Carbide Cutting Tools for Flexispeed

[James AParticipant @jamesalford67616]

I know that this is a perennial question, but I would appreciate the benefit of others' experience.

In the past, I had a Peatol lathe and used 1/4" HSS tools on it, which I ground myself. I never seemed to do a good job of this and my efforts with the machine were dire, although this was probably more due to my workmanship.

I now have a Flexispeed and although I still have the HSS tools from the Peatol, I am considering using carbide tools instead. I have seen this set from Warco and wonder whether anyone knows what they are like. They seem almost too cheap to be true, which tends to makes me suspicious.

Any recommendations would be welcome.

Regards,

James.

[James AParticipant @jamesalford67616]

[IanTParticipant @iant]

Hi James,

Well I'm probably not the guy you were trying to contact in this post, as I personally mostly use HSS tooling myself (3/16th generally)

I do use 'tipped' tooling for a few things – initial turning of castings for instance (getting under the hard surface). However, my view is that HSS (and indeed carbon steel) tooling is generally more than sufficient for most work on the smaller (and especially older) amateur lathe.

So my advice is twofold.

It is possible to sharpen HSS tools "free hand" but does need experience to do well. Much better (if you have not already done so) to make a good tool grinding rest and guide the tool accurately during grinding. It's one of those things where you have to invest some effort and time but where it is well worth it in the longer term. You will get sharper tooling that is easier to re-sharpen and keep it so.

My second thought is that if your lathe is (shall we say) "less than perfect" – then this may be another reason you cannot get the results you are expecting. I'm afraid that if this is the case, tipped tooling will not solve your problem – and probably only make it worse!

So my advice is (for now) stick with HSS – make a simple grinding rest and learn how to sharpen your tools to a good standard. Make sure you have as little overhang in your work and tooling as possible and try small changes in your work methods (e.g. speeds & feeds) and watch how things improve (or not). It may take some practice and time to get it perfect…

But (in my view) if you cannot get half reasonable results with a simple HSS tool – then you most likely will not solve your problem by just buying carbide tipped tooling. They certainly have their uses but are not a universal panacea.

Regards,

IanT

[Ady1Participant @ady1]

I have had very good results from 10mm square carbide tooling on my 3.5 Drummond.

However I bought an 8mm set and they chip very easily indeed, I think that there's too much flex in the shank(insufficient support) and carbide won't tolerate that

I've used 5% cobalt hss with reasonable success but the action of a lathe is no different from a grinder and the life of the edge isn't exceptional

On a shaper 5% cobalt hss is fabulous

My next experiment will be with M42 hss which is meant to be extremely difficult to grind, which in theory means it should have all the advantages of hss, but lack the chipping problems of Carbide

It would be nice to have an alternative to carbide for doing those really tuff jobs. I have a bit of cleveland mo-max which Will be used in the next week or so once I chop off a wonky slice from a 6inch thick billet of unknown steel

There's also some hss stuff called WKE45 which is meant to be the Mutts Nutts but I've never used ite

Edited By Ady1 on 05/07/2015 13:04:58

[VicParticipant @vic]

Try a Tangential tool holder. You can buy them from one of the sponsors, Eccentric Engineering on the right >>>

Or make you own, they're not difficult to make.

I use a Tangential tool for 90% of the turning on my Lathe.

[John HaineParticipant @johnhaine32865]

Don't buy a "set" of carbide tools. They will have brazed on tips, will easily chip, and are difficult to sharpen when they do. If you want to try carbide then get a holder that takes indexable tips which you can turn round to get a new edge when you chip one. But like others I recommend a tangential tool holder which gives good results and the HSS tools are easy to grind.

[duncan webster 1Participant @duncanwebster1]

If you only have fairly low speeds then carbide is difficult to justify on small lathes. High speed steel is sharper and you can put more top rake on which reduces cutting load. Top speed on my old ML7 was about right for 1/2" EN1 steel cutting with HSS, so about right for 2" with carbide, but you possibly then I didn't have enough torque available. Learn how to sharpen HSS, it's a lot cheaper. I can only endorse previous comment on tangential tooling. Brilliant. I use it for machining staineless.

