Carbide end mills in a hobby machine? your experiences please.

I take a very experimental approach to machining, ~

a surf of the web when i was starting out indicated hobby machines lacked the rigidity & speed for carbide end mills.

Thought i'd give it a go anyway.

Seems there must be a demand in the hobby market as they're available from the usual suppliers?

My philosophy on end mills,( whilst i still had some free cash ) was basically to buy whatever was going cheap, of either a known brand or from a trusted supplier.

Largely the diameter of the end mill is not that critical for general purposes unless you are slot drilling?

Anyway i ended up with a number of fairly esoteric carbides, for not much money really. Brst time to buy machines or tooling is always yesterday.

Tried a few test cuts, Seem to work at least as well as hsco ~ better in terms of a finish pass IMO.

Then i put them away & returned to hss/ hsco until such times as i really needed to use them.

Anyone use carbide EM's regularly?

Does it last on a hobby mill? Or are we looking at a quickly worn/chipped tool?

Just wondering if i'd be better selling on, or hanging on to till the need arises.

Have you found them of benefit in a hobby mill?

What if any are the issues?

As a slight aside, i seem to have a fixation with the number six in engineering.

For me itseems to equate with beauty or at least aesthetics in engineering. For example.

Six jaw chuck , six flute end mill. both elegant, .... & both probably don't really belong in a home workshop!

Hi Samuel. I have a large amount of HSS Clarkson cutters which are very good. I also have a large amount of solid carbide cutters bought in a large batch from a user that was packing in or so told. These are of extreme quality. Swiss tech & Merlin brand of which i would never have considered buying seperately as they are so expensive. I guess i got lucky with the purchase. I also got at the same time some 50mm & 63mm facemils with carbide inserts. My Milling machine is a Tom Senior which is not a mini mill, but neither is it a large machine. My experience & i have quite a bit from doing many projects is that the carbide is only to be described as fantastic.

You will get a variety of answers from others i am sure. That is just my experience of using them. I would not even think of selling them. They will last far longer than HSS. Unfortunately i am not aware that you can resharpen the carbide cuttters but may stand corrected on that comment. All my cutters are either 2-3 or 4 flute. I have no experience of using 6 flute.

I will say at times when machining soft materials like alloy & brass that i get as good if not better results from using HSS. Quite a few of my HSS cutters are now getting blunt & need a resharpen which i have no way of doing at the moment.

Sizes. I have sizes from around 2mm through to 16mm also some very large ones that i have no collets for.

Hope this helps Samuel. P.S do not drop the Carbide on a hard surface. Ask me how i know.

Steve.

I am slowly moving over to carbide for steel/iron as I replace worn HSS but now do a lot of my aluminium and non ferrous with carbide cutters that have a specific geometry for these metals. I also use carbide almost exclusively on the "hobby" CNC to make better use of the higher speed spindle and the resulting faster feed rates it allows.

Unlike the general purpose inserts solid carbide milling cutters are sharp so should put no more load onto the machine than HSS so you don't need extra power or rigidity. Also if it's an electric variable speed you can run faster which puts the motor in it's sweet spot. If you are wanting to try insert cutters than lighten the load by going with inserts for aluminium and non ferrous

The high spec 6 flute cutters are expensive so if you could half that to three flute that makes a reasonable general purpose cutter. You are also unlikely to be able to turn the handle fast enough to avoid too small a chip load so will end up with them rubbing which will blunt them. Also if used in a confined space you may not be able to clear the swarf which will result in recutting the swarf which again blunts the cutter. They are a bit more delicate than HSS so don't drop when changing and take care when touching off with a stationary cutter.. Looked after they will outlast HSS and more than cover the quite small cost difference.

This is a good video that shows that carbide if more than a match for HSS on a small machine even if run at HSS speeds I have posted this before when people say you cant get the speeds needed for carbide on a hobby/old machine

Edited By JasonB on 06/02/2023 08:05:12

Tend to favour carbide myself

Somtimes you get cast iron with chilled spots which can easily machine with carbide cutters. Recently I repaired a casting by brazing a piece on and the line next to the join was very hard but cut well with a carbide endmill and I have a small 25mm diamiter tip cutter which can remove surface hardness.

