Peter said he uses uncoated cutters, I would go further and say do not use coated cutters, you need cutters with a nice polished finish for aluminium to avoid the metal sticking to the cutter.

Martin C

There is no real reason not to use carbide on the lighter hobby machines if treated with care, my go to cutter for aluminium and non ferrous on the manual mill is a 10mm 2-flute aluminium specific one from ARC, keeps it sharp edge a lot longer than HSS. Carbide can also be run faster and or take a heavier cut than HSS so you get the job done a bit faster.

I also use quite a few HSS FC-3 cutters by Hertel, you can get these from MSC but flute length can be a bit limiting. So for longer the HSS or Carbide from APT work out quite reasonable price wise. For Aluminium I'd go with their 3-flute uncoated carbide and steel the coated 3-flute carbide or HSS which is what I mostly use on the CNC but they do find their way onto the manual mills more lately. I also get a fair amount of use from the NC (New Century) ones that Cutwel do in the 3-flute coated carbide for steel and CI. New Century is YH-1's factory in China but like the other ones mentioned above they are all a cut above the basic cheap cutters but not as pricy as the very high performance ones.

Good video that shows how much more a carbide cutter can remove compared to an HSS one run at the same speeds.

I tend to use mostly carbide cutters on my SX2P most of which I get from ARC, 2 flute uncoated for aluminium and coated types for steel. As Jason says they are Chinese but of better quality than the cheapies you see advertised, I know some swear by the cheap cutters and inserts that you can find but that has not been my experience. Also there is no need to go for the really expensive ones for use on a small mill, all the mid priced ones I have used have given good results and decent tool life.

I bought all my tools from China and £10 is way too expensive. Just ordered a 10 mm Co8 HSS end mill and it cost just 20 Chinese Yuan or about £2.4. All my other tools are carbide. A 10 mm carbide 3 fluter cost about £5. Globalization is one of the reason why there has not been much inflation over the last decade ( pre COVID 19 ) although governments have been printing money like crazy.

Edited By Y C Lui on 29/03/2022 09:36:17

As has been said step one is to get a reliable brand. I tend to buy mid range industrial ones as my machine is a Bridgeport.

Step two is to make best use of what you have bought within the limitations of the machine. My Bridgeport is a monster compared to your X1 but its still only specced for endmills up to 1" diameter!

There is much more to be gained by setting into a proper technique to get longest life than by stumping up the extra ££ for a super duper extra quality cutter costs over decent mid range.

Coatings are generally thermally sensitive and usually need to get hot to work properly. No point in paying the extra if you aren't going to see any real benefit because your machine cannot work them hard enough to heat up. However even if the coating doesn't get into working range the cutter may still last a little longer but this is usually more due to the base cutter being of higher quality than a simple mid range one. If a good maker is going to go to the trouble of coating it makes sense to start with a high quality cutter.

If buying off brand a certain care and feel for prices is needed to avoid the low end cutters dressed up with a pretty coating for showroom appeal. Rather like the pretty TiN coated drill sets in the bargain bin.

Normally too messy for us but decently arranged coolant, either mist or flood, is probably the best way of extending cutter life. On my Bridgeport decent but inexpensive with mist is about the equal of good (mid range industrial) dry for lifetime.

The big neophyte error is babying the cutter with tiny cuts rather than letting it cut. For best results and life you need to get close to book values. Oh and use the sides, book says depth same as diameter at 1/4 diameter width for endmilling and 1/2 diameter depth for slots so get as close as you can given the job and machine specifications. I can just follow the book, you will need to be more circumspect with larger cutters.

Fundamentally the cutter lifetime is defined in number of turns and number of passes. Crudely twice as many passes at half the feed means 1/4 as many jobs per cutter. Keep the chips clear, recutting chips still counts and conditions are unfavourable.

Don't go mad as you are machine stiffness limited but it's well worth sacrificing a cutter or three just to get a good handle on what works for you. When you have found out the best settings, whether by experiment or inadvertently mid job write them down.

