Author Topic: Working on a new tiny shop (Read 157768 times)

CrazyModder · « **Reply #125 on:** December 29, 2014, 03:28:58 PM »

EDIT: oops, that got rather long, sorry for hijacking your topic.

Quote from: vtsteam on December 29, 2014, 11:05:14 AM

Crazy, I was just thinking about inlaying a section of angle iron in the bench edge with tapped holes to accept a second piece for bending sheet metal -- is that what you had tried?

I can't take a good photo now, but here's one that accidently shows part of my solution.

On top of the work, there goes another angle iron. Pressure is applied by a sturdy piece of stock and two threaded rods which go through holes in the table (one of which is visible). The angle iron dangling off the table is then pulled up, which does not take much force and is easily done by hand for the sheet thickness you see on that image (0.75mm). I did not pay attention to the the round edges of the angle irons when buying them, and actually had to mil down the lip of the angle that presses down on the work. I also milled recesses for the hinge-joints to move the active plane of the angle iron more into center (sorry, I think my foreign language skills are breaking down right now

) but could not be bothered to make that completely perfect.

Test pieces could be bent very well.

Setting up is time consuming though, since there are no stops of any kind, and much trial and error. I could live with that, but unfortunately, the whole solution quite suddenly stops working at all when you consider works of different length and with bits protruding on the side of the currently bent area.

Well, live and learn; the box on the image was then bent with your method, easy enough.

DavidA · « **Reply #126 on:** December 30, 2014, 07:23:56 AM »

VT,

Just been looking at the pictures of your pulley assembly. It's sort of similar to what I have for my red lathe. But I am a bit puzzled.
You mention an over-centre device, presumably to lock it in position, but I don't see it.

Just how does it work.

I know, I know, Must be thick as a brick. Put it down to the cold weather.

Dave.

vtsteam · « **Reply #127 on:** December 30, 2014, 08:38:46 AM »

No problem David, it's not obvious at all from those pix. I'll post some photos this evening. But It's straight out of David Gingery's little paperback on building the lathe.

You pull the handle forward to unlock and change belts, push it back to lock and tension belts. There's a small pair of links that do the over-center trick.

It's extremely handy having a clutch on the spindle at times, and that along with the crank on the leadscrew are two things I missed greatly when I started using the Craftsman 12" lathe after the Gingery. I found the rack and pinion traverse on the Craftsman very clumsy -- it isn't fast enough when you want to move the carriage out of the way -- especially on a long bed, and too coarse (fast) to put on a fine cut. It doesn't do either thing well.

The Gingery lathe handles fast traverse by simply unlocking the half nut and sliding the carriage by hand along the ways. This is easy and fast on a small lathe -- just like sliding the tailstock. Once you engage the half nut, you have a nice 16 to 1 turn rate on the leadscrew crank, which can give you an easily controlled fine cut. Sometimes cruder is better!

vtsteam · « **Reply #128 on:** January 07, 2015, 01:43:19 PM »

The shop has been very usable in the cold weather so far, but tomorrow will be a real test. We have -26C predicted tonight with winds up to 30 kmh, wind chill as low as -32 C. Not unusual for this time of year, but I'm definitely looking forward to warmer weather!

Looking at my last post, I promised to get a picture of the over-center drive lock -- which I forgot to do. Sorry, will do that this evening. And give you a climate report inside the tiny shed!

DavidA · « **Reply #129 on:** January 07, 2015, 07:11:11 PM »

Just hoping that the predicted winds (70 - 100 mph, probably neared 70 where I live) over the next couple of days don't damage my shed or greenhouse.

Dave.

vtsteam · « **Reply #130 on:** January 07, 2015, 09:18:47 PM »

Gee David! I hope you're okay. That's a hurricane!

My shop was everything I hoped for today and this evening. a small electric oil filled radiator on a timer kept it comfortable for working, and I was just a few steps away from the house. My wife calls it my bunker.

Here are the promised photos:

The over-center link in the closed position:

What it looks like on the inside while closed. The two horizontal pieces butt against each other when the link is closed:

And what it looks like opened:

There's a nice snapping action when it closes.

The motor frame was riveted together with simple headed-over pieces of 1/8" rod.

DavidA · « **Reply #131 on:** January 08, 2015, 06:39:54 AM »

Thanks for the pictures. Ingenious.

I haven't been in the shed (either one) for the last couple of days. But I need to get in the big one and move the Denford lathe to it final position. This will require the use of crow bar and rollers.

The bad weather is due to start showing itself late today or tomorrow. We seem to be getting a lot more high winds than we use to. Gusting 50 to 60 mph is becoming common.

