Zyto Lathe

[steve ellis 1Participant @steveellis1]

Hi. I have bought an old Zyto lathe, and although no engineer (a joiner by trade), I knew it was pretty tight, and should be accurate. After a bit of fettling, it seems to be cutting fine. I am making something from a book, that calls for bits I don't have with the lathe. I have a plate with the pin in it, that goes in the place of the chuck, but I now need a centre (is it called a "dead centre"?). I have a No 2 morse taper centre in the tailstock, but now need one in the headstock end, to mount the workpeice between the two points. When I remove the chuck, there is of course, a hole through the shaft that material can pass through. This does not appear to have a morse taper to it though?. How do I fit a pointed centre into the shaft, so that I can screw the round plate to the shaft?. Hope that makes sense?. A month ago, I knew zero about metal lathes, and thought I was doing well till I got to this bit. lol

[steve ellis 1Participant @steveellis1]

Newbie query

[Thor 🇳🇴Participant @thor]

Hi Steve,

Welcome to the forum. I assume you have already found this info on Zyto lathes? The headstock may have a MT 1 and a 3/8" bore, if you can't get a MT 1 centre to fit just put a mild steel rod in the chuck and turn a 60 deg. (included) taper and then you can turn between centres.

Thor

[Pete RimmerParticipant @peterimmer30576]

Hi Steve

The plate with the slit in it is called a catch plate. It 'catches' the driving dog on your part.

The headstock and tailstock are both more taper. I am not sure what taper is in the headstock but I can check when I get home this evening if you like.

Pete.

[steve ellis 1Participant @steveellis1]

Thank you Thor and Pete. What brilliant (and fast) replies. They both make perfect sense. That would be great if you could check tonight Pete. Thank you.

[Pete RimmerParticipant @peterimmer30576]

Steve just so you know a live centre is any centre that turns with the work. A dead centre is any centre that does not. Nowadays the trend is to call solid centres 'dead' and revolving centres 'live' but that's not strictly correct.

With a dead centre the part that is mounted onto it will always turn on axis because the point is 'dead', it does not move. If you put a solid centre into a revolving spindle the point is 'live' in as much as it is rotating and if there is any kind or runout it will be translated into the part. Worse than that if you dismount the part then re-mount it between centres the runout will be translated into the part but possibly in a different orientation. This is why if you ever mount a live centre you should check the end is running true with a DTI before you use it.

Alternatively you can mount an un-hardened live centre into your spindle and turn the point true before mounting the work on it.

[steve ellis 1Participant @steveellis1]

Thanks for that Pete. I have a lot to learn….. Its funny, as I can tell anyone about Joinery and Carpentry, and probably lose them within seconds. A lifetimes experience (about 48 years worth) adds up to a lot of knowledge. Its nice to pass stuff on to help people out though.

Many thanks, Steve.

[Pete RimmerParticipant @peterimmer30576]

Okay so the taper on my Zyto for both the headstock and the tailstock is MT1.

[steve ellis 1Participant @steveellis1]

Thanks Pete. I have been poking different sized wooden dowels down the headstock hole tonight (because I am a joiner, and so I dont scratch the taper) and its definately tapered like you say. I have measured the opening, and it suits a #1 morse. Thank you.

Mind you, me being impatient, chucked a bit of scrap Phosphor Bronze 5/16" tonight, and used the tailstock dead centre, and turned the centre (con rod) section down to 1/16". I must admit, it went well. I am making a piston for the Tubal Cain "Polly" engine, which I assume, every engineer knows about?. This was just a trial piston, but in your opinion, would it be better to sort out the MT1, the catch plate, and drive dog, and do the finished piston this way?.

If you need to know anything about woodwork, I can help you out with that. lol.

[SillyOldDufferModerator @sillyoldduffer]

Posted by steve ellis 1 on 31/01/2022 20:03:06:

… This was just a trial piston, but in your opinion, would it be better to sort out the MT1, the catch plate, and drive dog, and do the finished piston this way?.

…

I'm about 10 years into the hobby and have yet to use a Catch Plate and Dogs. It's a traditional method dating back to the time before chucks. I wouldn't bother unless there's a particular reason using it, like the need to squeeze a large object on to the lathe.

