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Excellent work Nigel. Great idea to run the assembly on the lathe to 'run it in'. The difference in the noise level (before and after) is palpable! In use of course it won't run at anything like the speed of the lathe :)

So, after one difficult experience - not caused by eBay but probably due to your own lack of security, you would sooner promote an alternative company who have a Russian link? Even with today's situation with regard to Ukraine? I think not!

or even "three make one and six" which is what we sang in the midlands.

I've only just come across this thread so I'm a bit late responding but that statement is so wrong!! The 'Florin' introduced in 1849 was the UK's first attempt to change to 'Decimal' currency. At 2 shillings or 24 pence (d) it was 1/10 of a pound (20s or 240d). The fact that the original...

That would have been a different game then! The CPC 464 had a 4Mhz Full spec Z80 CPU & 64K Ram compared to the Spectrum's 3.5Mhz Cut-down Z80A CPU and generally 16K Ram. The introduction of the 464 was a major revalation as far as reliability was concerned. We expected in excess of 20%...

Hi Rik, I was busy with other pressing matters yesterday so didn't see this post 'til this morning so apologies for the delay. The Root of your Gear should be 3.74" so your 3.75 could mean that the Hob used to cut it was using a smaller dedendum multiplier but is irrelevant as far as a new...

I have Taps & Dies down to 12BA - though I seldom use less than 10BA - but when I was an apprentice, I spent some time in the 'Plating' shop where I had to 'wire up' ready to chrome plate the inside threaded portion of 20BA screw ring gauges - the bore on that being ~0.34mm !

Ah -- That makes sense :) I think the Basic dimensions of the BA 'Standard' was (is?) the most mathematically determined, and yes, the choice of 0.9 as the ratio does seem somewhat arbitrary but I suspect that it was determined very specifically after many hours of calculation. I haven't...

I'll agree that there were some strange decisions made but it was early days. I don't think the use of numbers as a reference is arbitrary for small diameters - it's so much easier to use a single character as a designation - Can you imagine having to write (say) 2.8 x 0.53 BA rather than...

Being born in Coventry (well physically Leamington Spa due to it being Wartime!) and my father being a Capstan Setter/Operator, the name of the company was very well known to me when growing up. Anyone in the midlands area knew that if you wanted to be a toolmaker then getting an...

Thanks Sandyn - very useful - No, I don't (didn't) have such document, I've been working from first principles, plus information remembered since my apprenticship at Coventry Gauge & Tool Co. Ltd. - (1956 - 1962) :eek: - I'm sure you will know CG&T through their 'Matrix' branding - though I did...

@Sandyn - You are quite correct on both counts, my reply - on re-reading - does look to be abrupt and aimed at @Craywater - actually it was seeing the Imperial figures which roused my ire ! so appologies to @Craywater :oops: (I can't find a real 'Embarrased' Emoji) I was coding for 16...

That is one of the worst types of BA Data sheets! - It simply lists the imperial aproximations, and does nothing to address the question which is about the formula that equates the OD to the pitch.

That link is much more concerned with the automotive industry rather than the British Standards for screw threads. There are numerous size charts like that but they just show a list of the sizes rather than the formulae which determine the Thread Series. Since posting the question, I have found...

I know BS 93:1951 is obsolescent but BA threads are still in regular use, particularly in Model Engineering. I've always known the 'Series' to be the most scientific in that the Pitch of each higher 'Number' is 0.9 of the previous rounded to 2 places. That's fine and causes me no problem but...

:D You're welcome Nigel - I more than doubled my knowledge of Bevel Gearing during the excercise. I could suggest that fitting a 'fence' with a Sine Bar would be better than a line scribed in engineer's blue though 🤣 Edit : I hadn't read your 9½° write up when I wrote that!

I've never used Larch so can't help on that score but if building a fence I would always use 'Godfathers' - those things you refer to as 'repair spur' or 'stub posts'. When I was in that business, I never considered them a 'Repair' option they were always 'original equipment' items.

Oh no it wasn't!! A Woodruff Key is a 'half-moon' shape which sits in a slot cut with a Woodruff Cutter. A Square key is just a short length of material, often with rounded ends, which sits in a groove cut into a shaft sometimes of limited length cut with an end-mill but usually...

When no gal'll give in ...

I quite agree that it has its own agenda - but I certainly wouldn't apply 'Nasty' to its description. The prime use to which its appearance is paramount is in Violin (et. al.) Bows. I've only used very small amounts for box finials and inlays so have not experience 'cracking', though I have...