Lathe Size

[Robert Greenwood 1Participant @robertgreenwood1]

Hello,

I am new here, i started many years ago building a 3 1/2 Gauge Britannia sadly due to ill heath i wasn't able to complete. I am back now and would love to start again a build.

I am planning a large build in the form of a 5" Gauge Britannia, my question is what would be the best lathe to have?

I have been looking at the ML7 and also the Clarke CL500 size,

Would these be too small for machining things such as the wheels etc?

Many Thanks in advance!

Rob

[Robert Greenwood 1Participant @robertgreenwood1]

[BazyleParticipant @bazyle]

welcome aboard!

If you aren't too hung over tomorrow there are lots of equivalent threads to read giving advice about lathe selection.

To start with avoid the Clarke as it is a bit of a fish out of water. Look for a Boxford AUD or BUD or for new a Warco WM240 or Chester equivalent. You don't need anything bigger like a Colchester or Harrison not that they aren't nice to have.

New and used both have advantages and disadvantages so take a while to decide, join your local club if you can, and make sure first that you have a decent insulated workshop with a dehumidifier and good security before you splash out on your rust magnet.

[its-smeeParticipant @its-smee]

I started off with a small Clark Lathe but soon found it inadequate especially when trying to machine the wheels on a 5" gauge. After "blowing up" motor and controller twice I then fitted an AC motor with an Inverter but still wasn.t happy. I must have looked at every post on purchasing a Lathe and settled for a Warco 250V-F and later a VM16 mill both machine are performing well and still getting used to the "larger" size. my small workshop now looks full as space is at a premium.

[Robert Greenwood 1Participant @robertgreenwood1]

Sorry for the long delay, work has taken over.

I think after looking at what you suggested i like the idea of a Warco Lathe.

The come in at over 1K so i better get saving…

Thank you very much for the advice!

Kind Regards

Rob

[Larry Coleman 1Participant @larrycoleman1]

Rob

A Lathe is your most important purchase for your workshop and if it is too small or not rigid enough you will pay the price in the future. I can not see the fascination with the small Myford lathes. They are a nice little lathe but if you start to make large parts they will do some things but you will be limited by the spindle bore size.

I have a Taiwanese lathe and a Chinese lathe, The TI lathe has a spindle bore of 25 mm and a 6" chuck. The Chinese lathe I imported from china and has a 36 mm spindle bore 8" chucks. Both machines have cutting fluid pumps. By the way that TI lathe I bought in 1975 and it is still as good as the day I bought it.

Now here are some features you should look for:

Minimum 25 mm spindle bore.

6" to 8" chuck.

Flame hardened bed.

Norton gearbox for cutting threads.

Separate longitudinal & cross feed shafts. A lathe using the screw cutting shaft for Longitudinal feed will ware later on and hinder screw cutting accuracy.

Longitudinal & cross feed.

Now the choice between geared head and belt driven head. Belt driven head is best. When you have trouble with a geared head machine some time down the track you may find it hard to get replacement gears.

V belts are easy to find.

Distance between centre's can be a consideration when machining long shafts.

You will need fixed steady, Face plate and live tail stock centre.

Consider getting a quick lock tool head or a box tool head if to expensive for you.

If you can get a decent lathe in the begriming you will find the hobby interesting.

Regards

Larry

[Bob Brown 1Participant @bobbrown1]

Posted by Larry Coleman 1 on 17/01/2015 14:19:27:

 

"Now here are some features you should look for:"

"Minimum 25 mm spindle bore." Why 25mm?

"6" to 8" chuck." Swing is more important than chuck size

"Flame hardened bed." not necessarily true

"Norton gearbox for cutting threads." not necessarily true

"Separate longitudinal & cross feed shafts. A lathe using the screw cutting shaft for Longitudinal feed will ware later on and hinder screw cutting accuracy." not necessarily true

"Now the choice between geared head and belt driven head. Belt driven head is best. When you have trouble with a geared head machine some time down the track you may find it hard to get replacement gears." I do not agree.

