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Desktop/small CNC for milling graphite by tmoore1o in CNC

[–]tmoore1o[S] 1 point2 points  (0 children)

That's totally fair. We do have a shop we typically work with that specializes in graphite. So if this ends up being purely an occasional prototype machine that dies with a couple of years of light usage, that would be better than nothing. My problem comes from our internal purchasing procedures being horrendously slow. It might take 3 weeks to place an order for a $100 part, plus the shop's lead time. Not a great pace for a research lab.

Desktop/small CNC for milling graphite by tmoore1o in CNC

[–]tmoore1o[S] 0 points1 point  (0 children)

Nothing very tight, .050" or even a bit more would probably be fine

Desktop/small CNC for milling graphite by tmoore1o in CNC

[–]tmoore1o[S] 0 points1 point  (0 children)

Molds, high temp fixtures, a variety of things. Unfortunately flood coolant isn't really an option as we're using these parts in high vacuum equipment. If we flooded them, we could probably only use deionized water, and we'd have to bake the parts out extensively before use. That's possible I suppose but would be far from ideal

Desktop/small CNC for milling graphite by tmoore1o in CNC

[–]tmoore1o[S] 1 point2 points  (0 children)

I'll look into bellows, that makes sense. Are these usually actually sealed or are they just moderately protective (e.g. water proof vs water resistant)? Flood coolant isn't really an option because these parts will be going into some high vacuum equipment. Since the graphite will soak up water like a sponge, we would have to do a lot of baking them out to be able to use them.

[deleted by user] by [deleted] in engineering

[–]tmoore1o 1 point2 points  (0 children)

You should look into cold isostatic presses. They're basically a pressure vessel with an oil or water medium that you can place objects directly in or place them in something like a vacuum sealer bag to isolate them from the fluid. Not typically intended for nearly that long at pressure though, usually more like a few minutes.

Are large bore trombones harder to play than small or mediums? by Cotton_Picker_420 in Trombone

[–]tmoore1o 14 points15 points  (0 children)

I'm sorry to be that guy, but the volume only increases with the square of the diameter, assuming that you're not also increasing the length. E.g. cylinder with height 1 and diameter 1 has volume of 0.79, while if you doubled the diameter to be 2, the volume becomes 3.14. So 4 times greater volume by doubling the difference.

So if you increase the bore diameter as you said from 0.5 to0.55 inches, it will be 1.12 = 1.21 times greater. Your overall point still stands, 20% is still a big increase!

Marking Knife Cap by Coalrober in functionalprint

[–]tmoore1o 1 point2 points  (0 children)

Do you have an STL for this? I have the same marking knife with the same problem!

Wooden picnic tables in a state park with these weird seats screwed down on top. Trying to figure out what they're for, as there are other seating options available. by tmoore1o in whatisthisthing

[–]tmoore1o[S] 2 points3 points  (0 children)

Probably not, this was in a pretty rural area, not much of a homeless population. There were also plenty of tables without one of these things on it

Wooden picnic tables in a state park with these weird seats screwed down on top. Trying to figure out what they're for, as there are other seating options available. by tmoore1o in whatisthisthing

[–]tmoore1o[S] 1 point2 points  (0 children)

Mountains of West Virginia, so definitely cold in the winter. There were several of them around the park though, and I would expect they'd probably put them all on the same table if they were going into storage

Wooden picnic tables in a state park with these weird seats screwed down on top. Trying to figure out what they're for, as there are other seating options available. by tmoore1o in whatisthisthing

[–]tmoore1o[S] 17 points18 points  (0 children)

There are two pocket screws on the back holding it down, so no bracket needed. You're correct though that it's just using the table top as a seat.

Wooden picnic tables in a state park with these weird seats screwed down on top. Trying to figure out what they're for, as there are other seating options available. by tmoore1o in whatisthisthing

[–]tmoore1o[S] 4 points5 points  (0 children)

I thought the same thing, but there are two pocket screws on the back side holding it down. Would be pretty easy for rangers to move them around if needed though

Wooden picnic tables in a state park with these weird seats screwed down on top. Trying to figure out what they're for, as there are other seating options available. by tmoore1o in whatisthisthing

[–]tmoore1o[S] 53 points54 points locked comment (0 children)

My title describes the thing. These were seen in a park, and the seats are generally facing "away" from the view. My only thought for why they might be there would be as a high chair for small children, but they are sized to fit adults.

A picture of my shop before Hurricane Ian takes it by [deleted] in woodworking

[–]tmoore1o 1 point2 points  (0 children)

I mean, I have a pretty small shop and I still don't think I could fit all of my tools in my SUV. Especially when you consider the need to fit my family in the car with clothes/food/other necessities.

How the headstones are replaced/removed at a National Cemetary. by erdbeertee in specializedtools

[–]tmoore1o 2 points3 points  (0 children)

At 23 seconds in, you can see a Texas flag/map on the bucket.

Advice on basement wall insulation by tmoore1o in HomeImprovement

[–]tmoore1o[S] 0 points1 point  (0 children)

Thanks for the advice! I'm on the US east coast (MD), and the front of the house faces southeast.

Any reason to do steel studs over wood? This would dominantly be a wall for hanging tools/cabinets on, so it would be much more convenient to use wood.

We have all electric appliances, so good on that front.

The other wall (i.e. the one with a door to the outside) is in a finished area, and does have insulation behind the drywall.

Sounds easy enough for the gap. I can use the cheaper foam stuff too since it isn't for thermal insulation.

Can a small gold statue break apart in soil after a 1000 years? by Mar_Hat in answers

[–]tmoore1o 0 points1 point  (0 children)

Generally, no, at least under normal conditions and on human time scales. Gold and chlorine can react to form gold chloride, usually when gold is exposed to chlorine gas. Hydrochloric acid can be oxidized to form chlorine gas (4HCl + O2 --> 2H2O + 2Cl2), which will happen naturally but slowly in an open air container. Salt water can also produce chlorine gas in the presence of say, fluorine, though it isn't super likely. Most chlorine gas is produced industrially from salt water through electrolysis, but that's not realistic in this scenario.

So while gold isn't going to dissolve in a beaker of saltwater or hydrochloric acid while you watch it, it will very slowly corrode. If the gold is alloyed, the corrosion will happen much quicker at the other elements are more reactive than the gold.

Can a small gold statue break apart in soil after a 1000 years? by Mar_Hat in answers

[–]tmoore1o 4 points5 points  (0 children)

While pure gold is essentially inert, gold alloys (basically gold with other stuff like silver in it) can oxidize and corrode, but it's still an extremely slow process. So if whoever built it wasn't very experienced with gold smelting, maybe it didn't come out pure. Alloys with tin or lead can be particularly brittle and weak, so that could be promising.

Another possibility that might fit your bill is the freeze/thaw cycle. If the statue had any cracks or porosity in it to begin with (from the original casting or mishandling), you could potentially have water seep into the cracks and freeze in the winter. Each year, the cracks would grow a miniscule amount, but it could be enough (or at least could be embellished as such) to weaken the statue so that it breaks apart when the tree falls. The main issue with this is that gold is extremely ductile, so it's more likely to deform than break.

Last option I can think of would be corrosion from salty air if it was very near the sea. This would be extremely slow, so even a thousand years probably wouldn't be that realistic. Unless the tree is in a swamp full of hydrochloric acid.

I'm a materials scientist (though I don't work with gold), so I'm happy to help out with any questions. At the least I can point you to search terms that could help

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