Beginner with newly bought lathe – many questions

[ell81Participant @ell81]

Hi All.

So, I have recently bought my first lathe.

It is an old Zyto.

I want to buy a live centre, and a drill chuck for the tailstock. How do I know what size I need? I think it’s MT2, which is fine, but since it’s a pretty small lathe I can’t just buy any live centres and drill chucks right? Since they might be too long.

Also, what is the best belt to use to get the drive to the lathe?

I also want to know what the marked spindle/gear thing is for please. When I match up it’s gears with the gears on the lathe the lathe won’t turn, like it jams it. Thanks.

Here is the lathe:

And the marked bit I don’t know what is for:

[PeteParticipant @pete41194]

Those would be what are called back gears, they provide a fairly deep gear reduction with a large increase in torque. I don’t know enough about that lathe to advise how to disengage them, but someone here will.

[noel shelleyParticipant @noelshelley55608]

Check out ” lathes.com” or is it .co. As Pete says it is the back gear. Also keep an eye on a couple of similar threads on the same subject for help and advice for beginners.  If you have trouble getting a belt, try using a polyV of the right length inside out. Do not use grease for lubrication, a 10W oil for the headstock and a 30W for the bed Etc.Good luck. Noel.

[PeteParticipant @pete41194]

https://www.lathes.co.uk/zyto/index.html

I forgot to add, those white marks would have been used by the previous owner to do rudimentary dividing.

For anyone unfamiliar with machine tools, there far more DELICATE than the average person might think. It’s extremely easy to break or permanently distort irreplaceable parts. For entry level people, a hammer or pipe wrench at any time should be absolutely forbidden. It’s not if you’ll break or damage parts, it’s only how long until you do with tools like that. There’s always another way. If your not 100% sure of what your doing, then ask here. Trying to remove a tightly threaded on chuck is a prime reason those back gears can be damaged. Yet there’s a simple and easy method of preventing those very hard to remove chucks.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi ell81, as has been said, your arrow is pointing to the back gear, but before you can use it, you will need to disengage the three cone pulley drive from the lathe spindle, and that maybe a grub screw needs backing off, which might be in that small hole on the small cone, if it is, it will be poking into a small dimple on the shaft, and when you want to re-engage the cone pulley, you must make sure the grub screw goes back into the dimple, otherwise you will end up scoring the shaft badly. As for chucks and live centres, they are all pretty much the same, given the size of Morse taper in the tailstock.

Regards Nick.

[Clive Brown 1Participant @clivebrown1]

Re buying a tailstock centre. Slight pedantry but you are referring to a rotating or revolving centre, not a live centre, which fits in the headstock. AFAIK the morse taper will be no.2, the large diameter end will be ~0.700.” It might possibly be MT1 at 0.475″. Make sure that you check. Other than getting that correct, there won’t be much variation in length between different makes apart perhaps from some large diameter “special”.

My interest in Zyto is that I have one of their milling machines.

[Charles LamontParticipant @charleslamont71117]

I think you will find the means of disengaging the big gear (‘bull wheel’) from the pulley is most unlikely to be a grub screw as suggested above. I think you will find it here:

[Howard LewisParticipant @howardlewis46836]

The Back Gear may well be engaged/ disengaged by swinging the shaft in eccentric bushes.

When engaged, there will be a pin or grubscrew which disengages the drive from the spindle (otherwise everything will lock up beacus you have two gears, of different ratios, engaged at the same time.

DON’T be tempted to use this to remove a chuck that is stuck on the spindle. If you do, broken gear teeth are likely to result, and replacement gears will be difficult, if not impossible to find.

Being an old British lathe, the threads will be whit form (BSW or BSF) possibly with BA for gib adjusters.

The gears behind the Headstock are changewheels. Different ones are set up to provide different ratios so that the lathe can be used to cut different screw threads, or to provide a powered feed for normal turning.

It may be fairly small, but can still produce good work in the right hands.

Good Luck

Howard

The slower that the Leadscrew rotates, relative to the chuck, the finer will be the feed, and the finer the finish.

