Warco lathe

[TakeawayParticipant @takeaway]

I am in the process of choosing a replacement for my existing lathe. I have been looking at Myfords but I am attracted by the convenience of variable speed and the abilty to threadcut with just a flick of the wrist/s that the more modern machines can offer. However, I have to be careful of length due to my cramped workshop. Can I ask if any one could answer a couple of question about one of these:

**LINK**

To the extreme left of the machine the end part casing looks like it might be hinged at the rear as an access door for the drive belts etc. Is it? If so, apart from changing a broken belt what else would I need to go in there for? The reason I am asking is that if I am going to need to open it frequently I might have to think again a choose something shorter.

I could wait till we visit the Harrogate show (just ordered our tickets today), but I would like to get an idea before then.

Apart from, Sandown, I have not been to a big ME show since the annual one (I think it was Olympia) back around 1984 (ish) so I am very much looking forward to it – even my dear lady is coming to keep an eye on me – she quite enjoyed the royal carriages at Sandown while I was quite taken by a beautiful piece of tool making in the shape of a stepper lathe.

ATB

Stuart

[TakeawayParticipant @takeaway]

Evaluation

[JasonBModerator @jasonb]

This does not have a screwcutting gearbox, you still need to change gears on a banjo and that is why you need access to the end. If its anything like my 280 then you get three tpi per banjo setup but as the banjo also provides feed rates for the carrage you will have to change back to a finer feed ration after screwcutting.

Warco have an openday fairly soon.

J

Edit this is whats behind the cover, you also need to access the drive belt to select high and low speed range though I just leave mine in low without problems which gives me 50-950rpm

Edited By JasonB on 10/02/2013 17:59:53

[AndyfParticipant @andyf]

I have one of its baby brothers. sold by Warco as the WM180 and by other retailers (eg Amadeal and Chester) under other names. They are made by Weiss Machinery in China, and are almost identical to the range sold in Germany under the "Optimum" name. I think the factory producing the Optimum machines may be under German management.

The overall design of mine looks very similar to the WM250. My gear/pulley cover was originally held on by a couple of knurled nuts, but I found that inconvenient and hinged it at the back. I did find myself going in there fairly often, both to fit changewheels and to switch one of the drivebelts between pulleys. The 50 to 2500 rpm variable speed on mine isn't continuous. Rather, it is in two bands of 50 to 1250 or 100 to 2500 rpm, and the drivebelt has to be shifted to get from one band to the other. That was a fiddly and tedious job, because to slacken/tighten the belt an Allen screw on the back of the lathe had to be accessed by feel. I have modified that to make life a bit easier.

As mentioned above, mine is a smaller version, and the WM250 may differ from it in relation to the way the gear cover is retained and the drivebelt. It looks as though it has a tumbler reverse and a knob offering a choice of fine feeds, so is obviously a more sophisticated machine than mine. The ideal thing would be to hold off until you have seen one, at Warco in Chiddingford Surrey (they used to have models on display at Newton Tesla's place in Warrington, but I don't know if it's still there or whether there is a WM250 on display), at Amadeal in Leytonstone or at Chester Tools in both Hawarden near Chester and in Burntwood Staffs.

Andy

[magpieParticipant @magpie]

Hi Stuart

The cover on my Chester DB10GVS is held in place with two knurled nuts about 30mm dia. I can not remember if the cover has a bottom to it, if not you would only need to undo the nuts then move the cover about 15mm to the left and lift it up over the top.

Cheers Derek.

[Mark P.Participant @markp]

I've got one,had it for a few years now and am pleased with it.It does all I ask of it( and takes a bit of abuse!) only complaint there is no back gear as standard but have made a set of parts for one, to fit when I get round to it.

Regards Mark P.

[nick feastParticipant @nickfeast85472]

There must be loads of people like me who wanted a lathe for hobby use and bought a 180 style chinese lathe from one of the importers. I have been pleased with mine over almost nine years, built several locos and had no trouble with it. A few marks showing on the bed but I paid £750 and got 3 and four jaw chucks and a faceplate, fixed and travelling steadies. It is very heavy for a small lathe, but this is a good thing I reckon.

