drilling angle iron

HI all,

I have to drill hundreds of 6 and 8mm with the odd dozen or so 10mm holes in concreted in 50x50 angle iron....some of the holes I'll have the luxury of standing over the material but mostley it'll have to be drilled with a mains powered drill up a step ladder....

seemingly there seems to be lots of hard bits in the angle iron......

my question :- will solid carbide drill bits stand up to drilling free hand ?

Ive been using Tin plated drill bits and De-walt extreme bits (double ground) with limited success ......have tried so called quality drill bits but they don't seem to fair much better considering the extra cost..........

the 6mm holes I drill without a pilot and use a 4-5mm jobber as a pilot for the 8mm holes as this seems to work better........but nothing lasts.....the drilling speed is not to fast as flat out it just burns the drills edge......

any suggestions as I'm fed up....and I don't really have the facilities to sharpen the drills in the field...literally........

many thanks Clogs

Hi Clogs,

I'm fed up too. I've been chain-drilling angle all day today (100x100x10mm), plus milling the edges. Not quite the info you need but I just used a normal HSS bit in the mill. A drop of oil helps a lot although I did this lot dry with one 7.4mm drill (it was within reach), about 700 to 800 RPM.

Regards,
Ed.

I've done a lot also- I bought cobalt 8% drills, got them of the net, not very expensive, 6mm & 5mm. They seem to last much longer, haven't sharpened one yet. Slow speed without lubricant seems best. If you can don't use pilot holes, the larger drills don't like it.

I tend to buy Heller cobalt twist drills from my local merchant, have found them great for handheld drilling, generally using an 18v cordless. For 8mm I pilot with a 5mm first.

Hi Ed - I have to ask - why??

Clogs, if you can use a Mag type drill depth of cut can be controlled so you don't take the edge off the drills when breaking through the angle and into the concrete. This would also be a bit safer when drilling from steps.

Emgee

You could try these **LINK** as they say drills, masonry, wood, aluminium, structural steel, plastic, concrete B35 and multi-layer materials such as tile on concrete.

If it is normal steel stock angle iron, it shouldn't be a problem, although if you have that many to do a mag drill is the way to go, they are a popular hire item. It is old bed angle iron that has the hard spots in it, and I have burned the end of many a 1/4 drill trying to get through the hard spots!!

Hi I think the most important thing will be the speed your drilling at , anything around 600 rpm would be good or slower wont hurt . some lube will help too . I suspect if you try to run slow the drill will pull up, or at least slow down and thats the trouble with electric drills not much torque. unless its a really good one . drilling by hand (not easy up a ladder ) .General rule, if you can see the turnings coming off and they are grey silver spirals you have hit the spot speed wise . lots of time and a good supply of drills. good luck Stewart PS carbide tipped drills may be ok on the concrete but not on the steel . A solid carbide drill may help but only if you have deep pockets.

Hi Fizzy,

It's for a box pan folder, more photos and a half rendered concept in one of my albums.

Other than a hacksaw or endmill it's the only way I have to cut large pieces of metal. A power hacksaw is high on the todo list.

Ed.

I agree! It looks like a metallic modern art take on the stepped pyramid of chitchen itza!

Michael W

I remember someone extolling the virtues of regrinding carbide-tipped masonry drills to form a tipped metal drill. Get the longevity of a carbide tip with the flexibility of steel. Never tried it myself.

Mag drills are great on reasonably clean steel, but it doesn't take much in the way of concrete flashing etc to screw up the mag field. And I don't think I would enjoy humping a decent mag drill up and down a ladder hundreds of times, and deploying it with a single arm (the other one being dedicated to the preservation of life - mine! ).

Can we ask why so many specific-sized holes in such an awkward place?

Roger

Edit: Would it be feasible to drill another piece of angle down here on earth, then attach it in place, either bolted or welded?

Edited By Roger Head on 19/06/2016 01:54:27

I would think of an angle grinder with a thin blade instead of chain drilling if possible.
BobH

- £10 jigsaw would have done it very quickly though

Slap on some cutting oil and it WILL make a difference.

Neil

The average mains operated power drill is usually too fast, if your drill runs at 400 to 600rpm, you can drill all day, but if like a lot of drills it runs at 2000rpm + you could turn a 8 mm drill blue after the first hole. You need a good sized machine with speed control, larger machine to give the power/torque required at lower than optimum speed. Ian S C

Ian

Couldn't agree more with your comments though lugging a good sized drill up and down a step ladder doesn't sound attractive. The other problem that unless he is secured safely then if the drill bit jams, with that extra torque, remaining on the ladder could be somewhat challenging.

It would be best to work off a stable platform with, as you suggest, a more powerful and controllable drill and not risk an involuntary collision with terra firma .

Martin

How about making a jig using one of the cheap drill presses made for the attachment of an electric hand drill.

You could attach a vice to the base and clamp the whole assembly on the angle iron. This will give you the required leverage and control.

See link found at random below, there appears to a number of suppliers, Although they all look similar! remarkably I just picked one up in the street... It was hard rubbish day. It is destined for a similar use. It only weighs a few Kg. an easy lift drill and all.

**LINK**

If I had hundreds of holes to drill like this, I would rig up a bench grinder on a plank of wood or whatever was available at the site. You can buy cheapie 6inch bench grinders for hardly anything these days.

Then grind the drill bits so they have a bit more clearance (relief) angle than normal. They cut better and faster that way. Yes, they wear faster too, but if you keep a few in your pocket and change them as they go dull, you can sharpen them as a batch at smoko break etc.

And for a 6mm drill bit I would be spinning the drill at more like 1500mm and the 8mm at least 1000rpm. With today's variable speed drills you can slow down a bit if/when you feel it hit a hard spot. HSS bits will not burn out at these rpm IF THEY ARE GOOD QUALITY. Which I guess is the next thing I would do: use only top quality drill bits for jobs like this. They make life sooooo much easier.

On tough stuff, or drilling way overhead where you struggle to get good pressure on the drill, a smaller pilot drill, even down to 1/8" but more often 3/16", works well too.

That's the way we did it when I worked engineering construction in a former life, and being a lazy sod I worked hard at finding all the easy ways!.

If you have hundreds to do & you are doing ot one handed then you should not be doing it of a ladder

Presumably this is a commercial operation and a proper risk assessment should have been done with a proper method statement written. I do not believe " balancing off a ladder" is a proper method. If you continue then i suggest someone is an idiot.

Re assess the job & look at it properly . Then you will find it much easier & may i suggest possibly quicker