More beginner questions

[Nick WheelerParticipant @nickwheeler]

Posted by SillyOldDuffer on 25/05/2023 11:47:01:

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.

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.

[Martin ConnellyParticipant @martinconnelly55370]

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

[not done it yetParticipant @notdoneityet]

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.

[Dave WoottonParticipant @davewootton]

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

[FulmenParticipant @fulmen]

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.

[Nigel Graham 2Participant @nigelgraham2]

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".

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