Which size hole punch for a 3/4" threaded fitting?

[Smellyglove]

Anyone knows which size the hole punch should be to make a tight fit with a 3/4" OD fitting? I can't seem to find anything about it.

Blichmann says that for their 1/2" autosparge the hole should be 13/16. I haven't gotten my hole punch yet so I don't know how big the hole is comparing to the autosparge-fitting. It it possible to just size up to figure out what the 3/4" hole should be?

 

[plumber_bob]

Anyone knows which size the hole punch should be to make a tight fit with a 3/4" OD fitting? I can't seem to find anything about it.

Blichmann says that for their 1/2" autosparge the hole should be 13/16. I haven't gotten my hole punch yet so I don't know how big the hole is comparing to the autosparge-fitting. It it possible to just size up to figure out what the 3/4" hole should be?

I use a 7/8" holesaw and have had no issues at all. 13/16" holesaw would probably be better but I'm not sure how easy it would be to find one.

pb

 

[Smellyglove]

I use a 7/8" holesaw and have had no issues at all. 13/16" holesaw would probably be better but I'm not sure how easy it would be to find one.

pb

Hmm. Blichmann recommends a 13/16" hole for their 1/2" Autosparger. And you recommend the same size hole for a 3/4" fitting?

 

[plumber_bob]

Hmm. Blichmann recommends a 13/16" hole for their 1/2" Autosparger. And you recommend the same size hole for a 3/4" fitting?

IIRC you stated your fitting was 3/4" OD, right? I believe that's standard for 1/2" ID male parts that are threaded.

3/4" OD = 12/16". So 13/16" will work just fine.

What I was getting at is that for my fitting in this size range I use a 7/8", (14/16"), and have no problems.

With all that said, I just got an order from Bobby M, part of that order is parts to add a bottom valve just for whirlpooling. The rest was a set of step bits. I will definitely try a 13/16" hole before I go to 7/8" to see if it is that much better.

You will get it to work with either size hole, I'm sure. My original response was more of a, I found the 7/8" hole saw for the better price and it worked just fine, type thing.

Ideally I figure your bulkhead should just fit into the hole with the threads not being buggered up. But a tad of slop won't kill ya either.

pb

 

[microbusbrewery]

So is the OP using 1/2" fittings (approx OD 3/4") or a 3/4" fitting (approx OD 1")? I was assuming it's a 1/2" fitting as well. So 13/16" gives a snug fit and 7/8" will have a bit of play until you snug things up. I use Kal's Blichmann style fittings on my equipment. Before I got my hands on a 13/16" chassis punch I used a step bit and drilled it to 7/8" and they both work fine for 1/2" fittings.

 

[plumber_bob]

I was assuming 1/2" ID fittings.

pb

 

[Smellyglove]

I was assuming 1/2" ID fittings.

pb

Here is the piece I'll try to fit:
http://www.ebay.com/itm/290943442045?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I'm from metric country, all these inches, feet, elbows and toes are making me confused

 

[microbusbrewery]

I'm confused too. Why do you want to use the bushing in a larger diameter hole when you can do a 13/16 or 7/8 hole and use the included nuts to mount it?

 

[plumber_bob]

Here is the piece I'll try to fit:
http://www.ebay.com/itm/290943442045?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I'm from metric country, all these inches, feet, elbows and toes are making me confused

That's s bushing adapter. Now we have a different beast.
You are basically going from 1/2" ID to 3/4" ID.

Hole sizes shouldn't change though. 13/16" - 7/8" should not work fine.

pb

 

[WPStrassburg]

3/4 pipe is 1.050"OD (1.05"*25.4mm/in=26.67mm) so you will either need a 1 1/16" drill bit or a 1" hole saw is usually sloppy enough that it ends slightly up bigger than the nominal size indicated.

http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

 

[plumber_bob]

3/4 pipe is 1.050"OD (1.05"*25.4mm/in=26.67mm) so you will either need a 1 1/16" drill bit or a 1" hole saw is usually sloppy enough that it ends slightly up bigger than the nominal size indicated.

http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

In bushing sizes, most use ID sizes for reference. so 3/4" on the large side of a bushing is still 3/4" ID. and that is the same as the OD for 1/2"ID.

pb

 

[Smellyglove]

I'm confused too. Why do you want to use the bushing in a larger diameter hole when you can do a 13/16 or 7/8 hole and use the included nuts to mount it?

I shouldn't have mentioned the autosparge. I was only wondering if I could use the same relative diameters. Don't mind the autosparge, it has nothing to do with this.

 

[Smellyglove]

That's s bushing adapter. Now we have a different beast.
You are basically going from 1/2" ID to 3/4" ID.

Hole sizes shouldn't change though. 13/16" - 7/8" should not work fine.

pb

I might be slow... But (once again the autosparge as an example) the autosparge,which actually fits into the bushing, should have the same size hole as the bushing?

Or to put it this way. A larger diameter (the bushing) should have the same diameter hole as as smaller diameter fitting? (The autosparge)

And again. I'm just using the autosparge as an example since I know the holesize for it.

 

[plumber_bob]

I might be slow... But (once again the autosparge as an example) the autosparge,which actually fits into the bushing, should have the same size hole as the bushing?

Or to put it this way. A larger diameter (the bushing) should have the same diameter hole as as smaller diameter fitting? (The autosparge)

And again. I'm just using the autosparge as an example since I know the holesize for it.

Okay, is the bushing going through the MLT?

Post a link to this part maybe.

pb

 

[Smellyglove]

Okay, is the bushing going through the MLT?

Post a link to this part maybe.

pb

Yes. The bushing(s) will go through mlt, hlt and bk. I posted a pic of the bushing earlier.

 

[plumber_bob]

Yes. The bushing(s) will go through mlt, hlt and bk. I posted a pic of the bushing earlier.

Then you should be good with either size hole. 13/16" or 7/8" which ever you can get.

pb

 

[WPStrassburg]

If you are using the 3/4" to 1/2" PIPE reducer bushing you are going to need at least a 1" hole. We are not talking about a sleeve bushing. The major (largest) diameter on the threaded NPT bushing is just under 1.050", not 3/4".

 

[plumber_bob]

If you are using the 3/4" to 1/2" PIPE reducer bushing you are going to need at least a 1" hole. We are not talking about a sleeve bushing. The major (largest) diameter on the threaded NPT bushing is just under 1.050", not 3/4".

Okay, I have gone to my stash of fittings to double check, and I stand corrected. A nipple for 3/4" ID pipe is closer to an inch. Thank you for speaking up.

I must be getting dyslexic in my old age!!!

pb

 

[Bobby_M]

I don't have anything constructive to add but this whole thread reads like a plumber's version of "Who's on First". Carry on.