Colchester Bantam MK1 - Old, but New to me.

Hi All,

I'm hoping to find some info about a Colchester Bantam I picked up today. I paid the grand sum of £300 for the Bantam - it's been sat in someone's shed for years and gathered a significant layer of surface rust.

I got it home and managed with plenty of bed cleaning and WD40 to free off the x & y axes. I removed the cover at the top of the machine and the gearbox looks like new.

The machine has a 240v single phase motor so I connected it up and gave it a go and it runs but does a few strange things. I understand that this would have originally been 3-phase but I don't know what compromises are now in place due to the single phase conversion. To start the spindle I turned a lever which is on the center or the cabinet. It runs for a bit and then stops - it then won't restart until something electric clicks - this takes a minute or so. Does anyone know what this night be?

The lathe sounds ok but when the power feed is selected and the "bar" is rotating it is quote noisy - is there any reason for this? I also can't get the power feed lever to select on the apron - seems like it is stuck in the off position.

I definitely need to buy a couple of bits - the plaque with the screwcutting information is not readable - are these available anywhere? I also need the tailstock handwheel. Any ideas where to get these?

Any help with this machine is greatly appreciated.

Thanks,

Matt

Hi Matt,

You would probably benefit from an investment on a user manual.

If it is a change wheel model the gear train may be worn or not set up properly (so noisy).

There may be an interlock operating which prevents both long and cross travel power feeds operating at the same time.

Epay, lathesdotcodotuk or the yahooforums might well provide a manual at reasonable cost or free to download.

Lathesdotco is likely your best port of call for basic information on your lathe. A superb site for info of all kinds on machinery of this type.

Hi Matt

Join the Yahoo Colchester Group and you will find the Bantam manual in the Files section, many other tips and tricks concerning the Bantam have been written in earlier posts on the group.

The click you hear is most likely an overload re-setting automatically in the starter.

Emgee

https://groups.yahoo.com/neo/groups/ColchesterLathe-User/info

group link added

Edited By Emgee on 21/01/2018 10:06:17

Yes, sounds like electrical overload breaker tripping out and resetting after a set time. Big problem is to find what is causing the breaker to trip. I would not run the lathe any further until you have worked out what the problem is.

Is there oil in the gearbox and the headstock bearings? When the lathe stops, can you turn the headstock spindle over by hand? If not, your problem may be bearings nipping up due to lack of lubrication.

Definitely a user/workshop manual is a must. Then work from first principles.

Disconnect the belt or gears from the motor and see if the motor will run indefinitely while not driving any part of the lathe. If it still trips out and stops, you have a motor problem, either wiring or possibly dry bearings seizing up.

If the motor runs ok while "freewheeling", next step is to hook up the belts and trace through the drive train, making sure all bearings are free and lubricated. Then try running it again. If it trips out again, feel around for hot bearings around the headstock, gearbox, drivetrain, etc. If something is tight enough to overload the motor and trip it out, it will be getting very hot to the touch in the process. Anything too hot to touch, or close to it, is suspect.

I've got a Bantam and all the manuals / parts lists for it. Let me know (PM me) if you want any of them.

The motor is easy to change - there is loads of room and it takes a foot-mount motor. You need a good 1.5HP or more to run this properly - have you checked what is fitted? You may find it's woefully underpowered by the mystery motor. A modern enclosed 3-phase motor and VFD transforms these machines.

You can run the coolant pump from the same VFD or from single phase if you get a suitably sized (and cheap) motor run capacitor.

Murray

Thanks all.

i spent more time with today and made some progress.

Feeds are now working thanks to wd40 and some wiggling.

I removed the lower gearbox cover - there is damage to teeth on some of the gears. This will account for some noise. I don't know how worried to be about this - I've not looked inside the screwcutting gearbox on a lathe before but assume that some damage is not uncommon, particularly on hobby / training type machines. I put it back together and it's certainly quieter with fresh oil in.

One stupid question - do the micrometer scales on the handwheels move independently of the wheel on this model machine - mine don't but could well be rusted together presently???

The lathe has had the suds pump removed - there is nothing at all in terms of coolant system. I would like to reinstate this.

I ran the lathe and it seems ok at the 2nd highest speed setting - I assume this corresponds to 510 or 1020 but this would have been with the original 2 speed motor - seems quite slow to me so more like 510 or less. If I run it on the highest setting it runs for a while and then cuts out for a minute or so until the click and then it will run again.

Also the lathe only appears to run in the standard ccw direction - is this due to the single phase motor? can a single phase motor be configured to go both ways?

I also noticed that a significant part is missing! The lower changewheel has nothing holding it on! I have a copy of the manual and parts manual and it should have a knurled nut - 30579-1, collar 30566, washer 30606. the nut is an odd thread (3/4 OD, 20tpi). Does anyone know where I can buy these items?

