Not sure about this Flycutter

[GreensandsParticipant @greensands]

I have recently acquired this carbide tipped flycutter mounted on a 3/8″ diameter shank gripped in a nicely made holder but when I came to use the tool I realized that as fitted it did not have the required clearance to make the cut. Is this a case of an incorrectly fitted tool or am I missing something. Most flycutters I am familiar with are fitted on a square section shank. Any views on the topic would be of interest.

[FulmenParticipant @fulmen]

What happens if you rotate the cutter 180°?

[old martParticipant @oldmart]

It certainly looks as if the flycutter is meant to rotate backwards, is that the picture reversed?

The choice of background is unfortunate, but it looks like the first part of the cutting edge to make contact is the inboard side. There is no way that the relief can be judged from that photo.

More info is required, please.

[JasonBModerator @jasonb]

Looks more like it is set up for boring than flycutting and running backwards at that.

[old martParticipant @oldmart]

It would certainly work boring in reverse, but adjusting the size would be a nightmare.

[GreensandsParticipant @greensands]

Hopefully these photos taken against a white background will make things a little clearer. The additional view is with the cutter rotated through 180 degs

[FulmenParticipant @fulmen]

The fact that it’s assembled to cut in reverse should at least make you go “hmmm, that’s odd”. Not that it’s anything wrong with running a cutter in reverse or anything. Some of my favorite cutters do run backwards. No, really  🙂

But alas, it doesn’t help much.

 

[HopperParticipant @hopper]

It looks like a right hand thread on the shank, so you would expect the spindle rotation to be in the normal direction with the tool mounted as in the upper picture of the above pair.

How is the tool clamped? Don’t see a grub screw etc in the pics?

It definitely looks more like a boring tool than a fly cutter. It could be off something like a small engine (motorcycle etc) cylinder boring machine. Some of them were fairly crude and cutters were set by a gauge by clamping the cutter to match the gauge. Or it  could be somebody’s one-off special tool.

Does the thread match that used by holders for threaded milling cutters in Clarkson Autolok holders etc?

[GreensandsParticipant @greensands]

The thread is a standard right hand M10 and is a very nice fit into the Clarkson Autolock collet but as the photo makes clear the proportions are not right for genera use in an Autolock. The cutter is held in place by a grub screw as illustrated. I am coming around to the conclusion that the tool is designed for use with a boring head and not as I first thought a flycutter

 

[Ian PParticipant @ianp]

Not sure how this device would be used with a boring head, as they normally have plain parallel holes and take boring tooling direct locked in with grubscrews.

Milling machines, or lathes for that matter, do not have spindles with an internal M10 thread so not likely to be what this tool was intended to be used in.

The carbide tipped cutter might just be an oddment filling a hole and stopping the grubscrew getting lost

Does how it was acquired give any clue to its purpose?

Ian P

 

 

[David George 1Participant @davidgeorge1]

I have a small fly cutter. A 1″ diamiter body and a 1/2″ shank and takes a 1/4″ diamiter cutter which I use either HSS or solid carbide diamiter with an edge ground on. It works great and has for the last 45 years.

 

David

[Martin of WickParticipant @martinofwick]

Clearly, the tool will not ‘flycut’ a surface in current form because the bit shank will always be in contact with the job surface before the carbide bit cutting surface. Most likely an extemporary workshop made  boring tool, possibly other cutter shanks were also available but were lost.  Would readily convert to a basic fly-cutter using some round HSS of 3/8 diameter with a suitably ground cutting face. Or, make up a carbide tool(s) of your choice using some 3/8 bar. A useful tool holder.

[old martParticipant @oldmart]

If that cutter body is going to be used with a Clarkson Autolock, be sure that the threaded shank has a centre in the end, the same as all threaded shank endmills. Otherwise you risk breaking the Clarkson. I would not be happy to use it with only a wet noodle 10mm shank stiffness. It needs to be screwed into a substancial holder that uses the full diameter of the body to stiffen it.

[GreensandsParticipant @greensands]

Scanning through Ian Bradley’s book “The Amateur’s Workshop” may have provided the answer to the intended application of this tool holder. As illustrated, it does makes a very good fit in the small Myford catch plate when used as a fly cutter and overcomes any potential problems of lack of rigidity if contemplating use of a Clarkson Autolock or a parallel shank arbor. The problem of the lack of tool clearance still remains of course with the existing cutter but I hope to overcome this by grinding up a new tool on a fresh length of HSS tool steel.

[Graham MeekParticipant @grahammeek88282]

The tipped cutter above was originally intended to go in a pre-set boring bar. When I was at Rank Xerox we used to make special boring bars for the CNC Mills which finished several diameters in a bore in one pass. The cutters could also be arranged to chamfer the outer edge of the bore as the boring operation neared completion.

The cutters can be had in solid carbide. I would expect the lack of relief on the cutter shown for two reasons. One it is carbide and the other is it was probably intended for quite a large bore. Smaller bores tended to use the solid carbide cutters and these had secondary clearance ground in. The cutters could also come in Rt and Lt hand, just to confuse things.

Some of the larger boring bars had individual micrometer adjustable cutters. I should know the name of these cutters but at the moment I am struggling to remember.

Regards

Gray,

[JasonBModerator @jasonb]

“Microbore” Like this one of mine

[old martParticipant @oldmart]

It looks like the answer is the custom CNC boring head attachment. However, the Myford catch plate would fit directly on one of the British made mills vertical head which had external threads as well as internal toolholding. I forget which mill it is, but somebody will know straight away.

If you heat the end of the cutter, the carbide will come off and it could be silver soldered or brazed onto the end of a suitably angled replacement. That would make touching up the edge much easier.

[Graham MeekParticipant @grahammeek88282]

Thanks Jason,

“Microbore” put me onto the name I was trying to remember, “Devlieg”. Working on the Devlieg Horizontal Borers in No1 Shop at Dowty Rotol was the first time I came across these cutters. They used to be had in all sorts of different shapes. Adding the carbide insert to the design is clearly a modern upgrade.

Regards

Gray,

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