Thread: Squaring my lathe

Originally Posted by ftkalcevic

Seeing we are so far off topic from my initial question...
Are there any sellers of "good" small lathes? In Australia?

Well all depends on the size of your bank account

With some tweaking and modifying, what you have may turn out to be a good machine... You have the level, you have the test bars, you have the moglice... If you have the time, what do you have to lose?

Well, it could be fettled in to a relatively accurate lathe, however there's more to making a "good" machine than merely getting it to jump through some hoops developed by a German gentleman almost a century ago. Unfortunately there's a reason good machines cost what they do, and herein lies the debate between many as to whether it's better to buy a used machine of good pedigree but is worn and inaccurate. Conversely buy a brand new machine that may or may not turn accurately out of the box ( Chris insists they do, I've heard countless examples where they didn't, but what would I know). With enough time and effort the old lathe can be bought back to the same level of standards as when it first shipped, but it's a LOT of work. As you well know Richard. Conversely manufacturing errors, if they're there, can be corrected on a new lathe, but there is only so far you can polish a , and nobody should be under any illusion of anything different in this regard,

There's no right or wrong answer, but people should be fully aware of what they're buying in each instance, and not somehow be convinced that with a little scrape and align their $1000 special is going to morph into a Monarch EE!

Originally Posted by ftkalcevic

Seeing we are so far off topic from my initial question...
Are there any sellers of "good" small lathes? In Australia?

Short answer: no.

Longer answer, not unless you're prepared to spend very serious money for a toolroom lathe that masses at least 5X what one of those copies of an Emco Compact 8 masses, and is priced at 20X or more.

You get what you pay for. That's why a lot of us prefer to have old iron and restore it.

Now if you move your goal posts to the 12x36 lathes and your budget to over $6000, then yes, you can get a new machine that's a good lathe.

PDW

Back on topic....
One thing really worries me about the work you have done and are doing is your floor.
When i did my lathe it was bolted to the concrete floor and baring an earthquake it could not move. If your moving your floor just by walking around the machine any time you try to take any readings they will be falsified by your weight on the floor. Remember we are talking in accuracies that your next door neighbor sneezing may effect.
Do you have any concrete you can bolt it to just to do the tests? Or get under the floor and add some more support, wedge up shrunk bearers etc?

On another note i'd like to see a range of test reports from a bunch of these small Chinese machines. Another thread maybe? I have seen first hand how wrong the small granite plate test certs are. Not only are they the same but my plate is definitely concave (when compared to my big plate), not convex as the chart says.

Cheers,
Ew

Originally Posted by Ueee

Back on topic....
One thing really worries me about the work you have done and are doing is your floor.
When i did my lathe it was bolted to the concrete floor and baring an earthquake it could not move. If your moving your floor just by walking around the machine any time you try to take any readings they will be falsified by your weight on the floor. Remember we are talking in accuracies that your next door neighbor sneezing may effect.

I would agree. If your floor can move randomly, then any check you do with a level, no matter how good the level and how skilled the operator, is a waste of time. You have no way of separating out floor movements from machine movements/alignment.

My floor is 100mm of reinforced concrete floating slabs poured over a heavily compacted substrate that we watered & rolled hard in layers using a ride-on vibrating roller. A fully loaded 20 tonne truck barely made an impression in the compacted ground. The slabs float independent of the load bearing footings. Things do not move.

In your case if you couldn't do anything else I'd be looking to lay down some 25mm thick BC grade ply or 15mm thick compressed fibre cement sheeting under the lathe bench, at minimum.

PDW

Just to throw a bit more fuel on the RDM fire, there is absolutely nothing wrong with the principles behind RDM to establish whether or not the axis of the headstock is parallel to the ways.

As a method of analysis RDM is just fine, but you have to draw a clear distinction between the analysis method and what some RDM articles then advocate you do with that information. Twisting the ways??? Gimme a break!!!!!!

A year or so ago I had a minor crash on my Hafpos 14 x 40 which moved the headstock, which is only bolted in position. (The horrors that I found when I investigated the headstock fixings can go in another thread). Happily, by using RDM analysis I was able realign the headstock with the ways and get it clamped down again. (And yes I did first make sure the ways were true).

So now my lathe specs are even better than those on the test certificate that came with it. Its an odd thing, and I'm sure its just my imagination, but I reckon I get a whiff of roneo whenever I pick up that piece of paper.

I think the money you will end up spending on this lathe will go a long way to buying a new lathe of the same size. The 9 x 20 lathe is so small and light, I doubt very much attention to mounting etc, is going to make a lot of difference. There are plenty of machinery shops selling lathes, often the same lathe with a different brand name plate or sticker. H&F are a tried and tested seller of lathes, they provide warranty, parts and backup for whatever they sell. I've had 5 lathes, only one (the last) actually came with a report but all were very accurate, certainly most all the model makers and hobbyists seem to think so. Buy new and cheap first and when confident in your knowledge and abilities you'll have a better idea of what will suit and whether or not you are prepared to spend the time and effort bringing an oldie back from the grave (another hobby in itself). Chinese or quality? Well when your ready you can post another thread entitled 'Chinese or Quality' and stand back and watch the fun.