FWIW, buy a set of Zeus charts, and a book on lathework, such as Stan Bray’s “Basic Lathework” Workshop Practice Series 45) or Harold Hall’s “Lathework, a Complete Course) WPS 34.

[Martin WhittleParticipant @martinwhittle67411]

As Charles mentions above, there is spring loaded pin on the right hand face of the bull wheel which engages with a hole on the right hand side of the pulley block.  Look for a little knurled screw (on mine), pull this out and give it a quarter turn to stop it springing back.  this will disconnect the ‘straight through’ drive from the pulleys to the spindle, and enable the back gear operation.

NB – make sure the pin is correctly engaged in the hole when you switch back out of back.  Mine has some breakage to the side of the original hole, so a previous owner has repaired by drilling a new hole at another location on the pulley block.

The headstock is a No. 1 Morse taper; the tailstock is No. 2 Morse

I use a Halfords car alternator drive belt to connect to the motor, a poly-vee type which is a bit wide for the flat pulley width, but it works OK.  The smallest pulley (highest speed) can’t be used but that is not a problem.  It does require the spindle to be removed from the headstock assembly to insert the belt into position.

Best wishes with your new lathe!

Martin

 

[Martin WhittleParticipant @martinwhittle67411]

I have been looking for some photos – I think I also had more on the old ME website, but below is the only one I can find immediately.  I shall look further tomorrow.

Martin

 

[Martin WhittleParticipant @martinwhittle67411]

Adding to above, the locking pin is visible in the middle of this view from the above image

[MacolmParticipant @macolm]

By changing the contrast of the first picture, it looks like you disengage the button or pin as already described. Then there will (or should) be some sort of retainer to temporally unlatch so the backgear shaft can be moved. It simply slides along until both gears engage. Ensure relatched in whichever position before running. Retrace steps to restore direct drive.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, thanks to those who pointed out the correct way to disengage the cone pulley drive from the spindle, My thoughts were based on my fathers RandA lathe, although I did wonder if it was on the Bull wheel, as my Myford “M” type is via the Bull wheel.

Regards Nick.

[Adrian R2Participant @adrianr2]

On the belt, get some Balata flat belt and Flexco alligator joiners, you can then make up a length that can be fitted without dismantling the headstock.

[SillyOldDufferModerator @sillyoldduffer]

Pete correctly says ‘… back gears, they provide a fairly deep gear reduction with a large increase in torque.”, but no-one has explained what back-gear is for!

It’s a “good thing”.  Normally a lathe spins jobs at high speed, up to about 800rpm on a Zyto.   (That’s slow by modern standards, but not a showstopper.  Use HSS rather than carbide cutters.)

Rule of thumb guideline, cutting mild-steel with HSS, RPM = 10000 / diameter of job (in millimetres).   So the operator needs a range of speeds depending on the job in hand:

• 4mm diameter ideally requires 2500rpm (too fast for a Zyto – it will kill the bearings!)
• 10mm = 1000rpm
• 50mm =  200rpm
• 100mm = 100rpm
• etc.

On a Zyto the required speeds are achieved, approximately, by moving belts between pulleys.   This Zyto has 6 basic speeds. 2x by moving the V-belt on the motor,  3x by moving the flat belt on the lathe:

Though swapping belts works, moving them is a pain!   Modern lathes reduce the need for belt changing by speed controlling the motor, often supplemented by a 3-speed gearbox, much more convenient, but reduced torque at low RPM can be a problem.   Expensive lathes have pricey gearboxes throughout.

Operations like threading and parting-off are best done at low rpm, perhaps as low as 10rpm, when it’s good to have plenty of torque (turning power).    Whilst low rpm can be achieved by speed controlling the motor, doing so loses torque, leading to stalls.  Much better to spin the motor at full speed and gear it down.  Fast turning motors maintain their rated power output, whilst the gears reduce speed and multiply torque.  Win win!

Backgear is an extra low gear ideal for threading etc.   Backgear may not help parting-off because the Zyto isn’t particularly rigid – small lathes tend not to be!

Dave

[Nigel Graham 2Participant @nigelgraham2]

Ell81 –

The frame holding the countershaft pulleys looks as if made without a ready way to slacken the flat belt to change speed. So doing that on this lathe will be a pain as Dave says!

