Axminster Engineering Lathe Course - Update

As requested a (brief) update on the Axminster 2 day Engineering Lathe Course I attended recently

The course ran 09:00 to 17:00 on consecutive days with 5 attendees. I felt out of my depth as I entered the training suite, one glance at the workshop immediately put mine to shame. However, Bob Rolfe soon put us all at relative ease - the SC4 lathe is a bit bigger than my WM180 with more features - though still familiar

Apart from tinkering over the past few months I haven't touched a lathe since 1977 at school, the basic principles haven't altered, but my confidence was more the issue, I want to do things the "right" way from the outset

In preparation I had read a couple of books though a couple of others remain unread

When I looked at a sample test piece and drawings my immediate response was that I would never be able to make a similar test piece to the same standard. But that's the point - develop the skills and expertise to make the test piece

Two days passed in a blur, an awful lot of information is imparted in such a short space of time. Of paramount importance is workshop safety, and honestly I had ignored or forgotten some simple stuff so am grateful I haven't injured myself previously and appreciate the *reminders*

Conducting the simplest operations gave me plenty to think about, which way does the tool move when turning the dial, and by how much? because the dials are calibrated in segments with length per segment ie 0.02mm per segment

Digital micrometer has been a revelation too, I knew my digital calipers were ok to a point, but the lack of accuracy really showed up when comparing to digital micrometer - problem now solved

I hadn't realised the calibration rings move either so zero can be set and pieces cut using the calibration rings. And as an aside, it turns out very few, if none, of the entry level machines are accurately calibrated before leaving the manufacturer (broad sweeping statement...) so the only way to get accurate dimensions off the machine settings only is with DRO

I digress...

I left the course thinking my WM180 is a piece of crap, but when I went back to my machine it turns out to be better than I thought, I do need to adjust the saddle but in all other respects - as far as I can tell - it is a pretty much spot on

As the course progressed, and as my confidence improved, I managed to produce a half-decent test piece. Still much to learn, but already with the skills I learnt and improved confidence I feel much more able to deliver precise results

Now my next challenge is to purchase a bigger lathe, because the WM180 just isn't long enough... and until Santa arrives I hope to go on the Axminster Milling course so I can get 2 prezzies, because I can already tell my mini-mill won't be big enough either

To finish, I cannot recommend the Axminster course highly enough. Bob is an excellent - and patient - instructor and throws in real-world experiences to back up the practice. The course has taken me from incompetent novice to competent but inexperienced novice with a desire to learn more

Sounds like you have enjoyed the course a lot, where are the courses held ie which county/town/city?

Ian

I think you will find that it is Axminster in Devon - the home of Axminster Power Tools. A net search for them will give you a view of all the goodies available and details of courses. I do go over there from time to time ........ but it can get expensive as I always seem to find something that I need!

Norman

I went on the same course in August and I have to agree with Andy that I also cannot recommend this course highly enough. I had never done anything on the lathe before, although I had bought a small Chinese one. I was so impressed with the work piece that I managed to produce. I am thinking of going on the 5 day, lathe and milling course some time next year.

Unfortunately, when I cam back from the course I looked at my lathe and decided that it wasn't good enough so immediately order a Sieg SC4 (the same as used on the course) from Axminster.

Keith

the only way to get accurate dimensions off the machine settings only is with DRO

Andy,

Not necessarily true. They would, of course, like you to purchase one! The accuracy is in the consistency of the lead screw threads, once you take up the backlash. DROs come in various flavours.

Those that highlight readings to 0.01mm may well have a much poorer accuracy (+ or - 0.04mm?), once you read the smaller print. Those that read to 0.001mm should be at least better than 0.01mm absolute - but they are rather more costly than the basic 0.01mm type.

Glad you enjoyed your course. Being safer is a good plus point on its own.

Also depends on what accuracy you think you need, I seem to manage without a DRO on my lathe, plenty of running models can't be wrong!

Really curious as to what the test piece is - go on show us a picture.

Regarding my comments on DRO - I tried to convey above that the lathes are only accurate to a point, and off-machine measurements give true accuracy. DRO are much better but still not necessarily accurate enough for some work. As I am learning, there are several ways to do things, but the lack of accuracy inbuilt into the lathe came as a surprise

I'll post a picture soon

How do you think they made Spitfires then? No DROs in those day, but plenty of accuracy.

Not unusual for lathe work to be done to tenths of a thou using the dials and operator's "feel". One trick they used was to turn the topslide to about 6 degrees. By using the topslide handle to put on the cut, one thou movement of the topslide moved the tool inwards by one tenth of a thou.

Exactly!

Top slide trick is an oldie but goodie, especially with a shear tool in the tool post.

@Hopper - please re-read exactly what I wrote and not what you think I wrote. My comment about DRO relates to the machine calibration, not how an operator compensated for the lack of machine precision. I am very aware there are excellent machinists producing superb work on imperfect lathes

I think you may be running into metric > imperial compromises. A lot of lathes have a 1mm pitch cross slide screw then mark the dial in a way to make it look like thou divisions so of course they are a bit off. You just do a precise measurement at the last few thou.
However there was one period I believe when Myford used rolled threads which weren't quite accurate.

Interesting point. I've noticed that many Model Engineers like to check their lathes, sometimes as a hobby in itself. Headstock and tailstock alignments, run-outs, bed wear, bed twist, levelling, Rollies Dad, etc. etc.

All very interesting but I don't think I've seen anyone mention careful testing for vibration, or confirming the accuracy of their lead-screws. I've come across both checks in professional sources. Can anyone explain why amateurs don't seem to bother much about vibration or their lead-screw accuracy?

Ta,

Dave

Edited By SillyOldDuffer on 16/10/2017 09:47:19

Edited By SillyOldDuffer on 16/10/2017 09:47:40

On top of the above post, Myfords with a single lead screw (standing in in for a power feed drive) was a cost cutting compromise. Power feeds do not need to be so precise/accurate, but threading lead screws do. Wear on the threading lead screw, for power feeding, is not an ideal situation and will eventually lead to some inaccuracy along the length of the screw.

A DRO or any other device on a lathe indicates distance moved not the size of the part in the chuck. I allways use the dials as indication of movement and used a micrometer to tell me the size of the part.

Anyone know of similar courses available in Australia?? TAFE Qld used to have adult ed classes in all sorts of things but they don't seem to offer them any more.

I think both are covered on the forum but couched in different terms such as headstock noise and leadscrew wear.

SillyOld Duffer,

I have measured the accuracy of the leadscrew on my ML7R lathe, using the most worn section in front of the chuck to do so and then extrapolate the measurement to the whole leadscrew length

The value I obtained was + 0.0018 inches in 25 inches of leadscrew. The positive figure indicates that the travel induced by the leadscrew is greater than for one of perfect pitch. The comparator for this measurement was the Newall DRO on the machine.

I thought that was pretty good for a well used hobby size machine and certainly not worth worrying about

Regards

Brian

"Wear on the threading lead screw, for power feeding, is not an ideal situation " -

It's a valid point that, with the Myford, the leadscrew is used for powered feeds as well as for screw cutting - the question is though - how often do you use your lathe to cut screw threads ? In my case hardly ever. On the other hand powered cross and longitudinal feeds I use all the time.

Norman

Not as often as I use the power feeds, but nevertheless quite a lot, probably over a hundred. I rarely use circular dies on the the lathe. But my lathe does have separate feedshaft so I don't need to worry about wearing out the leadscrew.

Andrew