threaded holes. If they do, put more packing in.
The wheel may need a few knocks with a soft face mallet to break the rust seal. After that, doing up the bolts alternately should pull it off the axle. Once it moves a bit, it comes off the taper and so is only held back by the key.

Next up, we unbolted the axle boxes. Removing the triangular plates behind each wheel:

We found a nut on a fine thread. Note the grub screw locking the nut in place-the sort of thing easily missed until you scrap your axle. Two came out fine, two broke and had to be drilled out. The nuts had to come off, as the slot in the frame for dropping them out is too narrow:

You can see the fill-in piece of metal under the axle end, and that the nut is removed. You can also see the waxy, gritty 80+ year old grease.

Next up, we tackled the axle keep plates. These are two flat bars that run under the frame, and hold pieces of metal that plug the gaps under each axle that allow them to come out. The bar also put back the strength lost by having 4 huge slots in your frame. The bolts here have taken the brunt of derailments and damp, yet we only had to angle grind 3 of them!

By the end of the day, we had this. The axleboxes are held in by one bolt at the top, so we're about ready to drop them out.

Thursday, 11 July 2013

BEV 551 part 1 of millions

This was BEV 551:

Built in 1924 (ish), BEV is an 18" gauge battery electric loco, built for hauling things round factories.  The above is a photo in service, the writing tells you more history. It's a scan from Industrial Narrow gauge Railways of Britain, published by Barton Press.

Many decades later, it looked like this, after arriving from Gloddfa Ganol in wales to Steeple Grange in Derbyshire:

BEV sat under a sheet for a few more years, until a younger, over-optimistic me bought a 49% share in order to start getting it done up a bit.
About a year later, and I had this:

Then work, house and women took over. But at least BEV was kept under cover for the next 5 years.
February this year, I felt I finally have enough room at home to fetch it here and do a bit more. So after a chat with Bob, who owns the other bit, and Dad, who loves moving heavy things and moaning about being asked to do it, most of BEV came to a secret location in [CLASSIFIED].

The painted bits have stayed up the railway for now, so I can spread the chassis over a greater area.
So anyway, BEV arrived, was dumped in the shed and then some bloody enfield got in the way...but monday, work began!

The plan is, roughly, this. First, rip the chassis apart, get it blasted and painted, then reassemble the frames. Next, we overhaul the wheelsets. BEV is so basic it's ridiculous, one motor driving some huge straight cut gears and no suspension at all. So all (!) we need is a good clean, new bearings and some rather pricey gears.
After that, things get a bit murkier. We have the controller and resistance bank, but no motor. Also, if we're fitting a new motor and gears, we might as well pop in some air brakes so it can pull passengers on her triumphant return. Probably in the year I retire, but you never know.

Bit of detail: The staff sticking up is for the brakes, which are removed. The big ugly gears drive a countershaft affair. The motor sits in the middle, sticking out one side. Here's a photo of BEV 640 at the East Lancs Light Railway, thanks to Alan Jones:

So, Bob came over monday, and we took 3 hours to get a wheel off. Not quite Formula 1 territory, but god only knows when they were last off.

Heavy buggers too

This shows the utter pain in the arse we're dealing with. To undo those nuts, you need the wheel off. As far as we can see, dropping out the whole wheelset in the normal way is impossible. Thankfully, you can drop the axles out-I though at first you could only remove that and the gear by splitting the frames

It'll be a long project, but you've got to start somewhere. Interesting change from bikes at any rate. I'm thinking of making up drawings too, and might even have a go at modelling it in 5" gauge. Be useful for air brake design at least. Next work party is this monday, so we might get another one off!

Monday, 24 June 2013

Another one done

At last, the enfield is MOT'd!

Naturally, it fought me all the way. Putting the engine in got pretty traumatic, you have to do it one specific way to avoid it all fouling round the centre stand/bottom plate. The frame flexes a bit with no engine too, so the holes took some persuading to line up.

I had one stroke of luck however-I found a nice solid bench on the scrap heap at work. I had to saw the legs down to fit in a hapless colleagues estate car, which bought it to the perfect height for shoving bikes on. Getting them on is a bit hairy, using a long plank and an assistant, but it was £250 cheaper than a proper bike lift.

