Tapping plastic

[Tangy1]

I want to put a threaed 1/4" fitting on my Ca reactor lid. I know I would have to drill the top and tap it somehow. Does anyone have any experience tapping a drilled hole? what equipment would I need and how tricky is this to do??

Thanks for any help

 

[Anonymous]

hi.
It is not difficult to do at all, but for first time tapper, I strongly suggest you to practice the drilling/tapping on a piece of spare acrylic with similar thickness before you proceed to work on the real thing.

The practice will be more of a confidence builder more than a refinement to your drill/tap skill (a skill most 9 year old can master in 10 minutes).

 

[smokie]

For 1/4" pipe tap you need a 7/16" drill bit.

 

[DJ88]

Tangy,

You will need to buy two things.

a 1/4" NPT tap. Make sure it is an NPT as others won't work. THese can be a bit harder to come across than NC or NF taps. Phone around to mechanic supply stores.

Then the drill bit you need to get the hole to the proper size before tapping it. Most taps will come with teh proper drill bit size written on the package. SOme you will need to look up at the store or with the manufacturer.

After the hole is drilled take the tap through slowly and evenly. Make sure you are all squared up(the ta is going in straight) so you don't get it all wonky loking. It will still thread fine but looks better if the fitting goes in straight.

It isn't really hard to do. I don't even use a holder for the tap. Just a vice grip and some force to twist it in. Has always worked fine for me.

hth

[ May 06, 2002: Message edited by: DJ88 ]</p>

 

[adamsaquatics]

Run the bit at a high rpm, and ease the bit in carefully. Hold the piece securly. It may help to drill a tiny hole first.

 

[GKL]

I have found that using high RPM with acrylic will just melt it and make a mess. I use a moderately slow RPM with a drill ground for cutting plastic, sheet metal, etc.

 

[Tangy1]

Thanks for all the help. I am going to try and see if home depot has a tap that I can buy. I have seen taps online and they look like a drill bit. Do you put the tap into the drill or do you have to turn it by hand?

 

[DJ88]

Well the two above you were talking about drilling so keep that in mind while you drill the pilot hole. Push the bit through slowly and slower RPM. Too fast and it melts the acrylic. Take everything with acrylic as a slow time evolution and you will do fine.

When you actually tap the holes you need to do it by hand. As it was passed on practice a bit first so you get a feel for it.

 

[billzie]

The HD in my area don't carry NPT taps. Ace Hdwr does. Harbor Freight has the best deal though, online. HTH, Bill.

 

[Big_fish]

I just bought a 1/4" NPT tap at Ace Hardware yesterday. The price was $5.99 for just the tap, no handle. It's not a bad price if you consider that I didn't have to pay shipping.

HTH,
Scott