Minnie Traction Engine – Rotary Lathe Cutter

This topic has 13 replies, 5 voices, and was last updated 12 April 2018 at 09:22 by Malcolm Farrant.

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4 April 2018 at 11:30 #348771
Malcolm Farrant
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@malcolmfarrant93389
I need to make a rotary cutter for the various 'curved castings' on the Minnie

I may well have asked this question before, but seem to have lost it apart from the post from Brian O'Conner.on 27/9/2017

I am almost at the stage of needing this.

1. What diameter rodr is recomended ?

2. What diameter cutter should I use ?

Needless to asy any other bits of advice are very welcome.

Edited By Malcolm Farrant on 04/04/2018 11:32:03
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4 April 2018 at 11:30 #9150
Malcolm Farrant
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@malcolmfarrant93389
4 April 2018 at 11:55 #348775
Oldiron
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@oldiron
I am sure that there are many machinists on this forum could give you an answer. I am not sure how many have all the dimensions for Minnie castings. A little more info' would be of great help. I can only say that the heavier and more rigid the tooling you use the better the job is likely to turn out.

regards
4 April 2018 at 12:23 #348777
JasonB
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@jasonb
Are you talking about a cutter to do the curved underside of the cylinder and chimney base?
4 April 2018 at 14:25 #348791
Malcolm Farrant
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@malcolmfarrant93389
JasonB,

Yes that is correct.

There is no very hard material to turn, but I need to do a good job of it.

Please give me ideas for the way forward !

Best wishes

Malcolm
4 April 2018 at 14:53 #348795
Richard S2
Participant
@richards2
Hello Malcolm, Your original post on this is here-

LINK

If you need any more info on a 'Between Centres' Boring Bar, I'll sort some dimensions of the one I made.

Regards
4 April 2018 at 15:32 #348797
JasonB
Moderator
@jasonb
Well I would say that the other post was about traditional flycutters that are more often used for machining flat surfaces though they can be put to use doing curves and so can boring heads. Though having said that Mason also calls the between ctrs bar a flycutter.

I would suggest a bar of 3/4" to 1" diameter and a square or round tool bit of 3/16". Drill across the bar to take the tool bit and then at right angles to that hole for a screw to retain the cutter.

Something like this can be driven by a chuck and the other end supported with the tailstock ctr.
4 April 2018 at 16:01 #348798
Malcolm Farrant
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@malcolmfarrant93389
JasonB, Yet again thank you,

I think that gives mr all i need to make progress.

Best regards

Malcolm
4 April 2018 at 16:16 #348800
Richard S2
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@richards2
I'll get my coat !.
4 April 2018 at 16:32 #348801
Russell Eberhardt
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@russelleberhardt48058
If you drill for the cutter at about 80° to the axis rather than 90° it is easier to measure the cutting radius accurately with calipers at 90°.

Russell
5 April 2018 at 09:04 #348871
Malcolm Farrant
Participant
@malcolmfarrant93389
As always thank you all for your comments. It is now up to me to get it right !!!

Regards to all

Malcolm Farrant
11 April 2018 at 18:44 #349846
Malcolm Farrant
Participant
@malcolmfarrant93389
HELP PLEASE I'm back again.

I have the round bar, and 3/16th tool steell I need to creat my Fly cutter, all I need now is to what profile should i grind the tool.

Is it a simple V shape or or os it ground at any spesific angle.

Perhaps there is a suitable link I can find on google ?

Best wishes

Malcolm

Edited By Malcolm Farrant on 11/04/2018 18:46:00
11 April 2018 at 20:10 #349864
JasonB
Moderator
@jasonb
Assuming the work will be fed towards the chuck then you want the toolbit ground up like a lefthand hand turning tool. Something like this but when you come to mount it in the bar have it upside down pointing facing towards you.
12 April 2018 at 09:22 #349902
Malcolm Farrant
Participant
@malcolmfarrant93389
Jason, many thanks for that. I will now try and make the tool. I will then test cut, before doing any actaul casting. !!

Best wishes

Malcolm

Edited By Malcolm Farrant on 12/04/2018 09:23:29
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