Zyto Headstock Repair or Replacement ?

[Paul KennedyParticipant @paulkennedy14200]

Hey guys, Ive got a ‘scrap’ Zyto lying around that I had thought  about restoring. Its been a bit knocked about, a bit neglected and a bit ill used and has a fair bit of damage as a result ! Most of it I can deal with in time but the MAIN problem halting progress is the Headstock Casting is broken ! The rear bracket that supports and secures the spindle has cracked right through and the top can be removed after the tightening bolt is removed ! I am looking for advice on how to repair this or if this is very difficult or expensive then would a undamaged headstock and spindle be available ? My thought is that someone out there might have just what i need. ? Ive looked into repairing it and it seems unlikely with my equipment and as soon as I get a fab/eng shop to look at it then this will be too expensive considering the value of the small lathe ! Welding needs pre-heat/special rods and even then might warp the headstock, brazing seems like the best option but again requires pre-heat and risks warping the headstock. Using some form of brace combined with small bolts or screws to join the two parts further combined with some form of Liquid Metal eg J.B. Weld MIGHT work but Its not a real option as far as I’m concerned although I’ve never tried ! Your thoughts on this are appreciated. Lastly Milling a new Headstock and jig boring it etc could be done but yea :/ I’m not that inclined as i don’t really have adequate facilities to tackle a precision job like that ! My best option is that someone has a Zyto partially stripped for spares for a ‘Good’ Zyto and has a spare headstock casting ! If anyone can help I would be very excited to hear from you ! Kind Regards all and stay safe and warm this winter !

[peak4Participant @peak4]

If you have Facebook, there is a Zyto Lathe Group, though I’m not a member

A photo of the broken bit might help, so folks with the relevant experience can offer some advice.

Also on FB, Machinist’s Museum had a post a while ago about that.

Bill

[Brian WoodParticipant @brianwood45127]

Hello Paul,

Pictures would be helpful but having owned a Myford ML4 which Tyzack used to clone the Zyto, the failure you describe is common in these lathes that pinch the spindle to adjust clearance. Owners fail to realize that cast iron will only flex so far without a suitable spacer in the gap to close down onto.

Whereabouts in the country are you? It might be possible to cobble a repair together to keep you going while you search for a replacement as a short term solution.

Regards   Brian

[Michael GilliganParticipant @michaelgilligan61133]

I agree with Brian … detail pictures would help a lot

Generally speaking, though: I would tend towards machining the lower part down to a flat surface and making a new cap retained by two fixings.

The original is just plain cheapskate design.

MichaelG.

[Paul KennedyParticipant @paulkennedy14200]

[Michael GilliganParticipant @michaelgilligan61133]

Lovely job, Paul

I’m sure opinions will vary … but I stand by mine

MichaelG.

[Paul KennedyParticipant @paulkennedy14200]

I am a fair way North ! In the Scottish Highlands. I actually have a ‘good’ Zyto and this one was sold as scrap which i got for spares and am now thinking I may as well ‘fix up’ but its 50/50 if i bother. She’s in fairly poor condition and will need a lot of work but who can turn down another project 😀 Cross slide leadscrew is bent and the top slide leadscrew is snapped. The backgear shaft is bent as is the small gear pin/shaft for the change gears. Lots of parts are missing but there’s enough there to cobble together a lathe with basic functionality if not for the Headstock issue ! A lot of the parts i could remake myself or repair, however if the costs are prohibitive then I’m not going to tackle it as the lathe is in such poor condition that any money spent wont be recouped due to the relative low value of these small lathes and the general condition of this one ! The cross slide table is chipped from contact with the chuck and partial break out on one T Slot ! The Tailstock Thread for the Barrel is partially broken but operational now after i fettled the threads where damaged. The Topslide toolrest has had teeth hacksawed into its face as has the topslide toolpost clamp. The toolpost retaining post is also bent and the threads bashed. When I received it EVERYTHING was completely seized ! After intensive cleaning,and bathing in WD40 and more cleaning and wire brushing and heating and more WD40 thinks started to come apart to reveal all the oil holes had been painted over at one point or were so choked with dirt, no oil would ever have penetrated to where it was supposed to. I’ve still been unable to get the backplate of the spindle but now i have the headstock stripped i’m thinking about making up a couple of C Clamp collars to suit so i can clamp the spindle in the vice and get some real force on the backplate. More work though so until I decide what to do about the headstock I’ve put everything else on hold ! Whoever had it before me was ham fisted idiot and rather than strip,clean and oil moving parts decided to brute force it until parts started to break and then likely considered the lathe to be cheep junk ! OK so it likely is made to a price point but still … Anyway.. Its likely still better than some chineese knock offs and I got it dirt cheep. If its not fit to repair then i will store the parts as spares for my other zyto but Id like to get her fixed up and back together if I could. Its just a pity about the Headstock otherwise Id have a go. As it stands I’m more than a bit doubtful. I know its not ‘worth it’ but i just hate to see lathes go in the scrap. Do people not realise the time,effort,resources,skill and investment in infrastructure,tooling and materials it takes to make a lathe or mill or engine or anything really ? Why are we manufacturing anything if these bloody fools just break or destroy it for ‘likes’ or ‘subs’ or out of general ignorance :/ Meh

[Paul KennedyParticipant @paulkennedy14200]

[Howard LewisParticipant @howardlewis46836]

Could be quite a project to fix all the problems.

