Rotary Table And making A Radius.

[Peter GoodchildParticipant @petergoodchild34034]

Newbie question. I understand a rotary table is used to make an outside or inside radius on a part, what other ways could a radius be made?
Thanks.

[Peter GoodchildParticipant @petergoodchild34034]

[Anonymous]

Same as for internal corners, several ways:

1. For general radii, on the ends of connecting rods for instance, a rotary table is a pain as it is only too easy to rotate a tad too far and leave an indent. I prefer to use filing buttons. Although controversial I regard filing buttons as sacrificial and leave them soft. It is often quicker to use buttons than mess about setting up the job on a rotary table

2. A rotary table for complex radial slots that need to be accurate in size and placement

3. CNC mill, especially good for parts with multiple radii and splines

4. Mark out and file by hand

5. Machine on a lathe if the geometry of the part allows, that can include turning a circle and then cutting away waste material

Andrew

[Chris Evans 6Participant @chrisevans6]

Radii can be achieved with a boring head and also by calculating many intersection points. The maths are square root of radius squared minus distance moved squared. easy with a CAD package but not essential.

[Chris Evans 6Participant @chrisevans6]

Radii can be achieved with a boring head and also by calculating many intersection points. The maths are square root of radius squared minus distance moved squared. easy with a CAD package but not essential.

[Martin ConnellyParticipant @martinconnelly55370]

The most basic method is filing. Similarly grinding or sanding (belt sander for example).

Outside radii can be produced by rotating around a pin if there is a suitably positioned hole at the radius centre. Also if there is a hole at the centre you can mount hardened filing buttons and file an outside radius to the size of the buttons.

Inside radii can be produced with drills, milling cutters or hole saws with a suitable diameter but often this will that the hole is made early in the production of the part so that the tool is not only cutting over part of its cutting edges as the uneven forces may cause problems of accuracy and size as well as risking damaging the tool.

I think there will be plenty of examples of these methods on YouTube.

Martin C

[Paul LousickParticipant @paullousick59116]

A CNC mill can machine a curve but it can also be done by calculating the x,y coordinates for the radius manually.(although very slow and time consuming). Some DRO displays have a function that calculates and displays the values for you. The smoothness of the circular cut will depend number of moves.

[Peter GoodchildParticipant @petergoodchild34034]

OK thanks for the input everyone.

[Bob Unitt 1Participant @bobunitt1]

Posted by Paul Lousick on 17/07/2023 11:52:23:

A CNC mill can machine a curve but it can also be done by calculating the x,y coordinates for the radius manually.(although very slow and time consuming).

A variation on this I've used successfully is to draw a scaled-up version of the shape (not necessarily a simple curve) on graph-paper, then read off the X-Y co-ordinates direct from the graph-paper, allowing for the diameter of the cutting tool. Finish with a file.

Edited By Bob Unitt 1 on 18/07/2023 11:58:23

Edited By Bob Unitt 1 on 18/07/2023 11:59:29

[Peter GoodchildParticipant @petergoodchild34034]

Posted by Bob Unitt 1 on 18/07/2023 11:57:48:

Posted by Paul Lousick on 17/07/2023 11:52:23:

A CNC mill can machine a curve but it can also be done by calculating the x,y coordinates for the radius manually.(although very slow and time consuming).

A variation on this I've used successfully is to draw a scaled-up version of the shape (not necessarily a simple curve) on graph-paper, then read off the X-Y co-ordinates direct from the graph-paper, allowing for the diameter of the cutting tool. Finish with a file.

Edited By Bob Unitt 1 on 18/07/2023 11:58:23

Edited By Bob Unitt 1 on 18/07/2023 11:59:29

Thanks,

As a newbie, only starting to learn about milling machines machining. I've been told learning to use a manual mill can be compared to going up a hill but CNC is like going up…. a mountain, have to learn the CNC language and the licence cost of the software is astronomical. Your approach sounds good, may well get back to you on this, when I'm a bit more advanced with things. I've been watching the Blondihack YouTubes on the basics of the lathe and mill, more geared ( no pun there ) to where I am now, also find very interesting and educational.

Most of what the guys have said goes way over my head, at the moment, will need to research and read up a bit on things they have suggested.

Cheers again Bob

Regards,

Peter.

[bernard towersParticipant @bernardtowers37738]

Filing buttons 95%of the time and soft as Andrew.

[bernard towersParticipant @bernardtowers37738]

Sorry Andrew that doesn't read very well!

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