Thread: Carbide tooling Chinese lathe

Not really.

You may find that the Carbide dosent leavve a great finish on your mild if you cant run it at the speed and feed or depth of cut it likes,this may be better suited to HSS.

The other materials should be fine.

Only consideration you really have is the tip geometry you want,these smaller lathes seem to like a small nose radious .2/.4.

The other thing to consider is the shape of the tip,might be cheaper for you to try and get tooling that uses the same size tips or at least limit it to a couple of different tips rather than numerous different sizes/shapes.

Hi there and congratulations on your purchase!

When I aquired my lathe I had ZERO experience with any machining. After looking at tool geometries required for tool sharpening I figured id go the "easy" road and just buy indexable tc inserts and learn about hss tool sharpening along the way. But alas there are inherent issues using tc on smaller lathes as mentioned. You are seriously limited with minimum DOC. With my experiences, anything less than about 0.2mm DOC and the tool finish is compromised and the tool tends to rub or combination of tub and cut causing a less than satisfactory finish. Needless to say, sneeking up on a final dimension to within a tight tollerance is all but impossible. I find myself mostly using hss now but use tc when I need to remove large amounts of material and then switch to hss close to the final tollerance.

With hss the home hobbyist has such flexibility. One piece of hss can be made into any tool you need or desire. If you break it then regrind it and its good (never happens to me of course ))

Im a novice compared to many here so be interested to others views. I personally have managed far superior finishes on a correctly shaped hss tool than on tc indexable tooling.

Cheers

Simon

Originally Posted by newmanwoodlands

I have just purchased a HAFCO AL-320G lathe and require suitable tooling. I have read various articles where people suggest that carbide insert tooling is not the best option for small lathes. Most cite cost as the main issue. Leaving cost aside, are there any other reasons why carbide is not suitable? As a woodworker, carbide is almost a no-brainer when it comes to saw blades, router bits etc. Does the same apply in metalworking? I plan to work mainly in steel (mild & medium carbon) with perhaps some stainless, brass and aluminium. Thanks, Kevin

I am not an expert but I will explain what I know.

Carbide tools need fast traverse and heavy cuts to perform at their best. They also require rigidity as they are brittle. This is why most hobby style Chinese lathes don't work well with carbide. I have a Chinese lathe, but it is industrial size and quality. Carbide is a delight to use on it.

Before this lathe I had an old well worn Nuttall Australian made 16 x 30 lathe. It was big and solid. I bought a set of cheap 20mm shank carbide tool holders. They were useless. The carbide was very brittle and the wear in the lathe made them chip almost immediately. I got hold of a Seco holder with Seco tips. These worked pretty well. Huge improvement. The main problem with movement in the lathe was due to the toolpost not sitting flat due to over tightening and I suspect a crash. The details can be found in my "New Lathe" thread. I fixed the problem and then found that the cheap tools would work better.

My point here is that you need rigidity, and those cheap sets such as this one 12mm 1 2" 9PCE Indexable TIP Metal Lathe Tool SET Free Postage | eBay should be avoided at all costs. Compare the price of their tips with top quality tips and you will realise that in the long run they are very expensive. I was paying $9 per tip. These tips are also not made to industry standards like all the rest. I can buy replacements for my Seco's from any tip maker.

I won't comment specifically about your lathe's ability with carbide as I have no experience with hobby sized ones except for one that made yours look big, that a mate owned.

While you are thinking about tooling have a look at the Diamond Tool Holder at http://eccentricengineering.com.au/. Pricey to start with, but the advantage is the ease of sharpening. It uses standard HSS and anyone can sharpen this very quickly with the supplied grinding jig. It is available in right or left hand and can be used for threading with extra grinding with anothe jig, also supplied. This operation requires some fiddling. You need to adjust the jig to get the correct angle. Either 55 or 60 deg. Once this angle is ground on one side, this piece can then be used with normal sharpening until it is ground down to nothing. The tool holder has a built in centre height adjustment. Set to approximate height then use the tool to fine tune. This tool also has a self retracting safety feature built in.

Dean

Hi kevin,
When it comes to woodwork carbide is used much like steel, it is sharpened to positive rake angles, and since it is cutting a soft material it holds up well. To get carbide to "cut" steel in needs to be comparably blunt, to the point where it does not really cut (there are plenty of high rake carbide tips that do-but they are really designed for aluminum) but push the material off. Because of this they require more HP and a more rigid machine than HSS needs.
Many many people use carbide on small lathes, and very well. But once you have seen carbide working properly on a bigger lathe you really appreciate just how poorly it works on a small machine.
My suggestion is get a Diamond tool holder from eccentric engineering. This will take the hassle out of sharpening HSS and let you get some turning done.

If you do want to get some carbide, stick to postive rake tooling, tips like CCMT, TCMT.

Cheers,
Ew

Edit, Dean you no longer have to grind the side of the tool bit down for the DTH. I however think the rake angles supplied on the blank by Garry are a bit high.

Avoid those crappy cheap sets of holders like the plague.

To dip your toe in the carbide water I would suggest a CCMT holder from someone like CTC. Order some spare screws while you are at it.