Brazed carbide is good for machining cast iron if it has hard spots, otherwise I used HSS, just sharpen it again after the last cut. I now have a more powerful higher speed lathe, and do use insert carbide, but not all the time, and certainly not on interrupted cuts

[duncan webster 1Participant @duncanwebster1]

I should have said sharpen it after the first cut!

[Roderick JenkinsParticipant @roderickjenkins93242]

James,

I've pondered this question for my Flexispeed. I can only endorse what the others have said. Flexispeed lathes tend to have lowish power and a restricted top speed – the headstock bearings shouldn't really be run at more than 1000rpm. For this reason sharp HSS tools with plenty of top rake are recommended. However, having said that, a large selection of different carbide tips are available these days and sometimes the convenience of readily changed tipped tooling can outway the perceived disadvantages. For example, highly polished tips with good top rake can be bought for cutting aluminium alloys. I have used these successfully to get a good finish on mild steel (although not yet tried on my Flexispeed). I was shown some stainless specific tips today that also looked like they would cut nicely. I haven't yet bought a small enough holder, I think 6mm would be suitable for the Flexispeed, but if you would care to experiment I'd be happy to learn of your outcome. JB Cutting Tools are nice people, they had a stand at the Guildford show today with a good selection of tips and holders. Unfortunately I'd already run out of money

HTH

Rod

[Nick_GParticipant @nick_g]

.

Have you considered the offerings from Eccentric Engineering.?

Not cheap I admit but they are excellent and foolproof to resharpen in you use their jig.

Nick

[Ady1Participant @ady1]

If you do use the fancy hss stuff like the cobalt mixes don't plunge cool it when grinding a tool shape, they are prone to thermal shock

Apparently fast temperature changes cause microscopic cracks which weaken the cast matrix, especially at the edges

The same goes for coolant, either flood coolant the tool or none at all, don't drip/paint coolant on the tool

[Ian S CParticipant @iansc]

Ady1's comments also apply to carbide, and with carbide because of the effect of shock cooling, its often best to use no coolant at all when machining, just let the chips come off blue.

Ian S C

[mechman48Participant @mechman48]

Concur about the Tangential tool from Eccentric eng. use mine for most of the stuff I have done / am doing. My indexible set is in the tool cabinet now.

George.

[Clive HartlandParticipant @clivehartland94829]

The Flexispeed does not go fast enough o warrant Carbide tooling, remember you need 150% higher speed to ensure carbide tooling works correctly.

Stick with HSS , just learn to grind cutters to suit the jobs you do. Much cheaper.

Clive

[James AParticipant @jamesalford67616]

Thank you all for the comprehensive and useful replies. On balance, it seems that using HSS, properly sharpened, is the more appropriate type of tool for my little lathe. I looked at the tangential tool posts and cutters, as suggested, but whilst they look excellent, for now, at least, they are a bit too expensive. I shall make myself a grinding jig for the bench grinder and fabricate or source an adjustable height tool post: I recall the frustration of fiddling around with pieces of packing under the tool bit too vividly to wish to repeat it unnecessarily.

Regards,

JAmes.

[VicParticipant @vic]

That's another advantage of the Tangential tool holder James – no need for packing just move the tool bit up in the holder.

This is how it's done on my machine with a centre gauge made for my lathe. Very quick.

I have a four way tool post and rarely use packing. The Tangential tool does most of the work and is very quick to set the height when required. my Insert tool holders have metal strip epoxied on the bottom so are always on centre height. in most cases a quick change tool post wouldn't really be so quick in my workshop, just expensive!

[Michael GilliganParticipant @michaelgilligan61133]

The general enthusiasm for the tangential toolholders is evident, and quite understandable.

