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Colchester Student Mk1 Won't Start

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Richard Kirkman 126/03/2020 12:27:44
310 forum posts
761 photos

The 21 and 22 have continuity when the contactor is NOT pushed down. So they are normally closed? Hence the NC? Is this a problem?

The listing for the contactor stated this "Chana CC1-2501 3 Pole Contactor with 1 normally closed auxiliary contact on body of contactor, 2NO auxillary contacts supplied loose to fit on top of contactor. "

I'm not sure what it means by auxillary contacts supplied loose to fit on the top, but I didn't receive anything else in the box?

Overload pics coming right up

Richard Kirkman 126/03/2020 12:43:42
310 forum posts
761 photos





Richard Kirkman 126/03/2020 12:59:54
310 forum posts
761 photos

I suspect I've just bought the wrong contactor againblush At least I'm learning, hopefully it doesn't frustrate you too much.

Do I need to get one with NO?

If so, I'll order this one right away and return the other


Phil Whitley26/03/2020 16:18:35
1328 forum posts
147 photos

Hi Richard, Yes, swap the contactor for one with a NO contact. Pity you didnt get the auxillary contacts supposedly "supplied" with it, as they would have done the job. turn the overload screwdriver switch from manual to auto. this means it will reset automatically when it cools down (although in practice it will probably never, ever trip) on the overload use 95 and 96, connect a link from the A2 coil connection to 95 and then put a link from 96 to one of the contactor NO contacts, along with the red wire from the C&D limit switch, if you follow the instructions, whilst looking at the wiring diagram I drew, it will make more sense! after this carry on as above! I bet your 3 phase hook up is on hold now! never mind, we will get there!

Been to the workshop for a couple of hours today, making cold frames for my youngest daughters roof garden. My woodworking skills are more "Creative" than precise!!


Richard Kirkman 126/03/2020 17:26:23
310 forum posts
761 photos

Definitely the right contactor ordered this time (should be here 28-30th). I hope I've kept you from getting too bored by making you explain it all!

I'll follow all your instructions when the new new contactor arrives. Meanwhile, it's gasket replacement and cleaning poop out of the lathe gearbox. It's an absolute state. I wouldn't be surprised if its never been cleaned. Plus its definitely been run without the gearbox top on too, since the drill bit was in there. previous owners must have not cared one bit!

Yep, I will not have three phase for a very long time it seems. Should have stuck with the converter.

I'm sure your woodworking is fine, it's all about being creative anyway. Just hide your mistakes well and no one will look twice!



Richard Kirkman 126/03/2020 20:58:18
310 forum posts
761 photos

I just finished putting the gearbox back together. Cutting the gasket was very easy since the old gasket was still in decent shape.

I've filled it back up with some old oil I had from the last time I filled it up, hopefully this will stay in this time. However, I will empty it out again and put in the proper tellus 41/Iso100 oil that's needed, I'm just using this oil to check for leaks.

I've cleaned everything up and put a paper towel under it, so leaks should be very easy to spot. I'm hoping for the best, only time will tell. 1 gasket down, 3 to go.




Phil Whitley27/03/2020 10:05:34
1328 forum posts
147 photos

Hi Richard, funny you finding a drill bit in the gearboxm I found a circlip jamming one of the slots, and a spacer, both parts of the gearbox, which had been removed, "lost" and the box reassembled without them! keep the drill bit, it will be old and good quality!


Phil Whitley27/03/2020 10:40:44
1328 forum posts
147 photos

Nitrile gasket is a good idea, I am using a thick paper one, the first one leaked, but the cover on my gearbox was a very tight fit over the dowels, I have a feeling it might be a foreigner, fitted after the original was broken in an accident, one of the gear selector levers is brazed on the inside too! I improved the fit with some needle filing, and it is fine now, though there is a slight dribble from selector shaft at the end. It is British, of course it leaks oil!!


Richard Kirkman 127/03/2020 10:56:46
310 forum posts
761 photos

Unfortunately, the drill bit is snapped so not much use!

I don't seem to have any leaks this morning, But, I'll leave it sitting for another day or two before I flush it and put the correct oil in.

The nitrile seems to be doing a good job. I think the old gasket was paper.

