Carbide Insert Designations & Suppliers

[Peter SpinkParticipant @peterspink21088]

Posted by magpie on 10/05/2020 10:04:40:

My fly cutter. I get a really great finish with this one.

Is that an 8mm square shank?
Been looking for one just like that so could fit my present flycutters.

May I ask where from?

Edited By Peter Spink on 10/05/2020 19:38:23

[John HinkleyParticipant @johnhinkley26699]

Peter,

JB Cutting tools do a "button" insert holder in 8mm. It uses an 8mm diameter insert. If you want a larger radius, you'd have to get a larger tool and grind it down. Or a carbide end mill might do the trick, too.

JB tool 8mm shank

By the by, I bought a box of 10 CCGT polished inserts at last year's Doncaster show (from the JB stand) ostensibly for machining aluminium, but just lately I've been using them more and more on steel. Once I got the speeds (high) and feeds (low for my lathe),right, the finish was really good. Incidentally, I use a righthand insert tool in my flycutter with good results. Not that I use it very often.

John

[Michael GilliganParticipant @michaelgilligan61133]

Posted by ChrisB on 10/05/2020 19:05:09:

Look like you did not get the gist of Michael's post Vic

That's supposed to be a flycut finish, but as you say its a brushed finish…

.

Only just got back to the forum … so Thank You, Chris

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 10/05/2020 19:36:50:

1000s of passes with a very small step over

.

… and the tool mounted on an arm of infinite radius

[Peter SpinkParticipant @peterspink21088]

Posted by John Hinkley on 10/05/2020 21:35:06:

Peter,

JB Cutting tools do a "button" insert holder in 8mm. It uses an 8mm diameter insert. If you want a larger radius, you'd have to get a larger tool and grind it down. Or a carbide end mill might do the trick, too.

JB tool 8mm shank

By the by, I bought a box of 10 CCGT polished inserts at last year's Doncaster show (from the JB stand) ostensibly for machining aluminium, but just lately I've been using them more and more on steel. Once I got the speeds (high) and feeds (low for my lathe),right, the finish was really good. Incidentally, I use a righthand insert tool in my flycutter with good results. Not that I use it very often.

John

Perfect John,

Many thanks

Peter

[JasonBModerator @jasonb]

Michael, no, the lines are what the stepover leaves at the edge of the diameter of the cut so size of tool would not matter. Totally impractical but would give straight marks on the surface.

Peter, those plain shank flycutters are usually 1/2" or 12mm shank so that tool looks to be 6mm sq

John, how do you get on with aright hand tool when I put one in my flycutter it would need to run in reverse and it also puts the insert off of the radial line so you end up with negative rake.

Left

Right

Left lined up well

Right not lined up

[Dr_GMJNParticipant @dr_gmjn]

Jason – that’s posed another question: As you suggested I bought a plain-shank fly cutter holder (still waiting for it). Presumably the angle that the tool holder is held at is a standard, and the geometry of my DCMT holder will put the insert’s cutting edges and clearances at the correct angles to the work? I guess the nose radius takes care of any slight angular differences, because it will touch the workpiece at a tangent? Would a square rather than rhombic insert holder place the insert’s tip at a different angle for example?

Also, I guess depending on the width of the fly cutter’s slot, I might have to shim the tool to align the cutting edge with the centre of the spindle?

Thanks.

[JasonBModerator @jasonb]

My main worry since you said you had DCMT is that the more pointed shape of the blade may act like a wood plane if the depth of cut is too high and peel a burr off the top. The larger the tip radius the less likely this will be and it will also be more durable as the more commonly use rhombic and round inserts are a bit more robust and present an obtuse angle to the work rather than the DCMTs accute.

A mm or two due to tool thickness won't be much of an issue

[Peter SpinkParticipant @peterspink21088]

Posted by JasonB on 11/05/2020 07:00:12:

 

Michael, no, the lines are what the stepover leaves at the edge of the diameter of the cut so size of tool would not matter. Totally impractical but would give straight marks on the surface.

Peter, those plain shank flycutters are usually 1/2" or 12mm shank so that tool looks to be 6mm sq

John, how do you get on with aright hand tool when I put one in my flycutter it would need to run in reverse and it also puts the insert off of the radial line so you end up with negative rake.

