Saturday, May 17, 2014

Much Needed Lathe Mods - A Little More X

There are a couple of things that have been a pretty consistent source of aggravation when trying to work with my mini lathe, one is how it seems like Im always looking for a sweet spot. Depending on the part, I have to decide where I want to lock down the compound and the tool post, so I have enough travel to do an entire 3" face but the angle of my tool post or compound aren't so extreme I can still do other work without having to tweak my setup in some way. Basically when you're at the limits of your travel and working envelope it gets harder and harder to use both axes completely without having to move something, for instance when going from facing to turning or to turning from boring and those sizes are way out near your limits, switching tools can be a lot more of a job than simply throwing the relevant tool holder on your handy quickchange post, and making chips, like youre accustomed to.. So, its a big deal that I gained over an inch on X. I have some 4" material I haven't even considered for much, because I was pretty much maxed out at 3".

I stole the extra travel by turning the compound back almost to 180 degrees, pointing right at me. Its about 25 degrees shy of making 180. Moving this around I can squeeze a out little more if Im ever pushing limits again, which will no doubt happen.  Honestly though, I think the bed is going to be a size barrier before X travel. Im not 100% sure, but Im pretty damned sure that I have more X travel now, than I have actually space to accommodate a piece of material that big.

Of course it wouldn't even be worth mentioning if I didn't have to modify something to make it work. The retaining block that holds the feed screw in the compound was hitting parts of the cross slide, so clearance had to be created by grinding the bottom of the retaining block. The pics are pretty self explanitory. Speaking of pics, you'll notice that the handle and the dial are gone from my compound slide as well. Im not a big fan of the compound slide and dont use it much anyway. The machine is just too small to try to squeeze it in. Threading is the only time when its even remotely useful imo, and since in that case it would be in a more 'standard' position of 29 degrees(damn I gotta see how to do a degree symbol) I can just put them on when needed. I need the travel more than I need to thread.



You can see the retaining block being an asshole and ruining my inspired, clever, simple idea--to flip the compound around and claim my free prize, a truly larger work envelope. The block doesnt do anything besides attach that feed screw to the top half of the ways so it can be moved against the tapped hole in the bottom half, the swivel base part. Grinding some off the bottom wont affect anything in how it operates, when I do want to use the dial and handle it will still work fine. To keep the compound as immobile along its own axis as possible, I have the gibb screws pretty tight. This should be fine.




After the grinding and a bit of filing, it clears. I know it looks a bit catiwampus, ie the angle of the new flat is not parallel with the top half of the cross slide. It cant be easily seen, since its at the back of the machine, and it has no impact whatsoever on how it functions. I could always mill it a bit deeper, make it parallel as hell, but I have no fucks to spare at the moment on such a pointless thing.



Here you can see the total amount of extra X clearance I picked up. And yes, I can easily make it to center and beyond without having to change the angle of the compound or the tool post. Also, switching out the type of tool, like boring bar to turning tool, or especially from turning to parting off or threading, now I can just throw the needed tool on the tool post and start making chips. You can see in this pic the approximately 25 degree angle of the compound. At first I had planned to keep the compound at 180 once I had clearance on the retaining block, but the rest of the compound slide etc were hitting the part when the tool was only about .600" in on Z. Where it is now, around 25 degrees, gives me a mile all over, everything fits with plenty of room to spare. Usually when Im out in the 3" neighborhood like this, tool changes can become rather involved and shitty. Ive been through some shit with that damn part off blade and 3" material lol. It fucks your whole roll up when just a tool change takes more than a few seconds to a minute, especially if you're high too. It makes trying to maintain any momentum a joke. I think that now, I at least have a chance stay focused on the actual machine work when working with 3"+ rather than jugling shit around.

I was actually pushed in to doing this tonight by starting on the other mod, to be discussed next, and running into travel issues right away. That's actually the offending part in the chuck in that last pic. That piece will become a handle. It'll all make sense after the next post.


                                                                     


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