Well that generated a lot of advice and thanks for it! I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. I'll get some of that Aluminum Tap magic, some new taps and new drill bits. Good idea about drilling the end plates first and drilling thru to match. Between the end plate and the tube is a gasket that needs to seal pressure and moisture tight. That's why I used 5 per side. Will let you know how it turns out. Cheers, Corby

On 18/05/2017 4:34 PM, cdelect@juno.com wrote: I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. Or go back to the shop and get a new quote with them knowing it's not bottom tapping, only 1/4" threaded depth. Michael

Content by Scott Typos by Siri > On May 18, 2017, at 4:34 PM, <cdelect@juno.com> <cdelect@juno.com> wrote: > > Well that generated a lot of advice and thanks for it! > I think I might do it myself and go with a 1/2" hole depth and 1/4" > threaded depth. > I'll get some of that Aluminum Tap magic, some new taps and new drill > bits. > Good idea about drilling the end plates first and drilling thru to match. > Between the end plate and the tube is a gasket that needs to seal > pressure and moisture tight. That's why I used 5 per side. > > Will let you know how it turns out. > > Cheers, > > Corby > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

If you need pressure moisture tightness you are going to want to have machinist mill tube ends and plates flat if you take off say 075-100 thousands deep and .225 thousanths around edge of plate and have machinist predrill holes in cover plate you will have both a tight seal and drill guide for the tube drilling and tapping. Content by Scott Typos by Siri > On May 18, 2017, at 4:34 PM, <cdelect@juno.com> <cdelect@juno.com> wrote: > > Well that generated a lot of advice and thanks for it! > I think I might do it myself and go with a 1/2" hole depth and 1/4" > threaded depth. > I'll get some of that Aluminum Tap magic, some new taps and new drill > bits. > Good idea about drilling the end plates first and drilling thru to match. > Between the end plate and the tube is a gasket that needs to seal > pressure and moisture tight. That's why I used 5 per side. > > Will let you know how it turns out. > > Cheers, > > Corby > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

On 5/18/17 1:34 PM, cdelect@juno.com wrote: > Well that generated a lot of advice and thanks for it! > I think I might do it myself and go with a 1/2" hole depth and 1/4" > threaded depth. > I'll get some of that Aluminum Tap magic, some new taps and new drill > bits. > Good idea about drilling the end plates first and drilling thru to match. > Between the end plate and the tube is a gasket that needs to seal > pressure and moisture tight. That's why I used 5 per side. I would make the end plate "real thick",with a machined groove for the o-ring, and use some sort of latches to hold it in place, rather than "lots 'o screws". Unless you've got a real tight space constraint. How much pressure do you have to hold? That will determine the clamping force needed on your gasket (and potentially, on your fasteners). Do you need the full 4.5x4.5" inside clear space? A 1/4-20 bolt in the corner might be a good way to go. There's also inexpensive surplus vacuum equipment around, as well as run of the mill plumbing. Unless Steel (stainless or not) isn't an option. > > Will let you know how it turns out. > > Cheers, > > Corby > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Corby, Is it a 'pressure' seal or a 'vacuum' seal? Vacuum should be much easier to achieve. Joe -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of cdelect@juno.com Sent: Thursday, May 18, 2017 3:34 PM To: time-nuts@febo.com Subject: [time-nuts] Machining some aluminum help! Well that generated a lot of advice and thanks for it! I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. I'll get some of that Aluminum Tap magic, some new taps and new drill bits. Good idea about drilling the end plates first and drilling thru to match. Between the end plate and the tube is a gasket that needs to seal pressure and moisture tight. That's why I used 5 per side. Will let you know how it turns out. Cheers, Corby _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

I worked on a project like this once. No screws at all. Rather then a 0.1 PSI over pressure. the interior was flush with dry gas then pumped out with to a crude vacuum with a hand pump. Air pressure alone force the cover plate on. OK a couple screws where there just to aid in assembly but the cheap $12 hand pump was good enough. "high vacuum" requires expensive equipment and is a black art but "crude vacuum" is easy, easier then holding a pressure because the forces are pushing the seal together for you. On Thu, May 18, 2017 at 2:46 PM, jimlux <jimlux@earthlink.net> wrote: > On 5/18/17 1:34 PM, cdelect@juno.com wrote: > >> Well that generated a lot of advice and thanks for it! >> I think I might do it myself and go with a 1/2" hole depth and 1/4" >> threaded depth. >> I'll get some of that Aluminum Tap magic, some new taps and new drill >> bits. >> Good idea about drilling the end plates first and drilling thru to match. >> Between the end plate and the tube is a gasket that needs to seal >> pressure and moisture tight. That's why I used 5 per side. >> > > I would make the end plate "real thick",with a machined groove for the > o-ring, and use some sort of latches to hold it in place, rather than "lots > 'o screws". Unless you've got a real tight space constraint. How much > pressure do you have to hold? That will determine the clamping force needed > on your gasket (and potentially, on your fasteners). Do you need the full > 4.5x4.5" inside clear space? A 1/4-20 bolt in the corner might be a good > way to go. > > There's also inexpensive surplus vacuum equipment around, as well as run > of the mill plumbing. Unless Steel (stainless or not) isn't an option. > > > > > > >> Will let you know how it turns out. >> >> Cheers, >> >> Corby >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California