Tapers

Oily Rag,

Have you considered measuring it a little more accurately yourself? Two ball bearings, of different but known sizes, used to measure the distance from a fixed point to the balls when dropped in the taper, then apply a little trig to calculate the angle. Possibly closer than guessing.

Possibly get to within a smidge with a good digi angle gauge?

Or can you just use the half centre to set the cutting/grinding angle on the lathe?

Howard,

Well yes indeed, the collet system for the Aciera is Schaublin W20 which uses a delightful drawbar thread of 19.6mm dia x 1.66mm pitch. At least this system is shared with a few other machines, few being the operative word. Getting an item like an ER25 or ER32 collet system to mate with a W20 spindle means going to Rego-Fix, no options for Charlie's parts here!!

Michael,

But dreams can soon turn into nightmares - having said that I bought 2 F3's for far less than new Charlie built machines and they are so well made that they are a 'dream' to work with, even after nearly 60 years old for one and approaching 40 for the other. The shear range of optionals gives the ability to manufacture just about anything.

NDIY,

The male taper I have - so it is easier to measure that than dropping ball bearings down female tapers. I mounted the male taper on a sine bar to measure the included angle on a surface plate and with a digital height gauge. I then double checked by measuring with my clinometer the Sine bar taper and correcting against a measure of the surface plate orientation. The taper on the Sine bar stack measure came out at 4 degree 2' 20" (by interpolation against Tangent tables) The clinometer after correction for surface plate gave 4 degree 1' 50". The Tan values for 1' at these small angles is ³⁄₁₀ of a thou so 20" is therefore equivalent to ⅒ thou. The Clinometer is a 'double bubble contra' movement with readings taken off a graduated wheel to 10" (ex RN gun laying calibrator ). So I'm pretty happy to guess a 2 deg taper is a good start point followed by a bluing test! Other than that I'll mount the taper in the lathe between centres and 'clock it off the top slide'.

Martin