Axminster Engineering Lathe Course - Update

I’m pretty relaxed about it - a replacement leadscrew for the S7 is about £120 - and I doubt that I will need one in the near future !

My interest is at the “small” end of things and BA sizes are the “norm” so taps & dies are the usual order of the day.

Norman

I have yet to meet anyone whose actual requirement for accuracy exceeds that of their lathe in a hobby context.

Plenty of people who worry that their lathe isn't accurate enough.

Lots of people who don't realise that the errors they seek to eliminate may be beyond their capacity to measure them, especially when it comes to angular and pitch errors.

Working with telescope guiding is fascinating, when you need to track something over degree or two's movement to a sustained accuracy of a second of arc and you see how big the cyclical error in a 'precision' worm can be.

I agree. I think the most accurate thing I can measure is time, closely followed by frequency to about 1 or 2 parts in 100 million. Lots of 'ifs and buts' about it though.

Around room temperature I can measure a steady temperature to about 0.2C.

DC Volts, Amps and Ohms, about 2%, again over a limited range. AC, no better than 10%

In the workshop, the best I can do with length is 0.01mm with a micrometer up to 25mm. My digital calipers are no better than 0.02mm up to 150mm and that depends on feel. I don't have a good general way of accurately measuring lengths greater than 150mm. The worms on my lathe and mill are 'reasonable' compared with a DRO, but a microscope (which can see sub- micrometre differences) reveals that they're only accurate on average. There are inconsistencies per turn if you look close enough. My DTI has the opposite problem. It's pretty good at 0.01mm differences, not so hot adding them up over a few millimetres.

Life gets difficult when you're serious about accuracy. Calibration becomes essential and maintaining accuracy beyond the range of your equipment is a real challenge unless you can do some sort of comparison. Most of the time my metalwork is rough and ready. It is interesting to see how close you can get though. For example, as a challenge, how accurately could you make a rod close to 3.0000 metres in length at 18C?

Dave

There are some applications that truly do require precision. Here's an old mate of mine talking about what they can achieve these days with commercial equipment. In contrast, my workshop activities are at the agricultural engineering end of the spectrum.

I love state of the art machines with control panels that look like something out of Blake's 7

My first thought was that nobody here would remember Blake's 7.

Immediately followed by my second, was that the average age on here is probably abut 70, so they will!

Do you remember the first episode that stretched credulity with a portable TV camera no bigger than a shoe box linked to a video recorder fitted in a briefcase. Clearly as impossible as the Star Trek communicator with no whip antenna you could hold in one hand. A spaceship was easy of course as it would be atomic powered like the steam express trains.

Here's the test piece

That's exactly what I made. I took a few pictures this morning with the intention of uploading them, but you beat me. Lol.

Keith

Hia, any recommendations for accommodation I've booked for January, cheap is the key! And pub would be preferred! Ta bram

I stayed at the Cottage Marsh B&B, 25 minute drive away from Axminster. Cost me £79 for 2 nights, but make sure you book for 1, as I booked for 2 initially and price was £120. 1 pub/restaurant in walking distance, a second a short drive away. I would even be willing to take my wife there for a couple of nights.

Keith

Hi Keith, do you remember the name of the pubs? Thanks phil

**LINK**

Bram,

I 'goggled' the place, 'goggled' for pubs near that post code and came up with the link above. Seems like the Flintlock Inn is the closest

I ate in The Eagle Tavern on the Monday and The Flintlock in on the Tuesday. The Flintlock Inn doesn't open on Mondays and you may need to book in advance as they were turning people that hadn't booked, away. Eagle Tavern was good value, Flintlock Inn, was better quality and pricier.

I'm thinking of doing the 5 day engineering course in April and would plan to stay there for the week.

Keith

Hi don't think Flintlock inn have rooms, found Whiteheart inn think it's about 7 mile away that have rooms fairly cheap, may fit the bill !!

Hi Keith posts crossed there, which one are you thinking of staying at the eagle or flintlock!! Didn't think it looked like flintlock had rooms!

I was planning to stay at the Cottage Marsh B&B as it was very reasonably priced, no problem with parking, nice breakfast and only 100 yards from The Flintlock Inn. To be honest I couldn't anything as nearly good value. You suggested that you wanted to stay in a pub, well the Cottage B&B used to be a pub the owner told and the rooms there are in what used to be the skittle alley. So you get your wish, it's just that they don't sell alcoholic drinks any more.

Keith

Can I ask if the threads were cut with Tap and Die or turned?

We had the choice, Bob demonstrated external thread cutting to us on my course, but I'm pretty sure that everyone including me used a tap and die.

Keith