The advice against carbide cutters is primarily against the insert kind. Generally the holder diameters are too large and the inserts designed for heavier cuts at higher speeds than your X1 likes. But, as with lathe tooling, there are a fair number of inserts that work fine in lighter machines at well below book speeds and cuts. There are also some that will leave a ploughed field finish if used off book. Experimentation is expensive!

Normal endmills in carbide will be fine. Handle with care as they are very sharp. They don't like vibration which can lead to edge chipping. Given the much greater durability of the sharp edge relative to HSS this is the one time where going light on cuts may be an advantage with a small machine which doesn't have the mass to tamp down vibration.

Carbide shanks are "more slippery" than steel ones so they don't hold as well in collets. Collet needs to be pulled up well. ER are better than Morse or 5C but you should use book torques. Don't even think about bodging one into a drill chuck to save changing the chuck out. It will walk straight out under cut! Learned that the hard way many years ago when I "only wanted a quick counterbore" on a drilled hole. My carbides are weldon flat types.

Clive

PS Sorry for repeating some previous advice. Slow typing. + 1 Andrews recommendation for Cutwel, a very good supplier.

Edited By Clive Foster on 29/03/2022 10:13:58

I buy end mills now from Ali******s as seen here in the photo,
the 4 mm are about £1 each and the 6 mm £2 each
delivered ,they are most probably the best cutters i have ever
bought .

At least one of the suppliers mentioned on this thread
had supplied me with cutters in the past that were blunt,
after an exchange of words with the proprietor he actually
admitted that he knew of the problem and came out with
the old excuse lots have others have had them and not
complained .I sent them back and was refunded i only wish
that i had sent back the supposedly ball end mills as well
as the were also rubbish.

These Ali******s mills are carbide TiAIN coated and most
on here would call them cheap cutters ,perhaps it would
be as well to remember that all of the cutters that you
buy over here are most probably also made in China.

John

Dont be put off and think that carbide cutters are not suited to your SX1 as I mentioned most of the cutters I use on the SX2 are carbide and that is also a small hobby mill. I also use the ARC 10mm Carbide 2 flute uncoated cutter (as Jason shows) and mine is still good after 3 years. The thing to remember is your mill is a small hobby machine so dont ask it to bite off more than it can chew take it easy to start with and put in some practice. Also I would suggest not getting hung up on what the books tell you re feeds and depths of cut etc. You will soon find that the machine and the cutter and the finish will tell you what its happy with .

I find Drill Services is another good UK supplier.

Tony

Welcome to the forum David.

I dislike the word 'quality' in engineering because it's meaningless without a specification. Cutting metal is a science. Professional tool catalogues don't mention quality at all. Cutters are chosen to optimise an economic work-rate. A huge range of cutters are available to meet production needs from inexpensive disposables to extremely costly items made to cope with difficult materials. Professionals try to define Value for Money and Fit for Purpose. They don't waste cash on expensive tools or buy brands recommended by a bloke on the internet!

At home metal cutting is more art than science and many Model Engineers are self-taught: I still wish we would avoid the 'Q' word.

Four things cause machining bother: the material, machine, cutter, and operator error:

