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This topic has 10 replies, 3 voices, and was last updated 25 October 2009 at 00:40 by mgj.

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18 October 2009 at 18:01 #44309
ROB M
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@robm68321
Hi. Im looking to buy a Chester Centurion 500 3 in 1 lathe with the hope of building a 4 inch Little Samson traction engine. Could anyone give me any advice or information about the lathe and whether it would be able to do everything I need when building the engine.

Edited By ROB M on 18/10/2009 18:01:57
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18 October 2009 at 18:01 #4798
ROB M
Participant
@robm68321
Chester Lathe – Centurion 500 3 in 1
18 October 2009 at 18:24 #44310
mgj
Participant
@mgj
Cast or built up wheels? Edward will machine the wheels if you cant get them on your lathe. The cast wheels are 18″ so does that Centurion have a gap.

The only other biggish chunk is the cylinder block. I did the 3″ one on a Dore – Westbury which has a fair amount of table space. You really need to get a tilting sub table onto your “mill” to be able to square the block up. (Or get a slab of 1″ steel and clamp that to the “table”. Or evening classes or ask someone who has a big enough mill)

Final drive pinion is about 12″, and you will need to turn that. Gear cutting? Will it mount 6″. Thats the only problem with a combi – you cant hang a big disc off the side of the milling table into free space.

Chimney base needs a 4″ + radius. You won’t get that on an angle plate on the faceplate, so you need to be sure you can get that 8″ flycutter into place. Cylinder block ditto, but you have to flycut that vertically for about 4.5″ on the 3″ so it will be about 5″ on the 4″?

OTOH, you could get Edward to do those too!!

The rest you should be fine with. – got a fair bit of overhang with the piston rod guide.

Edited By meyrick griffith-jones on 18/10/2009 18:26:46
18 October 2009 at 20:07 #44316
JasonB
Moderator
@jasonb
If you are going to put rubbers on the cast wheels rather than strakes then only the bore and face of the hub needs machining and can be done on a mill, but the combi does not really have a big enough table. Rubber can be vulcanised straignt to the cast outer face.

The table is also a bit small for mounting a rotary table and centre for machining things like the conrod

Quill travel is not likely to be long enough for flycutting teh chinney saddle or cylinder base, if you try to do it with a between centres bar there may not be enough travel between centres.

Why not ask on Traction Talk Forum, bothe Edward(littlesamson) and Dave(daveko974) who wrote the books “a dream comes true” are regular posters there.

http://www.tractiontalkforum.com/forumdisplay.php?f=36

Jason
18 October 2009 at 21:08 #44323
ROB M
Participant
@robm68321
Thanks for replying. Do you think a 3 in 1 lathe is ok or would you think it better to get individuals.
18 October 2009 at 21:48 #44325
JasonB
Moderator
@jasonb
Personally I would go with two machines, though I made the minnie in my avitar with just a lathe and did the milling using a vertical slide but not practical in the bigger sizes

J
18 October 2009 at 22:16 #44326
mgj
Participant
@mgj
I agree – I think 2 machines is much wiser. Like Jason, I think you would struggle with that relatively small table.

I think also you would want something that is Boxford sized for a 3″, and a 6″ lathe for a 4″. Distance between centres is less important. There is nothing really long. Its not that one cannot cram some of these bigger items onto a smaller lathe, but you are starting to get into a different league in terms of overhangs and fixtures, so on a bigger machine jobs which would be heart in mouth efforts become quite easy.

Depends how much you are prepared to sub contract out/buy in of course.

How big a lathe Jason? -Just out of interest. I understood Haining chose 2″ specifically because it could all be done on a 3 1/2″ ?

Edited By meyrick griffith-jones on 18/10/2009 22:27:10
19 October 2009 at 07:29 #44333
JasonB
Moderator
@jasonb
The Fowler I’m doing is not one of hainings designs but you could do most 2″ engines on a 5″ lathe, remember the 3 1/2″ Myford that most things were designed for can swing 10″ in the gap. Thats based on not having to machine wheel rims or the drum on a ploughing engine

You also have to watch height over crossslide if doing any between cts boring/flycutting.

Jason
20 October 2009 at 17:58 #44365
mgj
Participant
@mgj
Thanks. I bought a 6″ Chinaman, and actually was quite glad of it, even with a 3″ LS. Wheels of course, but even so mandrels for putting cylinder bores on and the like – its nice not to have a parting off game before you start.

Talking to the gents down at the club, in terms of “relative expectation” I think TEs tend to need bigger lathes than locos. Mills OTOH seem more stretchable.

Edited By meyrick griffith-jones on 20/10/2009 17:59:27
24 October 2009 at 21:27 #44488
ROB M
Participant
@robm68321
Sorry not responded sooner. My internet has been down. Thanks for your help and comments. I will have to give it some more thought and decide what to do next. I went to the Model Engineering Exhibition at Warwickshire Exhibition Centre and looked at the lathes there. I may need to save a bit more money before I do anything.
25 October 2009 at 00:40 #44490
mgj
Participant
@mgj
Rob, I think that most people would say you need a 6″ lathe for a 4″ engine. That means a 6″ gap bed.

I know Jason says that LS is not massive- and he is right, it isn’t. Even so when you go to the Dorset Steam Fair and other places, I’d describe the LS as a compact 3″ engine rather than a big 2″ one. Its a whisker under 4 feet long. So you have some fairly chunky bits to machine. You certainly need, for the 3″, a bigger lathe than a Myford – subject to Jasons very valid points – but don’t forget you need to mill. And the Myford/3 1/2″ will not do that for you.

This is mine – I have got rather further with all the valve gear and cylinder complete, but it gives an idea of size against the table and door.

Give you an example – the cylinder block. On a 3 1/2″ lathe you are going to have to pack it up, and then bore between centres, and then fiddle around to face the end of the block. Then you have to face the other end, and then cut on a 3″ radius, the curve on the block to fit the boiler, and I don’t think you can get that on the Myford saddle. Its just too big for the centre height.

On a 6″ lathe—– just pop it in the 4 jaw, bore the cylinder face this end for the cover, and square the mount face. . You now have a datum to turn it round and face the other end. And then you can do the steam chest. – ain’t going to get that on a vertical slide!!!!..

This is the same block being rotary milled for insulation – the table is from Ivan Law (MES) – home built, as is the DW mill of course..

This is the second motion gear being cut on a GHT head – that is centre height for a 3 1/2″ lathe. Even on a mill. I had to hang it off the back of the table, use the head for indexing and a clamp to put the thrust into the table.

This is going back to the start – boring the smokebox, which is 6 1/2″ od.

Turning the front wheels in the Myford, before I got the Chinaman. They just fit for diameter – but the overhang is such that you cannot turn it round to face the other side for the hub caps – though you could do it in a mill. Hadn’t got an indexable TCT tipped tool with enough length either. (Stil don’t)

This is just indexing something or other. Same home made GHT head

Now – with bigger machinery, life is a lot easier.

Edited By meyrick griffith-jones on 25/10/2009 01:06:38

Edited By meyrick griffith-jones on 25/10/2009 01:07:49
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