kneadle said:
I like that joke!
Since this is an international forum, we do get a hint of the Metric/Standard measurements clash. Nice to get some ammunition for the defense of the USA being the last holdout against the Metric onslaught.
Alas, not too long. The elementary schools are teaching the kids Metric. Oh, well.
Of all the "duh" moments that have been on me for the last week or so, this one's cheerfully on you: Duh! Heh heh heh. Just teasing, of course.kelticwizard said:
kelticwizard said:
Over the course of 6 3/8", a 22.5° angle will derive from the axis by roughly 2 5/8". I measured the inside of my jig guides according to that, and sawed to the inside of the marks as best I could.
I have to say, the results have made me proud. I saw with as much accuracy as I can imagine. Seriously, with a crosscut handsaw, I'm well within a plus or minus 1/16th" error rate. I don't think a power saw solution could be much better, save a powerful bandsaw.
At any rate, I'm taking off at noon to a workshop, so at least I can stand upright to saw. No power saws, but a well-lighted workshop.
I'm assuming you're checking my 2 5/8" number, but I want to extend the courtesy of asking please. Please double check my math on that one.
dave
kelticwizard said:
And I like THAT joke! Back in the 70s they were doing the same thing. They even changed some road signs to show both systems. Then, in the early 80s, if I recall correctly, they very quietly took down those signs and put the old ones back up.
It'll never happen here...
MR
MRehorst said:
That's because a mile is a mile, doggonit, not 2.8 kilometers, or whatever. I mean, can you imagine throwing a football a "Kountry 2.8 Kilometers"? Remember 7-Up's "A Liter Bit More" campaign from the 70s? I was just a wee lad...
Uh oh, I might be hijacking my own post, here. We should probably cease and desist since so many metric types populate this forum.
Dave
Kneadle:
Your measurements are right on the money.
One last, lingering concern-I'm trying to forecast potential problems so they cannot catch us by surprise.
That 2 5/8" inch measurment was made from the inside wall of the jig, correct?
As long as the inside wall was measured as being 2 5/8" shorter than the inide of the other wall, you are fine.
If, on the other hand, you made one outside wall of the jig 2 5/8" shorter than the outside wall on the other side, and you used 1/4" material, your angle is 20.89°.
If you used 1/2" material for the jig and you measured from the outside of the walls, your angle will be 19.58°.
Even if you did this-and I am not saying you did-I don't know how much it would affect the structure. If you were building a flat octagon, there would be a space left between two pieces when you tried to fit it. But with a spiral, I don't know that such differences would necessarily be noticeable.
But I just thought I would mention that.
Have a good afternoon cutting in your workshop. Let us know how it's coming.
Your measurements are right on the money.
One last, lingering concern-I'm trying to forecast potential problems so they cannot catch us by surprise.
That 2 5/8" inch measurment was made from the inside wall of the jig, correct?
As long as the inside wall was measured as being 2 5/8" shorter than the inide of the other wall, you are fine.
If, on the other hand, you made one outside wall of the jig 2 5/8" shorter than the outside wall on the other side, and you used 1/4" material, your angle is 20.89°.
If you used 1/2" material for the jig and you measured from the outside of the walls, your angle will be 19.58°.
Even if you did this-and I am not saying you did-I don't know how much it would affect the structure. If you were building a flat octagon, there would be a space left between two pieces when you tried to fit it. But with a spiral, I don't know that such differences would necessarily be noticeable.
But I just thought I would mention that.
Have a good afternoon cutting in your workshop. Let us know how it's coming.
in reality, the octagon was just a starting point. due to the nature of the spiraling angles, you will not end up with an octagon when viewed from the top or bottom. (in architecture we call that a plan view, by the way.)
you don't have to imagine it - the plan view is shown on my diagrams.
what you'll end up with is a wierd polygon with vertices that overlap and pass each other...remember the old spirograph drawing toy? it drew shapes (okay they were curves, but the principle is the same) that seemed to be rotated upon themselves. that's sortof what our 'octagon' turns into when we do that 11° rotation at every joint.
if you laid out the pieces flat on a horizontal plane, you would get approximately an octagon. (i say approximately because with the rotated cut, you won't be able to assemble it as a flat shape.) but once you start rotating the pieces into their place in the 'z' dimension, the angles change when viewed from the top (plan view).
ok, the platonist theory is done...back to the reality of jigs and saws...