You can see I got the primary drive, gearbox etc refitted by that point. It also sprouted front indicators, as I used various delays to find those rotten little jobs that delay an MOT.
The next puzzler was the head. New valves and guides meant it needed the seats recutting, and the seating faces for the head nuts looked like this:

The upper holes are for the cam tunnel bolts, which some clot has utterly destroyed. The early crusaders didn't have them, so I'm hoping this one will manage without too. The lower two holes are for the main head bolts, after hacking out some bits of old washer.

This work meant going to the workshop of Dave Hodgkinson, a well known name in local car and bike circles. Dave mostly does rebores, having done many thousand since the 60's. One of the loveliest and most interesting people I've met, and with a very nice honda 50...I look forward to having more work for him.
Anyway, after recutting the seats, milling those ugly holes flat and me grinding in the valves whilst sat in bed watching films, I had this:

Which, with some new valves, springs and collars, became this:

Next job was to check Valve clearances. The old piston showed signs of valve collision, so I wanted to be sure it wouldn't happen again. Before putting the piston rings on, I assembled the top end with plasticene as shown in the valve pockets:

With the head and the valvegear assembled, turning over the engine squashes the plasticene between valve and piston. Take the head off, carefully slice the plasticene with a knife and you can see the minimum clearance. Thankfully, it was well clear.
The rings were an utter pain in the arse. When I tried checking the gap in the bore before fitting, I found an overlap. The replacement set had the same problem, so in the end Hitchcocks sent me some genuine hepolite rings at Indian made cost. Much better!
Throw it together, splash of oil, kick until I realise the spark is timed 360 degrees out, and eventually...

It runs!

The last jobs were footrests, genny cover and tank/seat. In a pleasant turn of events Nigel (the owner) came over as I was finishing these off, so lent a hand. We had a few rides each up my yard, before it was MOT'd the next day.

And here it is! It's not quite over yet, the registration is in progress and it will need testing/setting up/running in. But its at least in one piece.
You might be expecting me to say "And the moral is, don't take on unknown projects for other people!", but I'm not. Despite the constant setbacks, cock ups, delays and unpleasant discoveries, it has been very rewarding to put it all right. The lovely old classic has emerged from the grotty old deathtrap, I've learnt a huge amount about a bike I couldn't really afford...well worth while.

Next up, my turn to spend money on my poor old 400/4...

Wednesday, 24 April 2013

Going back together!

First things first, that head repair worked a treat.
To Recap: I drilled it back to round with milling cutters, then tapped out to a convenient size.
So, next step was turn up the new ally bushy. I could have used steel, which would be less likely to strip the thread. However, heat expansion might work it loose, and without a proper mill it'll be a swine to file flat. The file will chew away the soft ally instead of the steel.
If this had been a straightforward thread strip, I'd have drilled and tapped the bush on the lathe. Then, you use a lock nut and bolt to screw it in. If you look back, you'll see this wasn't. Instead, I machined it up then did NOT part it off-I took it out attached to the billet, applied loctite and screwed it in.

This shows the dog end of billet being chopped off somewhere near. Note the scrap ally plate protecting the casting from the saw, if you hold the saw against it it's much easier than praying you don't damage the preciuous things.

Bush filed flat, 4 dot punches to really lock it then a final flatten over the whole head with a lump of old grinding wheel (please note, NOT an offhand grinder!)

Finally, I used the rocker assembly to mark out the new hole, and drilled/tapped

On saturday, Nigel the owner came round, and we had a day cleaning and fettling the crankcases and head. By fortunate coincidence, a big parcel from hitchcocks came too.
I originally intended photoing every part and stage, both as a guide for whichever lonely crusader-owning soul stumbles across it and to show any future owners it's done properly. Then I got carried away...

