Casting and Machining Angle Plates for the Lathe

[vtsteam]

I built some patterns today for some solid cast angle plates for lathe faceplate work. They will be cast in aluminum to reduce weight, but are otherwise very substantial at 3/4" thick. They don't need webs. They do feature one radiused  edge of 4-1/2" to match the 9" swing of my lathe.

The first job of these plates on the lathe, will interestingly enough, be to machine square their own rough castings.

[vtsteam]

It's been a very long time since I've cast aluminum -- it's been iron, iron, iron this year since relining the oil furnace. It was a great pleasure therefore to do an aluminum pour this evening again. Very relaxing by comparison, and very quick to melt. I didn't have time before supper to cast both angle plates, but here is the first:

[tom osselton]

Nice finish on that.

[vtsteam]

Thanks Tom. Have you been casting anything lately?

[tom osselton]

Not yet I put the battery reconditioning charger on the quad last week because my casting stuff is behind it then I have to retemper the sand that’s been sealed for 2 years it should be fairly funky. 
I have a garbage can of Aluminum and a garbage can of brass to melt.
Currently I have been looking at the Cnc lathe and am inquiring about using Centroid controls to modern it up hopefully I’ll be able to use the Simons 611 controls and servos.

[vtsteam]

Tom, it's surprising how fast sand will come back into condition. I hadn't used the sand for this last pour for a very long time and it was completely dry. This is my non-ferrous sand. The iron sand has been in use for the last several months.

Anyway, a couple hours before I was going to pour the angle plates, I remembered the sand was all dried out, so I added a little bit of water at a time while using a small flat mason's trowel to condition it -- I had about 70 pounds in a rectangular plastic storage bin. It took me about 15 minutes of cutting and shifting the contents and about 2 cups of cold water to re-condition it.

This sand was old stuff. Just sand and fire clay, not even Bentonite (which would have probably needed less water). Leaving it for a couple of hours always seems to improve it. By the time I needed it it was ready to go. I didn't have finer facing sand ready, so the mold was just made up of ordinary old molding sand.

It would be good to have some company casting here, if you get the chance!

[tom osselton]

I’ve got bentonite in mine the sand is a finer grade for grouting tiles. I usually use a tarp for mixing with a old spray gun for the water rather than drag out the hose. What is your mix for iron seeing as coal dust went out with the Dodo.

[vtsteam]

Same as Ironman Tom, 8% Bentonite, 4% water. No coal dust in the regular sand, but I've used both sawdust and coal dust in the facing sand: 2-1/2% finely sifted sawdust or 4% coal dust.

I don't have much sand -- I've never worked with more than 100 lbs. I just keep re-using it. So I just need a cup or two of water to re-hydrate, and I often use a spray bottle, as it spreads it out better between turnings with the trowel. My aluminum sand has worked for at least a decade. Iron sand probably will need replacing more frequently, but I'm still working with my first batch.

[vtsteam]

I cast a second plate just like the first. Then the first operation in machining the angle plates was to face off the longer leg of each plate. This was accomplished by using a length of pipe as furniture and bolting through the lathe faceplate.

[vtsteam]

I then bolted the shorter un-machined leg to the faceplate. I added shims and checked with a machinist's square to ensure that it was standing at right angles to the faceplate.

[vtsteam]

I then bolted the second angle plate to the first. Both machined faces together. This meant that the second angle plate's longer leg was also perpendicular to the faceplate.

[vtsteam]

I then faced off the second angle plate's shorter leg. This made it perfectly square to its long leg. It was now a true 90 deg. angle plate.

By unbolting the whole assembly from the face plate and turning it around to re-bolt (without shims this time), the second angle plate could also be trued to 90 degrees.

Here is the first truing operation:

[vtsteam]

And here are the two finished angle plates, ready for use. 

No mill, or mill setups needed. Quick easy and accurate. And yes, Virginia, a lathe can make square objects.