New toy: Setting up Colchester Student lathe

My new lathe arrived yesterday, so I've spent much of today cleaning and setting it up:

Attachment 3963
I was impressed how effortlessly that crane picked up the lathe. Getting it up the garden was completely the opposite though (I'll post that in the thread I started earlier).

Here it is in place:
Attachment 3964

We still need to move the worktops into a more optimal location (big hammer!) and fix them down. The lathe is pretty stable as it is.

The bed of the lathe looks in good nick for the most part. In some places there's a tiny bit of discolouration - probably rust but I can't feel a bump or anything so I'm happy with that. There's a few small nicks in it near the tailstock end, again nothing major.

It's come with a 200mm Burned chuck. The mechanism is nice and smooth, but I cleaned it all out anyway. No chuck key, but it didn't take long to make one! There's no external jaws for it, but I can get 4" bar in without them anyway and I don't envisage needing more at all often. I can use the (free!) 10" 4 jaw chuck that came with it for bigger stuff. There's also 3 soft jaws.

Problem: The jaws on the 3 jaw seem to be worn such that it's holding bar at an angle to the axis of rotation of the spindle. When I tighten the chuck it looks like it grips the bar closer to the spindle first, then if you really tighten it the end of the jaw near the tailstock grabs. It looks like the jaws are tapered. :sad: I wondering if I should skim a bit off the jaws? 10mm from the chuck the runout is 0.22mm, 50mm away it's 0.44m, 30mm it's 0.32mm - so it looks pretty linear.

The headstock has sufficient oil in it for now - the gauge is half full, or half empty...However the threading gearbox appears to have no oil, so I need to find some. It says in the manual here, but I'm not sure where to get it:

http://bbssystem.com/manuals/colchester_student.pdf
(page 11)

The autofeeds both seem to work fine, if a bit slow.

There's a bit of backlash in the cross slide and compound slide, more in the former. That could be a problem... It does seem to vary, so maybe the screw is worn unevenly. The slide is a bit stiffer near the end where there seems to be less backlash. I'll investigate this tomorrow.

I swapped the wires in the motor to run it on 220v instead of 440v and wired up the 2.2Kw china VFD from the router with the relevant settings changed. It worked first time :surprised:. The main belts look a bit worn, I might replace them just to be safe.

It would be nice to put the coolant pump on the VFD. I've read that it's OK to have two motors on the same VFD and I'll be changing the spindle speed with the gears for the most part so I won't have an issue with the pump not going fast enough. I'm still not sure that it's wise? I'm right on the limit of the VFD as it is. The VFD is 3HP, and so is the lathe motor. If I put it at full tilt (50Hz with highest gear - apparently 1200rpm) the VFD reads about 6 amps (upto 10.5 on startup but not for long at all). I've got the spinup time set to 5 seconds.

More to follow as and when I think of it and find out.

In the meantime, can anyone advise me on the chuck, coolant pump and oil please?

If it's anything like it's big brother that I bought, headstock oil will be listed as Shell Tellus 27, with the screwcutting Tellus 33. Shell still do Tellus oils, but they're not the same as the old Tellus oils from the era of that manual.
From much googling, modern equivalents are hydraulic ISO 32 and 68 oils.
One word of caution when dealing with ISO 32 or thinner oils, wear gloves. 32 is thin enough to get in skin pores, and cause problems.

Quote:

---

Originally Posted by m_c

From much googling, modern equivalents are hydraulic ISO 32 and 68 oils.

---

Thanks, I'll have a look where I can get them. Do you think I should remove the old oil and clean it up a bit first?

Edit:

Found it on eBay:
http://cgi.ebay.co.uk/Premier-ISO-32...item19c370ed6a

and

http://cgi.ebay.co.uk/Premier-Slidew...item19c434faaa

Hope that's enough!

This is a better deal if not:
http://cgi.ebay.co.uk/Hydraulic-Oil-...item2562b7e483

Just thought - the misalignment on the chuck could be the headstock that's out of line. I'll check it by putting the DTI on 'top' of the bar, then the 'side' to see if they're different readings.

In the manual it says 32 and 68 oil, I should have read it properly!

