Enjoy this picture of a 4,500 HP electric motor

On Mon, 8 Feb 2016 10:44:31 -0800 (PST), Christopher Tidy


Being from 1959, it's probably real Honduras mahogany. That's the most moisture-stable, warp-free wood you can get -- a key reason that Linhoff and others used it for view-camera frames.
Most of it is pretty soft, but it varies through a wide range of hardnesses.
I'm down to around 30 board feet of it, harvested in the late '30s.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Am Montag, 8. Februar 2016 19:53:52 UTC+1 schrieb Ed Huntress:

Interesting to know the likely source. Just looked out my pictures and the date is actually 1955. Here's a cross section (I put a little linseed oil on the cut surface to highlight the grain). Looks like this mahogany was laminated somehow: https://www.dropbox.com/s/zrugo6vnozxwtdv/1955_Mahogany.JPG?dl=0

Wish I could find some wood like that.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 8 Feb 2016 15:08:29 -0800 (PST), Christopher Tidy

Hmm. Those white lines are characteristic of Honduras mahogany end-grain, but it does look like it might be at least a couple of layers laminated.
Honduras mahogany varies wildly. The old-growth stuff, which was logged out around a century ago, could be dense and moderately hard. Old corporate boardrooms (like the old one at LeBlond Lathes in Cincinnati, before they tore it down) were often lined with veneered panels made from the old-growth stock. Most harvested by the 1950s was pretty open-grained and soft.
Here are some photos that give you an idea of the range of appearances:
http://tinyurl.com/julgl82

You probably won't. It can be traded only by permit -- it's an "Appendix II" species. (Swietenia humilis). The few hard and figured pieces that can be obtained are confined mostly to making musical instruments. The prices are staggering.
The little bit I have was left over from a boat that was built around 1950.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Interesting. I wonder why the old-growth stock was so much denser? Does it depend on climate, or the state of the soil, or what?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 9 Feb 2016 12:52:09 -0800 (PST), Christopher Tidy

I don't know. I'd have to look it up.
With most deciduous woods, slower growth produces harder wood. But with ring-porous wood (like oak), just the opposite is true. I thought that Honduras mahogany was ring-porous, but maybe that's wrong.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hey Ed, I held a Christie sign post outside the polling place while the state rep I was chatting with took a break. --jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 9 Feb 2016 17:34:37 -0500, "Jim Wilkins"

Just don't bring that thing to New Jersey. We're thinking about leaving him in New Hampshire.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Older heartwood vs younger sapwood?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 9 Feb 2016 16:32:34 -0500, "Jim Wilkins"

Maybe.
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Am Dienstag, 9. Februar 2016 22:32:21 UTC+1 schrieb Jim Wilkins:

Ah. Probably right. Good point.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The pieces of oak I'm making the antenna insulators out of came from a slab off my sawmill, cut into narrow "stickers" to space the planks apart while they dried. The boundary between soft sapwood and denser heartwood runs diagonally across them it and gives me trouble clamping and milling them. --jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 9 Feb 2016 16:32:34 -0500, "Jim Wilkins"

Heartwood is denser, stronger, and much more weatherproof and insect resistant than sapwood. And old-growth stock had much more heartwood because they were much larger and older trees. All of the above are true, tho. Soil and climate can make differences, too.
--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 7 Feb 2016 12:11:35 -0500, "Jim Wilkins"

Yeah, PBS died, SciFi Channel died, History Channel got out of date, Nature got a new persona which SUCKS BIGTIME. In essence, there are five hundred channels with nothing but bullshit on them. Reality programs which have nothing real in them, movies with no actors or plots, etc. As for news people, they all sound the same (with the emPHASis on the wrong sylLABBles) and give you their opinions, not the news. Cronkite is rolling over in his grave. I used to like that rat bastard Peter Jennings until I realized how Liberally skewed his broadcasts were. Then I saw the TEEVEE bigwigs put him up on stage fifteen minutes after 9/11. The Bigs forgot to give him -any- news whatsoever to divulge and he muttered for 45 minutes with the ten words of news they did give him. It was one of the last straws for me with TV. I have much better uses for $90/month. (I used to get the digital music channels, but no longer listen to much music.)

