Cross slide improvement for a 9 X 20 lathe

I shall soon be uprating one of these lathes and amongst other things, I want to replace the rather pathetic cross slide lead screw and nut.

There is a wealth of information on doing just this, on the Yahoo 9 X 20 lathe site. Most people seem to make a larger lead screw and nut. I have seen one reference to using a larger precision lead screw and nut using some of components which are said to be readily available for CNC homebrew machines. These are supposedly of very good quality and reasonably cheap to buy. So they seem attractive, better than making them ones self.

Does anyone know a source of such components? I have tried Googling, but I don't seem to be using the right words! I can't remember if I need a right or left handed system, but I can sort this out if I can find a supplier.

Anyone got any leads?

Thanks,

Andrew.

Andrew,

Try putting "trapezoidal leadscrew nut" in an ebay search

... You should be overwhelmed by results.

MichaelG.

Andrew,

You could have a look at these people. They seem to supply what you are after at a reasonable cost. I've no experience of dealing with them - I just came across their web site one day and kept it on my bookmarks, "just in case".

**LINK**

John

Thanks, Michael and John,

I shall follow up your suggestions. Why can I never (well hardly ever) manage the correct phrase when trying to Google something? Must have a different type of brain!

Thanks,

Andrew.

Hello, Andrew,

I have had one of these lathes for several years, and over time have made several changes (some of them not always improvements!). I would be interested to know what you are planning. I guess you have seen there is a lot of stuff in the Internet for these machines.

I would say easily the best improvement I can think of was to junk the original motor and belting, and fit a VFD - it transformed the machine.

The cross-slide screw is rather flimsy - mine actually broke one day at the junction between the thread and the shaft. At the time I needed it urgently, so I simply drilled into both broken ends (on the lathe), and fitted a steel pin, and sweated the whole thing back together with silver solder. A bit of judicious tapping, and it seemed to run better than it ever did before. Of course, I intended to replace the whole thing for something a bit more substantial, but somehow it has never happened. The only thing I did was mill part of teh slide away to allow greater movement of the cross-slide - its on the internet somewhere.

Plus one for Automotion Components. I bought a 1 metre length of 16 diameter x 4mm pitch left hand screw and two bronze nuts a couple of years ago for around £60

Enough to make three new cross slide screws for my 14x40 lathe and one spare nut. Should see my time out.

Thanks Chris,

Looks like Automation Components is the way to go.

An Other,

The lathe has had very little use, but I find that there are many shortcomings. The first of which will be the "Pipkin donut" modification rather than the 4 bolt hold down mods. I will then put in a beefier central tool holding bolt.

After that it will be a larger diameter cross slide wheel and larger diameter feed screw and nut for the cross slide, together with a ball raced mod. Maybe even a new lead screw for the top slide.

Next on the list will be a tumbler reverse and a gearing reduction to enable spindle speeds below 120 rpm.

Why spend so much time on what is a pretty crappy piece of gear as delivered? Well it cost me virtually nothing and is little used, so it is really only my labour plus a few ponds and this should give me a very usable lathe.

What surprises me is that these mods, if done at source, would deliver an infinitely better lathe at relatively little cost to the manufacturer. These lathes are only sold in the UK by Chester as far as I am aware They retail at something over £700. If they were modified to be usable out of the box, then I doubt they would cost more than £1000 and the extra cash would turn a pretty awful lathe into something that was actually desirable!

But we are so used to wanting stuff for peanuts that this is not going to occur.

Andrew.

Hi, Andrew,

I agree with your sentiments about these lathes entirely, but would make a couple of points:

I bought mine because like many people I simply did not have the money to buy an alternative. At the time I lived in Germany, and spent something like 18 months looking for a suitable lathe, including secondhand etc. Eventually I fixed on the 9x20 because IMHO it gave the best value for the money, and even when I bought it there was plenty of info around on modifying them.