"V belts are easy to find." all the belts I have "found" have been broken.

 

Edited By Bob Brown 1 on 17/01/2015 14:43:00

[Larry Coleman 1Participant @larrycoleman1]

Hey Bob

You seem to be on another planet ! Your not a Myford lover are you? No insult intended.

The reason I said Minimum 25 mm spindle whole is because a lot of small pistons for small stationary engines are about .750 to 1" Dia and it means you can place a bar in the lathe with out ending up with all those small short lengths.

Yes swing is important and you will find that the bigger the swing the bigger the chuck. Lets not get into gapped beds.

In regards to hardened beds. A machine with a soft bed that is rarely used will not have much ware but have a close look near the chuck and you will normally have small dings where either the chuck has been dropped or a small job has dropped on it. Now most clever people use a special board on the bedway when changing chucks. And if you use a tool post grinder and you don"t cover you bed the lapping paste will form and the soft bed suffers.

I have had two lathes with a hardened bed for over twenty years and is still accurate, Apart from the time I slipped with the hacksaw and ripped of all the teeth on the blade. Did not harm the bed.

Bob I am surprised you say a Norton gearbox is not essential. The alternative is changing gears on the drive train for all the different thread pitches.

Now be sensible if your screw cutting feed shaft is also your slide feed shaft it will get very sloppy close to the chuck. The best machine is fitted with a screw cutting shaft and a feed shaft. Have a good look at a Colchester and the third shaft is for on off lever to start and stop the machine. The feed shaft provides drive to the longditudinal & cross feeds you don't have a feed shaft for each purpose.

In regards to V belts, try looking in a bearing supplier or hardware shop they will always be new ones.

Don't get me wrong the Myford lathes are a nice little machine and the turret from the Milro turret lathe will bolt strait on to the old flat bed models. I also like the little Hurcus.

So if you have the time to muck around with gears when changing thread pitches and when it comes to large face plate jobs you use your mates big lathe get a small one.

But the lathe you buy when you first start out will be with you until you either have the money to up grade or get put into a pine box. The Chinese lathes are not to bad, I have one and there cheap. One thing most people do not know is that some chinese lathe manufacturers are US companies set up in China.

Later I will post some pictures.

Larry.

[JasonBModerator @jasonb]

Posted by Larry Coleman 1 on 18/01/2015 08:07:33:

Hey Bob

The reason I said Minimum 25 mm spindle whole is because a lot of small pistons for small stationary engines are about .750 to 1" Dia and it means you can place a bar in the lathe with out ending up with all those small short lengths.

As most pistons are a lot thinner than their diameter I find them the ideal thing to use up all thoseodd bar ends on eg a 1" dia piston is only going to be 5/16-3/8" long. Thats if they are not provided as a casting which will be short anyway.

And lets face it if you are making stationary engines with that size piston you don't need a big lathe, infact I made a 3/4" bore steam engine on a Unimat 3.

As for gearboxes. I have said it before think of the type of thing you want to make and then decide if you will be screwcutting on a regular basis. Most stationary engines won't need anything screwcut, even on my traction engine which took the best part of 1500hours I only screwcut one thread as it was a square one. For that amount of use I'm happy to save my money and swap a couple of gears when needed. I can also cut odd pitches that may not be provided by a gearbox.

[Bob Brown 1Participant @bobbrown1]

Myford had nothing to do with it as I own a Boxford AUD but although it has a screw cutting gear box the number of threads I have cut is less than half a dozen and for these I would be happy with change wheels. In any case I have to change them if cutting an imperial thread as the lathe is metric.

Lead screw drives the split nut and the feeds BUT although only a single shaft it has a keyway to drive the feeds so no wear on the lead screw.

As for spindle bore sod's law says the bar you want to fit is too big anyway, plus you should not have too much hanging out the back of the spindle as it can and will whip which is dangerous.