/andrew - likes a good jig every now and again
you don't have to imagine it - the plan view is shown on my diagrams.
what you'll end up with is a wierd polygon with vertices that overlap and pass each other...remember the old spirograph drawing toy? it drew shapes (okay they were curves, but the principle is the same) that seemed to be rotated upon themselves. that's sortof what our 'octagon' turns into when we do that 11° rotation at every joint.
if you laid out the pieces flat on a horizontal plane, you would get approximately an octagon. (i say approximately because with the rotated cut, you won't be able to assemble it as a flat shape.) but once you start rotating the pieces into their place in the 'z' dimension, the angles change when viewed from the top (plan view).
ok, the platonist theory is done...back to the reality of jigs and saws...
/andrew - likes a good jig every now and again
kneadle said:
A mile is 1.6 km. All our cars and roads are marked in km and we buy gas in litres and i still measure my mileage in miles/gallon (not those wimpy US gallons, but real Imperial gallons) and can do the conversion from km/litre in my head (still easier than trying to think in km/l 🙂)
dave
continued success
It's 2:30. I have 7 pieces duct-taped together. It looks pretty good. I can see that the human element causes unexpected variations from the pattern, but all-in-all, we're on the road to a decent set of speaker enclosures.
I don't have my camera here, but I will return after some meetings and dinner in order that I may keep you apprised with photos.
Gemuetlichkeit!
And yes, nothing in the world matches an imperial pint.
Dave
It's 2:30. I have 7 pieces duct-taped together. It looks pretty good. I can see that the human element causes unexpected variations from the pattern, but all-in-all, we're on the road to a decent set of speaker enclosures.
I don't have my camera here, but I will return after some meetings and dinner in order that I may keep you apprised with photos.
Gemuetlichkeit!
And yes, nothing in the world matches an imperial pint.
Dave
Re: continued success
Actually the difference between imperial & US happens because an Imperial Quart has 2.5 pints in it ans a US quart has 2 pints in it... the pint is the same size 🙂
But you would be drinking an Imperial pint in Canada, UK, Oz, or NZ where the beer is not so watery...
dave
kneadle said:
Actually the difference between imperial & US happens because an Imperial Quart has 2.5 pints in it ans a US quart has 2 pints in it... the pint is the same size 🙂
But you would be drinking an Imperial pint in Canada, UK, Oz, or NZ where the beer is not so watery...
dave
Concerning pints: Me and my big mouth. I could have sworn an imperial pint was bigger than a US pint. Maybe just more potent.
Hey, it turns out that the 90° mark I described several posts back is very helpful when assembling the pieces. I simply line each one up, turn it a half inch (the 11°) and ouila! An octagonally-resemblingly-spirally-thingy is emerging.
Hey, it turns out that the 90° mark I described several posts back is very helpful when assembling the pieces. I simply line each one up, turn it a half inch (the 11°) and ouila! An octagonally-resemblingly-spirally-thingy is emerging.
kneadle said:
😀 Molson's Extra Old Stock* has left many an American wondering what hit them
*(a good example of a nationally available brand -- some of the smaller local labels have even more kick)
I have heard Europeans refer to American coffee as black water. They have an even less appetizing would (describing a liquid of similar colour) for the beer.
dave
Re: Re: continued success
Both Europeans and Americans agree where beer first enters the body, and both agree where it eventually leaves. Where they differ is that Americans see no reason why the beer has to be the same temperature on both ends of the journey. 😀 😀
planet10 said:
planet10 said:
Both Europeans and Americans agree where beer first enters the body, and both agree where it eventually leaves. Where they differ is that Americans see no reason why the beer has to be the same temperature on both ends of the journey. 😀 😀
Re: continued success
I really do think that most any glue that sticks to vinyl will stick to PVC. If the PVC glue is too quick-drying, there is a tech help number I could call for you tomorrow to find out about slower-setting alternatives. There are quite a few glues that stick to vinyl, and very few, if any, that stick to polyethylene. That is why, if you need clear plastic wrap for a project, you'll find that Saran wrap, (vinyl), can be glued and most any other brand of plastic wrap cannot be.
