- Thread starter GraemeVW
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Seadog
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It's known as a Bastard Thread.
You could always buy a set of taps
You could always buy a set of taps
GraemeVW
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Spendy!It's known as a Bastard Thread.
You could always buy a set of taps
I think the lathe will cut 7tpi. I could always get it close and finish with a tap. I'll keep my eyes peeled for a cheap one in case. Then I don't need all 3.
I imagine hand tapping 1.75" 7tpi would be energetic.
GraemeVW
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So ive been reading.
I have a 3 jaw and a 4 jaw that already have back plates.
But I'd like more chucks so it's something I'll need to sort, but not for a few months.
Seadog
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If you're going to screw cut I would suggest that first you cut a male thread as a reference. A lot easier to do and you can use a thread gauge to see how accurately it's made.
Also, make a go/no-go gauge for the register.
Also, make a go/no-go gauge for the register.
Agroshield
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Why is that? Just down to its size and awkwardness? The diameter and pitch combination is standard BSF.
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Dr Al has a good three wire calculator on his site (https://www.cgtk.co.uk/metalwork/calculators/screwmeasurement). Zoro sell 2.1mm drill blanks for £1.59 each (https://www.zoro.co.uk/shop/cutting-tools/hss-drill-blanks/series-j400-hss-drill-blanks-metric/f/167).
Trying to do a three wire measurement on nylon will likely give misleading results as it is squishy.
Seadog
Save the planet. It's the only one with rum!
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Solely because its a non-standard size in relation to BSW and BSF threads.
Chippie
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But he already has pre threaded backplates to reference his plug …
Use aluminium as an alternative then….a bit more £££’s
GraemeVW
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I have some aluminium already
Agroshield
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This is the bit I do not understand. 1 3/4-7 is absolutely bog-standard BSF. It is in every BSF thread chart that goes up that high.
To me, it would make more sense to measure the spindle of which he is trying to make a facsimile. You would only ever make one dummy spindle nose in a lifetime, so it is worth doing it right.
GraemeVW
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Fortis. British clausing 100 copy.
on here about it
GraemeVW
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Videos on YouTube?
I think it has been mentioned elsewhere on the internet that this has 55° angle threads.
It will have to wait untill theatre is back in one piece though is that's what I'll have to make it on. My other lathe won't do it.
Pete.
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BSF are whitworth form, just with finer pitch than standard whitworth threads.
You will find that BSF (or any vee form) threads actually ARE self-centring, even if they ar not designated as such. Even chucks with very sloppy registers will pull up true due to the thread taper. If you took the spiral out of a vee form thread you'd have - a taper.
You will find that BSF (or any vee form) threads actually ARE self-centring, even if they ar not designated as such. Even chucks with very sloppy registers will pull up true due to the thread taper. If you took the spiral out of a vee form thread you'd have - a taper.
Thread Data Charts-FINE PITCH (BSF) BRITISH THREAD DATA CHART
