Pittler spiral cutting test

[vic neweyParticipant @vicnewey60017]

My Pittler lathe is capable of many different types of turning and milling. Here I am trying out milling a spiral using the lathe being driven by the leadscrew itself via an overhead drive to the tailstock mechanism.

The power then passes up through the reversing box and onto the headstock mandrel. The chuck and saddle will turn very slowly, dependent on the worm and wheel used. It’s most important that the headstock pulley is free to turn so the flat drive belt for this must be slackened off or temporarily removed. My video on Youtube can be seen here

https://youtu.be/wOrPeptvLJ4?si=oRUHl6WAOwA0KK6i

In total there are 4 belts running and 7 pulleys are used!  The cutter is a 1/2″ ball nosed endmill

[John HaineParticipant @johnhaine32865]

Neat.  Actually it’s a helix – not sure how you would mill a spiral on a lathe.

[BazyleParticipant @bazyle]

Very interesting but needed to be stopped every few seconds as it was flying around too fast to take in the details. Alos liked the other videos you have on this lathe.

Now I’m curious about the thing with a big hole in it under the lathe in the above picture.

[John Haine]

on John Haine Said:

Neat.  Actually it’s a helix – not sure how you would mill a spiral on a lathe.

Fusee making involves cutting spirals. Fusee engines are a specialised form of lathe for doing so. Jerry Kieffer has shown a setup on a sherline lathe for doing so which uses a curved template.

[Bazyle]

On Bazyle Said:

 

Now I’m curious about the thing with a big hole in it under the lathe in the above picture.

It’s a rare Pittler radial compound slide, it has 3 handles compared to normal compounds with 2, the 3rd handle rotates the top slide. See:  https://sites.google.com/view/pittler-lathes/c3-lathe-menu/radial-compound-slide

You can always pause the Youtube video

[Clive Brown 1Participant @clivebrown1]

For cutting the helix on the “Quorn” vertical column, Prof. Chaddock illustrated his set up for driving the lathe via the leadscrew whilst milling a 3/32″ wide slot. Each pass along the column took nearly an hour. I think that his lathe was a Drummond.

Fortunately, the MES materials kit at the time offered this operation pre-made.

[John Haine]

On John Haine Said:

Neat.  Actually it’s a helix – not sure how you would mill a spiral on a lathe.

Maybe it’s a helix but mister Pittler would not agree as he has sections and tables in the catalogue under spiral cutting. Examples are shown of spirals cut on a round ball, all produced on this lathes standard equipment.

 

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