Jonathan i used those machines when i was an apprentice and they were old then as the square headstock models came out so that lathe is at least 45 years old and probably older. It will have not only be used but abused so you should stand back amazed that it is in such good condition.

Re the chuck, small pieces were held and the chucks overtightened so again hardly surprising the jaws are bell mouthed.

You wont be able to SKIM them they need to be ground, obviously you can skim the soft jaws. I would check the fit of the jaw profile in the chuck body worst case a new chuck around £200

Congrats in getting it in.

Phil

Quote:

---

Originally Posted by M250cnc

Jonathan i used those machines when i was an apprentice and they were old then as the square headstock models came out so that lathe is at least 45 years old and probably older. It will have not only be used but abused so you should stand back amazed that it is in such good condition.

---

The owner said that it had had very little use from him since they've got bigger and better lathes. I tend to believe him since the nut you undo (should be a lever) to rotate the toolpost was extremely hard to undo. I think is the slightly newer version of the old lathe as it's got the later apron and the better bearings.

Re the chuck, small pieces were held and the chucks overtightened so again hardly surprising the jaws are bell mouthed.

Quote:

---

Originally Posted by M250cnc

You wont be able to SKIM them they need to be ground, obviously you can skim the soft jaws. I would check the fit of the jaw profile in the chuck body worst case a new chuck around £200

---

Would they be machinable with a carbide tool any plenty of coolant? I read someone doing it on a mini lathe with a diamond tool spinning fast, and the lathe on full speed so the centripetal force pushes the jaws against the thread. That was only to remove a tiny bit though. I guess it's worth a try? Alternatively could I anneal the jaws, machine, then harden again? Just thinking aloud!

I've had the jaws out and there were some burrs on the thread.

Just checked with the indicator and it's the same runout wherever I measure, so must be the chuck at fault. With the indicator on the body of the chuck I get about 0.015mm runout.

Edit:

It's just occured to me, I removed the burrs on the back of the jaws easily enough with a needle file, and somebody's machined them else where which implies that they are machinable. I have a glanze boring bar and some new inserts for it.

Quote:

---

Originally Posted by Jonathan

The owner said that it had had very little use from him since they've got bigger and better lathes. I tend to believe him since the nut you undo (should be a lever) to rotate the toolpost was extremely hard to undo. I think is the slightly newer version of the old lathe as it's got the later apron and the better bearings.

---

Well he would say that wouldn't he. Not, no mate it's completely flipped.

You can check out the serial number here http://www.lathes.co.uk/colchester/page34.html

Quote:

---

Originally Posted by Jonathan

Would they be machinable with a carbide tool any plenty of coolant? I read someone doing it on a mini lathe with a diamond tool spinning fast, and the lathe on full speed so the centripetal force pushes the jaws against the thread. That was only to remove a tiny bit though. I guess it's worth a try? Alternatively could I anneal the jaws, machine, then harden again? Just thinking aloud!

---

Not really, they are ground when made new so there is your answer. Stop thinking out loud don't even think about annealing them

Quote:

---

Originally Posted by Jonathan

I've had the jaws out and there were some burrs on the thread.

Just checked with the indicator and it's the same runout wherever I measure, so must be the chuck at fault. With the indicator on the body of the chuck I get about 0.015mm runout.

---

If the runout was repeatable at the same point on the chuck it might be worth it, but if the run out changes position then you live with it or buy a new chuck.

Phil

Quote:

---

Originally Posted by M250cnc

Well he would say that wouldn't he. Not, no mate it's completely flipped. You can check out the serial number here http://www.lathes.co.uk/colchester/page34.html

---

Yes, of course he would. He didn't realise the 4 jaw chuck was in the cabinate until he started shifting the lathe, so I got that chuck for nothing. I'll check the number tomorrow.

Quote:

---

Originally Posted by M250cnc

If the runout was repeatable at the same point on the chuck it might be worth it, but if the run out changes position then you live with it

---

Sorry I'm not sure what you mean by 'at the same point'?

The machine No. is F 2/65795 - I think that's 1968 so not too bad considering they stopped making them in 1972. Still more than twice as old as me :lol:

Quote:

---

Originally Posted by Jonathan

Sorry I'm not sure what you mean by 'at the same point'?

