2015 POTD Thread Archive

[ogberi]

Not bad
Brass and bronze do take some heat. I have been suspected of throwing in a handful of smallest denomination coins, to replace what zinc burns off (greenish flames), but of course I would *never* do that because it's illegal to destroy or deface copper-plated zinc discs of currency......

Be careful of lost foam casting if you have birds. The fumes made by it burning off are nasty to us humans, much, much more dangerous for birds. Since we now have chickens about 70' from the workshop, lost foam is out for me. No big loss, though. Mine rarely turned out well. Too much cleanup, voids, smoke, fire, nasty fumes, etc.

Be sure to post how it cleans up when machined! What's it for?

 

[jererp]

Whoo hoo! cast my first bit of brass today.
All old plumbing bits and pieces.
I cannot believe how much heat it took and how much scrap rendered down to almost nothing or so it felt.
Heres the chunk, it was a lost foam pour but in greensand.
Awful surface finish which surprised me because I wrapped the foam in masking tape but as it must be machined down I'm not particularly worried.
Whats more important is the metal where I've cut the runner off, it looks perfect, no inclusions or porosity.
Its a fair bit larger than required because I was unsure how it would turn out.
View attachment 106038

I've seen commercial lost foam aluminum casting done, and they dip the foam into a ceramic slurry (thinking a thin mix of plaster of Paris), and let it harden before putting it in the green sand mold. That may give you a better finish. My guess is that the tape you used burned away from the heat.
Never done this myself, just a thought.

 

[savarin]

I just didnt feel like making up a pot of slurry just for this one cast. I've used the masking tape trick with aluminium and it worked great actually leaving the imprint of the tape on the surface.
I believe though that liquid brass is not as viscous as aluminium which is why it passed through into the sand and also I didnt ram particularly hard which probably didnt help.
Hopefully this is to machine an internal threaded joiner for the tubes on my 80mm telescope project.
I'm feeling restless because I cant machine this straight away as I still have one of the tubes in the lathe polishing out the dings and scratches. (shouldnt have bought cheap second hand tube)
Only two more to cast but they wont be as large as this one.

 

[Strtspdlx]

Id love to learn how to cast. I'm sure YouTube is full of how-to's. I should really get to learning as I'm more of a make it then buy it type of person.


Regards-Carlo

 

[savarin]

Id love to learn how to cast. I'm sure YouTube is full of how-to's. I should really get to learning as I'm more of a make it then buy it type of person.


Regards-Carlo

Hi Carlo,
yep! theres heaps of videos on youtube and heaps of web sites out there on casting.
I started with charcoal in a pot then very quickly upgraded to a garbage bin and propane.
It really isnt difficult to cast the metal but getting good casts does take a bit of work.
It can be messy, noisy, smelly and obviously dangerous so you do need understanding neighbors.
I was a bit nervous lifting the full crucible of brass out of the furnace as it was considerably heavier than the same one full of aluminium.
I hope to start machining it today.

 

[JimDawson]

A few years ago I replaced my 300 watt halogen torchiere lamp that I used at my desk with a dimmable CFL type. I kept the 300 watt dimmed but one day I but an amprobe on it just out or curiosity and even when almost off it was still drawing about 150 watts. Dissipating most of the input energy into heat, but very little light. It was time to get a more efficient lamp.

The CFL lasted a number of years and died last night. I changed out the bulb but it turned out to be the ballast was bad. The ballast for that type of lamp is not available anywhere, every vendor I looked at was out of stock and the production has been discontinued. OK, I'll go buy another lamp, NOT! No longer made. Well poo, time to go to plan C. I want to keep the torchiere style lamp because I like the diffuse light bounced off of the ceiling at my desk, I can see the computer screen better. If I need direct lighting I move over to my electronics table.

The next option was to replace the bulb/ballast with a dimmable LED. So off to Home Depot, and walk around the lighting department a bit to see what was available and design a new system on the fly.

Here's what I came up with:

This is a 'can' type light, normally used in overhead lighting for kitchens, etc., and a plugin type dimmer rated for dimmable CFLs and LEDs. Total cost = $29.00


I dug the old halogen torchiere lamp out of the storage shed, because I needed the metal reflector, the CFL torchiere lamp had a glass reflector. You can't tell it, but it is actually white on the inside (on the right) , it's a bit dusty in the shed I guess, only been sitting in there for about 5 years. Projects like this is why I keep so much old junk around. Those reflectors are actually about the same size, must be the camera angle



So here is what I had to work with, I decided to pop rivet the 'can' spring wires to the metal reflector, now white(r) after a little cleaning. The reflector does nothing now but support the LED assembly.




And the almost finished system, still needs a couple of pop rivets


It sticks above the rim a bit but no problem. It works great! and my desk is lit again.

 

[T Bredehoft]

I discovered today that the pulley on my riding mower that turned the blade was on it's last leg, when the hub separated from the pulley. I tried silver solder, while doing that wondered about gas welding, but didn't do that. The silver solder didn't hold, so I've now ordered a new pulley. This is more home maintenance, but it took me from my hobby shop.

 

[Mark_f]

I don't get much time in the shop yet. I sneak out every chance I get, but hopefully the doctors will tell me I can do what ever I want soon. I sneaked out for three hours today. tried to tie up a lot of loose ends. I worked on finishing details for my dividing head .
I made a new handle for the hand crank. I discovered why they have a full cover on the handle. Now it is easier to pull the pin and hold it while turning the crank. I also made a back plate for the 4 inch chuck and installed it on the head. I made a spindle thread protector for when I use collets. Now this dividing head is officially complete. I used it once already and it works great.
Another view of the new handle and the chuck.

I finally threaded the spindle in the center of the 4 inch manual turn table. I can take the chuck of the dividing head and put it on this turn table or even put it on my south bend lathe. This will be handy for multiple operations on the lathe or mill without ever unchucking the part.
I was saving these tasks to do all at the same time because they all are 1 1/2"-8 threads and I just did them all at the same time once I set the lathe up. So now all my projects are complete so I guess it is time to start making fixtures for the T&C grinder and experimenting with it.

 

[JimDawson]

A beautiful piece of work Mark. !

 

[jrstech]

Ok had a couple minutes when I came home. The first pic and the right side of the second pic are the first shot with inserts as they came. Left side of the second pic is after turning two of the inserts. Each face received a 3 minute rubdown with Autosol polish. No wiper inserts available yet so not a fair comparison Chevydyl.