SCLCR/L INDEXABLE TURNING TOOL HOLDER #I28
KORLOY CARBIDE INSERT CCMT NC3020 (10 PCS) #J01

Don't listen to those guys when they say they are not experts or they novices! They know a hell of a lot.
Me however, I know very little. Although, I am also new to the lathe world, I've owned my lathe for abou two months.
I ended up buying a starter kit for my 9x20 Chinese lathe from littlemachineshop.com
It came with carbide holders, and a quick change tool post. I was intimidated to use HSS becuase I had no idea how to grind it, and it was too much to handle at the time.
So I've been practicing with carbide bits.

I have learned however, that the finish is not fantastic with it, and as they said you need to cut deep and fast to get a nice finish, which my lathe does not really like. So I bought a HSS kit from CTC on ebay. It comes with a few different sizes of HSS bits and I've watched some youtube videos on how to grind. I'm not perfect at grinding, but I'm not building an aeroplane, so the finish is pretty good. Its much nicer to cut with HSS than carbide, and its not really that hard to learn.

I don't regret using the carbide or buying the carbide, I like having it there, and I've pulled it out on a few occasions still, and its good to have when you cant fire up the grinder in fear of waking the house up.

If the whole thing is all new to you, maybe best to practice on carbide, get familiar with your machine, as its one less thing you have to worry about, and then you can move up to HSS when you're ready.

I would like to put in my two bobs worth about http://eccentricengineering.com.au/.
I have an old, old flat bed patternmakers lathe which is basically a glorified wood lathe.
It spins way too fast for steel cutting but I cut steel on it anyway, up to 50mm diameter.
The reason I can do it is because of the Eccentric holder.
I was bit surprised when I got it, it seemed so tiny compared the other tool holder lumps.
This old lathe has a 4" tool post on it.
But with the Crobalt cutting tool, I had no problem with turning 50mm Dia bright steel.
The HSS would burn almost immediately, mainly because of the speed the lathe runs at.
A little trick I found that helped me was I could put 9mm HSS by packing the Eccentric holder out,
and larger tooling did not burn and held it's edge a lot longer, with a bit of care.
I was forced into it because I had run out of 1/4" Crobalt.
Some may say that's mad, and are probably right but the seemingly delicate tool holder took it, no worries.
10 out of 10 for the Eccentric.

I almost exclusively use HSS for both turning and milling.

The only time's I have used carbide is when I've turned or milled cast iron or needed something to get around a lack of the right tool for a job. For instance I recently needed to cut a large diameter hole in some 3 mm aluminium sheet. The choice was either precise or quick. I could have used the boring head, it would have been precise but taken a little while to set up. I chose quick and pressed a carbide wood router bit into service.

16062014-013.jpg 16062014-010.jpg

These two pictures show the 3 mm thick aluminium plate that needed a large 32 mm diameter hole drilling in it and the router bit that I used to do it. The speed was relatively slow at 1000 rpm compared to the same bit used in wood. In this instance I first put a pilot hole in the plate to clear the nose.

Another example ! I picked up an old cast iron barbell weight from the scrap yard and decided to use it as a base for a tapping stand, so I needed to face it on both sides. Cast iron has a skin which is usually much harder than a HSS tool bit ! The trick is to get a depth of cut such that you can get underneath this skin. Unfortunately not always possible. The barbell weight had raised lettering embossed on both sides. Carbide will survive much better than HSS under these conditions.


TS01a.jpg Base-01.JPG

These two pictures show the finished tapping stand with the base made from the barbell weight turned with a brazed carbide tipped lathe tool. The second picture shows a cast iron base, approx 3" diameter turned with a HSS lathe tool. You can see the change in material composition as a darker area round the outside.

I use indexable inserts on occasion, but mostly HSS. I don't have a 'small'? lathe like the AL-320, mine would probably be classed as miniature (280 x 700), but I still use them on occasion. I've never had a problem with poor finish though, I find the finish superior. I have more of a problem with the inserts being so brittle. To be honest I don't think the cheap Chinese inserts are worth the trouble... The decent ones are just too expensive for a hobbyist like me to justify though. One day, no doubt, I'll get sick of them breaking and buy a decent set.. Many years ago I bought a set of cheapies from the Pooraka markets in Adelaide, the inserts were brilliant - hardly ever broke one. Unfortunately the business was burnt down and I haven;'t been able to get any decent ones since.

There is another point right there. Th more rigid the machine the longer the inserts will last for. Any flex of the machine moving the cutting insert in, out or down (not likely to go up is it!) Will knock the corner off before you know it.

Don't underestimate eBay for good quality brand name inserts at good prices.

Ew

Problem is, every manufacturer has to have their own shape and design, you really have to also buy the holders. I have two sets now, neither are compatible. It'd be nice if there were a standardised size and design. Wishful thinking!

You can use any ISO insert in any matching ISO holder. All of ctc tools and Taiwan tools holders are ISO. Ccmt goes in an sclc holder, wnmg in a mwln.....etc.

It's those cheap Chinese sets that are not ISO so you have to buy the inserts from the same guys.

Ew

Didn't know there was such a thing as Iso inserts to be truthful, one day I may get around to buying a couple of decent holders, for now I'm happy with my homemade diamond tool holder. My poor old lathe has just been a pretty blue ornament standing in the corner for a while now.

Cheap chinese inserts are not cheap to my knowledge. You can buy ISO inserts cheaper.

I had a look at Eccentric Engineering's site again today. They have bigger holders now. Up to 25mm. The picture displaying the range of left and right was upside down tho.

Dean