I tend to use a ER40 chuck, 100mm 3 jaw and 4 jaw independent and although I have other chucks they do not get used very often may be once a year so is size that important.

It all boils down to what you want to make and in this case a 5" Gauge Britannia.

Bob

[Larry Coleman 1Participant @larrycoleman1]

Bob

So you understand what I am saying about the ware in the screw cutting shaft if you don't have that key to drive the feed mechanism. some of the older lathe's like the Myfords & the Hurcus only has a screw shaft to drive all the feeds.

I am not talking about your lathe which I have never seen so how about showing me, post a picture.

I have been to many model engineer clubs here in Australia and you have old men hanging on to their old machines because they have not kept up with the new equipment and are defending their lathes because they can not afford a new one and are resistant to change.

I have been a machinery importer for a while and some of the new equipment is very good.

Have a look at my Album.

Larry

[Larry Coleman 1Participant @larrycoleman1]

This lathe I bought in 1967. Apart from a dulux overhaul it is still a very good machine.

[BazyleParticipant @bazyle]

Just find the sixe of the Britannia's wheels and smokebox and ensure your lathe can swing that. Any bigger is just wasted air though a bigger lathe will be more 'solid' which is a good thing. A seperate feed rod is not required provided there is a slot down the length of the leadscrew which shows it is being used as a drive for the feed (as in Boxfords for example).

A screwcutting gearbox is actually worse than gears if you want to do any Metric or BA threading. Powered cross feed is as necessary as a self opening umberella.

Your biggest problem with new lathes is the rather high minimum speed and electronic speed control that goes pop.

You should think of your lathe as matching your car. If you drive a new Merc with electric everything you can afford a fancy lathe with lots of gimics. If you manage like me to get around in an 850cc Perodua that can still transport a loco or a Meddings drill by taking the seats out then you probably have the budget and ability to make do with a more basic lathe.

[martin perman 1Participant @martinperman1]

Bazle,

Why do you say the Clarke CL500 is "a fish out of water" I own one, it may not be pretty but it does, in my view, what it was built for, its reasonably accurate, you can thread cut, It comes with a good selection of tooling i.e. fixed and moving steadies, 3 and 4 jaw chucks, face plate and a raft of other bits, it has its faults but this is because its built for a price but fitting half nuts to the gib strip adjusters to lock them and making the measurement rings a little more user friendly helped.

I bought mine on a stand with the milling attachement for £350 from a company I worked for because it wasn't man enough for what they thought they wanted with hardly any use at all, it was all I could afford but even today, now that I can afford to, I wont spend a large sum of money on a new lathe as I trust mine as it does what I want.

Martin P

[Larry Coleman 1Participant @larrycoleman1]

Bazyle

I see your point but not every one fits your requirements. When I was importing machinery from china I had access to small lathes at very cheep prices but I refused to sell jewllers lathes and to top that off I imported vertical mills similar to the Bridgeport but with improvements. The first vertical mill that size that could operate on 240v single phase.I tried to sell them for $5600 au. A bloke rang me and asked what was wrong with them. I said nothing they are brand new machines I then offered it to him for $25,000 which other equivilent 415v machines were selling for and he said I could not afford that. And I said well thats what is wrong with them. It took me two years to sell them and I landed them in Oz for $5000 each.

I am starting a 5" Garret soon 4442 and my lathes will suite making that model. But I don't know what I will do next.

So I have found that when buying your first lathe make it a decent size machine and for a working man buy it through finance.

In regards to speed my machines have back gears and the next low speed would be stopped.

No don't match your lathe with your car because usually your car would be buggered.

I have just up graded to a toyota Camry station wagon V6 which will pull a duel axle 2 ton trailer. When I bought my first lathe I was driving a Morris 1000 sedan which was a great little car but my lathe I got was top notch.

I don't follow you at all about the screw cutting box I cut those threads all the time on my lathe. It all about TPI and a different tool angle.

Power cross feed is esential when facing large dia plates.

Regards

Larry

[Larry Coleman 1Participant @larrycoleman1]

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