loader cylinder replacement help

[oldnslo]

I haven't bought anything from SC, but the few cylinders I have bought have NPT threads in them. 3/8 NPT = # 6 SAE.. The ones that take the o-ring are called ORB (O ring boss) type fittings. Straight threads with an O-ring to seal.

Sean

In the USA, SAE is ORB. #6 SAE is 9/16-18 thread and requires an )-ring. And NPT is NPT, they do not interchange. Not sure how things are done in Canada though.

 

[zmansmac]

On Surplus Center's web site some of their loader cylinders are indicated as having NPT threads. So that's why I'm thinking that the ones indicated as having SAE 6 ports are different. I'm going to go ahead and order the cylinders today and a couple of their adapters that I think are what I need. If they're not what I needed then my fittings bucket will get a little fuller and I'll have to wait a little longer to change out the cylinders until I get the correct fittings. If anyone is interested for future purposes I can post the results after I get all this set up. Thank you all for your valued input.

JohnZ
B7500

 

[LD1]

I haven't bought anything from SC, but the few cylinders I have bought have NPT threads in them. 3/8 NPT = # 6 SAE.. The ones that take the o-ring are called ORB (O ring boss) type fittings. Straight threads with an O-ring to seal.

Sean

Incorrect

In the USA, SAE is ORB. #6 SAE is 9/16-18 thread and requires an )-ring. And NPT is NPT, they do not interchange. Not sure how things are done in Canada though.

I agree with you.


There is a big difference between SAE and NPT.

SAE is straight thread. Take the #/16 and that is the ID of the fitting. In the case of the #6. that is a 3/8 ID fitting with 9/16-18 STRAIGHT thread as oldnslo already indicated.

3/8 NPT is also 18 TPI, BUT it has tapered threads, NOT STRAIGHT.

 

[oldnslo]

LD1 and others,

you absolutely correct that there is a big difference between SAE and NPT. Problem is that:
1/4-18 NPT and #6 SAE 9/16-18 thd
1/2-14 NPT and #10 SAE 7/8-14 thd
3/4-14 NPT and #12 SAE 1 1/16-12 thd

ALL of the above NPT threads will screw into the corresponding SAE a thread or two so people think they fit. A LOT of pipe dope or thread sealant and torque the heck out of them and they may seal for awhile.

If you are real lucky all you destroy is the fitting. Other wise you just ruined the cylinder or what ever component you screwed the fitting into.

For identification purposes, ALL SAE ports should have a spot face on them that is smooth and perpendicular to the threads. This is machined in to help insure a metal to metal seal between the fitting and the mating component. This metel to metal seal keeps the O-ring from extruding and also help prevent the fitting from loosening.

Roy