going carbide on a Myford

A senor citizen said dont waste your money (but you can waste you free time sharpening and resetting hss bits)

it seems going carbide really is a walk on the wild side

ive been struggling with it for some time

I remember a machine tool ex had a harrison set up with a 3: billet of steel, the assembled crowd were fenced back and he set it going at a helluva lick, then took a fat cut and a blue swirl of swarfe shot off contunuously and dangerous. when stopped we all gasped at the mirror finish and the fact the tool and work piece were cold, and no coolant - dry cut

from then on i knew my days on a Ward 7a were numbered

So here is a vid which i hope isnt a promo but it goes a long way to demystifying some stuff, hope it helps

https://www.youtube.com/watch?v=rsFFWYo8ugw

carbide for dummies

I have lots of HSS tooling that came with the Myford. But most of my toolholders are loaded with insert tooling. On odd occasion i will use HSS but rarely.

Steve.

For hogging you can't beat carbide but HSS and Cobalt HSS still have their uses

Cobalt HSS in particular has very good high torque low speed properties for both lathe and shaper work

I still use a couple of old carbon steel tools. can't beat them for finish on free cutting materials.

Roy

No reason you can't use carbide tools on a Myford. What counts is the combination of tool and material, not the badge on the machine; and I find it necessary to choose tools on that basis.

Recently I turned a piece of right rough old steel, a portion of 18mm dia cable-drum tie-rod. Carbide tools would not work on it at all, fast or slow, without tearing. A freehand-ground but sharp HSS tool, reasonable speed and brushed-on cutrting-oil gave a fair finish despite the unpromising steel. Same lathe - an ML7.

There is a big advantage using carbide inserts in industry. The carbide can withstand higher temps generated with bigger cuts so that if there is sufficient horsepower, deeper cuts and higher feeds cuts down on the time from raw stock to finished product. The carbide is harder so it lasts longer and the inserts can just be changed out without having to stop and sharpen and since they are a standard size the tool doesn't have to be readjusted, just pop in a new insert and you are ready to go. However, being a harder and more brittle material than HSS, they cannot be as sharp or the edge will break off too easily. No problem with enough power but on a lightweight, under powered machine the sharp edge is needed. Carbide inserts can be sharpened to make them cut more like HSS but then much of their advantage is lost as sharpening them takes more time than HSS. With all that in mind, I use a combination of HSS tools and carbide inserts. I have trouble seeing the fine details so a treading insert will get me better threads than a tool that I sharpen. Boring bars with carbide inserts seem to be better for my purposes as I can get them in small enough sizes to use in my small lathe.

I use carbide; they can be brittle and expensive, but otherwise superior than anything I can shape up with hss bars.

Hi Brian,

I use both carbide tipped tools and HSS tools. Using carbide tipped tools on a small lathe has not given me any problems, you can get carbide inserts that are ground and polished. They are intended for non-ferrous metals but in my experience they work well also on mild steel. Carbide tipped tools work even if you are taking light cuts at lower speeds than industry uses. If machining castings (or other materials with hard spots) I use carbide for the first cuts and HSS for finishing

Thor

My view? Why bother with this? The clear intention is that of machine replacement (not addition).

See this THREAD

OP, it seems, would be better off simply getting on with spending his ‘up to 10 grand’ on a new machine which would be capable - without messing about with this machine which is clearly considered inadequate.

I have a Super 7 and all the tools in QC toolholders are carbide except for one tangential tool and a home-ground 60* threading tool. No problems. An existence proof that carbide works fine in a Myford.

Also works well in a mini lathe.