• Avoid scrap! Instead, buy metal where the spec mentions 'free-cutting' or 'Good Machinability'. Makes a big difference, ordinary mild-steel is prone to smear, making it difficult to get a good finish. Work-hardening stainless ruins cutters in a blink. Leaded mild-steel is much better!
• All machines have an envelope within which they work well. Determined by size, rigidity, power, and whatever features it has. Easier for operators to get results with a heavy, rigid, powerful industrial machine with all the bells and whistles than a small lightweight basic hobby-machine but, with practice and patience, hobby machines do just as well.
• Cutters are chosen to suit the job and the machine. I own a WM18, 1100W out, max speed 2500rpm. It's not fast, rigid, or powerful enough to get the best out of carbide so I have only two carbide cutters, a 4-flute 10mm used for roughing out steel, and an insert boring tool. Otherwise, all my milling cutters are mid-range HSS bought from established UK hobby suppliers, who usually respond well if they happen to sell a dud. I have both 2 and 4 flute cutters. 2 flute are for plunge cutting and slotting. For other cuts, 4 flutes remove metal faster. I avoid internet and exhibitions 'bargains', because they're anything between top-end surplus to cheap and nasty. Too cheap is one way of conning customers, another is reassuringly expensive! Fewer tears when a mid-range tool is ruined and the money saved can be spent on something else. When better tools are needed I cough up, but not before.
• Many problems are caused by the operator! David mentions poor finish 'even at a very slow cutting speed and shallow cutting depth'. Unfortunately slow, shallow cutting is an excellent way of blunting cutters, ruining them. Don't do it. Tools should cut, not rub, requiring the operator to get RPM, depth-of-cut, and feed-rate about right. Pussy-footing and over-heavy cutting are both sins, the first because it blunts tools, the other because it cooks the motor, stresses the drive-train and bends the machine. Mincing swarf under cutters also blunts them quickly. Lubrication improves finish and tool-life. Messy flood cooling extends tool-life considerably, but is only worth it, I think, when removing lots of metal quickly.

Tools didn't stay sharp long when I was learning – poor technique. I could have wasted a lot of money ruining expensive cutters! Instead, I practised on mid-range and found they last when used properly. I start with RPM = 10000/tool diameter in mm (about right for mild-steel), cut-depth a bit under 20% of tool diameter, and feed-rate increased until the machine is heard working moderately hard, not labouring.

HSS is often coated with a layer of extra-hard material to keep them sharp about 15% longer. Aluminium tends to stick to the coating, so uncoated is a better choice for it. I use TiN coated HSS for everything, but take care aluminium doesn't stick to the cutter because it wastes time.

Not much of the above depends on 'quality'. More to do with the operator understanding how his particular machine relates to the materials he works with and the required finish and accuracy. Rather than buy expensive high-performance tools that aren't needed, I buy mid-range and go up market only if they're not good enough.

In the good old days, cheap tools were rubbish and it paid apprentice craftsmen to buy the best they could afford and make it last. Not how the modern world works. Now tools are expected to do a job for a reasonable amount of time, and are then replaced. What's meant by a 'reasonable amount of time' is specified, allowing cheaper tools to be used when long lasting tools aren't necessary. Or money to be begged/ borrowed/stolen when only the best will do! How long your tools should last needs thought. A sad feature of the forum is relatives selling off workshops full of tools that lasted longer than the late lamented Model Engineer.

How best to self-teach is tricky. I like books and magazines – not for everyone. Much of the Workshop Practice Series is excellent except modern stuff like carbide and DROs are missing. Jason Ballamy's book is up-to-date. I've found the forum excellent because it allows question and answer.

Be wary of Internet videos. Often an inglorious mix of good and bad in the same clip, together with product placement, misunderstandings and duff opinions.

Dave

I make components of smallish size and I'm not really interested in cubic inches per minute metal removal.

I do practically all my milling in the lathe (Warco WM250V) with a Myford double-swivel milling slide.

If I'm cutting steps and flats I use an 8 mm 4-flute carbide endmill – I've had it at least 6 years and I think it cost me 12 quid from Gloster Tooling. It's still sharp and produces a decent finish on anything I've tried it on – silver steel, titanium, ali, brass, phosphor bronze, several kinds of hardwood.

Flycutting for larger flats uses a standard 3/8 or 1/2" boring bar with a 3/16" 45 degree HSS toolbit. So long as it's sharp, it producesa a silky finish.

For slots I use a 2-flute HSS or carbide slot drill – I've got several sizes and none were expensive.

Some times I do parts for the railway and milling is mostly cutting hexagons in a divvy head on a Bridgeport. There's a 2" diameter 5-insert face mill I usually use if I can find it. There's sometimes a fair bit of metal removal to do there, but then it really isn't model engineering…

Edited By Mick B1 on 29/03/2022 16:29:36