Using a fly cutter

[Peter Simpson 1Participant @petersimpson1]

Is it possible to use a fly cutter to clean the edge of 6mm steel plate. I saw a video on u tube where a fly cutter was being used to cut out a radius on loco frames. I assume that the majority of the metal had been removed by chain drilling first. The fly cutter was then used to clean up to the scribed mark ?

[Peter Simpson 1Participant @petersimpson1]

[Brian WoodParticipant @brianwood45127]

Hello Peter,

Yes it is, but set the sweep radius to something like 25 mm or so and then cut in sweeps down the length of the edge. It will do the job across the 6 mm section but in much less satisfactory chopping actions, the other direction leaves a nicer finish.

Sharp edges are easily de-burred with a file cut file laid at an angle and used to run along the edges.

Regards Brian

[David George 1Participant @davidgeorge1]

Hi Peter you could use a fly cutter in such a circumstance but I would only use one to edge up plate as a last resort as the chipings get every where and it is more efficient to use an end mill.

David

[HopperParticipant @hopper]

End mills are so cheap to buy these days I would not mess about with flycutters except when absolutely necessary.

But a flycutter will do the job. Just takes longer and is rougher on the machine.

[Peter Simpson 1Participant @petersimpson1]

Thanks for the replies. Hopper I agree with " rougher on the machine" It must give the spindle a good shock every time the cutter comes into contact with the work.

Will go the milling cutter route

[Paul LousickParticipant @paullousick59116]

I had a previous project which required a large diameter tool like a flycutter but I was worried about the intermittent impact and the loading on the mill. My solution was to make the flycutter base from a 160mm diameter cast iron weight to add some mass to the cutter. (CI weight like the ones that you pump iron with at the gym). The weight acted like a flywheel and reduced the vibration and loading on the mill.

Paul.

[JasonBModerator @jasonb]

I quite often use a flycutter on smaller items and have never found it to be a problem, if the cutter is sharp and you don't go at it like a mad man they work well and in the long run will be far cheaper than milling cutters.

Bit of 5mm thick steel being cut earlier in teh week

Edited By JasonB on 30/12/2017 13:11:31

[Steve WithnellParticipant @stevewithnell34426]

My first lesson using a flycutter was that the typical ones sold on eBay don't have anywhere near enough rigidity or mass for anything only the lightest of work. I 'made' one one by bolting 25mm square bar (with a piece of 10mm silver steel as a cutter) to the 250mm face plate on my lathe and used that to face off some large chunks off ally. I don't think the finish would have been as good on the mill.

Regards

Steve

[EmgeeParticipant @emgee]

Another advantage of the faceplate mounted bar is that a second cutter can be added to the other end at a smaller radius so providing means of a finishing cut by projecting a few thou more than the other "roughing" cutter.

Emgee

[Brian WoodParticipant @brianwood45127]

Emgee,

I think that might be a fallacy, the tool bit to engage first with the work does the most work, in which case the roughing cutter should lead, to be followed by the finishing cutter. The clever bit has to be when the second cutter is set at a radius to just clean up the high ridge of material left after the roughing cutter has had a bite at the work.

A better way is to reduce the feed rate of the job across a single cutter to take off reduced cuts and leave a lovely shiny surface

Regards Brian

Edited By Brian Wood on 30/12/2017 15:06:46

[EmgeeParticipant @emgee]

Posted by Brian Wood on 30/12/2017 15:06:02:

Emgee,

I think that might be a fallacy, the tool bit to engage first with the work does the most work, in which case the roughing cutter should lead, to be followed by the finishing cutter. The clever bit has to be when the second cutter is set at a radius to just clean up the high ridge of material left after the roughing cutter has had a bite at the work.

Brian,

The roughing cutter will lead as it is at the greatest radius, the finish cutter will cut without disturbance from the cutting force on the rougher as it is at a smaller radius and on the opposite end of the bar.

Emgee

[Brian WoodParticipant @brianwood45127]

Emgee,

It isn't something I have tried so I bow to your greater wisdom

Brian

Edited By Brian Wood on 30/12/2017 18:20:53

[VicParticipant @vic]

I like using a fly cutter as I can remove a fair amount of material with mine and I get a great finish. What I don’t like is the chips getting thrown everywhere! I use HSS in it for Alloy and Carbide for Steel. The other thing I like when cutting alloy is that you can get an attractive radial surface texture if you traverse the part quickly.

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