Question for engineers. SOLVED

[tzsteve]

I do head re-profiles on a lathe,
This can also be done using a milling machine. The setup uses a rotary table with a side and face slab cutter fitted to the spindle with the spindle set at an angle.

Does anyone here know the maths involved with this set up.

This was actually a question on a C&G exam I did many many years ago, since then I have forgotten this bit of trig and also lost my student notes.



Any help really appreciated

[henri]

oh bugger ,its like being back at college on a thursday morning , down in portsmouth dockyard , with a hangover probably , facing the days apprentice torture . i think i know what your getting at , but not sure it will give as good a results as lathe work . i'm guessing this is squish band fine tuning , as any bowl work you'd need some fancy cnc to get a consistent curve from a flat faced cutter .if i'm correct , its just simple trig isnt it ,decide ya roof angle ,set machine/cutter to that angle an cut .
what notes ive kept from those days , rescued from my parents loft after they passed , are with my notebooks from 86-2000 , in the under stairs cupboard a place no sane man goes without 4 days food/water supplies, an a very large handgun .
if youve head on a rotary table , an a mill with adjustable spindle angle , i'd of thought easier to keep spindle vertical an angle table to be honest . i dont think you need trig unless ya programming cnc . just old skool ,pencil , fag packet n head scratching . H

[tzsteve]

Yes H,
we all have one of those cupboards where things lurk.

This is bugging me cos I used to be able to do the maths in 2 minutes and get the machine setup in a few more.

This was also one of the questions on my final C&G before I went onto some other study.


Using a miller this way can give very good results. But machine and cutter must be good ( a worn machine or damaged cutter will never give a decent finish )
Another way is to use a fly cutter on the spindle with the work on a rotary table.

[tzsteve]

SOLVED


Referred to technical formulae by Gieck and found a clue

[henri]

well share it then , so i can write it down in a notebook an put that in a "safe" place ,never to be found again .H

[tzsteve]

I'll do a doodle in a day or two with a few notes

[tzsteve]

drawings are a bit rough but im not an artist

The silly mistake half way down I say sellect a cutter with a radius of 150% of desired radius.

Silly Billy it's SELLECT A CUTTER WITH A DIAMETER OF ABOUT 150%.

We all make mistakes if we don't check our own work as if it was the work of a beginner.

[jonnysnatchsniffer]

just remember not to champfer where the squishband meets the bowl, old 130 polini heads, and standard ones all have one so the band ends i a curve rather than an angle at the end
but i bet you already know that lol