Drilling out 11mm hole to 13mm?

Knowing your background, I can understand why you are saying this, but I can tell you that opening up a hole will not produce a triangular hole in a piece of metal thicker than about 7/8s of the thickness of the diam. of the drill. BTDTWTTS

Dave

What would you suggest is the best solution for this particular application (i.e. opening a 11mm hole in 3mm mild steel by a couple of mm while on site?)

I really can't see any problem doing this with an ordinary HSS bit provided you have a drill that runs slow enough. Unless I'm missing something, it doesn't need to be precision engineering.

Well, in this thread, and NG, nothing.

And untill 2 days ago, I took him more-or-less as he appears here. Sane, prepared to ask when needed etc.

But...

It appears that TMH is not a cyclist, but chooses to be a mega-troll on that NG, posting as 'Dave- Cyclist VOR' ( whatever that means ).

Why the hell would someone who is not only not a cyclist, with no interest in cycling, but a rabid anti-cyclist, go there and cause trouble? Just go away from there. Stop trolling. Just go away.

His presence on that NG is entirely negative and trolling, and his posts are unbelievable rants.

Dave, if DIY and handymaning is your thing, then I welcome your contribution here.

Please give your trolling a rest on the cycling NG. You don't enjoy trolls here, and I don't enjoy them over there either.

That's only to remove the very centre of the drill to follow IYSWIM. Any pilot hole much larger encourages the larger drill to "walk" around the pilot hole producing a polygonal cut.

Reducing the rake angle of the 13mm drill might have helped Desmond get away with it.

And?

I've been there for ages & I'm not the only one from 'here' who is 'there'.

I certainly do have an interest in cycling. I hate cyclists.

You mean you have an opinion that differs from mine?

Very kind of you.

I don't troll anyone in particular, I dislike all cyclists equally.

It's not the thickness, it's the steel.

Desmond should do it for you - because he has a drill press. Doing this with a hand drill would be a horror. If you have to, use your slow-speed high-torque drill for plaster mixing and (in my case) timber framing. Use the long side handle too.

I wouldn't go from 11 to 13. I'd go up in the smallest increments I could, probably 0.5 mm (remember than 1/2" is 12.7). It's quicker to drill more, smaller steps.

You should get away with any drill, as 3mm is easy and steel is easy - unless the steel is awkward. Stainless could be a right pig, depending on grade and previous heat-history. High carbon steels too, if they've been hot before. In general though, gold-coloured drills are modern rubbish and old black HSS will at least still have come from a decent maker in Sheffield. Over 6mm in steel, there's no room for drill bits made of Silverline monkey-metal.

A tapered reamer is a wonderful tool. Buy a new Roebuck one (how much?

If you're bolting together brackets like this, it's worth having a parallel reamer (with a tapered lead) to ream both bolt holes in situ and to make them perfectly aligned and perfectly sized. Slow, but it's worth it for the extra strength if you're bolting anything really structural.

Heh heh - there appear to be quite a few cyclists doing just that on car groups.

The 'gold coloured' HSS drills Lidl sell as a set in a nice steel box are excellent for jobbing work - and a fraction of the price of Dormer etc, or at least where I can buy them.

I do realise it might be worth it for some to pay many times the cost for a 'name' drill, but for many I doubt it. Especially if most of the time you're using a hand held drill.

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I believe "Tu quoque" is the standard answer for that :-)

That does not mean they are not there - I am as capable of a brain fart as anyone else! ;-)

Well its interesting you highlight that, because I did pause as I wrote that and wondered if I had the right term. So it is entirely possible that its not a common (or for that matter even correct) usage. Web seems to be commonly in use, so perhaps its better I switch what I said above to that.

In message , "Dave Plowman (News)" writes

Often the difference is in the heat treatment. IANAMetallurgist but cheap bits always seem to have fully hardened shanks.

Also, the web (if we are calling it that) tapers on a proper drill: being much thicker near the shank.

regards

Who cross post car hatred. Thats how I got to the cycling group.

Right. That would account for them snapping more easily. But given how cheap the small ones are not much of a problem.

So those re-ground many many times ones you used to see not a good idea?

I'm not sure that being as nuts as Doug is something to aspire to.

Crikey. You must have lots of spare time on your hands.

That is equally sad.

I can't believe anyone can have such a rabbid dislike of something that they actually go out of their way to go find where thoe people are just to make trouble. And then spend *hours* just making trouble.

People judge you by your choices: what you say, and what you do.

These choices speak volumes, and not good ones.

In message , "Dave Plowman (News)" writes

I am sure we all have a few bits quietly purloined from factory production jobs. Mine are now very short through years of hand sharpening.

While we are on the subject..... I just happen to have two drill sharpening attachments obviously cannibalised from a proper cup wheel drill grinder. I shall never have a use for them but they might make a project for someone with the appropriate skills.

regards