Hope others will comment because I'm not god's gift to Model Engineering best practice, but this is my take:

• 3-jaw self centring chuck – quick set up, relatively high run out. Good for most general purpose work unless the work flow requires the job to be removed and replaced in the chuck because their reset accuracy is poor.
• 4-jaw self centring chuck – better grip in some circumstances, rarely useful in metalwork.
• 4-jaw independent chuck – slow set up, but work can be centred or off-set accurately. If no other chuck were allowed, this is the one I would choose. In practice most of my work is done in the 3-jaw because it's convenient, and the 4-jaw comes out only when the 3-jaw isn't good-enough for the task in hand.
• Collet Chuck – quick set-up, low run out, and high reset accuracy without fuss. Much faster set-up than a 4-jaw, but only suitable for work that can be held in a collet. Pricey because of the need to own a collet set but offset if the same collets are used on a milling machine. More popular for Clockmaking and similar than general purpose machining. I occasionally use a collet chuck, usually when work has to be moved repeatedly between mill and lathe
• Backplate and Clamps – very slow set up but can hold oversized and odd shapes with high centre or off-centre accuracy. I've never used mine!
• Mandrel – like a backplate but pre-drilled to hold specific jobs – good for repeat work. I don't know of anyone using them in a home workshop.
• Stub Mandrel – a short stubby rod held in a chuck or collet that's faced-off and either tapped to hold work like a mandrel, or has the job glued to it. I often turn thin blank discs by supergluing them to an aluminium rod.
• Working Between Centres – live or dead centres support the job between short holes drilled in the ends and packed with grease. The job is spun by a dog and catch plate. Takes a fair bit of setting up, but the axis is accurate and resettable from either end. I've never used this method because it's suited to long jobs that go in and out of the lathe, probably also requiring steadies. Something like an axle, which I don't do.

Planning the sequence of operations needed to convert a lump of metal into a finished object is all part of the fun, and there are often several ways of doing it. Not familiar with the Polly, but if the piston is like the ones I have made, I'd probably turn it on the end of a rod held in an ordinary 3-jaw chuck and part or saw off and face to finish. Pistons being short stubby objects, it's probably not necessary to support the tailstock end at all, and no need to mess with centre-drills, centres and dogs. Note when flipping the piston over to finish by facing off, it's unlikely to matter that the chuck reset isn't spot on, and that facing off is impossible when turning between centres. Lesson is work-holding depends on the circumstances: in my experience a catch plate and dog aren't worth the trouble, but it depends on what the lathe is used for.

Recommended read: Sparey's "The Amateur's Lathe". A little out-of-date in that it doesn't cover Carbide Inserts, DROs and such, but still excellent, especially for lathes of Zyto vintage.

Dave

[derek hall 1Participant @derekhall1]

Polly is a great little engine for a beginner. Just follow the guidance and constructional details by Tubal Cain and you will be fine!

It's also a good project in learning about your lathe and what equipment you need to buy or make.

It really depends also on what you intend to make in the future. I regularly use a faceplate as well as turning between centres with dog and catch plate as well as line boring with castings strapped to the crosslide.

You don't need a DRO and fancy carbide tooling to enjoy model engineering. Just get familiar with your lathe and tools and decide what works for you. You can get a lot of enjoyment and experience in making simple and useful tools as well.

+1 for Dave's suggestion about the book

Have fun with the Zyto!

Derek

[Roger WoollettParticipant @rogerwoollett53105]

If you are making a Polly you might be interested in the SMEE courses. The main one uses Polly ( albeit brought slightly up to date) as its basis.

SMEE courses

[Howard LewisParticipant @howardlewis46836]

If you can't find centres, you can make them.

Ideally you need a couple of scrap drills, with the Morse tapoers in good mcondition..

Cut off the flutes, or what remains of them.

Mount in the Headstsock,

Face to your chosen length

Off set the topslide by 30 degrees.

Turn the taper on the stub of drill, until you have a nice sharp point.

Repeat the above for the second ex drfill.

You now have two dead centres.

The one in the Tailstock will need to be lubricated where it enters the centre drillingb in the work, because the work rotates while the centre does not.

The none the Headstock does not require lubrication since there is no relative movement between the centre and the work.

It is advisable when turning between centres, to secure the driving dog to the pin on the catch plate, with a piece of wire to stop the work from rotating at anything other than the speed of the spindle. (You do not want it flapping about if the cut is is in anyway, intermittent. )

Enjoy!

Howard

[Neil WyattModerator @neilwyatt]

What bits do you have Steve?

Neil

[Nigel BennettParticipant @nigelbennett69913]

The thing that nattered me was the lack of calibrated dials on the cross slide and top slide. I had the brilliant idea of making some temporary ones in cardboard. I never actually got round to making more permanent ones before I got rid of the lathe and moved up to an ML7.

I well remember going to see my bank manager and asking to borrow the £45 to buy that Zyto… I learned a lot on that lathe and I hope you will too, Steve!

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