Colchester Student Mk1 Won't Start

This seems to me to be cheaper/lower quality capacitors changing value over time.

Cheapness is not always a good trait and MM do seem to often offer cheaper machine ‘lookalikes’ ... sometimes called ‘clones’

”You pays your money and gets what you paid for” may well apply in circumstances like this.

While I do occasionally make purchases from MM, I do tend to be very careful with my selection and often choose a better product from elsewhere.

This may be of interest, It is the technique I use on my Chipmaster for a VFD conversion.
My lathe has the original 1963 motor which cannot be wired for 240V (or at least not without digging into windings for star point). There is some loss of power, but it is fine for hobby use.

**LINK**

I doubt it is weak capacitors, if it were, I would think that the start relay would remain in the start position, because the motor speed would not build, and current flow would remain high. Something is switching off k2, and that should only happen when the motor is up to speed and current falls.

Phil

Still waiting on machine mart, no doubt it'll be another couple of weeks, but who knows!

Stuart, thank you, that link was quite an interesting read, I didn't realise you could do that with a VFD.

Not done it yet, yes I do agree, Machine Mart is best to be avoided, however I struggled to find a comparable converter or even a clone of the same product. The only other thing i could find was transwave, their converters seem much higher quality, If you're judging by the price! I'm not keen on spending twice what I paid for the lathe on the converter though. I'm trying to keep this cheap while keeping the machine as original as possible

Once the lathe's up and running, the next problems going to be sorting out the oil leaks from the headstock and gearbox. I don't even remember if i saw any gaskets when I took it apart (definitely one, but they're old)

Phil, I know you recommended that shelving cork with a sticky back for it, but would this stuff be appropriate?

I found someone selling gaskets on ebay for a student made from the same stuff.

Or would it be easier to just buy them instead of making them myself, as i'm not too sure how i'd go about cutting them all to the right shape

la-520699180922&abcId=1139126&merchantid=115678302&gclid=CjwKCAiAluLvBRASEiwAAbX3GXPMyTkzY8vO4NWmD5U24q-qRs-Zm34CKvHOhaY7gysSQqVPIc2x9hoCyNUQAvD_BwE">Ebay gasket sheet link

Ebay gasket seller

an alternative supplier of clarke products is Site Box **LINK**

they are often cheaper that Machine Mart,

Well, I have no idea if they need to be thick and compressible - some may even need to be ‘solid’ - and some can act as ‘shims’, so check them out first.

Forty quid for the few gaskets supplied is steep - even if they are of a suitable material. I’ve made hundreds of gaskets over the years. Mostly paper or rigid gasket card. Paper often just needs suitable ball-pein hammers, thicker material may need hole punches. Craft knife and scissors are good tools, as is a photocopier at times.

They are not difficult to make and you can practise on less important parts. Go for it!

The only gasket on mine is the quick change box one, there is no gasket on the headstock gearbox lid, and it doesnt leak! The cork gasket material is available on the net and also at any local agricultural engineers, but it can be pricey there. Look for self adhesive cork roll, available in a variety of thicknesses. For the rest, use Hylomar if you can find it, or failing that Hernetite.Unfortunately both of those latter products have been reformulated, so if you can buy old stock, so much the better, as the new stuff is, as usual, piss poor!

Phil

There should be gaskets on the main spindle too, near the bearings when you replace them.

Quick progress update

Spoke to man from machine mart, nothing's happened, seems like they've packed up for christmas a week or two early. But, such is life. Even if I do get a refund, sitebox says the pc60 won't be delivered till the 3rd jan, by which i'll be back at uni. So, i'm back to cleaning the lathe. Will be back to try the pc60 after ive finished my exams on the 15th. Unless I can find a better converter on ebay. Saw a transwave 3kw rotary converter go for 260 today, so definitely worth looking out for

I'm going to order some of the gasket material to make my own, I'll use 2mm nitrile rubber as if that's what the man on ebays's charging 40 quid for then it must work. I'm going to measure my current one, then scale the pictures from his ad to make my own templates. The headstock is going to need taking to pieces again to change the gaskets, so i might be able to sort out the gear misalignment issue too

Finally managed to get the toolpost off the lathe, much to my disappointment, realising that it's not going to be able to fit a QCTP as it's proper 4 way tool post with the built in mount. When the woman responds with some pictures of the spare parts lathe I may see if the top slide on her one has a t slot, might be able to swap them over.

