Thread: HOLE CUTTERS

I have some Irwin step drills designed like this. I've never used them for anything over 1 mm or so but so far they work well.

I've used them up to about 2 mm in steel .
They are handy to have .
But don't expected miracles from them .

Mike,
You can buy the same set at Bunnings for $9.95 and they are of pretty good quality.
I bought 3 sets thinking they would wear out fairly quickly compared to $45.00 each
ones from BJ Bearings. But low and behold I'm still using the first one 3 months later.
They are great for thin material, personally I wouldn't use them on any thicker than 3mm
being the thickest. That being said I have seen someone trying to drill a hole through 10mm plate with one.
I'm sure you can guess he was an employee using other peoples tools Some people shouldn't be allowed near workshops and other peoples belongings......

Hope this helps you in some way mate..

Matt

I have used them on 316 stainless with no problems.

Originally Posted by matthew_g

Mike,
You can buy the same set at Bunnings for $9.95 and they are of pretty good quality.

The bunnings ones are a smaller sized hole set; 4- 12 in 9 steps, 4-12 in 5 steps 4 - 20 in 9 steps
The ebay ones are 4-12, 4-20 and 4-32

I use mine mainly for drilling holes in plastic and thin sheet metal - very handy

I've got a set of the cheap Aldi ones (£10) and use them on aluminium and plastic quite often. I find that on thicker material the taper left in the hole edge can be a problem.

Originally Posted by BaronJ

I've got a set of the cheap Aldi ones (£10) and use them on aluminium and plastic quite often. I find that on thicker material the taper left in the hole edge can be a problem.

Finishing the hole from the other side halves this problem.

I have been using both stepped and conical types quite a lot over the past 40 years. They work best with plenty of lubrication. Early high quality conical hole cutters used to come in a cassette with a wax stick - like a giant diameter lipstick. WD40 is good for Aluminium. The biggest drawback of this tool is that there is no pilot. Originally, this type of tool was intended to only slightly enlarge existing holes. It is impossible to accurately locate the bore when using it in a handheld drill. Same in the drill press if the workpiece is floating. I usually mark the hole outline slightly oversize, then correct the hole location as I go. With some experience one can get holes to line up visually.... that is to +/- a quater mm or so.

Where more accurate hole placing is necessary, I prefer using a hole saw, because it is piloted. Then just finish off the last cut with such a stepped/conical hole cutter because of the much superior finish it leaves behind. It is also possible to use this tool in a drill press with the workpiece clamped - but I feel that if one goes to the trouble of clamping the workpiece, then one can better use a trepanning tool. Especially if its about multiple holes. The trepanning tool also needs less room below the workpiece, which is often a problem when clamping the workpiece and using a tapered/stepped hole cutter.

As for quality of the tool.... I still have my first 40 year old "Alldrill" conical hole cutter. Greatly used and abused. Still no chip broken off. Still useful.

For smaller holes I have a 3 piece set of these extremely useful tapered hand reamers, which I can highly recommend:
6280.jpg
http://www.pbswisstools.com/en/quali...tx_pbtools_pi3[tool]=PB_6280&cHash=39a6421c18e5be36bf7ae6af87143347

Finally, if you need several holes of exact diameter in not too thick sheet metal, consider hole punches like these:
q-max.jpg

in Plastic and Aluminium I find wood working Forstner bits can produce a clean reasonably accurately located hole.
Metho works as a lube on the Al and leaves nothing to clean up
The curlies made in Al are quite purdy.

Yes I use these all the time and have a few sets in various diameters. On thin material it's definitely the preferred option as the material won't grab.

Originally Posted by BaronJ

I've got a set of the cheap Aldi ones (£10) and use them on aluminium and plastic quite often. I find that on thicker material the taper left in the hole edge can be a problem.

You won't get a taper if you stop at the incremental hole size marked. The steps go up in specific rises (2 mm iirc) and if you drill to those sizes all is well, if you try to go to oddball sizes you'll get the taper. I actually use that tapering as a way to automatically debur the hole, drill from one side and just quickly run it through from the other side to debur and clean it up.

These are quite cheap and very effective for thin material. On aluminium just watch you don't drill the hole oversize as they go through the material remarkably quickly.

