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

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.

Lovely job, Paul

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

MichaelG.

On 6 November 2023 at 11:17 Paul Kennedy Said:

…

 

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

The other point of view is that tools are meant to be used, not mollycoddled, and replaced when worn out or damaged Beyond Economic Repair.

Years ago I picked up an old book on lathes which altered my perception of them.  I expected the book to be about using lathes, but it was actually about buying lathes for commercial use.   Written about 1920, the book warns British companies they must break the habit of buying heavy well-made manual lathes and expecting them to last 60 years.  The world was moving away from traditional methods, and it was obvious to the author that improvements were in the pipeline.  A company investing in a lathe in 1920 and expecting their business to be operating the same way in 1980 was daft!

Rather than ordering a solid traditional British lathe and waiting 2 or 3 years for it to be delivered, better he said to buy American off-the-shelf with the latest productivity improvements, and expect to replace it in 5 to 10 years with an even more productive machine.   He was right. Productivity improvements started with things like pneumatic chucks, then mechanical copying mechanisms, hydraulics, later numerical control, then CNC, and today multi-axis machine centres that combine lathe and milling in one.    Once factories were packed with lines of manual lathes, now manual lathes only have a niche role.  (Albeit an important niche!)

Too many traditional British firms went down the toilet, burbling nonsense about quality, and refusing to accept customers preferred cheaper products made by efficient competitors.   Manufacturing is cut-throat, not much place for sentiment.   Millions of manual lathes were scrapped by industry during the 20th century, many of them worn-out.

Hobbyists have a different perspective.   I’d rather make things than repair old equipment. and would rather have a modern Chinese machine than a perfect Zyto.   Others enjoy operating older kit, and mending stuff.

Not sure what’s needed to mend your broken headstock ‘properly’.  The bearing adjustment depended on the cast-iron having enough flex to take up wear.  Not good design, because cast-iron is brittle, and it’s very common for owners to have broken headstocks of that type in the past.    Cast-iron can be welded, but it’s tricky stuff, the cheaper variety being dirty and extra unpredictable.  Once welded, the spindle hole should be re-bored, possibly after welding some fresh metal in the hole to replace wear.  And then a new bearing –  the old one was worn enough to have cracked the casting.

Glue, bolts and similar might be ‘good enough’ to get the lathe working acceptably, but it won’t be ‘good as new’.   Much satisfaction getting it going again, but I wouldn’t buy it in that condition!

I am a horrible old cynic!

Dave

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.

Is that language really necessary?

On 6 November 2023 at 22:24 Mike Hurley Said:

Is that language really necessary?

No it isn’t. I think that whole post should be excised.

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

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.

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.