Drilling holes in plastic boxes

[Junkman]

What is the best way to put 3/4" and larger holes into plastic junction boxes? What is the best way that you have found successful, without breaking the plastic.

 

[rlitman]

I can't say that I've modified plastic boxes like that, but if it were me, I'd be using a step drill. That's the best method I've found for getting round holes into thin things, and it's also not that likely to crack plastic.

The $7 set from HF would be perfect for this.

 

[Ckerch]

I second that....I have used a step drill on plastic, bake lite and brittle plastic like lexan without cracking

Sent from my SM-G920V using Tapatalk

 

[pattenp]

I've always used a hole saw on blank PVC boxes.

 

[ducksface]

Hole saw with a wood backer.
Step drill would work but I never remember to use one.

 

[PCustoms]

Step drill works but you have to find one that has steps that work with the box thickness.

Spade bits work, hole saws too. Pretty sure I've used a Greenlee punch as well, very clean hole

 

[Marctrees]

For KO sizes I would use a spade bit, but not Any brand.

Find some that have longer than average cutting spurs on the OD.

Slow gentle feed, will cut quickly.

You should get through by far most of pvc thickness w just the spurs.

And, if by chance you can, may in some cases, finish the hole from the backside.

I never tried KO punches on PVC, , they may work great if it's not dead of MN winter temp. Marc

 

[Northislander]

maybe because i have a torch on jobs but i usually heat up a piece of copper or emt and melt a hole thru then ream the edge i find it safer than trying to hold a small box and drill a hole

 

[Marctrees]

If I had multiple ko holes to do, i would grind out that flat deeper to make the spurs longer.

Marc

 

[Marctrees]

maybe because i have a torch on jobs but i usually heat up a piece of copper or emt and melt a hole thru then ream the edge i find it safer than trying to hold a small box and drill a hole

I like that possibility, but definately keep yer nose from the smoke. Marc

 

[DC73]

What is the best way to put 3/4" and larger holes into plastic junction boxes? What is the best way that you have found successful, without breaking the plastic.

I've used a Forstner bit to put 3/4" holes in plastic junction boxes. Worked very well. Using a lower drill speed seemed to work a little better.

DC

 

[James-W]

I have a set of Greenlee bits and they work great for plastic or metal. Only thing is, I have no idea where they are. When I built the new garage I had to pack everything up in boxes and store them until I had the new garage built. Now I can't seem to locate them anywhere. I know I still have them, I just don't where to look next.

 

[Junkman]

That is my problem most of the time. I know that I have a tool or an item, but can't locate it when I need it. When I don't need it, I trip over it all the time, and when the time comes to look for it, my mind goes blank. I believe that it is old age. Now, what were we discussing in this thread!

 

[awdblazer]

greenlee ko set
works for just about any plastic fibreglass

 

[Hawk]

Hole saw run in reverse slowly.

 

[ard]

I have used:

hole saw
Forstner bit
spade bit
dremel

Preference is forstner if in a drill press, otherwise for field work a holesaw

 

[CJ7VFR]

I have used the same bits as others have suggested, as well as using a 3/8 inch regular twist drill bit to make a small hole, and then using the small coarse sanding drum that came with my dremel tool to open up the hole to the size I need.

It makes a mess, but it works.

Jim

 

[shteii01]

Ideal TKO carbide tipped hole cutter. Use it for pretty much everything, steel, stainless, plastic, even fiberglass but have to be careful with fiberglass because it chips. Just go slow.

Step bit works too. Just rarely had to use it because most holes I have to cut are "standard" size so hole cutter works perfectly.

 

[matt151617]

The good PVC boxes have threaded holes already in them. The cheap blue plastic boxes are so thin, it's hard to drill holes or attach anything to them without them flexing. I found it's easier to use metal boxes when you need to have anything besides Romex going in to them. The price difference is less than $1.

 

[rburke65]

As suggested....a step bit us really useful. I suppose you could do itwith a spade bit and a holesaw. Can never have enough tools!

 

[cort]

I agree with a hole saw in reverse for most plastic boxes, but if you are working in a code demanding situation, your best solution is to buy boxes with the holes already there or with knockouts for the holes you need. Modifying anything in code demanding situations is dicey. Sometimes an inspector will see this as deviating from the manufacturers intended use of the item and disallow it. Sorry for being a party pooper.

 

[PCustoms]

^^what's the manufactureres intended use of a 12x12x6 pvc box with a removable lid bit no penetrations?

 

[manwithtools]

I agree with a hole saw in reverse for most plastic boxes, but if you are working in a code demanding situation, your best solution is to buy boxes with the holes already there or with knockouts for the holes you need. Modifying anything in code demanding situations is dicey. Sometimes an inspector will see this as deviating from the manufacturers intended use of the item and disallow it. Sorry for being a party pooper.

^^what's the manufactureres intended use of a 12x12x6 pvc box with a removable lid bit no penetrations?

This is not true at all. Almost all junction boxes and electrical enclosures any larger than small pull boxes have no penetrations in them - unless they are rated NEMA 1 - even then, once you are above a certain size they may have no knockouts in them.

The only code requirement for making the penetrations in the larger boxes is the connections must be rated for the same or higher NEMA ratings than the box - if you intend to retain the enclosures NEMA or IP rating. Nothing unusual or code violation involved. Of course wire fill and some other factors do apply from a code prospective. If there are no penetrations from the factory then you have to make them.

Think of this way - how would a manufacturer be able to guess where and how many and what size holes you might need in box that is 16 x 16 x 8"? Or how about a 90" x 158" x 24" enclosure full of motor controls? I ship a few hundred completed enclosures per month with no penetrations in them, the contractor who installs them will make the holes for the conduit connections to them.

 

[manwithtools]

Oh, a step bit is ideal for drilling holes in plastic boxes. Buy a Harbor Freight set with the big bits in them - cheap and they will last forever in this use.

 

[LutzTD]

Oh, a step bit is ideal for drilling holes in plastic boxes. Buy a Harbor Freight set with the big bits in them - cheap and they will last forever in this use.

actually, the HF step drills last pretty long with thin metal too. Ive been using my set for a long time and have drilled some pretty heavy wall tube with them and they are still going strong. They are on sale a lot too so they are a good buy anytime to throw in your box. I would use the step drill for plastic boxes too, anything with a smaller pilot like a spade or hole saw can wallow out the center guide hole and mess up your finish hole size.

 

[mm08822]

^^what's the manufactureres intended use of a 12x12x6 pvc box with a removable lid bit no penetrations?

Allows you to layout the job as you need it. Nothing worse than having ko's too big, messing with concentric ko's, or being forced to drill partially into other ko's when there is no room to move otherwise.