Page 2 of 2
Re: Metacentric Height and Stability
Posted: Fri May 21, 2021 3:37 pm
by DetroiTug
There is Youtuber ''Project Farm'' that does all sorts of testing on different products with oftentimes surprising results. He did one on hole saws. I'd have a look at that before buying any. I have a set of Milwaukee brand that have worked pretty well.
Ron
Re: Metacentric Height and Stability
Posted: Fri May 21, 2021 4:13 pm
by barts
When I built Otter's boiler ( 25 years ago now, wow) I needed to drill a lot of 5/8" holes in the shell for the steel nipples I welded in for silver soldering the copper tubes. I found that a couple of lengths of pipe in the mill drill table slots kept the shell off the table and allowed me to clamp the shell securely as it was now supported a few inches apart with a t-slot clamp in between. This may be obvious, but it works like a charm.
- Bart
Re: Metacentric Height and Stability
Posted: Sat May 22, 2021 3:18 pm
by tandemcompound
good ideas all. thank you. I will use A106 pipe. Tube sheets are A516 and are now at machine shop. Annular hole saw seems to be the way to go thanks, remember cutting oil and slow slow slow
Re: Metacentric Height and Stability
Posted: Mon May 24, 2021 1:42 am
by tandemcompound
boiler shells, holes, and bushings have been on my mind last 2 days. It turns out I do not need to drill large holes, I can get the welder to burn the holes. I then put a Thread o Lets on. I am working off SBA drawings and they machine a shoulder on their bushings and pop them in an oversize hole and weld on the inside of shell as well. Dunno which is best. Think I will stick to ASME practice.
Re: Metacentric Height and Stability
Posted: Wed May 26, 2021 2:56 pm
by barts
tandemcompound wrote: ↑Mon May 24, 2021 1:42 am
boiler shells, holes, and bushings have been on my mind last 2 days. It turns out I do not need to drill large holes, I can get the welder to burn the holes. I then put a Thread o Lets on. I am working off SBA drawings and they machine a shoulder on their bushings and pop them in an oversize hole and weld on the inside of shell as well. Dunno which is best. Think I will stick to ASME practice.
Both approaches obviously work... but threadolets allow one to put a outlet in w/o needing to reach the back side, or weld in a tight space with limited visibility. The clearance angles on the threadolet combined with a proper root gap (perhaps a bit of wire at three spots) means one can get a 100% penetration weld.
Here's a picture of proper welding practice for these fittings:
http://www.wermac.org/fittings/welding_ ... tings.html
Even if you don't weld it yourself, the "pretty is better" mantra is easy to remember.
- Bart