Colchester Triumph 2000 leadscrew?

jim_cliff11 · Oct 26, 2019

Hi,

I have recently bought a Colchester Triumph 2000 lathe with a 50" bed. The lathe needs some work, but we paid next to nothing for it. It has dual metric / imperial dials, 16 spindle speeds, the 6" D1 camlock chuck mountand foot pedal to brake the spindle.

Basically, the thread cutting lever will not engage. The half nuts would not engage with the lead screw. To cut a long story short, we stripped the gearbox off the apron and removed the half nuts and leadscrew. The problem is that the leadscrew is metric with a 6mm pitch, yet the half nuts are imperial 1/4" pitch.... hense they wont mesh!

When I spoke to Tony at Lathes.co.uk and a colchester lathe parts company down south they both told the lathe serial number indicates the lathe was imperial coming out of the factory. However we have a metric leadscrew and metric swing arm gears. Under the leadscrew direction handle on the main gearbox it is even printed onto the fascia 6mm. This makes me think the lathe is actually metric.

Anyway, I have found a set of metric half nuts to fit, but before I buy I need clarification. Neither the leadscrew or imperial half nuts look new on our machine, so its hard to tell which one has been swapped. Someone has either fitted a metric leadscrew on an imperial machine, or a set of imperial half nuts on a metric machine. The serial number says imperial, but everything else points to metric.

My gut feeling is it is a metric lathe with the correct 6mm leadscrew, and the half nuts are at fault. If I fit metric half nuts to match the metric leadscrew yet the lathe does on the off chance turn out to be imperial, would this work? Or would the gearing be to cock. Thus, meaning I then have to invest in a new imperial leadscrew.

Sorry on the long winded explanation, but hopefully I've explained myself without to much confusion.

Can anyone help?

Thanks,
Jim

thermite · Oct 26, 2019

jim_cliff11 said:
Hi,

I have recently bought a Colchester Triumph 2000 lathe with a 50" bed. The lathe needs some work, but we paid next to nothing for it. It has dual metric / imperial dials, 16 spindle speeds, the 6" D1 camlock chuck mountand foot pedal to brake the spindle.

Basically, the thread cutting lever will not engage. The half nuts would not engage with the lead screw. To cut a long story short, we stripped the gearbox off the apron and removed the half nuts and leadscrew. The problem is that the leadscrew is metric with a 6mm pitch, yet the half nuts are imperial 1/4" pitch.... hense they wont mesh!

When I spoke to Tony at Lathes.co.uk and a colchester lathe parts company down south they both told the lathe serial number indicates the lathe was imperial coming out of the factory. However we have a metric leadscrew and metric swing arm gears. Under the leadscrew direction handle on the main gearbox it is even printed onto the fascia 6mm. This makes me think the lathe is actually metric.

Anyway, I have found a set of metric half nuts to fit, but before I buy I need clarification. Neither the leadscrew or imperial half nuts look new on our machine, so its hard to tell which one has been swapped. Someone has either fitted a metric leadscrew on an imperial machine, or a set of imperial half nuts on a metric machine. The serial number says imperial, but everything else points to metric.

My gut feeling is it is a metric lathe with the correct 6mm leadscrew, and the half nuts are at fault. If I fit metric half nuts to match the metric leadscrew yet the lathe does on the off chance turn out to be imperial, would this work? Or would the gearing be to cock. Thus, meaning I then have to invest in a new imperial leadscrew.

Sorry on the long winded explanation, but hopefully I've explained myself without to much confusion.

Can anyone help?

Thanks,
Jim

All I know - from research back when I THOUGHT I wanted one - is that the Triumph 2000 was "bragged about" as able to cut Inch AND/OR metric with very minimal fuss. Your dials support that. IF factory SN says Inch-only, then it may have been a cost-cutting order?

You need to do the tedious part. More research.

Checking ALL the literature to pin-down what it SHOULD have as to gears (most may be the same?) ascertaining if the crucial ones are.. whichever they are, and if it is as simple as finding just two you do not have already. Or MAY have already.

The mismatch, 'arf-nuts to leadscrew shouts monkey-patch to sell-it-on. The OTHER probability is that some previous minder was trying to restore the 'full" inch/metric capability, and failed to complete.

Should be resolvable, either way and a decent deal if the rest of it is in good condition.

TedinNorfolk · Oct 27, 2019

You'll probably find the dial on the tailstock is in metric-5mm a turn-in which case you have a "proper" metric machine.....in which case I'd leve the leadscrew as is and get metric half-nuts. Just my 2p worth.

Clive603 · Oct 27, 2019

Further to what Ted says if its a true native metric machine, whether by conversion or original delivery, the feed screws on cross and top slides will also be metric. If they and the tailstock feed screw are all metric you can treat it as native metric so you need to verify that the gearbox is correctly set up to use as a metric machine. If so fit metric half nuts and use it as metric native. If it was delivered as a true metric machine it will also have a metric threading indicator and should have the appropriate threading / feeds data plate.

However, as Thermite says, the Triumph 2000 is capable of cutting a range of non native threads (ie metric on an imperial machine, imperial on a metric machine) directly from the gearbox. If its a partial, shop brew, conversion of an originally imperial machine by changing leadscrew and drop gear chain from spindle to gearbox its going to be a right pain to drive.

I think a shop brew conversion is unlikely. Pretty much no point as you already have dual dials and the ability to do the common metric threads built in so its easy enough to drive metric. Shop brew change is a lot of work, tracking down those metric drop gears might take a bit of doing, and pretty expensive too.

From what you have said I agree you have a metric machine whose half nuts were stripped out. How? Probably lunched the leadscrew too hence used replacement. Replacement nuts ordered against lathe serial number. Serial number said imperial so imperial ones supplied. Which didn't fit so machine sold on cheap.

Consulting official experts is all well and good if things are what they should be and correct to documentation. When Bubba and his ilk have been fiddling or the official book is wrong you do better coming to folk like us.

Clive

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