I would have paid much more for a 'quality' product, but for a couple of hours use per week I couldn't justify the extra cost. I would buy the same or similiar again.

Nick

[TakeawayParticipant @takeaway]

Mark, I always get mixed up about what can and cannot happen at that end of a lathe. You mentioned that the lathe has no back gear as standard which has left me a little confused. I have googled the term "back gear" and it is defined as the means to adjust the speed from the motor to the spindle. So why is it necessary to have back gear on a variable speed lathe?

Stuart

[wheeltapperParticipant @wheeltapper]

Hi

Its used to change the speed relationship between the spindle and the leadscrew for threading.

Ive got a variable speed lathe and a stack of changewheels.

Roy

[David Clark 13Participant @davidclark13]

Hi Stuart

Google is not strictly correct.

Yes, back gear does reduce the speed but it increases the torque.

Running at a low speed with a variable speed setup would give virtually no power at the low end of the speed range.

Back gear lowers the speed and converts the available power into a useable force.

I worked in an aerospace company and they had a large CNC machining centre that had 50 horse power at very high speeds for aluminium. In his wisdom the boss put a batch of hardened steel components on it. At the low speed that was necessary the horsepower dropped to 2 HP. The job had to be done on that machine so the boss did not lose face.

regards David

[David Clark 13Participant @davidclark13]

Hi Wheeltapper

That is incorrect. The back gear comes before the spindle in the drive chain, not after.

regards David

[JasonBModerator @jasonb]

Further to what David says there is little noticable drop in torque on these lathes when you slow them right down. The only time I have notived it is when turning large diameters at the slowest speed, for example I found when machining a 9" dia cast iron flywheel that I could not take more than 0.025" depth of cut without the lathe slowing and much more than that would stall it.

But lets face it how many times on a model do you need to use close to the capacity of the lathe, on a stationary engine its just going to be the flywheel, on a loco the wheels and on a traction engine the flywheel and final drive.

The backgear is just a quick way to get a fast & slow speed without having to change the belt on the typical Myford type lathe and as its mechanical you get teh torque advantage.

J

J

[Roderick JenkinsParticipant @roderickjenkins93242]

Back gear is probably most use on a gap bed lathe where you can turn larger diameter items, such as flywheels, than the lathe would normally turn. As far as I am aware, most of the new lathes available to the model engineer don't have gaps so don't really need a back gear. Even though I have VFD I wouldn't like to be without back gear on my S7.

Rod

[Anonymous]

Both belt drives and back gears are constant power transmissions, ie, you get the power out that you put in, less any small losses. So either system can be used to reduce speed with a commensurate increase in torque. However, V-belt drives have limitations on how small the pulleys can be, as well as the centre to centre distances for the pulleys. So a large speed reduction with V-belts results in large pulleys with wide spacings. A back gear is a neat way of getting a large speed reduction in a small space, usually within the headstock itself. Since it is gear driven it is not prone to the problems of belt slip.

The loss of power at slow speeds is one reason I don't run my lathe from a VFD.

Regards,

Andrew

[Keith LongParticipant @keithlong89920]

The other point with a back-gear is that it allows you to slow things right down for jobs like screw-cutting up to a shoulder, don't think I'd fancy that at 100rpm+ unless I had some device such as Grey's screw-cutting clutch mechanism,.

Keith

[john kennedy 1Participant @johnkennedy1]

I've got one and love it. Very accurate. Like people say the torque is low at low speeds.Mine tries to compensate by piling the power on and speeding up. I wouldn't swap it for my old myford which was well worn and about the same price. The WM 250 is a handy size for most things.

Mark P. I'm interested,tell us more please…

[AndyfParticipant @andyf]

Wish I had a back gear. Not so much for turning large diameters, but more for screwcutting without the need for quick reactions as the tool approaches the end of the thread. My other lathe – a little Perris (now the Cowells) – has a back gear, but I have no changewheels for it, apart from those for fine feed.