It was bought new on offer for about 800 euros (when there were 2 Euros to the pound! - not so long ago) from a company in Luxembourg. (took it from Luxembourg to Darmstadt in the back of my car!), It came complete with a 120mm 4-jaw and 120mmm 3-jaw chucks, a boxed set of tools, a couple of centres and fixed and travelling steadies, so I think it was a good buy.

Although I was reasonably happy with it 'out of the box' (because the people I bought it from do a rebuild before selling - apparently not the case in the UK), but in time some things became a nuisance. The first and best was the motor/VFD, then I did the hold down ring instead of the bolts. I already mentioned the cross-slide screw (still amazed it hasn't broken again! - really must do something about it.). I also fitted digital scales, which save a hell of a lot of time. I have been faffing around with an electronic leadscrew using a PIC processor, but its really only for fun when I have time. Not been easy to find a stepper motor with sufficient power to turn the leadscrew without it costing the earth, and using gearing defeats the point of doing it.

I suppose it is a fact that financial circumstances force us to do unavoidable things, but I must say in general, I have been happy with my lathe. It has tackled all kinds of things, from repairing jewellery to making some adaptors so I could fit different wheels to my tractor - made from two pipe flanges which 'just' cleared the bed of the lathe and were about 3 cms thick - handled with no problems.

I also have a 7x10 chinee lathe, but I found I spent so much time modifying it so it would do what I want, and repairing damaged DC motor control boards, that now it is slowly rusting away on the garage floor - I realised I was spending so long working on the tools, that I never actually made anything useful.

Anyway good luck with your mods.

Edited By An Other on 15/01/2018 18:54:03

Hello An other,

Maybe I am a little bit too harsh in criticising the generic 9x20 lathe. You do get a lot for your money, so it isn't surprising that there are some basic problems!

There is no way I would pay full whack for a Chester 920. However having the opportunity to buy one for peanuts, it is worth while to do the modifications. Once done, most of the really annoying faults disappear.

I am not sure that I would fork out for a VFD. That starts to increase the cost significantly and I can modify the gearing without too much hassle, for very little cash. If I did go VFD, then it would have to be a cheap Chinese one. Despite people on the forum saying they are pleased with Huang Yang VFDs(can't remember the exact spelling!), I am not too enthusiastic and still doubt their reliability.

Regards,

Andrew.

Well Andrew you pays your money and makes your choice, one of my friends has had his Huangyang inverter for more than two years and its still working well. A couple of others have bought Huangyang more recently and they too are very happy. Not on commission by the was, but thought I'd let you know. I fixed the inverters to their lathes for them and did poke my nose inside and have a look, I couldn't see much difference to my pre owned, so called up market type which when new cost more than £220. John

Hello John,

I am aware of your success with Huangyang VFDs and also those that you have installed for friends. There is another person on the forum who seems to have a professional interest in inverters and his opinion is that they are a pretty poor piece of kit!

As ever on forums such as this, there is a wide range of opinions. I suppose I am always a touch pessimistic with Chinese kit and have to say there is some good stuff around and a perhaps larger amount of rubbish. I might just be tempted to give the Huangyang kit a try. perhaps against my better judgement!

Is there anyone UK based who supply them and actually give some form of warranty? Also do the Huangyang VFDs include filtering or is that extra?

One thing is for certain, I would not risk my hard earned cash by buying direct from China!

Andrew.

FYI - the VFD I fitted was a Moeller DV51 - I bought it new in Germany as I was living there at the time. I can't remember exactly what it cost (sorry - old age!), but it certainly wouldn't have been more than about 500 euros (2 euro to the pound then) because I simply couldn't afford it.

It is still in good order, and has far more functions than I would ever use. It has a small plug-in panel with an LED display and allowing manual (push-button) control for setting functions. The instruction manual is enormous - I don't think I ever read the whole thing. I just set it up so the motor soft-starts, and I can select 'jogging', forward, reverse and speed simply with a couple of button presses. I used to think about connecting it to my computer, so I could control the lathe from the computer. The idea was to connect the DROs mentioned in my earlier post to the computer, and program some sort of 'pseudo-CNC' system, along with the electronic leadscrew, but like many things it never got done - made tons of notes and drawings, but it lost out because I had to built a house (not that my wife bullies me, you understand...!)

