Fitting a (UK) commercial tap into the keezer collar

[CraigR]

I picked up a Guinness tap and lager tap from a bar sale and want to use them in my keezer build.
I removed the taps from the stands, but the shanks are quite short.

I thought the best way to proceed would be to drill a hole in the collar and fit a threaded insert, so I could screw the tap in.
Can anyone confirm the external thread size of a commercial tap please ?

 

[Clint Yeastwood]

If you get desperate, you can probably buy a thread gauge online for $5. They're easy to use.

Well, wait. If you mean a typical US shank like the ones most of us use, I can measure one of mine.

 

[Clint Yeastwood]

If you get desperate, you can probably buy a thread gauge online for $5. They're easy to use.

Well, wait. If you mean the same size thread as the US shanks most of us use, I can measure one of mine.

 

[CraigR]

… never thought about a thread gauge- didn’t realise they were so cheap.

Will pick one up

 

[Clint Yeastwood]

Don't forget to measure the diameter. You'll want a dial or digital caliper. I can measure one of my shanks if you don't feel like it.

 

[Deadalus]

The typical size for beer threads on shanks is 5/8" BSP. US measurements is shown to be 29/32"-14 for beer nuts but I am not sure that's a true match. Since BSP is British straight pipe thread and you are saying this is a UK tap it's probably 5/8" BSP but I don't know if that continues to be the standard there. It generally is here in the US from my own experience.

Curious what was on the back side of the shank that you got what looks like a ptc fitting on there?

 

[ClaudiusB]

I picked up a Guinness tap and lager tap from a bar sale and want to use them in my keezer build.
I removed the taps from the stands, but the shanks are quite short.

I thought the best way to proceed would be to drill a hole in the collar and fit a threaded insert, so I could screw the tap in.
Can anyone confirm the external thread size of a commercial tap please ?View attachment 847745

My solution to the problem.

 

[day_trippr]

US standard shank threads are 7/8"x14. I believe 5/8 BSP is close but iirc the thread angles may be different...

[edit] ChatGPT says this about the threads:

The thread angles for BSP (British Standard Pipe) threads and Unified Thread Standard (UTS) threads, such as the 7/8"x14, are different.

• BSP Threads: The thread angle for BSP threads is 55 degrees.
• UTS Threads: The thread angle for UTS threads, which includes the 7/8"x14 measurement you provided, is 60 degrees.

Having used 5/8 BSP threaded PTC tailpieces (JG iirc) on my 7/8"x14 shanks I can say they are definitely not a perfect fit...

Cheers!

 

[Deadalus]

I missed copying the "2" but fixed it for 29/32 x14 in my previous post which came from Morebeer when I googled "beer nut thread size." I do see other references to the 7/8" x14 size. However I just use the 5/8" BSP designation as I believe it's a holdover in the industry but I don't have a reference for that. Duotights shank adapters are 5/8" BSP to ptc in whatever millimeters, not sure the extent of all offerings but I have 5/8" BSP x 8mm on all my shanks which are a mixture of manufacturers. The threads are cut slightly different between the two systems as mentioned. In this particular application, it's just to hold the shanks in place and not to seal so not likely of much importance.

 

[Clint Yeastwood]

The web says US shanks are 7/8"-14 by our standards or 5/8" BSP, which is British Standard Pipe, not to be confused with BSPT or British Standard Pipe Taper. These sizes are supposedly the same. The US standard in this case is UNF or Unified Fine inch, which should be "UFI," but there it is.

The 7/8" figure is obviously the major diameter, which is from peak to peak across the outside of the pipe.

Looks like you need a short coupling which is female on both ends. I don't see it at McMaster, which makes me wonder if it exists. I found something in zinc that will work, but then you would have zinc beer.

You probably won't want to do this, but you can buy a 7/8"-14 tap to thread a stainless pipe. I think it would take a lot of torque and plenty of Moly-Dee.

Oh, hey, I found something at Grainger (okay, Zoro, or Grainger for soccer moms). I don't know if you can buy two of these, but you can get 10 for about $83.

https://www.zoro.com/midwest-fasten...kl7Q0m68sMZhbX4kbPxoCcLQQAvD_BwE&gclsrc=aw.ds

 

[day_trippr]

Do they also list a 7/8-14 coupling nut?

Cheers!

 

[Clint Yeastwood]

Here's something interesting: an HSS tap and die set, surely Chinese:

https://www.amazon.com/Burkit-14-UN...-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

 

[Deadalus]

Nevermind, I didn't see the post before what I quoted.

 

[Deadalus]

The web says US shanks are 7/8"-14 by our standards or 5/8" BSP, which is British Standard Pipe, not to be confused with BSPT or British Standard Pipe Taper. These sizes are supposedly the same. The US standard in this case is UNF or Unified Fine inch, which should be "UFI," but there it is.

The 7/8" figure is obviously the major diameter, which is from peak to peak across the outside of the pipe.

Looks like you need a short coupling which is female on both ends. I don't see it at McMaster, which makes me wonder if it exists. I found something in zinc that will work, but then you would have zinc beer.

You probably won't want to do this, but you can buy a 7/8"-14 tap to thread a stainless pipe. I think it would take a lot of torque and plenty of Moly-Dee.

Oh, hey, I found something at Grainger (okay, Zoro, or Grainger for soccer moms). I don't know if you can buy two of these, but you can get 10 for about $83.

https://www.zoro.com/midwest-fasten...kl7Q0m68sMZhbX4kbPxoCcLQQAvD_BwE&gclsrc=aw.ds

Just as a note but not as important here for what is wanted, UTS is Unified Thread Standard for fasteners, such as screws and bolts. BSP is British Standard Pipe. (The second p in BSPP is often left off because parallel threads are predominately used in plumbing there.) If anyone were actually extending the shank as a pipe connection, you'd want to stick with BSP fittings to maintain the seal. I'm more familiar with NPT couplings. The BSP couplings I think would need an internal face for the gasket to seal the connection. Usually one would just get the right shank size though.

 

[CraigR]

Many thanks to everyone for their contributions.
I like the images posted by Claudius B, I think I’ll whip out a router or a wide wooden bit and remove half the thickness from my 2 x 5, so the wider profile on the inside will allow me to attach a nut with a socket to secure the shank.
My metric measurements show the shank to be about 20mm diameter, and rather than using a threaded insert, I can use an appropriate sized nut, which will work out a bit cheaper. I’ll take my tap to my local Toolstation, they are pretty good.
The tube fitting into the back of the shank looks like a John guest push fit, so the material of the nut won’t matter, as the beer will never come into contact with it.