Left

Jason thanks for pointing that out – my flycutter takes 1/4" square toolbits (slot is about 8mm) so I would need a 6mm toolholder and shim it to get the cutting edge on the centre line. I don't think the CCGT button inserts are robust enough generally for interrupted cuts but maybe OK for a very fine finishing cut on Ally?

Edited By JasonB on 11/05/2020 10:01:29

[magpieParticipant @magpie]

Posted by magpie on 10/05/2020 10:04:40:

My fly cutter. I get a really great finish with this one. Sorry if I misled folks. After I finished cutting, I laid a sheet of 400 grit on a piece of glass and dragged the items once over the length of the sheet, that was all that was needed to remove the cutting marks.

Obviously RPM and feed rates will affect the finish, but being a complete novice I usually try new ideas on a bit of scrap first in order to find what gives me the best results. I thought of using this tool because I am not too good at grinding HSS tooling and a good friend had recommended a fair radius for fly cutting. The parts shown were for my fibre optic clock, the subject of a build thread in the clock section.

Dek.

[John HinkleyParticipant @johnhinkley26699]

Jason,

I'm afraid I got my lefts and rights mixed up! This is my set up:

As you can see, it uses an 8mm LEFThanded tool holder, which puts ithe cutting edge, as near as dammit, on the centreline. Good enough for my purposes, anyway. An HSS tool of the same width would have similar alignment, unless ground with a distinct offset. Maybe my flycutter has the toolholding groove machined in a different position (it's a commercially made item).

As you can see below, it's fitted with a polished tip, but can't remember when I last used it!

Hope that's cleared up any confusion.

John

[JasonBModerator @jasonb]

One for Michael. Straight lines left you a flycutter swinging a 50mm dia, sorry I did not do the whole surface aut even with this exaggerated stepover of 0.005" it takes a while. None of those toolmarks can actually be felt with a fingernail.

[Dr_GMJNParticipant @dr_gmjn]

Posted by JasonB on 11/05/2020 08:14:11:

My main worry since you said you had DCMT is that the more pointed shape of the blade may act like a wood plane if the depth of cut is too high and peel a burr off the top. The larger the tip radius the less likely this will be and it will also be more durable as the more commonly use rhombic and round inserts are a bit more robust and present an obtuse angle to the work rather than the DCMTs accute.

A mm or two due to tool thickness won't be much of an issue

Sorry that's confused me a bit – the diagrams show a side view of the fly cutter, feeding right to left?

Isn't feed rate therefore as critical as depth of cut for the planing effect you suggest might be an issue with the DCMT inserts?

I'm about to order a few DCMT 070208 inserts for the fly cutter, and try those.

Also some DCGT 070202 to try for fine work.

Thanks!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 11/05/2020 07:00:12:

 

Michael, no, the lines are what the stepover leaves at the edge of the diameter of the cut so size of tool would not matter. Totally impractical but would give straight marks on the surface.

.

Really ? …. I will need to think that one through

Are you proposing traverse in both X and Y, or am I missing a trick ?

MichaelG.

.

Edit: Just seen your follow-up 

 

Edited By Michael Gilligan on 11/05/2020 14:20:45

[Michael GilliganParticipant @michaelgilligan61133]

Posted by magpie on 11/05/2020 08:58:24:

.

Sorry if I misled folks. After I finished cutting, I laid a sheet of 400 grit on a piece of glass and dragged the items once over the length of the sheet, that was all that was needed to remove the cutting marks.

.

It’s fine. Dek. … I was only having a bit of fun.

MichaelG.

[VicParticipant @vic]

I’ve got quite a few RCGT06 inserts so I made a holder for them for my flycutter and they work very nicely on Aluminium Alloy.

[JasonBModerator @jasonb]

Posted by Dr_GMJN on 11/05/2020 13:36:43:

Posted by JasonB on 11/05/2020 08:14:11:

Sorry that's confused me a bit – the diagrams show a side view of the fly cutter, feeding right to left?

Isn't feed rate therefore as critical as depth of cut for the planing effect you suggest might be an issue with the DCMT inserts?

I'm about to order a few DCMT 070208 inserts for the fly cutter, and try those.

Also some DCGT 070202 to try for fine work.

Thanks!

Feed rate eg side ways movement would not effect things. If your depth of cut – vertical movement becomes more than the tip radius then you run the risk of what I showed in the sketch, all the time DOC is less than radius you are cutting more like the RCMT insert, the 0.8mm will be less likely to do this.