Originally Posted by BobL

The bunnings ones are a smaller sized hole set; 4- 12 in 9 steps, 4-12 in 5 steps 4 - 20 in 9 steps
The ebay ones are 4-12, 4-20 and 4-32

I use mine mainly for drilling holes in plastic and thin sheet metal - very handy

I must admit in my speed/haste in looking at the pics I overlooked the size

Used in their best application step drills are just wonderfull.

For electrical / electronic chassis bashing there simply is nothing like em.

Compred to screw down hole punches and hole saws they are way faster and easer in thin material.

I now a couple of workshops where a step drill is pretty well permantly in the drill press.

One issue is that they can wander, particularly as you get thru a number of steps.

as has been mentioned they are not piloted, so they can chew one way or the other and every step taken can introduce a new error

This issue can be solved by securing the job firmly in relation to the drill head.....like you always shoud

I learned this when I drilled up a batch of clipsal c2000 plates.....I marked them all carefully and pilot drilled thru both parts.....but when I drilled the parts with different sized holes, the regestration was not good ...a mm or so drift.

But if you have to bang a conduit or a gland thru the side of a box....and a mm either way does not matter.....hell..nothing like em.

I have 4 different sets by the drill press and a pair in the work truck.

Jaycar have two step drills, the smaller is good for switches and small plugs and the larger is good for glands and small conduits...cant remember the sizes off hand.

I have one that cost a good sum..from farnell electronics...but it is specifically stepped for common electrical sizes.

They leave a fairly clean hole, bump the next size up to debur....turn over and debur likewise.

no problems with getting the waste plug off the tool like there is with hole saws or hole punches.

I'm considering one of those sets of three..to cover sizes I don't have.

cheers

Many a true word !

Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

I have a 3 set of these made by Irwin. I picked them up about 5 yrs ago and have abused the hell out of them and they still cut. I always drill a small pilot but I regularly drill a 19mm hole through 10mm mild steel. Never had a problem. I just used cutting fluid and slow the speeds down towards the end.
I mostly use them in a cordless.

like always you get what you pay for. The Irwin's would be mid range in price. Maybe the cheaper sets are just as good? Maybe the Irwin's punch above their weight? I don't know about that one.

Besides all that, they are worth having in the workshop as it's another tool that can help solve a problem.
Technically, they are designed to drill large holes in thinner sheet metal which is quite difficult to do with regular twist drills.....well I find it difficult anyway.

Um yeh...I recon cutting holes in 10mm plate is a bit of an ask...most of these step drills only have a 2 to 5mm per step.

They do work well in the fabbing shop, especially with metric fasteners.....get the right step drll for the job and it will match up to a range of fasteners.

a good tool and looked after..( not pushed hard and lubricated)..will bash holes in light section steel and aluminium all day.....one drill one drill press all good.......just don't cut past the step you need

ANYway....many people don't realise they can be sharpened quite sucessfully.

First it must be understood that they have a fairly steep cutting angle...that is both good and bad.....the steep cutting angle is what makes these work without grabbing and gives the smooth finish that they leave and it makes for a very robust cutting edge.....but it means they do not cut fast and the edge can "go off" fairly quickly when cutting hard and heavy materials.

If you cut a lot of plastics or non ferrous, you would be wise to keep a set specially for that.

BUT back to sharpening.
the exact geometry differs from tool to tool but the sharpening method remains the same......these step drills are made from a series of mostly ( or nearly) regular cones with a slightly diagonal slice thru them.....
Look at the tool and you will see how they have been ground...all we have to do to sharpen them is the give them a very carefull touch on the side of a nice straight wheel, flat along the leading edge.

to get good clean access, to make a good pass, you will probably have to remove the rest from the grinder.
Like with most sharpening rehearse the cutting pass with the grinder turned off and the wheel stationary.

THE hardest thing is getting the cutting face presented flat to the wheel of the grinder....you need to get the corner of the wheel right into the corner of the slice in the tool and just touch the outer edge.

They will only take the barest touch....DO not over grind the outer edge or you will ruin the edge geometry and the very steep positive cutting angle will change to a negative angle angle become a scrape...cutting efficiency will suffer.

They also will not take a great deal of sharpening before the geometry is ffffforever ruined.


cheers