---

Chuck a piece of quality stock.

Check with your dti run out, mark the high point on the chuck with a marker pen and note the reading.

Take out stock then repeat the process and check the readings.

Phil



Sent from my HTC Desire using Tapatalk

Quote:

---

Originally Posted by M250cnc

Chuck a piece of quality stock.

Check with your dti run out, mark the high point on the chuck with a marker pen and note the reading.

Take out stock then repeat the process and check the readings.

---

Thanks, I'll do that tomorrow - getting late!

Just found this:

http://cgi.ebay.co.uk/BURNERD-7-5-3-...item2562cafe7d

Second hand might not be the best of ideas though.

I've done what you said, with a couple of different bits of stock a few times and yes the high point is always in line with jaw 2.

I think the jaws that are in there are soft jaws since there are machining marks on them and when I filed off the burrs it felt like mild steel.

I put the other (definitely soft) jaws in and found that one jaw was in the wrong place. It turns out that I have to mount them in the order 2-3-1 for them to meet at the centre. They seem fine then.

Found a C spanner on eBay to get the chuck off:

http://cgi.ebay.co.uk/Harrison-LO-Ta...item53e2a6afd7

I think that's the right one. Cheaper to CNC mill my own though.

Regarding the oils, one official cross reference I found was Texaco Rando HD (only reason I remember that, is that's what we used to use at work before switching suppliers).
What Rando HD is, is a pretty standard hydraulic oil with some basic additives, for use in most normal hydraulic systems.

The slideway lube you linked to will most likely have tack additives, so it sticks better, and I personally wouldn't be putting it in a gearbox.

Try some of your local agricultural merchants/dealers, as they normally stock hydraulic oil, although 68 is not a very common oil (32, 46 and 100 are all far more common)

Quote:

---

Originally Posted by m_c

Try some of your local agricultural merchants/dealers, as they normally stock hydraulic oil, although 68 is not a very common oil (32, 46 and 100 are all far more common)

---

I'll have to ask my dad nicely to take me then :smile:

I dismantled the 3 jaw chuck - there wasn't that much swarf inside. It made no difference to the runout though I didn't really expect it to. I did it so I can try and machine the jaws. The problem is if I machine the jaws it is surely only going to be accurate at the diameter I machine it?

I've been looking at getting a new 200mm chuck - wow what a lot of money! I'll need one of these backplates:

http://cgi.ebay.co.uk/RDGTOOLS-200MM...item5195a7ca4c

I've googled and apparently this chuck is reasonable quality - it's also the cheapest I found:

http://www.tilgear.info/products/272...mm___on_offer/

I don't know how long that is on offer for?

Either that or a new Pratt chuck is £229.

Dremel mounted on cross slide, will help rescue the existing jaws. Just make sure you clean all the grinding dust back of once you're finished.

Remember a three jaw chuck isn't good for accurate work. For accuracy you really need to be using a 4 jaw, or collets.

Quote:

---

Originally Posted by m_c

Dremel mounted on cross slide, will help rescue the existing jaws. Just make sure you clean all the grinding dust back of once you're finished.

---

I've got a die grinder for the air compressor - that should do it. Mounting it is going to be a faff as it's an awkward shape. I'll need to buy a suitable grinding stone for it too.

Quote:

---

Originally Posted by m_c

Remember a three jaw chuck isn't good for accurate work. For accuracy you really need to be using a 4 jaw, or collets.

---

Yes, I'm well aware of that. This chuck isn't even close at the moment though. I hope the 4 independant jaw chuck is good. There's less to go wrong with them I think.

Attachment 3967

I've reground the chuck jaws using the die grinder. I found a grinding stone that looked fine however the shaft was 1/4" not the 6mm I needed. I put it in the mini lathe with the 4 jaw chuck and carefully turned it down to fit. I used the autofeed on the lathe and took off 1 thou at a time.

I measured the runout the same as before and got 0.09mm (10mm from chuck) to 0.15mm (@50mm). It was the same with smaller stock too. I've not tried anything bigger than the diameter I ground it at (50mm ish) which might be the problematic one since then the corners of the jaws will be in contact.

