CNC'd Harbor frieght 8x14 linear rail upgrade...and maybe more??

So I've had a harbor freight 8 x14 lathe for a while, and I cnc'd it a while back, but after converting my mill to linear rails it had to happen to the lathe too. so this is what I'm starting with

And while a lot of work has already been done, such as ballscrews and spindle motor upgrades, there is so much more that can be done and this upgrade is a great excuse to do it. So I don't know where this build thread will take me yet, but ignorance is bliss at the moment. So on with the destruction! First step, strip it all down to the little bits.

Next up I have to mill the saddle rib off the bed. There's no place for that where we are going. But of course it's not as easy as just slapping it on the mill and going at it with some scrap carbide. Of course there's a whole bunch of gunk on the bottom of the feet. I bought the lathe used and I think the previous owner had glued around the mounting holes for some reason.

A little elbow grease later and both pads are clean as a whistle.

So on the mill she goes. I'm lucky to have a makerspace local to me with the needed tools to help out as it's a bit large to fit on my CNC mill. Tramming it in took quite a while. There are no real good reference surfaces to align too. I ended up using the saddle rib which isn't ideal, but worst case I can go back and reamachine the rib. I'm only keeping a small portion of it anyways.

obligatory action shot! I used a 3" indexable face mill to do all the heavy lifting.

Lest thing for today was to drill the linear rail mounting holes. They will get tapped for M4 bolts, but there just isn't enough hours in a day. thank goodness for my Albrecht drill chuck. it made swapping back and forth from the sop drill to the drill a snap.

Ok, I lied...I've been playing around with some sanding brushes I got off amazon, so after spotting nad drilling, I ran both surfaces back over with an 80 grit brush. Here you can see the before and after differences between the two legs.

the pictures don't really do it justice, but they look significantly better in person.


So i haven't been taking as many pictures as i should, but i have been working on this when I have time. I have the saddle plate made, as well as the top slide. Rails are temporarily mounted as is the saddle.

Here's the bottom side of the cross slide table. I machined strips for the rails to sit in as well as a pocket for the ball nut clearance. I had a bit of an issue with my tool pulling out. as a result there is that unsightly "L" shape. Luckly it's on the bottom side and isn't really an issue.

top side of the cross slide table was skimmed and machined for a combination of dowel pins and 1/4-20 threads. Hopefully this will make installing and aligning tools pretty easy
Hi, I just joined forum last week and came across your linear rail conversion. I've been thinking about doing something similar using linear rails and bearings but always wondered if they'd provide sufficient rigidity for machining metals. Seems like most of the builds I see using these are lighter duty i.e. router tables, 3D printers, etc. Any experience and/or insight you can share would be much appreciated.

Thanks - nice post,
Tom B.
yeah, you just need to size them correctly. I think pretty much all the Haas machines run liner rails. I've also converted my mill over to linear rails and it's working beautifully so far.
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