Cutting a Hole

[Jivemaster]

I need to cut some 15mmDIA holes in a plastic box! The ONLY 15mm drill I can find is £10 from RS and that is a metal cutting drill - not best suited for plastic cutting.

 

There are bits in B&Q but 13, 14 & 17 mm There are bits in sets at Maplin including ones specially for drilling plastic but even in their 200 piece set there is no 15mm drill

 

I'm in East London and cannot find a 15mm hole tool!

 

Will a Q-Max type cutter punch ABS sheet?

[paulears]

How about this ten quid set from screwfix and one is 15mm

 

link here

[Lamplighter]

I would invest in a step cutter, 10 to 20mm in 1mm steps. They are not cheap but will cut aluminium , steel and most plastics. I have used the same one for around 10 years and regard it as a terrific investment. They are available in most good tool stores as well as RS and Farnell. They leave a nice clean hole as you can use the next step to de-burr both sides. You can also get 20 to 30mm and so on but the price goes up exponentially with size!

Brian

[Wuddy]

Step cutter is a good idea, also hole saws are a good bet the type electricians and plumbers use, Starett make a range which is readilly available from most suppliers.

 

The Forsner bits that Paul has mentioned may be a bit vicious on plastic as would ordinary twist bits of 15mm.

[boswell]

Starett do not do a 15mm that I can see, only 16mm upwards, Black&Decker do some small ones (I've got a 5/8" in front of me) but don't know about metric ones. Step cutters only seem to go up in 2mm even steps, thus missing out 15mm.

Forsner bits should be OK on plastic as long as you use a pillar drill, slow speed, very light cut and workpiece vice.

 

Otherwise use twist drills but go up in steps, say 10,12,14,15

[Wuddy]

Hi, yes I've just looked at Starett web site, they don't do 15mm but they do a 14mm, I've often found that the hole saws aren't exactly accurate and the 14mm will probably leave a hole between 14mm & 15mm which you could open out with a file?

 

If you want dead accurate holes all lined up I always find the most accurate way is to punch them, costly but much neater job.

 

I also sometimes buy hole saws by CK Tools they may do a 15mm.

[themadhippy]

Ive found that q punches can split hard plastic boxes if you aint careful,whats wrong with a good old soldering iron and round file? just dont do it in a confined space.

[Jivemaster]

Thanks all! Before it gets too boring, I have an offer to do the machining for less than the cost of a drill bit! So will take that option.

[Simon Lewis]

Thanks all! Before it gets too boring, I have an offer to do the machining for less than the cost of a drill bit! So will take that option.

Glad to hear you have a solution.... If you do find a need to make 15mm holes in the future, an alternative to the stepped drill is the Conecut. It's a cone shape drill (duh!) so you can drill any size up to the largest diameter of the cone. You can either set the depth stop to get the size you want, or use a washer to stop it drilling any deeper. Just a thought!

 

Simon

[bruce]

Aldi are currently doing a set of 3 stepped drills, from 4-32mm diameter, in a wee wooden box, for £9.99.

 

Don't know what the quality's like yet - picked up a set this evening, but haven't opened it yet.

 

edit: had a closer look. Seem OK, but they go up in 2mm sizes, so no 15mm!

 

Not actually tried them yet. They may be fine, or they may be made from monkey metal...

[Wuddy]

.... If you do find a need to make 15mm holes in the future, an alternative to the stepped drill is the Conecut. It's a cone shape drill (duh!) so you can drill any size up to the largest diameter of the cone. You can either set the depth stop to get the size you want, or use a washer to stop it drilling any deeper. Just a thought!

Simon

 

Conecutters are ok, I use them in general contracting but I wouldn't recommend them for panel construction or prescision work. Because they are cone shaped the hole diameter can be 1-1.5mm larger on one side to the other dependent on material thickness, so you have to open holes up with a file, and because of the tapered cut the hole has a knife edge section at the back.

 

But for whipping in 20mm 25mm 32mm etc holes in electrical enclosures, fantastic as long as you aren't tempted to check the quality of the cut with your finger.

 

EDIT:- Just saw the punn :** laughs out loud **: "Thanks all! Before it gets too boring," was it intended

[lightsource]

Black & Decker's standard and ground drill bits go from 1mm to 16mm in 0.5 mm increments.

 

You're 15mm is there.

 

The B&D internal part numbers are 40015000 for the standard bit, annd 41015000 fpr the ground bit

 

Suitable for both plastics and metal.

 

You just need to find a supplier for them.

[Ike]

If you can make the holes in a well ventilated area and they don't have to be accurate to a fraction of a mm a bit of copper water pipe heated in a blow torch works well for 15mm and 22.

[Jivemaster]

As we have now reached oil! I am amazed by UK metrication I found a set of drills 12, 19, and 25 mm That's awfull like 1/2" 3/4" and 1"

[Brian]

Because they are cone shaped the hole diameter can be 1-1.5mm larger on one side to the other dependent on material thickness, so you have to open holes up with a file, and because of the tapered cut the hole has a knife edge section at the back.

Or use the cutter from the reverse side to finish to the correct diameter and then the taper is only half as big. And you don't get quite such a sharp edge. But in plastic they are the mut's nuts.

 

Or buy a hand tapered reamer. Even easier in plastic.