I'm happy with that for now. It's clearly not as good as a new chuck, but good enough for most things. It just means I'll have to use the 4 jaw a little more often.

This is how I set up to grind the jaws, except with newspaper down to protect the bed:

Attachment 3968

Jonathan

It seems the chuck is not too bad so why not buy new jaws for it.

Soft jaws are not really high precision they are really made to hold custom parts and being soft will be wearing quickly.

Using a 4 jaw chuck you will be getting jaw marks on your work so should be avoided at all cost you just cannot get the correct even grip without marks. Then add the time for centreing.

Phil

Quote:

---

Originally Posted by M250cnc

It seems the chuck is not too bad so why not buy new jaws for it.

---

I'll see if I can find some. I'm worried about if I buy new jaws and find it still doesn't hold accurately due to the scroll being worn for instance.

Edit: Found some jaws, not checked if they're the right ones:

http://cgi.ebay.co.uk/Hard-Inside-Ja...item53e7273419

Considering that whole new chuck is £125 they seem a lot...get what you pay for I suppose.

Quote:

---

Originally Posted by M250cnc

Using a 4 jaw chuck you will be getting jaw marks on your work so should be avoided at all cost you just cannot get the correct even grip without marks. Then add the time for centreing.

---

I've avoided that in the past on some things by putting strips of aluminium or copper in between the jaw and the work. That won't grip it as well though. Centreing is only a couple of minutes with two chuck keys (I'll make another) - but still annoying to do.

I've just wired the coolant pump up - took the end plate off the pump and changed it to Delta. To test it I've taken the main motor off the VFD and just connected the coolant pump without changing any settings on the VFD. It works fine, although there's not enough coolant in the tank to actually pump it round at the moment. I'll have to get some, again I'm not sure which to get and where.

The question that remains is if I'm OK to run the main motor and coolant pump on the VFD at the same time. The pump is 2 pole, and the main motor 4 pole, however the pump worked with the VFD still set to 4 pole. I've searched on other forums and people have done it.

The pump only draws 0.22A, but with a 3Hp motor on the VFD I'm right on the limit - especially with it being in delta(?) ... the problem is when the main motor has a big load on it is when I want to be running the coolant! If I do put the pump on the VFD I'll put a relay and switch in so that you can only connect the pump when the VFD is off.

This implies it is ok:

http://web.applied.com/base.cfm?page_id=3124#q5

Looks like a good sturdy machine. Those old colchesters are capable of hard work. Is the bed hard or soft? Some of the roundheads had soft beds. Watch out for the gamet bearings. If you have to get new ones you may have to dig fairly deep!

Even if the lathe is old it does not mean it has had it. Just look at the old DSGs and Halifax lathe in the mech eng toolroom at the uni!

I am sure you will enjoy taking cuts with a machine with a bit of meat. The saddle also has T slots which are great for boring jobs.

The coolant pump only uses a fraction of the power the spindle will use, so I personally wouldn't say it's going to be a major issue in terms of doing anything bad to the VFD, especially considering the coolant pump isn't likely to be running near it's rated power.
However, what if you want to use the VFD to change the speed of the spindle?

Other option is a simple static phase converter using a capacitor to power the coolant pump.

Quote:

---

Originally Posted by Andrew Wilding

Looks like a good sturdy machine. Those old colchesters are capable of hard work. Is the bed hard or soft? Some of the roundheads had soft beds.

---

There's a sign on the bed saying "Induction Hardened Bed" :cool:

Quote:

---

Originally Posted by Andrew Wilding

Watch out for the gamet bearings. If you have to get new ones you may have to dig fairly deep!

---

Are they not a standard size then? They seem fine at the moment - if I disengauge the motor and spin the spindle by hand it feels very nice and smooth. Having said that the headstock did get a bit warm near the chuck end when I ran it at 1200rpm for a while. I'm not sure if that's normal.

Quote:

---

Originally Posted by Andrew Wilding

Just look at the old DSGs and Halifax lathe in the mech eng toolroom at the uni!

