hennebury
Plastic
- Joined
- May 27, 2009
- Location
- Ontario, Canada
BSPP fitting in BSPT hole
Hi,
So i am rebuilding an old woodworking Machine. 1980 vintage made in Germany. It has a feed cylinder on it. an air over oil system . Air is the power , oil is the controlled feed. Thing is the end caps of the cylinder have BSPT taper/ conical bore R3/8" , but the tube fittings are BSPP thread which is a G type parallel or cylindrical thread/ The BSPP seals with an O-ring Boss and compresses the o-ring between the machined surface of the end cap and the shoulder of the fitting.
On this machine they have a straight fitting in a tapered hole. the o-rings have been removed from the fittings and thread sealant has been put in the o-ring groove and on the threads.
Can anyone shed some light on why it would be done this way?
The thing is this seems to have worked well for all these years, and appears that it was done from the factory this way, as i have another machine that seems to be done the same way.
Straight fittings no o-rings , solid sealant.
Straight fittings with o=rings
![Swivel-Elbow-BSP-Thread-PM[1].jpg](https://www.practicalmachinist.com/forum/data/attachments/245/245516-ce9addd303da77e871fa73bf7af72b1a.jpg "Swivel-Elbow-BSP-Thread-PM[1].jpg")
Tapered fittings
![B-Swivel-Elbow-BSPT-Thread[1].jpg](https://www.practicalmachinist.com/forum/data/attachments/245/245517-07f74ca0fc75f4ff2d17ea9169ab6fe1.jpg "B-Swivel-Elbow-BSPT-Thread[1].jpg")
Hi,
So i am rebuilding an old woodworking Machine. 1980 vintage made in Germany. It has a feed cylinder on it. an air over oil system . Air is the power , oil is the controlled feed. Thing is the end caps of the cylinder have BSPT taper/ conical bore R3/8" , but the tube fittings are BSPP thread which is a G type parallel or cylindrical thread/ The BSPP seals with an O-ring Boss and compresses the o-ring between the machined surface of the end cap and the shoulder of the fitting.
On this machine they have a straight fitting in a tapered hole. the o-rings have been removed from the fittings and thread sealant has been put in the o-ring groove and on the threads.
Can anyone shed some light on why it would be done this way?
The thing is this seems to have worked well for all these years, and appears that it was done from the factory this way, as i have another machine that seems to be done the same way.
Straight fittings no o-rings , solid sealant.
Straight fittings with o=rings
Tapered fittings