Here is my preferred case fettling routine:

Wash in jizer
File off any burrs, damage, or the raised area round stud holes
Run a tap down threads, helicoiling as needed
Ensure oilways are cleaned out, pipe cleaners are handy
Wash on the grass with a hose
Wash with washing up liquid in the bath, using a powerful hot shower to blast out nooks and crannies
Pop in the oven on low heat till dry

If you're fitting bearings, cases need a good half hour until water/spit will fizzle straight off. Make sure all seals/spacers are to hand, and have suitable drifts in case the need some help. Finally, always drive on the outer race or you'll knacker it. I know it's obvious to most folk, but we were all beginners once.

Crank sat in case ready to reassemble

New rod has the later, stronger big end allen bolts. Torque up to 22 lb/ft. Another beginners tip-torque up one a bit (say, 5lb/ft), then the other, then a bity more until you get there.

Two more hints: roller bearings are a twat to put together, you have to sort of jiggle it about to get it right. I also should have checked the stud lengths, they seem to have shrunk! I think they were only in a bit, whereas I've put them in as deep as they'll go. Personally I think that is better as more thread=stronger, so I'll knock up a couple of new ones as needed. Running a die down them revealed a few more BSF to BSW threads (see previous!), so they'll get binned as I reckon they must be a fair way toward snapping.

Finally, one bottom end:

The bog roll tubes stop the rod clattering about and getting damaged.
Tomorrow I might post about my 2 new honda 400/4 projects. Parts that fit just right and bolts available at screwfix? Joy!

Tuesday, 16 April 2013

Engine in bits

After a week off to prepare myself, I stripped the engine. Bit frustrating taking the gearbox and primary drive out again!
Almost immediately, it was proven worth while. I took off the internal oil lines...

Note the big lump of split pin about to go through the oil pump? I reckon it must have caught in a corner, it fell out as I took the pipe off.

It turns out that the engine holds the centre stand on the bike too, which wasn't too welcome when, 10 minutes before leaving for work, I was left holding the engine whilst sitting on the rolling chassis to stop it falling over. Eventually I extracted myself and left it looking like a slain animal.

Next day I split the cases. Here is the RH side, dripping in shitty silicone:
 And the gunge still in the cases. Remember, this bike was sold as having a newly rebuilt engine. Maybe Barry the Bastard Butcher was too poor to buy rags and jizer?

Here is the big end, showing where the split pins to lock the nut aren't. Nuts were hand tight too.

 Bit more rod damage, it's definately scrap.

Oil pump hole blocked with silicone

The above is a strange one, it shows the feed plunger on the oil pump. Look carefully and you'll see the metal round the eye has splintered off. If you own an oil pump with a similar bike fitted, you might want to check it.

Today, I turned to the cylinder head. I needed to knock the valve guides out to measure them, and take out the studs etc for inspection/cleaning. When I turned one stud, it went like this:

Once removed, I found a hole at a funny angle with the remains of a stud in it

Someone has obviously snapped a stud, tried drilling it out with a hand drill and made a right mess. This is easily done-as soon as the drill gets a sniff of the soft ally, it'll chew through that instead of horrible hard steel. He's then drilled it on the piss anyway, rammed a new stud in with lots of threadlock, then bent it to vertical. The top hole in the pic had a straightforward stripped thread too, so this end of the rocker gear was not far from escaping.
To sort the broken stud abortion, I used a dremel and dentist burr type bit to cut the stud remains in two down the axis. They then fell out. Next, using an ancient hand pillar drill, I carefully cleaned the hole out with end mills. First, I used one only just touching the sides to level off the bottom. Then, I went bigger until the hole became round.

End mills and slot drills (milling cutters) are great for righting wonky holes. The flat end is less likely to follow the previous efforts, and having 3 or 4 flutes makes it much stronger. You have to be very delicate though, and be careful-my hand cranked pillar drill is good. Ideally you want a milling machine, but if you clamp it down well a regular electric pillar drill should be OK. Like I say, be delicate.
Hole is now tapped to a convenient size, in this case 7/16ths Whitworth. You could use whatever came close, metric would be fine. Just don't remove more than you need to, and stick to a coarse thread for ally-Whit, UNCF or Metric standard are good. If, like here, the hole has some of the original thread remaining, make sure it is removed. The next step is to fit a plug of ally, so you don't want the recreated hole to break through the side. Finally, I'll use the rocker block and the three good holes to mark out where this hole should to follow, if it works.