---

I would if I was allowed in. I asked about if I could use the machines and they said only if I do the training (health and safety reasons), which I don't mind though I doubt it would be more than I'd done at school. Anyway, it never happened so the nearest I've got it watching standing on the balconies!

Quote:

---

Originally Posted by Andrew Wilding

I am sure you will enjoy taking cuts with a machine with a bit of meat. The saddle also has T slots which are great for boring jobs.

---

Definately - at school they have two M300's and one M250 which I used a lot. I never thought I'd own a similar lathe. There was also a bigger lathe - over 50 years old I think and it was better than the Harrison, except I was about the only one to use it because it had imperial dials. Now sold to make space for laser cutter...waste in my opinion!

Anyway I'm going a bit off topic...

Just to test I faced 50mm MS & aluminium bar and chamfered the steel, here's the result:

Attachment 3970

Attachment 3969

Not the most interesting test but it got a nice shiny finish. Happy!

Quote:

---

Originally Posted by m_c

The coolant pump only uses a fraction of the power the spindle will use, so I personally wouldn't say it's going to be a major issue in terms of doing anything bad to the VFD, especially considering the coolant pump isn't likely to be running near it's rated power.
However, what if you want to use the VFD to change the speed of the spindle?

---

I reckon I'll try them together tomorrow. Why would I want to change the spindle speed with the VFD significantly? It's easy to change the gears and keep the motor at full speed which will surely get more torque. If I want a speed between the standard ones I won't have to reduce the frequency much.

At the moment I've only ran the motors at 50Hz, however they both say 50/60Hz. I'm going to test the actual rpm of the spindle tomorrow.

I've found some standard oil for a better price:

http://cgi.ebay.co.uk/Smith-Allan-T3...item3a6147458c

T68 is the same price from that seller and as far as I can see T## is equivalent to ISO## oil. 10W oil is equivalent to ISO32, and 20W equivalent to ISO68 according to this site:

http://www.engineeringtoolbox.com/is...il-d_1207.html

I'm not sure if that means, for instance, 10W40 as used in car engines is suitable. It's widely available (Halfords, B&Q etc).

Mutli-viscosity oils such as 10W40 have viscosity modifiers so the viscosity remains more constant over temperature change.
A 10W40 oil acts like a SAE10 oil at 25degC, and a SAE40 oil at 65degC (at least I think that's what the temps are, but they're maybe 5deg of!).

Engine oils also have a lot more additives and detergents (with the exception of the more specialist SAE oils aimed at small engines/classic engines), which there is a possibility may cause issues with some seal types, and the detergents can dislodge drit/grime that would otherwise be sitting causing no problems.

Hydraulic oil on the other hand, is pretty much one of the purist oils you can get, with minimal additives, and certainly no viscosity modifiers.

Quote:

---

Originally Posted by m_c

...10W40 oil acts like a SAE10 oil at 25degC, and a SAE40 oil at 65degC...

---

How hot should the headstock get - not 65°C? At the moment it's a little warm, but not excessively.

Quote:

---

Originally Posted by m_c

Engine oils also have a lot more additives and detergents (with the exception of the more specialist SAE oils aimed at small engines/classic engines), which there is a possibility may cause issues with some seal types, and the detergents can dislodge drit/grime that would otherwise be sitting causing no problems.

---

I've searched on other forums and it looks like other people have used it. Some of the additives might be beneficial...

I'll get the hydraulic oils for £13.71 off eBay to be safe. It doesn't say in the manual how much is required, but I should think 5L of each is plenty.

Now the gearbox oil is sorted time to decide on cutting fluid.
I think this is suitable:

http://www.toolbox.co.uk/rocol-roc35...sol-5401-96554

I'm wary of using anything that's diluted with water. How good are the rust inhibitors? I don't want to risk the lathe bed rusting.

Biggest issue with soluble oils is them going off, but I've never had any problems with my milling machine and I've never changed the coolant since getting it several years ago.

Provided you lube the lathe with slideway oil, any coolant left on the bed will evaporate the water out before anything happens to the metal.
Only place I ever get rust on the milling machine is in any chips that have been left lying for a while, which is more likely to be caused by the dampness in the shed rather the coolant. The same applies to the bandsaw, which never sees any oil.