David

I use smaller carbide slotting cutters in my KX1 CNC mill pretty well exclusively since I cut a lot of non-metallic materials like styrene and HSS is not suitable for this. But I also cut steel, brass and nickel silver. I work in small scales so my usual cutter sizes are from 0.4mm to 2mm and initially I had to do a fair bit of experimentation until I found the best feed and speed to avoid cutter breakage. And they are brittle. I am now in the habit of hooking my little finger round the cutter when loosening the ER25 holder after chipping the ends of cutters when they dropped out of the collet onto the table when changing.

Jim.

I sometimes use small carbide cutters on my mill and they work ok most of the time. I have thought clogged a couple of cutters using them on Aluminium Alloy. I’ve had to resort to popping the cutters in some caustic soda to clean them off!

I have a few carbide cutters and mainly use them for roughing cuts, as David George says they cut even hard spots in a casting. Most of the milling I do with HSS cutters since I can grind the end teeth on endmills and slotdrills.

Thor

Slower feed rate and lubrication should cure most of the clogging.

Tony

I use 1mm carbide on my small CNC mill though I can only run it up to 5000 rpm so slow feed rates. Cutting brass and FC steel. Also have some 2mm which are very good. I've broken a few, just have to go easy on the feed.

I had a SX2P and got used to cutting mostly steel with solid carbide cutters from 3 to 8mm diameter dry and held in an ER collet chuck. Since moving to a larger machine I still do the same except when cutting larger widths I use cutters from 12 to 50mm diameter usually held in an R8 collet. Use very little HSS in either the mill or the lathe although I trained using HSS many years ago.

I use them all the time, the HSS ones only get used occasionally for aluminium as we don't have the means to sharpen them. I have bought used 6mm ones which were better than expected and very cheap so that a crash will not end in tears. With solid carbide, you must not drop one onto the mill bed or concrete floor, and never touch on to a surface, especially steel with the cutter stationary.

I bought HSS(2x flute) and 2x carbide 4x flute endmill sets. I milled a lot lately and am so impressed with the carbide endmills(Have not touched the 2nd set), found the 10mm & 12mm very usefull, used the 12mm the most.
Have not break one so far even the 4mm.
I was surprised how long they last, and the ones I got alliminium don't weld to it, unlike whats happenning on the lathe.

I use a lathe internal boring bar (12 mm DCMT inserts) for milling steel and aluminium in my hobby mill. I also made a holder for worn lathe CCMT inserts (4 cutting edges) that uses the 2 in the lathe unused cutting edges. Both work great for facing and "milling".
My 10 mm milling tool for APMT inserts is terrible. I am not sure if it is the lack of mill rigidity, the quality of the cheap inserts or the large nose radius.

With my hobby mill SX2P (2500rpm) and Warco 918 lathe (2000rpm) I use carbide cutters 99% of the time I only tend to use hss for making form tools. I have not had any problems with cutters running at slower than recommended speeds I just keep the feed rate and depth of cut lower depending on the job.The only thing I would say is to buy half decent cutters and inserts, I know some say they use cheap as chips carbide tooling and they are fine but that has not been my experience.

Huub, try some half decent APKT inserts meant for nonferrous, they are sharper and work on steel tool, usual 0.8mm radius should be OK with these

Jason,

I have got 2 types very decent AP?T inserts from a friend last year having a 0.8 mm nose radius. I was forgotten that I already bought a 12 mm holder for these inserts, found it in a drawer searching for the inserts. The next time I have to face some steel, I will test these 3 inserts under the same conditions. If it doesn't get any better, I will make some 12 mm boring bar holders for my DCMT070204, CCMT060204/8 and CCGT060204 inserts.

Thankyou all.

Quite suprised that carbide is the favoured option for hobby use.

Actually I was expecting tales of doom & re-directed towards HSS.

Oh & thankyou To JasonB for pointing out i might need to crank the handwheel pretty fast with a 6 flute mill~ I hadn't realised going too slow will blunt an endmill.

On a hobby machine, you can't utilise carbide cutters to the max. For that you need more power, more speed and more rigidity but you can still benefit from carbide.

For me, HSS is not out of the picture. For coarse threading, when I reach the limits of my lathe, I use a HSS threading tool because HSS tools don't break/chip that fast. My form tools are made from HSS because HSS is easy to grind and HSS dust is not so harmful.

Edited By Huub on 09/02/2023 22:37:43