Does anyone know what material the coolant tank is made from, when i cleaned that out there's been a bit of corrosion and some really small places have corroded through. I can borrow a friends MIG welder, and I have some experience welding, so will i be able to just fill the gaps so it's nicely water tight? Recommended or unrecommended?

Richard

I, for one, would never recommend welding on any closed vessel that has had hydrocarbons in it previously - unless proper precautions are undertaken beforehand.

I wouldn't call it fully closed, It could be cleaned out fully and could have a hoover in there too for fumes?

However, what precautions or other methods would be suitable?

If using a MIG clean the tank well and then fill it with shield gas to displace vapours and oxygen. Close the filler with a bit of plastic film and an elastic band so any thermally induced pressure increase is vented..

Robert G8RPI

Edited By Robert Atkinson 2 on 23/12/2019 07:21:21

I don’t think I used the term ‘fully’ and added the proviso re ‘proper precautions’. A tank with just a screwed-off cap would, in my opinion not be in any way termed as an open tank. Your description and proposal was very poorly/sparsely described.

There are too many, out there, that might give full agreement for some operation that is then carried out unsafely by the person who proposed it.

One then might wonder who would be deemed responsible, if injury or death should unfortunately follow that exchange, or after a third party has followed the same glib proposal and advice - clearly provided on an open forum. I don’t intend being blamed for someone else's folly and I stand by my reply. Simple, unrecommended.

Calm down chaps! all good safety info is worth listening to, but the coolant tank on a Colchester student is actually the centre base of the lathe, and is accessed by opening an 18" square door underneath the chip tray, no way could anything explode, and very unlikely to catch fire! A good soak in hot soapy water is all that is needed. The coolant tank is steel like the rest of the lathes stand.

Richard, those T slot top slides are as rare as hens teeth, and about £300 on ebay, whilst the QCTP is very convenient, a GOOD one is expensive, and by all accounts the cheaper chinesium ones are not much good on bigger machines like the student, Actually it is a bit odd that yours hasn't got a Tslot one, because most gap bed machines came with them as standard, post up a pic of your topslide with the toolpost off if you can. You could forget the T slot and use the existing bolt and modify a QCTP to fit your topslide. I have a spare plain topslide, and one of next years projects may be to cut a T slot into it, but I am not sure if the Tslot topslide has more meat inder the toolpost than the plain one has, will have to have a measure up, and there are more important things to do first!

Edited By Phil Whitley on 23/12/2019 13:48:08

Edited By Phil Whitley on 23/12/2019 13:51:16

these are worth watching Richard. he is a bit vague on detail, but I know what he is doing, he gets it working in the second video, and he is running a much bigger motor on a machine with much more starting load than the Student!

https://www.youtube.com/watch?v=lCHDZujmYzs&t=846s

https://www.youtube.com/watch?v=MJnEKopDIyI

Apologies, I haven't quite described it properly. By tank, i meant more fish tank, so more like an open box rather than a canister with a cap. I forgot to put pictures on.

As Phil says, there's an 18 inch opening for scale for the pictures.

Phil, the tool post is all back together now, and it was a pain to get to pieces, have to take the top slide all to pieces as well just to get to it. I'll see if i can find any similar pictures online and i'll watch those videos. Got some other jobs to do around the house first! Thanks

Before cleaning, about 1cm of gunk and rust and whatever else was down there

After cleaning and oiled. Holes are small, but would still leak.

When repairing similar on my M300. I got a thin sheet cut to just the right size for the base and got a local faricator to weld it to the base for a drink, rather than attempt to repair a very poor surface.

I'll go in and wire brush all the surfaces so they should be clean. It should be less welding for me to just plug the holes than put a sheet in. And I won't need to buy a sheet. The metal looks thick enough already I think

Phil, the tool post mount looks identical to the one in this post. If you haven't seen it, it's a good read for the first part but seems to not be concluded.

Colchester student QCTP

Video was helpful for how and why I would need to convert the static into a rotary, but if my machine will run nicely enough just from the static converter then why bother with it?

Thanks

if the holes are small, what about coating with an Epoxy sealant?

Thats not too bad Richard, I think I would just weld up the pits and then clean and dry it out thoroughly with a hot air gun and give it a couple of coats of two pack epoxy paint. The tool post you have is identical to mine, mine was very stiff too, so I stripped it..................it has never worked 100% since, but of course I dont know how well it worked before I got it! they are a pain to reassemble! Funny you should link to the above post from 2014, I actually commented in it!

Edited By Phil Whitley on 23/12/2019 15:35:36