At least you have another lathe with which to do the turning jobs.

Quite crude, but if you could clamp the broken cap in place, firmly, (having spotfaced it) could you drill and tap for a second bolt to hold it in place.?

The crystaline nature of the break means that you have myriad location points (A method now used on fracture split con rods and caps in internal combustion engines)

Howard

[SillyOldDufferModerator @sillyoldduffer]

[duncan webster 1Participant @duncanwebster1]

It’s beyond economic repair. Even if you fix the headstock which is a big job it’s has multiple other issues. Either sell it for parts or advertise it as a boat anchor

[MacolmParticipant @macolm]

I would agree with simply bolting it back together across the break. That is the only way the amount of work is not excessive for what it is.

The first thing is to be sure the break is indeed clean and undistorted. Unless there is next to no gap when exactly seated on the bearing, success is unlikely because it will not clamp the bearing diameter uniformly. Then, I would suggest two bolts rather than one. It needs careful assessment to ensure these are positioned in maximum metal for strength in the cast iron.

Two possibilities are conventional hex cap screw fixing with a plain hole in the top part clamping the parts together, or instead threading right through both parts with well-aligned holes. The latter distributes the forces better in the weak cast iron, but will of course not clamp tightly. It may help in this respect if bolts are used with the heads tightened onto the top face. This will pull the bolt upwards and so largely remove the inevitable slack due to the thread clearance.

In this kind of situation, I find it a good idea to mull things over for a good few days to spot the potential snags.

 

 

[Paul KennedyParticipant @paulkennedy14200]

Moderators Edit Reply deleted due to too much inappropriate language

[Mike HurleyParticipant @mikehurley60381]

Is that language really necessary?

[Nick WheelerParticipant @nickwheeler]

[duncan webster 1Participant @duncanwebster1]

[Mike HurleyParticipant @mikehurley60381]

[Brian WoodParticipant @brianwood45127]

I have looked again at the sad story Paul listed for this lathe earlier on. I am willing to bet the bed is also badly worn and things like change wheels, chuck (with key) will be absent.

Why he took it on in the first place I can’t imagine, having got a decent lathe already. As described it is junk, pure and simple and even when it has been prepared for sale it will surely be worth little more than £ 50 to £100 at best. Put that into context with minimum wage rate of about £12/hour there isn’t any margin that makes the job worth doing. Just cleaning it up will have taken many hours already and nothing has been fixed.

Do the math as the Americans say!

Regards  Brian

 

[Paul KennedyParticipant @paulkennedy14200]

https://www.youtube.com/watch?v=GSmmnajzrHE&t=11s

0_0

[Michael GilliganParticipant @michaelgilligan61133]

Getting back to the original question, Paul

I was interested to see that others proposed bolting-up the fractured surfaces

<u>There is a lot of merit in that</u>, but the problem is <u>then</u> that the resulting hole for the bearing will be some as-yet-unknown shape and size [because it was previously used, and abused, for adjustment.

By all means try it … but you may then need to line-bore the resulting hole, and find an alternative means of adjustment.

None of this is impossible … it’s just *rather*  difficult !

MichaelG.

[MacolmParticipant @macolm]

It is unlikely the cast iron has been bent much, if at all. After all, it broke rather than stretch. So if the two parts are clamped round the bearing and shaft, the aperture should be little worse in circularity than it was when previously tightened to adjust the clearance. Certainly contact in the bearing will not be uniform, but neither was it before. I seem to recall that old sewing machines used this method of bearing adjustment, and they seemed to last for ever.

It boils down to how much effort it is worth for something that will never be particularly good. Setting it up, clamping the broken faces tightly together, drilling two holes and threading them right though, and fixing with bolts or screwed rod should only take an hour. It might just work, and be instructive into the bargain.

[Robert Atkinson 2Participant @robertatkinson2]

If a repair is attempted I’d go for a bolted and bonded approach. Similar to Macolm’s sketch but I’d use cap head shoulder bolts. These act as a dowel. Clamp broken part in place. The fracture surface will self align. Drill one hole tapping size (M4) through both parts. Then tap body and drill clearance in the broken half. fit plain screw to hold it an repeat for second fastener. Then enlarge (drill) and ream hole in both parts to depth and diameter (5mm) of shoulder bolt. Fit first bolt, repeat for second hole. Ideally this would be done with the headstock set up on a mill. Degrease, check fit and then finally assemble using loctite retainer (or similar product) on fracture surface and fastners.

Robert.

[MacolmParticipant @macolm]

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