Small Thread/Tapping Job

[Pete F]

My concern with a S/S rod and S/S nuts would be that the two parts would gall and then they could not be moved.l

Yes I was thinking the same thing Michael, but when I was rolling it around my mind I remembered plenty of SS fittings on the yachts I used to work on, so wondered if it would be an issue in practice???? But agree, I think it would be something to consider.

Pete

[PDW]

Yes I was thinking the same thing Michael, but when I was rolling it around my mind I remembered plenty of SS fittings on the yachts I used to work on, so wondered if it would be an issue in practice???? But agree, I think it would be something to consider.

Pete

Binding most certainly is an issue in practice. I wouldn't do it given a choice and I'd definitely use a very good grade of anti-seize compound.

The best stainless for the job is 303 as it's free-machining and reasonably good mechanically. Not weldable but that's not an issue here. Do not under any circumstances use 304. 316L is not too bad, I use a lot of it as 303 isn't really good exposed to salt water and definitely not below the WL.

The LH nuts need to be tapped, nobody in their right mind is going to attempt to single-point LH threads in stainless.

I personally wouldn't touch this job for less than $50 a set and only if the purchaser was supplying the taps & dies. But then I hate doing 'simple' jobs like this where there are lots of opportunities for things to go pear-shaped.

Good job for a lathe equipped with a collet chuck like my P-B lever operated one though.

PDW

[Pete F]

I tried cutting this when I got home from work today to see how it would go. As expected M5 was going to be quite tricky over 30, never mind 50 mm, when single pointing on the lathe. I cut both left and right hand threads and only achieved acceptable results when the free end was well supported by a half-centre and faced off after the threading is complete. Even then it's not a piece of cake, as the minor diamater is around 4 mm and the whole lot wants to move around quite a bit. While the LH thread could be single pointed, it would certainly be easier if the threads were all cut with taps and dies, which would probably mean purchasing a LH tap and LH die.

Hopefully that's of some help.

Pete

[pipeclay]

Why would you face it after cutting the thread and not prior to cutting the thread?

[Pete F]

Why would you face it after cutting the thread and not prior to cutting the thread?

Well obviously both are required Peter. The first time before centre drilling for the centre, the second time to remove the run-in groove and centre mark.