[obviousely it would be possible to make a miniature version, but] Are they physically compatible with a small lathe like the Flexispeed?

MichaelG.

Edited By Michael Gilligan on 07/07/2015 09:31:29

[VicParticipant @vic]

I don't see why not but without actually trying it I can't say for sure.

The commercial ones are made in quite small sizes:

http://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=6&Itemid=19

[VicParticipant @vic]

I notice that most of the commercial Tangential holders use 1/4" HSS bits, as does my own home made unit.

My first attempt at a tool holder used 3/16" HSS though and I suggest this may be a better option for small lathes if you're making your own tool holder. The tool bits themselves would of course be a little cheaper to buy and easier to sharpen being smaller. You could even drop down to 1/8" HSS but I'm not sure how well this would work.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the link, Vic

I see that they can be provided with a usefully low height, but what concerns me is the 'tail' of tool-bit hanging below the holder … I may be wrong, but, it looks like [on a small lathe] one could only use short stubs of HSS.

I would be very interested to see photos of a tangential tool in use on something small, like a Flexispeed, or a Cowells.

MichaelG.

[IanTParticipant @iant]

To answer your question Michael – I have one of the original (medium?) sized tangential tool holders which I purchased for use on my Myford S7. I did use it on the EW (which I believe is larger than the Peatol but do not know wrt Flexispeed) but I found that to avoid fouling the tool-holder base, I had to extend it quite a way out (I'll attach a photo) which in turn severely limited the available cross-slide travel (just about halved it).

I still use the tangential frequently on the Myford (it works well on many jobs) but even on the larger lathe there are some occasions where I can't access the work. For instance, fairly slim work supported by the revolving tailstock centre is hard to get at – so I either have to swop my tooling or fit a half-centre. So whilst the tangential is a good general purpose tool, it does not suit all set-ups.

James – it may be that there is a smaller 'tangential' version that would suit your Peatol/Flexispeed lathe but simple HSS tools are really not that difficult to sharpen well with a good tool-rest and (in my view) HSS tools have a much wider range of application and are certainly a lot cheaper than a tangential. So my advice remains – learn to sharpen & correctly use HSS and only try some of these other devices once you have grasped the basics.

Regards,

IanT

[Michael GilliganParticipant @michaelgilligan61133]

Posted by IanT on 07/07/2015 17:57:17:

To answer your question Michael – I have one of the original (medium?) sized tangential tool holders which I purchased for use on my Myford S7. I did use it on the EW (which I believe is larger than the Peatol but do not know wrt Flexispeed) but I found that to avoid fouling the tool-holder base, I had to extend it quite a way out (I'll attach a photo) which in turn severely limited the available cross-slide travel (just about halved it).

.

Ian,

Many thanks for the very helpful answer.

… much appreciated.

MichaelG.

[IanTParticipant @iant]

No problem Michael

I'm not sure if it is obvious from casual inspection but (if you look closely at the photo) you can see that the cross-slide is already starting to come off the dovetails at the back and that's with the tangential clamped directly to my EW tool block. Cross-slide movement was very limited with this set-up.

The front bit of the holder (that actually grips the cutting tool) 'under hangs' the main body quite a bit and that's what I feel will cause problems on a smaller lathe (such as the EW) even with a short tool fitted.

If you have a longer tool fitted, then the under-hang problem increases because the tool slants backwards, further increasing the need to extend the whole holder forward and also further limiting the amount by which you can 'angle' the tool holder easily (for facing for instance).

So a useful tool but not a perfect solution on a smaller lathe.

Regards,

IanT

[VicParticipant @vic]

Can't see any reason why a Tangential couldn't be used on something small like the Cowells judging by the pictures on Lathes.co.uk.

[Ady1Participant @ady1]

I used a tangental knock off from a well known site a few years ago and it was good, it used a 1/4 inch tool I think, it was pretty small

Until I got a dig-in and the main shank snapped it worked very well

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