Endmill failure or wrong feeds and speeds?

[Lee Roberts]

I've not looked at the video yet but I can tell you right away the cheap cutters from screwfix etc are exactly that - cheap!

I have used pretty much all the brands in this category and all of them dont last at all and generally snap/fail exactly like yours have. This includes the Trend branded ones (green craft pro) and the black "pro" range, the Trend cutters being somewhat "better" at lasting but still not good enough for what we do with these machines.

So why did this happen and what can we do about it?
The cutters mentioned above are TCT (tungsten carbide tipped) the Trend cutting blades in the black versions are better because the whole cutting blade/edge are made from carbide rather than only "tipped", however that's where the carbide stops and hence why they can suffer the same fate when pushed on a cnc machine.

You need to source solid carbide cutters for cnc work, you can find them available all over the Internet from different places.

Years ago solid carbide cutters where very expensive and even more so when you started looking at the big boy brand names etc, you couldn't really get them in small quantities "cheap" like you can now and in abundance.

The market has changed, thank you China!
So with that in mind, have a look on ebay, amazon etc at what is available, pic a supplier and see how their cutters fair.

If you can wait for items to come from China then Aliexpress is your best bet, again its a minefield on what brands/suppliers you order from but generally they are all on par with each other in terms of quality, BUT like everything there will be some rubbish out there too

So if you don't want to pay £££ for cutters and can wait I'll give you the link to the brand I use, I have a draw full of their basic range of cutters (solid carbide no fancy coating) and they have been fantastic in everyday use in wood, for about 18 months I have been using these cutters so can definitely vouch for their longevity, the only breakages have been from user (me) error.

Quality control.
So they are cheap, that means they are not going to be exactly on the money when it comes to sizes, however the brand I'm linking below are very close, my findings are that shank diameters seem to be spot on, lengths can be off by +/- 1-2mm (usually on the flute lengths) however flute major diameters are almost always slightly under size, my conclusion is that they produce the cutters as blanks then grind the cutting flutes (obviously) but dont seem to have allowed enough material for grinding the flutes in and for them to remain on spec, however that's ok and to be expected at these price points...

If you know, you know
When you buy any cutter, from any source, from any brand and at any price - you should ALWAYS check the dimensions of each cutter yourself. This is standard practice and like i say - no matter how much you pay for a single cutter, measure them all, number them and add them to your tool library/inventory separately with their own individual specs.

Link: XCAN 1pc 4mm/6mm Shank 2 Flute Straight End Mill Carbide CNC Router Bit Engraving Bit Straight Slot Milling Cutter for Wood

I've linked you directly to the 2 flute straight cutters, straight flute generally gives the best edge finish with an emphasis on slotting operations, for real wood, plywood and/or laminates where the top/face edge needs to be great (sharp/chrisp), go with a down cut type flute, this will help stop splintering.

Hope this helps