Andy

[SpringbokParticipant @springbok]

Hi Stuart
David Warren kindly loaned the BSMEE a small lathe for our exhibition and I for 3 days demonstrated to youg persons and getting them to use the lathe. It took me a few hours to tidy up the jibs but turned out to be a very successful little machine. If it is up to 3.5g loco building. Do not know what you are planning to build. please let us know.
Bob

[JasonBModerator @jasonb]

One advantage of the variable speed is that you can cut most of the thread at a decent speed and then wind down the wick as you get near the end, mine will go down to about 40rpm which is not too scary and only a little more than a Myford on its slowest back gear.

The same method can also be used to advantage on large facing jobs where the speed can be increased as you get closer to the centre.

One thing I will say is think about how often you will be screwcutting, if like me its once in a blue moon then don't let having to swap a few change wheels be a major factor in choosing your lathe. For example my 2" traction engine probably has something like 1500 hours work in it and I only screwcut two threads maybe 1hrs work total.

J

[TakeawayParticipant @takeaway]

Thanks for all "back gear" comments – I am now much more in the picture. On the question of length of lathe and being tucked up for space, Jason has made the very helpful observation that on the rare occasions he cuts threads it should not affect the choice of length of lathe if space is at a premium. I can see your argument Jason as I cannot see myself as a future prolific threader either.

But to put things into perspective, my new lathe has to fit in a 6×8 ft. shed and its got to be on the 6ft wall with shelving sticking out at the tailstock end – it doesn't get much more cramped than that! I am already envisaging putting a trapdoor in the shed wall so I can go outside and adjust change wheels from the headstock end. It's either that or back to the shorter WARCO WM240. I think a hair shirt and self flagellation could be less painful than the buying decisions I have to make in the coming weeks.

Thanks Bob Springbok, reason for upgrading to heavier duty kit is that I like to scratch build from anything that is laying around. It is much easier to do this with larger machinery – you get a certain flexibility which makes the work that much more enjoyable. Doing big jobs on little kit is a pain in the rear!

Thanks all – Stuart

[MetalhackerParticipant @metalhacker]

The more important deficiency on the Small Chinese Lathe is the lack of tumbler reverse in the majority of cases. It can be very tedious having to wind the carriage back by hand when screwcutting and of course left handed threads are impossible without a leadscrew reverse. I can be done by putting an idler in the gear chain to reverse the direction but it can be tedious to arrange. I looked at the 280vs last year but ended up buying a boxford VSL. Much more versatile and far better than I am. Andries

[Mark P.Participant @markp]

Stuart don't think you will be unhappy with the WM250,I would buy another if I had too. It doesn't take up much room in the shed,my shed is 8×10 feet got lathe,mill,floor standing pillar drill two benches one with a simat 101 lathe on it a motorbike, bandsaw and room for the dog (just) when I'm down here!

Mark P.

[AndyfParticipant @andyf]

That will be a tight fit, Stuart. only about 630mm or 2'1" to spare, and the shelves to fit in at the tailstock end. Might they prevent you sliding the tailstock off?.

If the shed wall at the headstock end isn't on a boundary, I'd be templed to fit a sort of windowless oriel bay in it at the headstock end, to get a bit more space and so gears can be set up on wet days as well as on fine ones. Maybe with a little trapdoor so that really long stock can be passed through the headstock to the exterior, though a support would be needed to stop it flailing round.

Andy

[JasonBModerator @jasonb]

Re tumbler revers, just stop flick the switch into reverse and thats it, you can even give the speed knob a tweak and back out faster than you went in. But as you say for occasional screwcutting its not an issue

Stuart, the end cover does not hinge, you unscrew two knurled knobs and move it out about about 25mm and can then lift it up, I'l have a measure & take a photo in the morning of the exact amount of space needed, 250 may be a fraction less than my 280.

Also if you can afford the extra get the 250 with power cross feed.

[BazyleParticipant @bazyle]

Try and leave room for a mandrel handle. Useful for cautious screwcutting and tapping.

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