More beginner questions

Confusion indeed. It seems to me that the OP - Speelwerk - makes no mention of the levelling of the lathe, and that perhaps by 'clamping studs' Old Iron meant the studs which clamp the lathe to the bench. So, a different reading offers the likelihood that the lathe is not set up in the 'ready for use' sense as it may not be level or firm at all. This is not the main cause of the nasty turning finish, though.

First, set the lathe up firm and level, and attend to all other adjustments etc. You may find other things which need attention in the process. Then sort out a proper sharp tool of the right angles etc for the job in hand (and this includes knowing what you are turning).

Advice on all these points is there in the literature and from colleagues on this forum, but do try to put the setting-up before the trying out - it will help us to help.

Regards, Tim

Edited By Tim Stevens on 02/06/2022 16:22:37

Very sorry for the misunderstanding, only behind a lathe since 1971 and Myford since 1979, therefore will leave it to the UK experts to comment. Niko.

Not exactly a beginner, sold my ML10 a few years ago, now regret it and looking around the market.

My question is can you manually screwcut on a Seig SC3 lathe or are you forced to use the motor drive?

My previous technique was to insert a mandrel handle into the spindle, unhook the motor belt, set the change wheels and start winding. This was crude but very effective and easily controlled. I never really enjoyed the 'drop the handle and hope to pull it up in time' technique.

So, can you do similar on a SC3?

It was my preferred way on a mini-lathe, where the minimum speed was too high for comfort! As it had an ordinary DC motor, I didn't bother to take the belt off - with the power off, turning the motor with a hand-crank, didn't add significant resistance.

Is the SC3 brushless? If so the motor might be harder to turn. Another concern is the possibility of damaging the electronics because the motor will act as a generator when it's spun. I've not tried it, but I think damage is unlikely because hand cranking is slow, and because lathe control electronics don't pop when the emergency stop is pressed at high-speed. Doing that means the chuck will drive the motor as a generator until the energy is absorbed by the bearings, gears, and belt. Much faster at first than a hand-crank.

A good alternative on lathes that can run in reverse without the chuck unscrewing is to screw-cut away from the headstock rather than towards it, so that there's no risk of colliding with the chuck. This can be done at high-speed, might not need a hand-crank at all. At 30rpm minimum speed my WM280 is a perhaps just a tad fast for super-safe screw-cutting, so I often reverse cut considerably faster. One day I might experiment to see how fast threads can be cut, I guess hundreds of rpm are do-able.

Dave

Edited By SillyOldDuffer on 25/05/2023 11:47:27

30rpm is a tad fast??? I thought I was wimping out starting at about 100rpm and increasing as I get used to the job. Life's too short to futz around scraping a few microns off per pass, especially if it's a large and long thread like the M20 threads on both ends of the headstock bolt I made, or M14x1(I know, but it was a Russian aeroplane) jack adapters.

We had M14x1 on something at work, can't exactly remember what but I think it was part of a hydraulic hub fitting kit and possibly Italian.

Martin C

Dunno about screw cutting on a Seig, but I’ve never single-point thread cut, by manually turning the lathe. No problem with a back gear and variable speed - these days the VFD makes things even easier.

The only time I manually turn the lathe, when thread cutting, is (sometimes) when using a die.

Hi Chris

Could I suggest a very good book on using the smaller home workshop lathe, The Amateurs Lathe by Sparey it covers many of the questions that arise when starting out . There is also Using the Small Lathe by Mason and of course the Harold Hall books. The Sparey and Mason books are fairly old but still available and were written about the time your ML7 and similar small machines would have been common in the home workshop, they don't really deal wiyh modern carbide tooling but are full of good information to get you going.. Ian Bradleys Myford lathe manual also covers setting up the machine, although I believe the Sparey book covers that too. I'm sure they would be worth their modest cost in helping you get started with your machine, something to read in bed too!

Good Luck

Dave

M14x1 isn't that uncommon, IIRC it's used on brake lines or something like that. I actually have a tap for it. Used it on a couple of silencers, the thin muzzles often require a fine pitch. Besides they stay put with hand torque.

The Tracy Tools chart shows 4 ISO-M14 pitches:

2mm (in the "ordinary" coarse series),

1.0, 1.25 and 1.5mm, ISO Metric Fine.

So M14 X 1 is a standard pitch, not a "special".