Doing your own stuff from established systems may be what it is

I extend my MT1 taper system for fatter bigger requirements

As Michael says, it may be a descriptive type

Modding your tailstock is pretty easy for an artisan (even bodgers can do it)

Edited By Ady1 on 05/10/2022 10:09:43

If the rest of the lathe uses Imperial fittings, threads, etc, using Metric units may be counterproductive and confusing.

measure major and minor diameters, a carefully measured distance apart..

Convert your dimensions to Imperial and use those, to calculate in various formats..

The taper can be expressed in a variety of ways, Angle, Half Angle, Inches per Foot, Inches per inch.

the "Tool-n-Gizmos" website lists many tapers and their dimensions.

You may find what you require there.

Nothing on Lathes UK that helps?

Howard

Edited By Howard Lewis on 05/10/2022 10:39:09

That's something that is not as simply done as said.

Measuring the diameter of a taper at any specific point is rather difficult, let alone two specific points a known distance apart.

Maybe it could be done by setting up in a lathe, zeroing an indicator on something of known diameter, then taking comparative readings on the taper, along with tracking the distance apart.

That will find the taper angle or rate but length dimensions on a taper are more nominal/indicative than definitive.

B-tapers are just the small or large end of a Morse taper, so confirming the taper angle will allow you to see if they remain a possibility.

From Vic's dimensions I get the 'Angle from Centre' of his taper to be 1.7899°

From the tables at LittleMachineShop I can say it's not Morse, Jarno, or Brown and Sharpe. The only potential match is Jacobs #33 which is 1.8184°

Given the difficulty of measuring tapers accurately, 1.7899 might be 1.8184, but I'm not convinced a 19th Century German lathe would have a Jacobs taper.

I think one of my books lists a few more tapers: I'll see if I can find it.   They are:

Sellers Taper – 0.75 in per foot, with a keyway throughout

Reed Taper –  1:20, similar to Jarno

Standard Tool Company Taper – between 0.6 and 0.63 inches per foot

Dave

Edited By SillyOldDuffer on 05/10/2022 18:01:14

Easily done – every time I measure tapers I get them wrong! The corrected half angle is 1.5482° – still doesn't match any of the tapers I now of. The different ways tapers are expressed is a right pain: Ratio, Angle, Half Angle, Inches per Foot, Inches per inch etc. make some tables hard to compare.

Why is nothing ever easy?

Dave

The historical context is important in putting any of them forward as possible candidates. If a particular taper was invented or standardised after the machine was made, it can be eliminated. You also have to use common sense: an obscure taper used by a single US manufacturer has to be very low on the list of options.

I am not going to find a USB port on my CNC Bridgeport no matter how carefully I measure it.

I have been playing-around with a tiny spreadsheet, which I think is on the way towards being useful.

The layout can be tidied-up easily enough.

It does nothing that we couldn’t do in a minute or two with a calculator, but as the results are near-instantaneous and presented automatically I think it may have some merit.

I’ve done it in Apple’s iOS App ‘Numbers’ but it should easily convert to Excel, etc.

Constructive criticism would be welcome.

Note: for my sample input, I have doubled-up Vic’s measurements … this allows us to easily see the difference between the vulgar and normalised presentation of Slope.

.

.

If you want to fire some numbers at me, so that we can check the results … please do

If you want a copy of the file, to develop it yourself … please send me your eMail address by PM

MichaelG.

.

Thanks for that, but [entirely my fault for not describing it in detail] … the two versions of ‘Slope’ are not showing degrees and minutes.

The colon is purely text, and there to show a ratio

60 [or indeed any larger number] would be entirely reasonable

MichaelG.

.

Your’e welcome, Vic … it’s an interesting puzzle

The reason I was keen to express the ‘normalised half-angle’ is that it’s what one would use when setting-up the lathe to cut a specific taper.

Do you remember [before we had to use %] the way hills on British roads were described ?

1:4 described steep hills in a very concise way … one unit of Rise in four units of Run

MichaelG.

Edited By Michael Gilligan on 09/10/2022 13:12:11