Not much we can do about it.

Dave.

vtsteam · « **Reply #132 on:** February 12, 2015, 12:52:17 PM »

The need to cast pulleys for a new Gingery lathe modification, means I need casting capability in the new tiny shop. This is qoing to be quite a challenge this time of year!

I located and started to dig out my bin full of aluminum greensand as a first step:

That's a 3 foot tall green table on the left with 3 feet of snow on top of it. The end of the bin I want is the green square buried in the snow, to the right!

vtsteam · « **Reply #133 on:** February 12, 2015, 01:00:30 PM »

Free at last! Dragging over the snow to the tiny shop....

When I finally got it indoors, and opened the lid, I was encouraged to find the molding sand had dried out completely -- meaning I wouldn't have to defrost it -- just re-temper it with water. Ordinarily that would have been a pain, but in this case I was glad not to have to deal with a solid block of frozen sand!

vtsteam · « **Reply #134 on:** February 12, 2015, 01:25:55 PM »

I was going to re-temper the sand this afternoon, but checking the weather I decided to wait a week, unless I figure out some way to keep it warm overnight in the shop. We have coming what the weatherman has called "the most robust arctic surge of the season" through Tuesday -- sounds like this already difficult winter is about to get even worse with high winds and sub zero (F) temps. Maybe adding water isn't a good idea at this point!!!

awemawson · « **Reply #135 on:** February 12, 2015, 02:03:21 PM »

Water and antifreeze ?

Will_D · « **Reply #136 on:** February 12, 2015, 05:16:07 PM »

Before casting have a look at this re. MDF pulleys:

BTW: It is Gingery related

http://madmodder.net/index.php/topic,10444.0.html

vtsteam · « **Reply #137 on:** February 12, 2015, 07:10:29 PM »

Andrew, do you mean for tempering? I just wouldn't want to do that. I was thinking more in the line of a heat tape buried in the sand, light bulb, insulated cooler, etc. as we mentioned before here, I think.

Will, thanks, I'll answer there on the lathe thread.

awemawson · « **Reply #138 on:** February 13, 2015, 03:34:07 AM »

Yes I meant for tempering. It's basically ethylene glycol which won't affect the casting in the required proportions - or if you want to go eco safer use propylene glycol, which is the 'food grade'. I happen to have several 205 litre drums of diluted propylene glycol. When I dismantled my induction furnace before coming here, I pumped out all the coolant as it's not cheap, and brought it with me.

RussellT · « **Reply #139 on:** February 13, 2015, 05:15:40 AM »

Wouldn't glycol burn during the casting process?

I would have thought that salt might be a better antifreeze. Using excess salt would ensure that you always had a saturated solution and the salt crystals shouldn't do any harm. That would protect down to -21C (or -5F) which might not be low enough for Vermont.

Russell

awemawson · « **Reply #140 on:** February 13, 2015, 07:20:48 AM »

I'm sure some will Russell, but think of Petrobond type oil sands that specifically add hydrocarbons for a bond. Only the tiny bit close to the surface actually is burnt, and the products of combustion form a gas shield.

Coal dust used to be added to sand for iron casting to improve surface finish. The coal burnt producing gases that again formed a shield and not only protected the sand but averaged out the surface finish.

vtsteam · « **Reply #141 on:** February 13, 2015, 08:22:53 AM »

I sent for one of these heaters to try out:

http://www.amazon.com/Hydor-50w-Hydrokable-Substrate-Heater/dp/B0006JLPGS

Think I'll test it over a day, checking temps (without a thermostat) first. If it's sufficient to defrost and not too warm,
I'd like to use a 24 hour timer. Then I'd just hit the timer the night before I want to cast.

vtsteam · « **Reply #142 on:** February 13, 2015, 11:51:06 AM »

Guys, I don't know about the properties of antifreeze exposed in a mold to 1100 deg F aluminum, or the effects of salt and or glycol on molding sand physical properties, but one thing I do know: the last thing I want to do is dip my hands into a tub of subfreezing molding sand laced with antifreeze or salt to fill and ram a flask!

I'll take warm clean classically tempered sand any day, and I have a feeling a sub freezing chilled mold would exaggerate casting difficulties as well. Handling properly tempered sand is a pleasure itself.

For winter casting, heat has it all over chemicals in this tiny shop!

mattinker · « **Reply #143 on:** February 13, 2015, 01:28:20 PM »

I'm not a chemist, but a ceramist friend of mine warned against heating common salt as chlorine gas can be produced!

Regards, Matthew

JohnHaine · « **Reply #144 on:** February 16, 2015, 02:33:16 PM »

Matt, as salt is used in molten form for heat treating, I don't actually think this can be true. Chlorine and sodium are two of the most reactive things around, it will take a lot to persuade them to dissociate.