Oh, OK. Most of us didn't make our own TV antennas. <g>
OK, two poles, 5 insulators...so, which one sags?
--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

The antenna mast consists of fixed and sliding assemblies that telescope, so I can work on it standing on the ground or the roof and then raise it to 50' into the good signal above the shadow of a ridge. The strong permanent portion is a 2x4 attached to the house and extending about 5' above the roof, with a 5' removeable extension. Sliding up and down it is the rotator at the bottom of ~37' of steel mast, made from chain link fence top rail that costs $1 per foot versus $4 / foot for nearly identical Radio Shack mast.
The guy lines run over pulleys at the top and tie off at the base, where I can look up to adjust them to straighten the mast, something I can't do by myself from the outer ends. The weakness of this is that the pulleys increase the down force tending to buckle the tubing.
When ice, wind or falling branches overwhelm it, the steel tube bends at the top of the fixed section and costs me about 3 days worth of cable bill to replace. I bought and predrilled several spare sections. In three out of four falls the antenna wasn't damaged and it's back together now with wooden dipole insulators.
We have a week of storms predicted and there's nothing I want to watch this week on local TV that I can't get from a Boston station so it's staying down until the weather improves. I have an flat, unobstructed line of sight to Boston and that antenna is down low. The local stations retained their VHF channels which require a larger, more fragile antenna than UHF-only Boston.
The intent is to lower the antenna for bad weather, assuming they predict it correctly which they didn't. The local joke is that we're shoveling six inches of "partly cloudy".
The antenna lowers very easily but the guy lines, rotator wires, coax and the heavy ground wire tangle and make it troublesome to raise afterwards, and impossible if they are caught in ice. Of course it may have to come down late at night in a cold, windy rain or sleet while I can wait for better conditions to haul it back up.
--jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

[Sarcasm ignored] I get over 90% signal 'quality' at 30 miles from the transmitter. I can measure and tell you the levels in dBm if you'd understand what that means. The off-air recordings I care about are musical performances which would suffer from any noise or dropouts.
https://www.youtube.com/watch?v=ugae8zYMLaE

Fake Roman ruins were a favorite architectural theme in the late 1700's. That one represents Carthage after the Romans were done with it. I'm not sure what the Egyptian obelisk atop the mountain cave was intended to signify. I wish I'd had time to visit Vienna. I barely made it to Salzburg.
--jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 10 Feb 2016 09:08:39 -0500, "Jim Wilkins"

Where's the fun in that?

Yes, classical music has an extremely large dynamic range, with no room for noise, dropouts, or wavering. (can't recall the word for that) I used to care about dBm, selectivity, sensitivity, THD, and all other things stereophonic as an audiophile, but the tinnitus gave me a much different perspective. Now I simply want low distortion and no longer listen to FM at all.

I'm not much into musicals, Strauss, or waltzes, but the Blue Danube has always had a place in my heart. In quad sound at the theater during 2001, a space mess, it was outstanding.
--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Larry Jaques wrote:

'Wow and Rumble' was how it was referred to, for turntables and tape machines.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 10 Feb 2016 18:28:53 -0500, "Michael A. Terrell"

I was referring more to FM, but you can also see something like it on a weak TV signal. It has been a very long time since I've even thought of this.
--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Larry Jaques wrote:

That was referred to as 'Fade', or 'Flutter', depending on the rate that it happened. It was caused by a marginal signal that was outside the set's AGC range.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 11 Feb 2016 03:16:26 -0500, "Michael A. Terrell"

Yeah, those terms sound familiar. Thanks.
--
I would be the most content if my children grew up to be the kind of people
who think decorating consists mostly of building enough bookshelves.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.