Andrew, the Huan Yang (spelling?) VFD fitted to my Bridgeport mill is the best £90 I have spent in the workshop. Maybe 4 years now and faultless. My friend who fitted it for me has 5 or 6 of them in his workshop, one for each machine all without fault.

Good to see you going the Automotion Components route, I was impressed with the product/cost combination. I fitted the new cross slide lead screw at the same time as I made a new cross slide for my 14x40 Taiwanese lathe. A simple polystyrene pattern for the casting and then milled on the Bridgeport it is much stronger than the original and I now have tee slots the original lacked. Must admit to borrowing use of a surface grinder to do top / bottom and sides of the slide.

Chris.

Hello Chris,

Doesn't seem to be many suppliers in the UK selling Huanyang inverters for £90! There is a guy in Germany selling them for that sort of cash. Where did you get yours from?

Andrew.

I think the closest you'll get is Amazon UK but even then they are actually being sold by Chinese outfits (seems a bit questionable). Bear in mind that to sell products in the UK (EU), you need to meet the safety and EMC requirements. We can all be cynical about self declaration but as noted, it's illegal to sell here if goods don't comply.

Bottom line is, these VFDs almost certainly don't meet any of those requirements which is probably why you can't get them here and they probably don't even claim CE compliance. Use them at your peril....

Murray

I've had my Chester 9 x 20 for over ten years.....Agreed it has some shortcomings.... The topslide toolpost mount isnt the best....an easy fix...( well relatively..)

I fitted a vfd/3 ph motor....other than that no other mods....works great for me despite the negative comments....

Ok it doesnt have a tumbler reverse or the spindle speed doesnt go down to 120 rpm....

Horses for courses....if it doesnt meet your needs why buy it and then slate it....?

I'm not defending Chester, just merely stating that probably with any machine built for a price, it will have shortcomings.

Edited By John Rudd on 18/01/2018 19:48:03

I have 2 HY inverters and find them to be excellent. Got them here.:- **LINK** Supplier based in Germany. Fast delivery (less than a week) The 1st one cost me £74-38 & the second £80 63.

The price is now about £90. I run a 1.5HP motor on the Boxford lathe & a 2HP on my AJAX mill. Never had a problem of any kind.

I use these control boxes which cost £50 each and were a doddle to set up. **LINK**

Hope this helps a bit. regards

Hi Andrew, got my HY inverter from ebay.

I noticed that the last photo in the group on this amazon page is provided so customers can tell the difference between a Genuine Brand Huanyang Inverter and a 'Cheap Copy Inverter'.

This is a good sign. Stage 1 of a developing industrial economy is 'anything goes'. Stage 2 is the realisation that quality and reputation matter. It's the point at which selling junk costs an economy more money than it brings in. I wonder how many Chinese industrialists are fed up with the cowboys and are busy lobbying in China for tight copyright law and stiff penalties?

Stage 3 is the realisation that knocking out manufactured goods in clouds of pollution isn't particularly profitable. There are better ways to make a living, like high technology.

Dave

Hello John,

Not really knocking the 920 lathe, BUT there are some serious deficiencies, some of which you mention that you have fixed and others that you must be happy with. You get what you pay for, so no quibbles there.

I would not even consider buying a new 920 lathe, but if you are happy with yours, then fine, that is what this hobby is about!

I don't have the 920 lathe yet and the deal may well fall through for other reasons. However if someone wants to virtually give me a little used 920 lathe for absolute peanuts, then I will take it! I intend to sort out the deficiencies and then pass it on to a disabled friend who wants to indulge in some model making. It is easier for me to do the mods, so I shall not be using it myself.

So that is the reason I am getting the lathe, it were for my use, then I simply would not bother! But well worth while if it gets someone else started in the hobby!

Andrew.