My cover was also quite tight, but did go back on eventually. I expected it to be a lot harder.

I contacted the ebay shop about the auxhillary connectors that should have come with the contactor and they said they must have forgotten them. I also mentioned that there was a corner snapped off it, so they've refunded the whole thing, even postage! So I now have a spare 415v contactor. Who knows when I might need one!

I still can't seem to get the gear selector off the shaft, I've undone the bolt in the handle and the one in the end of the shaft, but it doesn't seem to want to budge.



Bob Unitt 127/03/2020 11:13:18
103 forum posts
11 photos
Posted by Phil Whitley on 27/03/2020 10:40:44:

. It is British, of course it leaks oil!!


It's like an old Triumph motorbike - the oil leak was to let you know there was still some oil in it.

Phil Whitley27/03/2020 20:27:34
1328 forum posts
147 photos

Actually Bob, I got that from the original saying about triumphs, and British bikes in general!


Edited By Phil Whitley on 27/03/2020 20:36:33

Phil Whitley27/03/2020 20:35:34
1328 forum posts
147 photos

Hi Richard, the reason you cannot get the handle off the shaft, and many have broken them trying, is that there is a difficult to see allen screw in the end of the shaft, between the shaft and the handle, acting as a "dutch key", when you remove this it comes off with ease, so check the hole to see if there is a second one in there!, but you must get it back in exactly the right place, or the gears dont select properly. Also I think the bolt needs to come right out of the handle, but can't definitely remember. In practice, it is a bit of a faff, but not impossible by any means. set the shaft right in to the gearbox, then fit the handle, counterintuitive, but makes it easier! Then check that the gears line up and mesh fully in each position. You can try a VERY gentle tap on a wedge or screwdriver to open the handle clamp slightly, but it is cast, and it will break, be carefull, try a bit of heat, hot air gun is good!


Edited By Phil Whitley on 27/03/2020 20:38:10

Edited By Phil Whitley on 27/03/2020 20:45:29

Richard Kirkman 127/03/2020 21:52:37
310 forum posts
761 photos

After a full day of oil sitting in the gearbox, we have a leak. The gasket is absolutely fine, nice and tight, but I must have not tightened the drain plug in the bottom tight enough as oil was leaking out of there.

I started to take the main spindle out again today so I can replace the gaskets.

So, first step, remove the gears from the end of the lathe. It's essential that you keep a bucket of the old headstock oil right below what you're doing, so when you drop your parts they land in there.



Then you need to remove 3 of the 6 end screws in the top plate. Only the 3 that are protruding more. As the others are through holes



Then undo the grub screw in the collar and twist it off using the two holes in the front. I just used a pinch to twist it off as I already did that last time, but the proper tool would be much better


Then once that collar is off, that's that end free. So you go to the chuck end and start to take the bolts out there


The locking ring for the L0 taper has different slots in it so you can get a hex key in there. Much easier if you have ball ended hex keys


Once they're out, the spindle can be tapped out with a block of wood. Once the head comes out of the bore, make sure to hold onto it as you tap it the last bit.



Then the gears slide off the spindle as you pull the spindle out.

Then there are some locking nuts on the front part which I presume holds the bearings in somewhere but mine are fine so I'll leave them be.


Inside is really grimy, I didn't realise how bad it was last time I took it out. I've started cleaning, but it's taking a long time.

I cut the new gaskets using the old ones as templates. I used my dividers to actually cut out the circles as they were just sharp enough to cut the rubber


Old vs new



I noticed that it was leaking from the high low speed selector at the front of the lathe, so i made a new leather gasket for it a while ago. Finally took it to pieces and the old one was pretty much gone. The new one is a very tight fit on the shaft so should hopefully seal nicely.


Still, lots of cleaning inside to do, then reassembly, and that should be all as far as oil and gaskets go.

Contactor should arrive tomorrow so I'll wire as directed

As for the tumbler arm, I had a good look at the end for the dutch key, since I remember you mentioning it when I was looking at your lathe. But the only grub screw I could find was in the middle of the shaft. I'll look again tomorrow



Richard Kirkman 128/03/2020 11:08:22
310 forum posts
761 photos

Finally got some wiring diagrams with this contactor, 3rd time lucky. I'll go and wire it as directed in Phils messages



Richard Kirkman 128/03/2020 13:11:26
310 forum posts
761 photos

Alright, all wired, as far as I could work out from the directions in the long messages.