I looked at the motor - the plate was pretty worn but looks like:

Frigidaire p/n 5496279

Crompton Parkinson

1/2kw, 230/250V, 50 hz, 8 cos theta

I couldn't read the rest.

Murray - bearing in mind that I am starting from scratch with the coolant system, would you still recommend 3-phase/VFD or stick with what I have an look for an aftermarket 240v coolant system?

Cheers!

Edited By mtrehy mtrehy on 21/01/2018 17:03:35

Edited By mtrehy mtrehy on 21/01/2018 17:05:22

The screwcutting gearbox is supposed to be protected by a shear pin next to the top gear of the geartrain, so it's a bummer that yours seems to be damaged. It is really useful having power feed, even if you don't do much / any screwcutting. Do you have the full selection of gears?

Yes, the micrometer dials should move. Reasonably stiffly (spring loaded ball??) so they don't slip accidentally. Best take them apart and clean them up.

You might as well get an aftermarket coolant pump and make it single phase for simplicity. But if you find a 3-ph one off ebay etc, they are simple enough to drive from single phase with the addition of a capacitor (no more than about £4-5).

Mine is the Mk II which has a 1600rpm top speed with the two speed motor running at the higher 2880 rpm range. So if you replace the motor like me, you might as well get a 2880rpm motor rather than 1440rpm. The bearings etc are fine at this speed. Sounds as if the single phase motor isn't set up to run in reverse. I use mine a fair bit in reverse, cutting at the rear of the work eg using a boring bar for external work. Also good for screwcutting away from the chuck.

1/2kW sounds underpowered, not least with heavy grease and rusted parts. I'd suggest 1.5-2kW and get a VFD if you can afford one.

I've just had my motor off to fit a brake linkage mechanism which was missing on my machine. The linkage came from Bede Tools in Newcastle who had broken a Bantam for parts. However, I believe most of those parts had been sold and that was 2-3 years ago. But keep your eyes open and you may see another one being broken on ebay etc.

Take it apart, clean it up and make any obvious repairs as you go. Unless it's been savagely abused (sounds as if it may have been), it should be capable of good work. Sounds as if a mild renovation would be advised before you start to use it in anger.

Good luck and let us know how you get on!

Murray

Edited By Muzzer on 21/01/2018 17:34:04

It didn't come with any additional change gears. It's got 35, 120, 100 & 30 installed. I guess I will need to get some others if I want to do metric threads.

I also like being able to run in reverse when screwcutting - any idea whether it will be possible to get the current motor to run reverse?

Thanks for your help.

HI Muzzer,

Would this motor be a good option with a VFD?

THanks

Hello matt

When you say the gearbox gears are damaged, do they have teeth missing or are they just a bit worn or slightly chipped?

If the gears are intact enough to run together simply stoning off any raised burrs might be enough to avoid having to organise expensive replacement.

Neil

That looks pretty good. You will be able to connect it in delta so it runs on the 220-240V range. Then it will do the 2820rpm at 1.5kW. It's a modern totally enclosed fan cooled (TEFC) motor, which is good. I assume it's foot mount?

Of course, you will need a single phase to three phase VFD but these aren't expensive. Either get a proper one or take your chances on a Huanyang Xmas cracker. Or get lucky on ebay?

What do you mean about the broken gears? Could you show some pics? As Neil says, chips can be repaired but broken teeth are another matter. Also, you be able to use some ratios but not others. There are 3 basic ranges and 6 sub ratios.

The main gears you need are the 30t (output / bottom) and 35t (input / top), plus the 120 to span the gap. The 127t gear is what you need for metric ideally.

I had my motor off yesterday to fit the brake pedal mechanism. As you can see, there's plenty of room if you pull the machine out to give yourself plenty of room. You can also see the coolant pump which just sort of hangs on the rear lip of the chip tray

Murray

Edited By Muzzer on 22/01/2018 20:57:57

There are no teeth missing - mostly wear and a few chips - the worst are shown here:

THe motor i have found is foot mount and looks similar size. Not sure about the pulley fitting but sure I can engineer some way of fixing the original pulley in place. Fixing centres are 145 width x 102 length. 15kg, 25mm Shaft x 50mm length.

I'm missing everything coolant related. Not sure what to do about this at the moment. Tempted to knock up a temporary windscreen washer pump to a heath robinson reservoir. Don't want this to turn into too much of a money pit just yet.

Thanks guys.

Edited By mtrehy mtrehy on 22/01/2018 21:18:22

Pretty much complete. Done quite cheap but lots of time spent!

New motor was about £25 and the used VFD about the same. I spent £40 on a 10L parts washer that will be the coolant system. A few quid on switchgear and sight glasses etc.

About 50 hours work I think - was stripped completely into component parts and bare metalled. Added a drawer to the stand and will add a large draw under the electrical panel when I get some time