Lathe auto-turret project log

[kong]

Hiya guys, following on from this thread, I am going to attempt to make the auto lathe turret as found over here.
I am following the plans that are available on the mach2 yahoo site, but will email the original author to see if he will allow me to post the drawings here.

So then, to start with, I have purchased a 6"x6"x4" block of cast iron for the body. It weighs around 20-25 pounds, and currently have it chucked on the lathe. I have got as far as facing one side, drilling through, and boring the two holes for the indexing spindle to ride in. As a slight change to the plans, I have bored the bearing hole 1/2" oversize, and I intend to sleeve it with phospor bronze. This is where I am at now....

[JFettig]

Kong, looks like an awesome project. Do you have any drawings or design plans you are going off of? I am still getting ideas, maybe some day I will build one, more likely if I was to get a bigger lathe.

Jon

[kong]

Hi Jon, I am using the plans available from the Mach2 yahoo group files section. Hell, I am even working in imperial measurements! That cast iron is not nice to machine, just figured it would all add to the rigidity of the thing. Just having a break for tea, then I will hopefully get the main piston cylinder bored out.

[DieGuy]

Originally Posted by kong Hell, I am even working in imperial measurements! That cast iron is not nice to machine, just figured it would all add to the rigidity of the thing.

I hear you about the cast iron, When I served my tool and die apprenticship (many moons ago) we broke a cast iron connecting rod in our 80 ton press. Guess who got the job of making the new one out a block of cast iron about 24 X 16 X 8. Nasty stuff.

[Mcgyver]

kong, cast iron's dampening and dimension stability make it right choice and as you've found it usually works best when machined in imperial units, but what’s going on with the cutting problem? aside from being a pain to clean up, I've always found good CI the nicest of material to machine, once you break through the outer skin that is. Machines easily, easy to get a nice finish, no stringy chips, no messy coolant or oil etc.

[MIKE JEFFERS]

kong
mcgyver's right cast iron should cut nice when through the skin
i used to make gravity dies from the stuff, if all you've cut before is ali or m/s
you'll find it a bit different but hopefully satisfying (eventually)
mind you the wife will start moaning when you enter the house looking like a miner
(...or maybe not..;-} )
by the way DON'T USE COOLANT ....low revs and a "brisk" feed.
finally there's something about the imperial unit thing .
maybe it's just me.
mike

[kong]

Lol guys, I am in the UK, and hence always use metric measurements! I can honestly say I have never machined anything to imperial measurements before!
Don't get me wrong on the cast iron, it is just that I am not setup for this large a piece, I am boring a 4" diameter hole, 3" deep into the iron with a 3/4" boring bar. This is why it is hard work! I usualy machine aluminium with bores upto 2.5", so that is what I am setup for.
I suppose I should do a quick update - the machining is slow on the iron for reasons mentioned above, hoepfully I will get that finnished off this evening. Just got back from the scrap yard on the lookout for bronze or brass for the piston - 4" dia, 1.5" long. Everything there was too big, and since they don't cut it, I would have ended up paying £22 for the closest size piece ($45). I will go look again on Monday. I will get some pictures up of my progress later on tonight

[kong]

Good, that is the boring bit done, boring, eh, eh?!
Nevermind, I will go back to work!

[Bloy2004]

Nice Kong,
heh...now I get to watch you!

[DieGuy]

I am watching this project with baited breath.

[kong]

Right then, next part! I have made two aluminium plates, bored one to accept a stepper-motor shaft, and have pressed dowel-pins at 4 points around the circumference. The second plate is the same size, and bored 10mm so it can be bolted to the main spindle. It also has holes around the edge, but these are slightly large so it can slide on the dowels.
When the turret is in the locked position, the two plates will be (almost) pressed together. When it is unlocked, the piston will push the spindle forwards, therefore pulling the "floating" plate with it. The dowels will keep the stepper motor connected to this floating plate, and will still be able to turn the main spindle. At the moment, they slide perfectly, but when I get everything assembled, there will probably be some binding. If this is the case, I will have to slot the holes slightly, being careful not to introduce backlash into the system.

Clear as mud eh?!

[MIKE JEFFERS]

looking good
mike