It should not be. I don’t suppose it takes more than 15 seconds on my Myford. The usual arrangement has some way to move the countershaft nearer the lathe to allow this, typically controlled by a lever operating an over-centre clamp or an eccentric arrangement so the shaft locks itself in the operating position. So if the frame does not have that quick-tensioning system, I’d investigate making one for it.

Also it looks from that angle as if the belt encloses the back-gear shaft, so fitting a continuous-belt replacement may need that lifting as well. These machines were made for belts that have a joining-clip in them. You thread the belt round the pulleys then assemble the clip to join the ends. An alternative arrangement, used for example on the Myford lathes, is to put the countershaft higher so the belt is entirely clear of the back-gear.

The Vee-belt looks too deeply engaged. Assuming those are standard-profile pulleys (which they might not be!) the correct belt’s outer width is that of the groove top, so it runs with its outer surface pretty well level with the pulley rim.

…

The cutting speed is a bit advisory: you can machine metals at much lower speeds than the books suggest, especially with high-speed steel tools, because the books are based on trade practice where time costs money. It just takes longer!  Note though Dave’s warning about excessive speed on a machine like this, with its plain bronze bearings and very basic lubrication.

…..

That slotted cross-slide is a bonus. Its primary purpose is for “boring between centres”, for maching cylinders too long to hold safely and accurately in the chuck. The work is packed up to the right height and clamped to the cross-slide, and the cutter is in a bar driven from the headstock centre or chuck, and supported by the tailstock centre.

Such a slide also allows using accessories like the rear tool-posts many of us use especially (but not only) for parting-tools; angle-plates and vertical slides. The current edition of ME&W carries an article showing such applications.

….

Morse-taper tooling such as centres are readily available from the model-engineering suppliers. The taper shank is of standard length for the diameter so that does not control how much of the lathe is hogged by the tool itself. Drill chucks and some die-holders are the longest.

…..

Howard has explained the change-wheels, on the outside end of the headstock. Disengage these when not being used, to reduce wear; and anyway you will need the leadscrew (the long one along the front of the lathe bed) disengaged from them when using the handwheel on its far end. I take it the disc visible inboard of the handle is a graduated dial?

That leadscrew handwheel is used when you need take a measured cut longer than the top-slide travel gives; by engaging the half-nuts by that lever with the curved slots. Normally you keep the half-nuts disengaged and use the saddle handwheel that drives a pinion engaging the rack fitted to the bed above the leadscrew.

Or set up the change-wheels to give a fine self-acting longitudinal feed using the leadscrew and half-nuts. There are a few change-wheels already on the machine but did the rest of set come with it?

…

That little dial on the right-hand end of the saddle is a thread-indicator, used when screw-cutting. It normally pivots in or out of engagement with the leadscrew, with a pin, screw or nut to hold in either position; and should only be engaged when screw-cutting.  Its graduations are not measurements as such but timing points for starting each iteration of the cutting, as it’s normal to take a series of cuts to complete the thread.

…..

A tip on using the tool-clamp. Your top photo seems to show it slanting downwards. It’s best set slanting down but quite gently to give the maximum clamp area gripping the tool shank. Never upwards – than can result in suddenly losing its grip.

The tool itself, ground appropriately for the material, is set so its cutting edge is exactly on the centre-height of the lathe, on a machine like this by using shims under the tool. Introductory books on turning should explain all these points.

 

The black fitting there on Martin Whittle’s photographed lathe, is a “Quick-Change Tool Post”. A steel block held to the top-slide, clamps to itself separate, channelled blocks that hold the tools themselves. Each has its own adjuster for setting that height. It speeds up repetition work, especially; but you need at least four tool-blocks to make the set worthwhile.  You can see four other blocks on the shelf above the machine, in Martin’s photograph.

I made a crude “Quick-ish Change” set of tool-holders for my much smaller EW lathe, by drilling blocks of steel to hold small tool-bits on an incline for height-setting.

 

……..

It looks a good lathe – keep us posted with progress and do please ask, if you need help!

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