[jamiedaugherty]

Hey guys, I'm in need of a little bit of help. I want to incorporate a tire valve (sometimes called a Shraeder or Shrader valve) into a part. I don't have the room for a fitting, I need to machine in the geometry for a valve core and the male threads for the cap. The problem that I'm having is finding the geometry for this feature. I found a couple pieces of info but nothing that gives me the whole thing with tolerances and such. I also tried contacting a couple of valve core manufacturers but it appears that all of these are made in China so you can guess what kind of help I got.

If anyone has this info or can point me in the right direction I would really appreciate it!

[litsc]

Schrader valves are classified by their material, diameter of intended rim hole, length, and shape.

• TR-4 - straight metal stem (8 mm dia.)
• TR-6 - straight metal stem (8 mm dia.)
• TR-13 - straight rubber stem (11.5 mm dia.)
• TR-15 - straight rubber stem (16 mm dia.)
• TR-87 - short 90° metal stem (10 mm dia.)
• TR-87C - tall 90° metal stem (10 mm dia.)

The standard Schrader valve has the following threads:
External thread

• Metric: 7.7 mm OD, thread root diameter is 6.9 mm x 0.794 mm pitch.
• English: 0.305 in OD, thread root diameter 0.302 in x 32 tpi (threads per inch)

Internal thread (to accept the threaded valve core)

• Metric: 5.30 mm OD x 0.706 mm pitch
• English: 0.209 in OD x 36 tpi.

For refrigeration, a 1/4" male flare fitting is used, with the same internal thread as above.

[jamiedaugherty]

Sorry, I guess my original post was a little confusing. I don't want the whole stem, I want to machine the geometry for just the valve core. The cap thread size (that you noted) is the only piece of info that I have been able to find. What I need is the geometry inside where the valve core screws into.

Thanks!

[BillTodd]

Any use?:

Patent: TIRE OR OTHER VALVE GEORGE H. F. SCHRADER

[jamiedaugherty]

Any use?:

Patent: TIRE OR OTHER VALVE GEORGE H. F. SCHRADER

Well, that's the idea. What I need is the specifics - angles, diamters, distances, tolernaces, etc. Without the exact dimensions the valve core won't work right. These valve cores are used in lots of places, I'm sure there is a standard out there somewhere.

[acondit]

Well, that's the idea. What I need is the specifics - angles, diamters, distances, tolernaces, etc. Without the exact dimensions the valve core won't work right. These valve cores are used in lots of places, I'm sure there is a standard out there somewhere.

What about taking a schrader stem and cutting it in half and measuring?

Alan

[jamiedaugherty]

What about taking a schrader stem and cutting it in half and measuring?

Alan

I might have to do just that. Unfortunately, my experiences with this type of reverse engineering results in something that doesn't work and requires a bunch of trial and error.

With such a common profile (think of the thousands and thousands of these that are made each year) I'm surprised there isn't a form tool available for it. I guess that I keep coming back to the thought that it shouldn't be this difficult for something so common.

[BillTodd]

Contact a tyre manufacturer ?

[Cruiser]

If you took the valve for a mag wheel which is all metal and modified the end to thread deep into your part you may have it the easy way. If you went to a hydraulic supply and asked for valve used on an accumulator maybe that would work. I know I have had some straight valves before and the best of the best was for an aircraft hyd accumulator used on the F-100 I used to work on. They were rated for High pressure too. used on landing gear and all manor of pressurized units.

[jamiedaugherty]

If you took the valve for a mag wheel which is all metal and modified the end to thread deep into your part you may have it the easy way. If you went to a hydraulic supply and asked for valve used on an accumulator maybe that would work. I know I have had some straight valves before and the best of the best was for an aircraft hyd accumulator used on the F-100 I used to work on. They were rated for High pressure too. used on landing gear and all manor of pressurized units.

The problem is that I don't have enough room to thread something in, even if it's modified to be shorted. I just don't have the wall thickness for this. I need to out a protrusion out one side the valve core and that's it.

Here's a picture of a similar part. What you can't tell from this picture is that the back side of this part is completely hollowed out:

[Weldtutor]

I don't have enough room to thread something in, even if it's modified to be shorted. I just don't have the wall thickness for this. I need to out a protrusion out one side the valve core and that's it.

Do you mean you can put a protruding section on the surface & nothing inside?

You asked for thread info & now say the wall thickness is not sufficient for threads.

Truck tire valves shown HERE could perhaps be used if I understand your application, by inserting them in a prepared opening.

Another solution might be to silver braze a brass valve stem to the surface of the part if it is steel. The valve stem will then accept the valve core.

[jamiedaugherty]

Do you mean you can put a protruding section on the surface & nothing inside?

You asked for thread info & now say the wall thickness is not sufficient for threads.

Truck tire valves shown HERE could perhaps be used if I understand your application, by inserting them in a prepared opening.

Another solution might be to silver braze a brass valve stem to the surface of the part if it is steel. The valve stem will then accept the valve core.

Right. I have room to add a protrusion to house only the valve core. Just under that there is no room for a thread (such as a 1/8NPT). If so I could just use a tire valve fitting and thread it in the part. Back to my original post, that is the whole problem. A fitting like you show is WAY too big, I don't have that kind of room.

If you look at the picture I posted again, the small protrusion is all that I have room for. I've e-mailed the tire and rim association (I think that's what it's called) but have not gotten a response yet. If I get something from them I'll be sure to pass it along.

[sparkness]

here you go from the www.schrader-bridgeport.com/ websitr

http://www.schrader-bridgeport.com/i...id=9&no_html=1

http://www.schrader-bridgeport.com/i...Id=5&Itemid=59

[jamiedaugherty]

here you go from the www.schrader-bridgeport.com/ websitr

http://www.schrader-bridgeport.com/i...id=9&no_html=1

http://www.schrader-bridgeport.com/i...Id=5&Itemid=59

Perfect! That's exactly what I needed, thanks a bunch!

[Riceburner98]

Very nice! The machinist here at work was telling me the other day that he searched everywhere to find the info and couldn't find anything.. Next question, how do you mill threads that small down a bore that small? Make your own tap?

[sparkness]

a 12-36 tap is very close, major dia 0.2151 and minor dia 0.2096
call a tap mfg, someone makes taps that must work

[rogerbsstt]

Guys,

the reason you are having trouble getting the exact angles and dims for an internal valve core is the industry does not want people like us just fitting valves into any old thing. The control of pressure and possible dangers have caused them to be a bit paranoid.
You may be able to access the American / English Standards for a valve core design that may give you the info you want.
Failing that, perhaps reverse engineering is the only option.
I will see if I can obtain any info for you.

rogerbsstt

[jamiedaugherty]

Well, I finally got the info I was looking for. See the attached pdf, page 3 shows the geometry. The ISO standard is a key piece, I've got a tooling supplier looking into what he can get.

[greatgrandpa]

Try this in google (ARI Standard 720-97)

[Mitcho_Chano]

After searching for well over an hour I finally found this thread and it gave me the solution to the more important half of my delema. Now I was wondering if anyone has seen a source to download 3D Solid models of the Schrader valves. I have to create a presentation of my design along with determining the motion of the assembly. I can create a crude model easy enough but I would love to have an exact model.

Thanks in advance for any help

Rob Stoll
Jiffy-tite Co. Inc.
Lancaster, NY 14086
716-681-7200