Lathe Question

[BrentD]

A couple of years ago I got one of the Harbor Freight "Multipurpose Machines" for Christmas. It's the combination Lathe/Milling machine, their Item #5980. Due to the store screwing up and making good on a couple of issues I ended up getting the machine for $399 including the 3-year extended warranty. I have used the machine a few times for various things and I have one rather annoying issue with the lathe:

When I put round stock in the lathe head and turn it on, everything looks like it's aligned perfectly, but as I cut or drill everything goes off-center. The weird part is that no matter what length the stock is, the end farthest from the headstock is always aligned perfectly, but as I move toward the headstock, things shift to one side so that it looks like the original stock was out of round. Drilling holes using a chuck in the headstock, the hole is always perfectly centered in the end of the work piece, regardless of length but if I drill deep enough the bit comes out the side of the work piece, or on shorter pieces, the hole at the far end is off center.

Measuring distances with calipers though, everything appears to be perfectly in alignment. Any ideas what could be wrong or out of adjustment?

 

[wdchyd]

If you don't already have one, you'll need a dial indicator and precision level.....first you'll need to level the bed, then use DI to check alignments......

Use new cutting bit and do a skim cut on some alum or soft steel to check for alignment of headstock to bed, and runout in chuck......

I don't know what kind of precision you expect but cheaper imported lathes will never be as good as Old Heavy Iron due to the weight/strength of the castings/bearings/tool posts ect.....

Homeshopmachinist.com & Practicalmachinist.com are a couple of sites to do searches on for tweeking/ lining up and leveling........

 

[kennyd]

Google search of "Rollies Dad" method of lathe leveling. Lot's of links to read, and a lot of them address the 7x12's.

 

[Stranger]

I am right along with both responses above!
I will say the "Rollies Dad" method works great. I used it after restoring an old Rockwell 10" cabinet model; thats a heavy machine!

 

[David Devuono]

I have one of their bigger combo mills. I know there is a way to set the tailstock to machine tapers etc. If like mine you can remove the drill chuck and put it in the tail stock. then get a 12 inch long straight rod, chuck it in the tailstock and see if it is pointing to the centre of the headstock?

 

[handirifle]

One thing you can buy to easily check it is the tools used to insure rifle scope mounting rings are in perfect alignment with each other. The tool consists of two 1" dia steel rods, that each have tapered ends that come to a point. If the points align perfectly, you're good to go. The only prob might be getting it in the tailstock chuck, now that I think about it.