Ian

There are new grades of carbide coming out all the time. The latest ones are very sharp and are extremely good for finishing and you don't need high surface speed or high RPM to get a good finish. I don't use the high speed range on my S7. I have a TNMG holder, the only negative holder I use. But use the positive inserts for that holder. Ones for steel and ones for aluminium. Lately I have been using what is sold as a wonder insert out here. See .my album. They work very well. There is a new range of ground coated inserts that are very sharp and are excellent for roughing out as well. When they dull from finishing become roughing inserts. The CCGT09 and the CCGT06 inserts I use in my boring bars and external turning tools. The DCMT11 is only for the outer turning. Here in NZ quite a few of the tool companies will sell one or 2 inserts to the home hobbyist. I only use HSS for form tools that are for a specific project.

Coincidentally I watched that video yesterday. That particular guy does have a mini lathe but most of the tools in that video are for a much larger machine. With retirement approaching I considered the cost of buying inserts compared to using HSS and investigated Tangential tooling. I’m very glad I did. It has built in height adjustment which is ideal if like me you don’t want to spend £ hundreds on quick change tool posts and holders. It’s very quick and easy to sharpen and is great for cutting to a nice sharp corner. The tool body itself is also easy to make in the home workshop. I’ve also “loaded” one of mine with carbide and turned some HSS with it! I still use carbide though and particularly like the polished inserts. To keep costs down though I chose TNMG inserts as you get 6 cutting tips for the same price as an insert with only two. There is one type of carbide though that I never use anymore - parting tools. I found them pretty useless on my machine and expensive to keep replacing the tips. I also found them unsuitable for many softer materials. I invested in a T shape HSS parting tool with the chip breaker ground into the top and they work extremely well and the blades last ages so far cheaper to use than inserts. If I want to use inserts I will but much of my stuff is still done with HSS in a Tangential tool or parting tool holder. Modern high cobalt grades of HSS work very well.

Vic

Get yourself some "Stellite" to use in your tangential toolholder, it lasts much longer before it needs sharpening again.
I use it all the time and occasionally give it a lick over with one of those plastic handled diamond files to keep it keen.

Phil

I’ll give that a try Phil, thanks.

I second the CCGT style of carbide insert for use on lower powered lathes.

Designed for use on Aluminium they are good for steel to.

The rake is a bit much for Brass but the sharpness is ok for small diameter work.

Steve

Edited By The Novice Engineer on 19/08/2021 23:03:58

What I forgot to say is, that these new very sharp tools that are available today, allow such precise cutting that was very difficult to achieve in the past. There are very sharp PCD inserts that will allow sub micron cutting in stable non ferrous materials. The carbide inserts will allow 1 micron to be taken as a cut off steel. Granted these are not easy to achieve , but are possible in the right conditions. Some of the new coatings are designed to be used dry. No coolant at all, which I find very interesting in itself, and also handy for the home shop at the same time. The latest insert technology is not priced in the unaffordable range either, generally in the same range as the previous coatings etc. Like the new ccgto9 inserts are still at $18nz for the new coating insert that now lasts longer than the previous coating inserts .

Slightly off topic, but, while searching for a solution to a poor finish on my Super 7 I sharpened the HSS tool, tightened the toolpost, locked all non moving parts. Still poor so put on tipped tool. Still poor finish even on lightest cut.

The only way to go was look at the headstock and yes there was movement. 10 mins of C spanner time and the cut finish is now perfect.
How often do people check the headstock ?

Good you sorted that out. The myford, as any lathe with a tapered bush instead of bearings do need checking & keeping well lubed.

Steve.

I obtained a couple of these non-ferrous inserts a while back and was initially pleased, but then had an iffy finish on a couple of jobs in Aluminium. On close inspection, i could make out a tiny peak of alloy built up on the cutting tip which was quite a job to chip off. Once cleaned, worked fine until the next time it happened again some time after.

I can't say what grade alloy was in use as I just have a general stock that was bought at shows etc, generally was cutting at high speed, so a bit bemused at the cause of the problem. Any ideas on the reason behind this anyone? Think I purchased them from a normal on line tool dealer I use regularly.and don't remember them being cheap & cheerful!

regards. Mike