I got as far as changing tips as I was going to see if the problem actually happened but all my flycutters are 8mm slot and my DC** holders 10mm sq.

[magpieParticipant @magpie]

Posted by Michael Gilligan on 11/05/2020 14:19:38:

Posted by magpie on 11/05/2020 08:58:24:

.

Sorry if I misled folks. After I finished cutting, I laid a sheet of 400 grit on a piece of glass and dragged the items once over the length of the sheet, that was all that was needed to remove the cutting marks.

.

It’s fine. Dek. … I was only having a bit of fun.

MichaelG.

[Dr_GMJNParticipant @dr_gmjn]

Posted by JasonB on 11/05/2020 16:03:48:

Posted by Dr_GMJN on 11/05/2020 13:36:43:

Posted by JasonB on 11/05/2020 08:14:11:

Sorry that's confused me a bit – the diagrams show a side view of the fly cutter, feeding right to left?

Isn't feed rate therefore as critical as depth of cut for the planing effect you suggest might be an issue with the DCMT inserts?

I'm about to order a few DCMT 070208 inserts for the fly cutter, and try those.

Also some DCGT 070202 to try for fine work.

Thanks!

Feed rate eg side ways movement would not effect things. If your depth of cut – vertical movement becomes more than the tip radius then you run the risk of what I showed in the sketch, all the time DOC is less than radius you are cutting more like the RCMT insert, the 0.8mm will be less likely to do this.

I got as far as changing tips as I was going to see if the problem actually happened but all my flycutters are 8mm slot and my DC** holders 10mm sq.

Ah I see. I was assuming a 0.8mm nose radius. I'll try some depths and see what happens. Around 0.3mm / 0.5mm should be ok for a first go I'd have thought?

Thanks.

[JasonBModerator @jasonb]

Yes with the 0.8mm inserts

[Dr_GMJNParticipant @dr_gmjn]

Yep. As suggested, I ordered a few inserts today to play around with: DCMT 0.4mm & 0.8mm, DCGT, 0.2mm radii. Hopefully all the stuff I’ve ordered will be here by Wednesday afternoon when I’ve got 1/2 day off and I can make more progress. Cheers.

[old martParticipant @oldmart]

DCMT 07 are cheap and easily available on ebay from China, if you are willing to wait 10 days, Inserts for steel and for aluminium are much better quality now compared to ten years ago.

[Dr_GMJNParticipant @dr_gmjn]

I should have posted this here I guess, just to say what I did as a result of the advice given (it's also in another thread). I got a selection of 4 types of insert from Cutwel. Ordered 16:30 yesterday, arrived this morning. DCMT, DCGT, 0.2mm and 0.8mm nose radius, some for cast iron, some for non-ferrous and others for steel. There was an online chat thing, so I was able to confirm I was getting the best inserts for my tools and what I wanted to do:

So the small fly cutter holder arrived today. I put my Sandvik 8mm left hand tool holder in it, fitted with a DCMT 070208 insert for steel, and had a go at fly cutting for the first time. Must say I was really happy with the results, finally a bit of progress. Workpiece was the same mild steel I've been using for the vice clamps. I went up to 0.5 mm cut depth with no issues.

The only slight problem was vibration due to the tool holder being long. I ground it down a bit and that resolved that. The grub screws in the holder appear to be made of cheese, so having got the tool well and truly stuck, I spent a good 30 minutes drilling them out and replacing with caphead screws, which was fun.

Missed the postman due to work, so the milling cutter test will have to wait, but in the meantime, for the 10V castings, what do folks recommend for facing: milling or fly cutting? I did get some DCMT070208 inserts for iron too.

Thanks.

As an addendum to this, I'm a bit unsure as to feed rates and spindle speeds. Pretty much everything within reason worked without any complaint from the machine. I got the impression I might have been running at too high an rpm though, becasue the chips appear to be blued by heat.

Still, I faced my remaining vice blocks, and got much better surface finish than milling, and parallel over 25mm x 40mm to within 0.0006" according to a my micrometer, over an average of 5 measurements. Sorry to mix units!

[Chris GeorgeParticipant @chrisgeorge68271]

I am glad I found this thread, Im looking to get carbide tips and was wandering where to start looking. Thanks for the info..

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