Another idea would be to set up a suspended floor that is mounted at the ends far enough that it does not effect the lathe. Just a long wood beam or ali scaffold beam if you know someone in the building trade who would lend you one. Even hang something from the roof.

Dean

A big problem with the timber floor is weather, humidity, temperature, as these change so does the timber change in thickness and straightness, the two bearers or joists at either end of the lathe would even likely move in different directions.
Any building project must have decent foundations, even a small lathe if you want repeatability from one day to the next. If the lathe had a sturdy cast iron base under it the problem with the wooden floor would disappear.

shed

Originally Posted by Ueee

...........................
On another note i'd like to see a range of test reports from a bunch of these small Chinese machines. Another thread maybe? I have seen first hand how wrong the small granite plate test certs are. Not only are they the same but my plate is definitely concave (when compared to my big plate), not convex as the chart says.

Cheers,
Ew

This was looked at many years ago at the Yahoo 9x29lathe group. Some dealers sell the Chinese9x20 lathes with inspection record, some without. It was found that those lathes that came with inspection records all had different looking figures and serial numbers matching with the actual lathe. It was concluded these were likely to be made out during final assembly of the lathe, and in good faith.

The Chinese are very good at making exactly what a dealer orders. The inspection record is one of many options, that the dealer can tick or leave out in his factory order. Just like the paint color, boat trailer wheel type spindle bearings or quality bearings, what quality of electric motor, what quality chucks etc etc. It all comes down to: the dealer gets exactly what he is prepared to pay for. Also note that very large dealers will employ a local inspector, to check quality during assembly and before the lathes and other machine tools are packed into containers. There are also companies in China, that do nothing else than offer such independant inspection services - of course at a price for the foreign dealer. And at the other end, there are backyard assemblers that assemble machines from faulty reject castings. A lathe that has several different color coats under the last top coat would be most suspicious.

Now if all dealers did add the same margin to their lathes, it would be easy for the end user to choose a cheaper or a better finished machine. Unfortunately that is not the case. Sometimes the dealer that screws the factory for the cheapest purchase price cutting all possible corners, is also the same dealer that applies the highest profit margin and tries to screw his inexperienced customers too. So for the end user, the saying "you get what you pay for" is not necessarily true, because visually it is near impossible to distinguish between a better made and a cheaper made model.

Originally Posted by bob ward

Just to throw a bit more fuel on the RDM fire, there is absolutely nothing wrong with the principles behind RDM to establish whether or not the axis of the headstock is parallel to the ways.

As a method of analysis RDM is just fine, but you have to draw a clear distinction between the analysis method and what some RDM articles then advocate you do with that information. Twisting the ways??? Gimme a break!!!!!!

Nothing wrong with the "two collar test" which is the principle behind RDM. It isn't RDM until you start twisting things "blind"*, and thats what I have a problem with.

Stuart

Originally Posted by shedhappens

A big problem with the timber floor is weather, humidity, temperature, as these change so does the timber change in thickness and straightness, the two bearers or joists at either end of the lathe would even likely move in different directions.
Any building project must have decent foundations, even a small lathe if you want repeatability from one day to the next. If the lathe had a sturdy cast iron base under it the problem with the wooden floor would disappear.

shed

This is only in relation to setting up the lathe, not a long term solution. One would have to ask the OP about whether it is possible to make changes to the premises. He has already said it is mounted on a sturdy base.

One other suggestion is to ensure that the base of the cabinet is not rocking on the floor because one or the other is convex.

Dean

Sigh. Ok here's how it really works. The company's purchasing department go on Alibaba and sort through machines that they want to sell. They then send a message to the various companies requesting a quote, together with how many pieces they require. The Chinese company replies and once a short list is complied the two companies sort out specifics such as branding etc etc. No Chinese companies are "screwed" in the process, if anything there will be lots if attempts of doing the opposite, at least in my experience.

The situation with on site inspectors etc may well be different for big value machines, but sure as heck isn't for a lathe that can be picked up for around $200 FOB!!!

Originally Posted by Pete F

Sigh. Ok here's how it really works. The company's purchasing department go on Alibaba and sort through machines that they want to sell. They then send a message to the various companies requesting a quote, together with how many pieces they require. The Chinese company replies and once a short list is complied the two companies sort out specifics such as branding etc etc. No Chinese companies are "screwed" in the process, if anything there will be lots if attempts of doing the opposite, at least in my experience.

The situation with on site inspectors etc may well be different for big value machines, but sure as heck isn't for a lathe that can be picked up for around $200 FOB!!!

Sounds about right. The situation isn't likely to change until the good/better Chinese manufacturers start selling under their own brand names and therefore have a reputation to protect. Which isn't going to happen any time soon with small hobby lathes as there's too little margin in it.

Funny how H&F advertises some of their higher priced machines as made in Taiwan and higher quality (price) than similar paper specification Chinese sourced ones......

Having said that, there's a couple threads on PM where some of the CNC machinists are talking about routinely holding tolerances that are down where you couldn't get other than by hand scraping, and doing it routinely, day after day. So using good enough machinery to make other machines to high accuracy standards in a mass production setup is certainly feasible.

PDW