Member postings for Andrew Tinsley

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.

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.

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.

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.

Brian's book is a gold mine of information and it is beautifully produced too. Well up to coffee table standards. That is where my copy lives, just to confuse visitors.

Andrew.

What sort of battery are you talking about? If it is a NiCd then the vent system under one of the terminals is producing NaOH which then turns to a white powder on reacting with CO2 from the atmosphere.

I too have a real problem with a couple of electronic tyre gauges. The contacts on the button cells are tight and corrosion free. Yet the contacts fail after several weeks. I can then clean them with a small amount of 3M abrasive and all is well for another 3 weeks! I am totally out of ideas for this one! I have a couple of other gauges of the same make, which are trouble free. Swopping batteries makes no difference, so it is a contact problem. However the contact plates are gold coated, so would not suffer from corrosion

Andrew.

The generic 920 lathes seem to all have aluminium nuts on the cross slide. At least the ones I have seen, have them.

They do wear out, but it takes a lot longer than you would expect. I have done a replacement on a friends lathe and that was using bronze. If I am going to the trouble of making a well fitting nut, I would prefer that it lasted, so I don't have to do the job twice!

Andrew.

I now have a couple of Dore vices made from a kit of parts. Remarkably good and as you make them yourself, the quality is what you put into them. I often use both of them to hold long workpieces and they are low profile. This means more vertical space than a conventional vice would give.

I do have a 4 inch Vertex and a modern style 6 inch Abwood. The latter gets used infrequently, because it is big and heavy. The Vertex is good too, but I don't like the rotating base.

Andrew.

Thanks gentlemen!

Looks as though I may as well sharpen the duff milling cutters and give them a try. I suspected that I may have been able to use them once ground and sharpened. Basically I was too idle to sharpen them and find it didn't work. Looks as though they may still be usable and definitely worth the effort of sharpening them.

Not sure about using them as parting tools, the hefty slitting saws won't have the side clearance necessary and any rotating system would have a large overhang. Maybe I have misunderstood how to use them in this application?

Interesting about cutting them up to use as a boring bar. how on earth would you cut them up to start with? Again I may well have got the wrong end of the stick!

Thanks,

Andrew.

I have just purchased a job lot of horizontal milling cutters. There are slitting saws, face cutters , side and face cutters and some profile cutters. Most are sharp and those that need sharpening can be done on a friends Quorn (Mine isn't finished yet, probably quite a common refrain!).

Now there a few large slitting saws missing a tooth and an odd side and face cutter, again with a damaged tooth. Is there any point in keeping these, for initial rough milling? If not, then can anyone think of other uses? Seems a shame to throw away a few lumps of HSS!

Andrew.

Hello Magnia,

I think this was where I came in! The only geared set up I could find initially was an epicyclic drive using gears from a car auto transmission. Not having access to such gears, I chickened out. I most certainly would not want to make a similar set up for scratch!

A screw cutting clutch is on my list of to dos, but a long way down the list at the moment! I will try out my DC motor, I already have a variable electronic DC supply on the shelf, so I will try it out. Again I have a DC motor and variable DC PSU on the shelf and the lathe is peanuts, so I don't have much to lose.

If it goes pear shape, at least I can try a 3 phase motor and inverter. That solution will however cost considerably more. Not too sure if it is worth it for a cheap 9 x 20 lathe, but it is in reasonable nick and could with a few simple mods could become a reasonable lathe.

Thanks once again everyone,

Andrew.

Please Mr Moderator, how do I delete a double post?

I seem to be very prone to this fault!

Andrew.l

Yes John,

I think you said it all, you need time to go through a good book on your choice of CAD. This begs which system do you learn? You won't know what the snags are until you are up and running.

It is the time element that I am not happy with. I can do an awful lot of real machining for the time taken to learn a CAD system AND be able to use it effectively.

I am older than you, so I probably have less time available to get things done before I drop off this mortal coil. I would rather use a drawing board and get on with the work than take time out to learn CAD. If I were a lot younger, then no contest. I would learn CAD! However, I begrudge the time to do so, at my advancing years!

Andrew.

I am with Adrian Newey all the way. I don't doubt the logic of youngsters changing from drawing board to CAD. However for someone like me. I don't have the time left to learn a new system and become competent in its execution. I am always "time poor" with so many things to do before I exit this life!

To summarise I like drawing boards and can do things quickly on one. CAD would take me months learn and become able to draw with any speed. I simply don't have the time to learn, nice though it may be to do so!

Andrew.

The black body locus is nearly flat at white heat, hence no colour change.

Andrew.

There seem to be a lot of infra red thermometers on the market these days. People use them for measuring the head temperatures of model IC engines for example. I don't know what range they cover, but it sounds as if they could measure the black body locus curve quite accurately. That is assuming they go to a higher enough temperature.

I am now able to follow the various "colours" that one sees with pretty good accuracy, but that is only because I have had plenty of practice. Not very helpful to a beginner!

One needs to view in very subdued lighting, otherwise I get caught out! So be warned!

Andrew.

Hello Neil,

What sort of printer was it? My laser printer has gone all streaky in vertical lines and colour rendering differs from RHS to LHS. Goodness knows how laser printers work!

Andrew.

Having got up to speed on DROs, it would seem that the cheap alternatives are not going to fulfil my needs. Some of the Chinese 3 axis packages are available for around £250 and look to be an interesting alternative. Has anyone tried them, they appear to be the same units available from some of our suppliers such as Chronos. There is no way I want to embark on the Yuri solution. I don't have time to do the build and I don't want to get involved in programming again. As I said before. I have had my fill of such things over my life, becoming adept at a particular programming language takes time and isn't worth it for using DROs

I think I shall keep twiddling hand wheels for a little longer, until the other workshop cash demands have been fulfilled! Thank you all for your inputs it has been a very good learning exercise for me.

Best Regards,

Andrew.

As perhaps to be expected, a lot of information, some of it conflicting. Looks as though the cheap ARC and Chronos systems, do have ingress problems as well as battery problems. I could fix the battery problems with a dedicated PSU and some extra wiring. Not so sure about the dirt and moisture problems. I will be using flood cooling on the mill at least when doing horizontal milling. So I expect the worst.

It seems that the glass systems are perhaps better(?) but more expensive in both display and scales. I can't afford £350 for a system or at least I have better things to spend that amount on!

A problem that requires a bit more thought and research!

Andrew.

Seems that I have caused a bit of discussion here! I was not knocking anything, just curious as to why an ACME thread might be better. Seems to be several answers to that! Very informative too.

I have an apology to make, I checked on the Emcomat 8e and id doesn't have an ACME form on the cross and top slides, so mea culpa.

Interestingly enough, the fix for the rather grotty system on the 920 is to use a larger diameter 10tpi thread of 60 degree form together with a ballrace and bronze nut. There seems to be a lot of info on the US forums about improving the 920s faults. A friend of mine is going to buy one and as he is a newcomer to the hobby, it might be that I have to help with the necessary improvements.

Looks like I will be considered as the "expert" go to, little does he know it will be blind leading the blind.

Andrew.