Have you decided on a glue yet? There is some talk that PVC glue dries too quickly.kneadle said:
I really do think that most any glue that sticks to vinyl will stick to PVC. If the PVC glue is too quick-drying, there is a tech help number I could call for you tomorrow to find out about slower-setting alternatives. There are quite a few glues that stick to vinyl, and very few, if any, that stick to polyethylene. That is why, if you need clear plastic wrap for a project, you'll find that Saran wrap, (vinyl), can be glued and most any other brand of plastic wrap cannot be.
What's the scoop on Plumber's Goop? That's what I bought way back when I started this.
The directions say that it works a little like rubber cement: you put it on the surfaces you wish to glue together, then you let it wait for a bit. Then you shove the pieces together, and it's a done deal within five minutes. It takes 24-72 hours to cure.
Dave
PS. #1 will be completely cut tonight. I'll post a pic at that time.
The directions say that it works a little like rubber cement: you put it on the surfaces you wish to glue together, then you let it wait for a bit. Then you shove the pieces together, and it's a done deal within five minutes. It takes 24-72 hours to cure.
Dave
PS. #1 will be completely cut tonight. I'll post a pic at that time.
And one more thing.
Does anyone have any doubts about the reverse 11° thing?
The first one I have always turned -11°, as I described late last night in that pic.
For the second set of segments, for the mirror enclosure, I plan to turn each one +11°.
Now, that should force the spiral the other way, right? I'm doing that one on blind faith so far.
Dave
PS, it is such a thrill to cut 6" PVC pipe using a jig, basically blind to the mark, and hitting the "x" right in the middle, so that all that's left is an arrow pointing into space. I've hit that a few times, now.
Does anyone have any doubts about the reverse 11° thing?
The first one I have always turned -11°, as I described late last night in that pic.
For the second set of segments, for the mirror enclosure, I plan to turn each one +11°.
Now, that should force the spiral the other way, right? I'm doing that one on blind faith so far.
Dave
PS, it is such a thrill to cut 6" PVC pipe using a jig, basically blind to the mark, and hitting the "x" right in the middle, so that all that's left is an arrow pointing into space. I've hit that a few times, now.
kneadle said:
yes, i have confidence that it will indeed spiral the other way.
i can't wait to see pictures............
Kneadle:
I have to admit that I am not 100% sure on the spiral thing. Only about 90% sure.
Look at it this way. I cannot see any way that it would not work that way.
Take a look at Post #181 on Page 13. That piece is cut in the direction that you are cutting now. If you reverse the position of the 11° angle line in reference to the centerline, how can you not go in the other direction?
I wouldn't stake my life on it,
, but I would stake an 8 foot long piece of 6" diam PVC pipe on it.
I have to admit that I am not 100% sure on the spiral thing. Only about 90% sure.
Look at it this way. I cannot see any way that it would not work that way.
Take a look at Post #181 on Page 13. That piece is cut in the direction that you are cutting now. If you reverse the position of the 11° angle line in reference to the centerline, how can you not go in the other direction?
I wouldn't stake my life on it,
, but I would stake an 8 foot long piece of 6" diam PVC pipe on it.
faustian bargin said:
yes, i have confidence that it will indeed spiral the other way.
i can't wait to see pictures............
Patience, grasshopper.
I have the camera here at the workshop, but I forgot the cable to get the pics to the computer here.
Last last laaaaast thing. When I'm assembling it, I'm basically turning every other segment over...
well, I don't know quite exactly what I'm doing. Every other piece points the exact same direction (I drew arrows). The ones in between? Dunno. Just sort of turning them. There ought to be a way to know for sure if I'm lining up the right marks.
Dave
Don't know what to tell you except that any two pieces ought to be join at a 45° angle with the left one pointed slightly up, (assuming that you are standing in front of the inside diameter of the two pieces.
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