Metric M42 8% Cobalt Twist Drill Bits Set for Stainless Steel and Hard Metal (1mm-10mm/19pcs)

Had a box for over a year now. One use was on quite a few bits of steel from old power pylons, fairly sturdy stuff, hand held drill due to location. Another use has been on galvanized steel field gates, again hand held drill. Holes are made very quickly compared to other bits I've used, but I am an occasional driller rather than professional. They may be more brittle than standard HSS bits as we had a 6mm snap and a few larger bits chip at the ends. I think more careful use could have avoided this but that's hard to do with a hand held drill in some situations. I contacted the seller about the broken bits and within a few days I had a full replacement set! I am seriously impressed with their customer service and warranty.

I have to say, I wasn’t expecting too much, but I needed some replacement 8% cobalt drills to take out a sheared off stainless bolt. These performed beautifully and the specially ground cutting edge allowed for less drift and thus more accuracy. These were very good value for money and did the job extremely well. Only tip, use either some lathe coolant or a good squirt or two of WD40. Don’t force the drill bit, keep steady pressure and allow the bit to cool a little if the job is quite big, especially on stainless. I was pleased and I think they were pretty good value for money.

The item was sold at a keen price and delivered in double-quick time. I ordered the Cobalt drill bits because, having read the description, I believed they would be a more resilient bit than the normal HSS type, and would do the job of drilling out the sheared stub of a fixing bolt. However, I used two of the new bits to try and drill a pilot hole in the end of the stub and both of them very quickly blunted and lost their cutting edge, making no impression on the stub (I am unable to say what type of steel the sheared bolt stub was manufactured from). In view of this, and previously having blunted and broken several HSS bits, I was forced to abandon trying to remove the stub and used the Cobalt bits to drill a new hole through the 2mm steel sheeting which was easily achieved. And so, although the Cobalt bits didn't perform as I had hoped, they do appear to be quite a sturdy product and easily able to deal with cutting through reasonable thickness, normal steel, without a problem. As a result of the above, I contacted the seller to request replacement of the two damaged bits under the terms of their warranty. They not only responded immediately but did more than I anticipated, sending me a full new set of drill bits, as well as giving me a full refund on those initially purchased! What more could anyone ask for? If that's not excellent customer service, I don't know what is!! I recommend the company highly.

very good &sharp

I only used a few of these drill bits. They were OK to drill aluminum but when I tried to drill an 8mm hole into mild steel the drill bit I used was useless. I had drilled a 4mm pilot hole into a mild steel plate and the drill seemed to melt away. I was using it on a pillar drill so there should have been no issue. I applied pressure and the drill seemed to lower but no swarf appeared. Raising the drill bit I saw that the 4mm hole remained and the first 10mm of the 8mm drill had been reduced to 4mm! The mild steel had machined the dia. of the drill down to the size of the pilot hole. Returned to Amazon for a refund.

Great tool! By far best drill bits I've used - I've had snap on to dewalt to Irwin and these are head and shoulders above. Not only that, some have blunted and broken as all drill bits do, the tray comes with a little leaflet inside telling you if any bit breaks, message them through Amazon and they'll replace the drill bit FOC. Ive broken 2 drill bits on separate occasions months apart, messaged them on each occasion and twice they have said no replacement in stock, but delivered a brand new full set of bits for free straight to my door on 2 separate occasions. Absolutely amazing service, value and quality.

I bought these to drill through solid steel rods. My previous metal drill bits had failed, but these worked really well! You just need a slow drill speed and a cup of cold water next to you to cool the drill bit every so often.

they break if used with a hand drill but good on a drill press

Testate su acciaio da 5mm forando con la n.4 come pilota e sembra indistruttibile, le altre più grandi le usate solo per allargare il foro. La 4,5 usata come pilota si è spaccata al solo contatto con il pezzo, alcune si sono scheggiate lateralmente, probabilmente difetti di fabbricazione. Ho contattato il fornitore che mi ha subito inviato le punte in sostituzione, solo per questo meriterebbe 10 stelle. Provate su barra in ferro da 5mm e forano come se fosse burro. Consiglio pienamente l'acquisto.

I purchased these bits sometime ok...They are very sharp and cut into any material with ease and some cutting fluid of course!! However I did break a few on a project and dulled 4 bits...I contacted costumer service and within a few days they sent me a complete replacement with no questions asked.... Best companies costumer service I dealt with in forever!! Awesomeness!!

Las compré para inoxidables y se soporta las cargas como todo con el uso prolongado van perdiendo filo pero dura bastante para su precio

Very good quality

La boite est assez qualitative et répond à ce qu'on lui demande. Les forets sont de très bonne facture et cela se confirme à l'usage. La coupe, que ce soit à l'entame ou pendant le percage, est très bonne. Il faut pour cela respecter les vitesses de perçage et parfois, l'utisation d'un lubrifiant de coupe sera nécessaire,, il serait urgent que les utilisateurs de forets sachent cela au lieu d'incriminer le foret. Un foret a casser, sans raison apparente. Après conact avec le vendeur, Stroton, un envoi de rechange m'a été envoyé très rapidement. Merci pour la réactivité et le sérieux de ce vendeur/marque.