That's encouraging, thanks. I have a dehumidifier in the workshop so that should help evaporate the water quickly. Do you think the coolant I linked to is a good, choice / what did you use?

There are so many to choose from:

http://www.toolbox.co.uk/rocol-roc51...ign=GoogleBase

http://www.rdgtools.co.uk/acatalog/C..._and_oils.html

http://www.ccw-tools.com/prodtype.as...story=category

I think I got mine from Chronos at the time, but can't be entirely sure.
General criteria I went for was it was wet, and cooled things!

Quote:

---

Originally Posted by m_c

I think I got mine from Chronos at the time, but can't be entirely sure.
General criteria I went for was it was wet, and cooled things!

---

:rofl: Probably this one then:

http://www.chronos.ltd.uk/acatalog/5...luble-Oil.html

Jonathan,
I hpe your are havng more fun with your new toy than I am with mine. My "new" Blomqvist is cutting at a taper. I spent a while last night setting up the tool holder ang cross slide with a dti guage so that it is at 90 degress to the chuck and it is still cutting a bit off. I have bored out a hole with the apron stationary while using the cross slide compound rest. Still not sure why it is tapering. It could be that the headstock is slightly off centre. I will need to check this later.

Ian

Quote:

---

Originally Posted by Web Goblin

Jonathan,
I hpe your are havng more fun with your new toy than I am with mine.

---

I've not actually made anything wit it yet - I'm trying to think of something!

Quote:

---

Originally Posted by Web Goblin

My "new" Blomqvist is cutting at a taper. I spent a while last night setting up the tool holder ang cross slide with a dti ... It could be that the headstock is slightly off centre.

---

When cutting parallel I always use the apron handle for the final pass. If you use the apron does it cut parallel, if not it must be the headstock.

Where are you putting the dti to test the top slide since the side of it might not actually be exactly parallel to the direction of motion? How far off is it? If it's only a very slight taper using the apron handle it could be that the bed is twisted.

I've not checked the headstock on mine yet.

Quote:

---

Originally Posted by Jonathan

When cutting parallel I always use the apron handle for the final pass. If you use the apron does it cut parallel, if not it must be the headstock.

Where are you putting the dti to test the top slide since the side of it might not actually be exactly parallel to the direction of motion? How far off is it? If it's only a very slight taper using the apron handle it could be that the bed is twisted.

I've not checked the headstock on mine yet.

---

The compound slide should only be used FOR cutting tapers, everything else you should use the saddle/apron

The only way to test is with a test bar that fits in the spindle taper and use a dti any other method you will be bringing other factors into the equation by making test cuts "Tool Deflection, Materiel Deflection ETC"

The only part that needs to run true is the cross slide to the spindle axis.

Phil

Quote:

---

Originally Posted by M250cnc

The only way to test is with a test bar that fits in the spindle taper and use a dti any other method you will be bringing other factors into the equation by making test cuts "Tool Deflection, Materiel Deflection ETC"

---

That's interesting, and seems logical, however in the manual for my lathe it says to test it by cutting.

First useful parts I've made on the lathe:

Attachment 3976

Socket spanner for the toolpost, I made the socket ages ago with the rotary table on milling machine before I converted it to CNC. It happened to fit the toolpost nut :cool:

Second is two small pins for my rc car, 2.8mm diameter - 45mm long. I have not got an MT3-2 adapter so can't use my centres yet so had to do it unsupported. It worked fine though. One of them is stainless steel by accident! They hold the wishbones on - the original is just a simple bar that keeps falling out.

Jonathan,
if you are after some morse taper sleeves I have some if you are interested.

Ian

I found the cheapest BD68 slideways oil on Radionics

http://radionics.rs-online.com/web/s...=bd+68&x=0&y=0

Phil,
thanks for the info. I have tested the lathe again boring a 16mm hole with a boring bar again. I set up the boring bar in the holder by eye and the tool holder by eye at right angles to the bed, the tool holder does not index.
Tried boring some brass bar and it came out good. Vernier was a good fit in both ends of the hole.

Ian