Steel drill bit advice please

[arboriculturist]

This is a simple case of 'you get what you pay for'

 

Follow the link below.

 

RBK COBALT JOBBER DRILL SET 1-10X0.5MM - Buck & Hickman

 

These are great people to deal with. There are better quality drills on the market but come at a premium.

 

High Cobalt drills are available singly also.

 

I have fabricated steel harder than En25 with these.

 

Good luck.

 

I meant to say En24

[Mull]

Can't recommend these as I just bought them yesterday, but I can tell you they were £54+vat. Hopefully less broken bits from now on!

[cornish wood burner]

We used to drill at least 10000 holes a year for many years on one job with a hand drill and found either Dormer or Presto the best. Pressed I would say Presto is the better. If you are drilling special steel then Cobalt but for general use as you have described Presto or Dormer.

[gensetsteve]

I use anything thats sharp in the box. Dormer chinese makes no odds. The reason I dont struggle is I use cutting oil. The difference is unbelieveable 1/4 thick plate is like butter even stainless is easy. Get some spray on modern super stuff your drills will last 10 times as long. Also learn to resharpen before you blue them out.

[Hanser]

Thanks, very interesting info.

[rustcutter]

"Drilling holes in forestry machinery" means you are going to be using hand held electric drills this is pretty unforgiving on bits. The most heavy duty builders drills usually have only one speed get a good maybe lighter drill with at least two speeds and variable trigger; speed is critical to drilling metals you wouldn't drive your pick up to a job using just one gear. Fast speed for small holes slow for big holes. Learn to sharpen your bits then you will better appreciate how they should be used and you can adjust the cutting edges to suit the job and the material and you are never stuck on a site with no drill bits when you have broken them all; I have used an angle grinder to sharpen bits on a site before now. Use cutting fluid, cutting grease or spray not ordinary oil but sometimes not possible; if you're blueing or burning out bits then then pay attention to sharpness of the bits, speed of rotation and feed pressure heat build up will be minimised if they are all right for the job. Don't forget some steel alloys are just a pain to machine anyway in which case it is easier to blow holes out carefully with the gas which can be done (after patient practice on scrap I would suggest).

Cheap drill bits are rubbish but sometimes they are all you have got or been provided with; it is better to learn to cope with them than spend on expensive bits. Quite a lot of trick drill bits are:

really hard stuff which is brittle

or only coated with the hard stuff and once sharpened just as useless as cheap ones

[Agi-Smash]

Also learn to resharpen before you blue them out.j

 

Totally agree. I use dormar or presto, whichever colin supplies me usually. I have found that all these sn coated and titanium to be no better than hss. A correctly shapened (118 degrees) hss, USED AT THE RIGHT SPEED, with cutting lube, pushed square with sensible amount of force to be the best out there. For mild steel use 23,000 divided by ( pi x dia ). And have a set ground to 130 degrees for stainless.

But you do get what you pay for.

[Breezeblock]

the dewalt extreme i thought they were crap blunted dead easily drilling into the frame on a jd harvester

[spudulike]

I tried cobalt drills by Bosch for the first time a while ago and they actually cut like you would wish them to. I use Bosch HSS for general work and the cobalt drills on tougher jobs.

 

Drills are like files, hacksaw blades etc - you KNOW when you have a quality product and cheap stuff just doesn't cut it!!

[eldon]

You need to learn to resharpen correctly. If your not interested or can't be bothered a worthwhile investment would be a drill sharpening device which can cheaply be picked up from ebay or wherever.