Please can this be checked over meticulously as I'm not confident that I did it correctly

I checked the cnd switch for continuity with the yellow wire, the safety circuit is working.





Edited By Richard Kirkman 1 on 28/03/2020 13:32:20

Phil Whitley28/03/2020 14:22:32
1328 forum posts
147 photos

Hi richard, the dutch key is in a hole which is drilled between the steel shaft and the cast handle, half the hole is in the shaft, and half in the handle, and it is usually full of grime so you cant see it. I am looking at the wiring now, I will get back to you on that presently. Thanks for the pics re spindle removal, that gearbox heeds a good flush out!


Richard Kirkman 128/03/2020 14:50:15
310 forum posts
761 photos

I'll go have a look again, I suspect it might have been filled with paint!

I'll try to do spindle reassembly too, but that's the tricky but.

The gearbox doesn't need flushing out yet, the muck is caked on so badly I'm having to get in there with a tooth brush. Somehow it's still red under there!

Phil Whitley28/03/2020 15:11:27
1328 forum posts
147 photos

Hi Richard, We have one two many A2 connections! If the A2 terminal on the overload end of the contactor is common with the one on the other end (multimeter check, look for the same resistance between A1, and either of the A2 connections. and check with the contactor pushed down to make sure that it is not switched by the contactor) then it is a common and we can use that one. Remove the link between the other A2 connection and the 13NO(the one with the red wire in it) There is confusion here, because the two wiring diagrams refer to NC-09-95 and NC-09-95N and your contactor is an NC-09-10, an example of Chinese inscrutability if ever I saw one!

Alternatively, you can use the A1 and A2 connections on the same end of the contactor, and wire from that A2 to the NC on the overloads, then from the other NC overload contact to the 13NO. there should be only two wires at this connection, and it should not be linked to A2.

This sounds a lot more complex than it is!, referring to the diagram will make it easier. You only need use one of the A2 connections, as the coil only has two ends, one end goes to a supply line (A1 to L1) and the other end goes into the switching and safety circuits and uses them to get back to L3 via the yellow wire, and when L1 and L3 are across the coil the contactor pulls in, and the motor starts. rewire it like this and post more pics! Tedious, but then, what else can we do in the present "interesting" times?


Edited By Phil Whitley on 28/03/2020 15:12:47

Richard Kirkman 128/03/2020 16:21:38
310 forum posts
761 photos

I've removed the link between A2 and the 13NO as suggested

I think I understand what's going on, but I was confused by there being two A2 points.

I used a multimeter and the resistance was the same for A1-A2 and A1-otherA2

Is this wiring correct now?



Now just two wires out of that one





Lots of pictures, because why not?

Cleaning the headstock is very nasty work. I keep hitting my hands off the gears in there as I scrub and cutting the backs of my hands. I've just about had enough, but it seems a lot cleaner. I'm currently flushing with the old oil again, then I'll clean it one last time and reassemble. Awfully cold out there today.

As for the tumbler arm mystery, you tell me if I'm being blind, I can't see a dutch key!

Looks like there's the starts of the threads on one the actual tumbler arm, but the shaft doesn't seem to have anything?



Edited By Richard Kirkman 1 on 28/03/2020 16:28:10

Phil Whitley28/03/2020 16:56:48
1328 forum posts
147 photos

Hi Richard, If you put your multimeter across L1 and L3, and push the start handle down partway, you should see the coil resistance if all is well. if you then push the contactor in, and move the handle into the run position, you should continue to see the coil resistance.

Fekk! I can't see a dutch key either, Your pic is of the right place, but it is small, and it should be there somewhere, clean it all back to bright metal before you say it is definitely not there! I can see what looks like about a 1/3 of a hole with a thread in it at about 4.30. Allen bolt in the centre of the shaft is for holding the shaft still whilst adjusting the gears. Never had that one off mine, I assume it is loctited in.


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