Swarfing · « **Reply #145 on:** February 16, 2015, 02:57:03 PM »

Line a container with thick straw, put your sand box inside and cover with more straw and a lid.

mattinker · « **Reply #146 on:** February 16, 2015, 05:31:58 PM »

Quote from: JohnHaine on February 16, 2015, 02:33:16 PM

Matt, as salt is used in molten form for heat treating, I don't actually think this can be true. Chlorine and sodium are two of the most reactive things around, it will take a lot to persuade them to dissociate.

The friend who told me about this is no longer with us so I can't ask him, he died of other, natural causes.

Salt Glazing

This process involves throwing wet salt (sodium chloride) into the heated kiln while the bisque ware is being fired. Wet salt at high temperatures decomposed to sodium and chlorine. The sodium reacts with the bisque ware to form a glaze. Large amounts of hydrogen chloride gas and possibly chlorine are also formed.

This is a quote from lower down the page.

http://www.baylor.edu/ehs/index.php?id=94374

regards, Matthew.

vtsteam · « **Reply #147 on:** February 17, 2015, 06:00:08 PM »

The 50 watt Hydrokable just arrived by post and I've got it burried in my tub of greensand to give it a test. It's a good test considering the low temps right now!

vtsteam · « **Reply #148 on:** February 17, 2015, 09:43:54 PM »

The test went well after about 3-1/2 hours. The sand was cool, but not cold, though there was some unmelted snow on the concrete floor of the shop, meaning subfreezing temps down at floor level. There were a few warm spots in the sand, too -- I hadn't buried the cable evenly some stuck out above the surface -- the bin is only half full of sand and the cable is 20 feet long.

Also it's dry sand right now so heat doesn't spread as easily. I didn't want to temper it with water until I had the heat cable to work with. Tough to warm up a big frozen block without some heat running through it!

I unplugged the heater. I don't want to run it overnight yet. Tomorrow morning I'll temper the sand and check how well that works with the cable. Then we'll let it freeze and find out how long it takes to thaw.

The bin is uninsulated at this point, but if needed I can add that, too. Looks good though without, so far.

vtsteam · « **Reply #149 on:** February 18, 2015, 10:58:40 PM »

I tempered the sand today and it sure is great to have good molding sand again. I just really enjoy that stuff when it's right. Cable in place. Letting it freeze overnight. Tomorrow we'll see how well it defrosts.

I also cut the top off of a 30 lb propane tank -- a little taller than the usual 20 lb tank. Cleaned it out to make a new melting furnace for the tiny shop, to fit under the bench. I need it now to cast my new lathe pulley.

I was going to go against my usual grain, and actually buy the expensive stuff for refractory -- cerrablanket, and zircon rigidizer per Ironman's style small propane furnace. But U.S. BS manufacturing distribution systems struck again!

I wrote to the only company I could find here that offered zircon rigidizer, naturally you had to write to their factory sales rep to inquire where to obtain it and how expensive a pint of that stuff would be (it does come in individual pints, so I can imagine it must be pricey!).

I received a note back from sales rep. "David" today asking what my purpose was. So I replied to that, saying a small metal melting furnace, propane powered, fiber blanket refractory, about 4 square feet exposed needing rigidizer. He wrote back that I shouldn't use their product in my application. No price given, no availabiltiy info.

So I said the hell with it -- this is why I like making things from locally available materials. Otherwise you can't just do what you want to do AS AN EXPERIMENT. If you go the high tech refractory route, you gotta face a bunch of industrial salespeople of limited imagination questioning your intent and your quaiifications to obtain their product.

I can go to my local hardware store and buy a chainsaw, some Drano, and a can of acetone, and NOBODY asks me what my intent and usage are, or what my business name is. They figure I know what I want to do with it, and that's enough. They also put prices on things, instead of asking you to contact them to inquire.

For heaven's sakes how do manufacturers like this zircon outfit think that most of the industries (including their own, no doubt) begin? A vast number have begun based on an individual's ideas, and invention. Luckily their founders 100 years ago weren't blocked from obtaining small quantities of whatever they needed to make new things because they were individuals.

Anyway, I said the hell with it, went to the hardware store, bought a bag of plaster of Paris and sand, Took an 8" diameter piece of leftover Sonotube, set it as a chamber form in the cutoff propane tank, and poured a lining. Took an hour total. Materials were $19 total with some left over. I'm sure it will melt my aluminum for the pulley. Sheesh.....

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Author Topic: Working on a new tiny shop (Read 157768 times)