Introduction: The Machinist's Woodlathe
Hey everybody! Zep here, and I'm glad to be back with you all...
So today's little story goes like this...
A year or two back, I made myself a woodlathe out of mdf, some threaded rod, some bearings and a little pressure washer motor. I made an instructable on that back then, which you can find here in case you are interested. So the little thing (not so little actually) I have used a loooot, and it gave me some valuable lessons, some beautiful turnings, and quite an amount of joy! I am proud to say that to this day, it's working like it's firts time. But....there is always a but!
Time has passed, evolution happened and fate brought me to the place I now stand, where I own another woodlathe! And I don't know if you have seen my "shop",just trust me, it's tiny! So with that in mind and the realisation that I always end up using my new lathe (which let's face it, is heavier and much much faster to setup) I decided that the space on the shelf was now too valuable to be occupied by the old-but-beloved fella...
So it was simple now, toss it or make it useful again. And I believe I have found a way to earn it a little more time. Turn it into an experiment......
(In the next step you can also find a video of the make)
Step 1: The Modification
So let's get to it, shall we??
For starters I decided that I don't want to keep the lathe this long. Then I measured everything so than I 'll keep just 30 centimeters of working length, and using a hand-saw I split the lathe's bed in two. It's convenient having a wooden 't wood-lathe, isn't it?!
After that, I disassembled the tail-stock and I chiseled out 2 25mm wide slots on the lathe's bed/ operator's side, one right at the front end of the tailstock's height, and the other one almost the other end of the machine (tail-stock side). Using some 25mm thick scrap plywood pieces I made two identical and quite-funny-shaped pieces that will go into those slot's and provide a place and the necessary clearance to mount the shaft that will guide the whole carriage and the threaded rod that we 'll use to drive it back and forth. Then I dry fitted those parts into them slots, abd after assuring a perfect fit, I got them back out , clamped them together and drilled them to hold the guidance shaft and the driving rod just above it, with a bearing to each side. This whole project was more of an experiment so I tried to get it done with mostly what I had in hand (let's see how this does and we may actually improve it over time here together ;) ). So I used nothing too fancy, just some skate board bearings (22mm OD / 8mm ID) and a plain M8 threaded rod. As for the guidance shaft, I some stiffness would be nice there, so I went 12mm thick steel rod (chrome coated) and some according linear bearings (LM12UU). So I put everything in place, skateboard bearings holding the threaded rod in place and mounted to the outer side, and the steel shaft underneath that with them linear bearings in place. I secured everything with some M8 nuts and washers abd cut both the rod and the shaft in legth using an angle grinder.
And it's time for the carriage, the cross slide you can call this!
Having said that I want to keep it simple as it gets and low-cost as possible, I run to the scrap pile and found a piece of melamine of 16 mm thickness. The good thing about melamine is that the outer shell is quite tough and slippery, so I believe we can make it work using nothing but that..
Went straight for the table saw where I cut the needed pieces and out of them I made the cross slide and compound slide. Here I got advantage of the consistent thickness of the melamine board, to make it rigid as it get. So I basically sandwiched three long melamine pieces, with the one in between being quite narrower. This gave me two rabbets, one on each side and having the exact opening as the thickness of the melamine used. Into those rabbets slide two little pieces of the same melamine, with all the friction rubbing on the tough polymer finishing. Those tiny pieces I bolted onto some vertical pieces, that will keep the whole compound from twisting left to right, and I connected them on top of the cross slide with a square part that will absorb the thrust forced and provide a place to mount the compound. I secured the whole cross slide structure to the linear bearings already on the guiding shaft using some seriously strong epoxy. I also used that to mount up there the nut that will convert the twist on the cross slide treaded rod to linear movement.
Then, using a ruler I measured the clearance between that higher spot on the compound slide structure and my head stock and calculated the needed height of my compound (tool rest). When we are done with this, the very tip of our cutting tool needs to be right next to the head stock (height-wise).
After that I found some square iron tubing I had laying around in the shop, cut it, drilled it and welded some nuts on it, to serve as my tool holder. I mounted it on my compound in a way that I can get it out and turn it sideways (not exactly a quick release, but we are getting there!) and also mounted some handles on the end of both of the threaded rods so that I can operate them somehow....
And I believe that's all...Let's give it a spin!
Step 2: Give It a Spin
Now we need a cutter!
And I never had a machinist's lathe (I always wanted to though...!) so we need to come up with something.
What I did was get an old file (made of some serious steel!), cut it with an angle grinder and sharpen it on my bench grinder, making all the necessary reliefs an all..
Basically what you need to do there, is give your grinder's rest a slight angle (15 degrees or such) and then just grind a triangle at the end of your steel piece!
Mount it on the tool holer, wear your face protection (mine is custom :D ) and enjoy!
Step 3: Last Thoughts..
Our little experiment turned out working even better that what I could wish for! And we are not done here just yet..
I need to come up with a way to stiffen my tail stock, which for now gives quite an amount of vibration, and also secure the back end of the cross slide to the lathe bed. After that, we could just eliminate any backlash on the screws, throw up there a couple of steppers, and make ourselves a CNC woodlathe!
But thats all for another time folks!
Until then, thank you all for being here and I wish you happy makes!
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More coming up.....