thanks I guess I'll have to grind it.
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Chinese 7x12" lathe, tailstock centers 1/8" above head stock center.
- Thread starter wahooo
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- Dec 18, 2019
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All of these mini-lathes are a kit... Some worse than others. Overall, I still like mine, even with a high tailstock. I still can make stuff.
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How about some basic measurements, so we can help figure this out? What is the height of the headstock spindle axis over the ways? What about the tailstock? Can you take a picture of the tailstock mounted on the lathe? Can you post a few other pictures of the lathe? Sorry to sound like a broken record, but, even a single picture can convey a LOT of information. We can eventually sort you out, but we do need some more info.
It looks like I have no choice but to correct a lot of problems. If I go thru all that, i wont be selling it, unless somebody really wants it badly. enough to pay me for all of that tedium.
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Fix the lathe for yourself to use. Not to flip!
Made this recently on my mini-lathe. It's a practice piece, but it taught me a lot. About 2" high and 1.5" in diameter, made of 1045 steel. Bored it and single point cut the threads inside the bore and on the cap. Will make another one, but out of 304 stainless. Didn't need an accurate tailstock for this piece. It's far from perfect, but was fun making it. The o-ring makes it water-tight.
Made this recently on my mini-lathe. It's a practice piece, but it taught me a lot. About 2" high and 1.5" in diameter, made of 1045 steel. Bored it and single point cut the threads inside the bore and on the cap. Will make another one, but out of 304 stainless. Didn't need an accurate tailstock for this piece. It's far from perfect, but was fun making it. The o-ring makes it water-tight.
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- Jul 28, 2017
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If you mostly want to drill holes, an alternative would be a toolpost-mounted chuck. I got a chuck that mounts with a 1/2" threaded hole, and a tool holder for a 1/2" boring bar. I screwed in a long-enough 1/2" bolt, mounted it in the BB holder and was good to go.
It takes a little time to line up the chuck but a couple lengths of 1/2" drill rod make it easy. I faced the end of each one so I can install one in the headstock chuck and the other in the drill chuck. Run them parallel to each other to align the axes, then face-to-face to align the X and Y. A QCTP makes it easy to zero-out the vertical offset, but shimming the OEM tool holder works too -- and in fact mine is now dedicated to the drill chuck.
One advantage of a toolpost mounted chuck is when you're enlarging a hole by step drilling, since you can easily move the chuck back to accommodate larger (and longer) drill bits.
That 1/8" vertical offset is terrible! It would be interesting to see a photo of that tailstock.
It takes a little time to line up the chuck but a couple lengths of 1/2" drill rod make it easy. I faced the end of each one so I can install one in the headstock chuck and the other in the drill chuck. Run them parallel to each other to align the axes, then face-to-face to align the X and Y. A QCTP makes it easy to zero-out the vertical offset, but shimming the OEM tool holder works too -- and in fact mine is now dedicated to the drill chuck.
One advantage of a toolpost mounted chuck is when you're enlarging a hole by step drilling, since you can easily move the chuck back to accommodate larger (and longer) drill bits.
That 1/8" vertical offset is terrible! It would be interesting to see a photo of that tailstock.
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- Aug 2, 2020
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No way you are going to hand grind/scrape that much material and have an accurate piece of equipment when you are done.
Pay the $150 and have it done. It will still likely be inaccurate even then but maybe you can use it to make some taper pins.
Threads like this make me realize why PM forum doesn't allow posts about China made machinery.
Pay the $150 and have it done. It will still likely be inaccurate even then but maybe you can use it to make some taper pins.
Threads like this make me realize why PM forum doesn't allow posts about China made machinery.
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- Jul 31, 2020
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- 765
If you are going to get it machined, be clever, send your headstock too. This way they can be matched.
And to answer an earlier question. Yes, it could be that the headstock is off it's expected dimensions too.
Remember, there are TWO reference points here... headstock center AND tailstock center. If either is wrong,
then you do not get alignment. It is easy to blame the tailstock, but it could be the headstock, especially if
two tailstocks show the same error.
And to answer an earlier question. Yes, it could be that the headstock is off it's expected dimensions too.
Remember, there are TWO reference points here... headstock center AND tailstock center. If either is wrong,
then you do not get alignment. It is easy to blame the tailstock, but it could be the headstock, especially if
two tailstocks show the same error.
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If you haven't done anything like this before, I have to agree with @Ultradog MN on the chances of having an accurate lathe when you are done.
Pretty easy to screw it up badly. Hard, but not totally impossible, for a non-expert to make it good. But, if you have a spare, why not? Maybe you can learn something. If you do try it, please share the experience, both your triumphs, or your (hopefully not,) tragedies. We try to share both triumph and tragedies of a machining sort here, so we can all learn from the experiences of others.
To be successful you will have to measure a lot of stuff, in the correct way, so you can understand what you need to take off and where. You need to correct the height, and make sure the quill stays coaxial with the spindle, not pitching up or down, nor yawing to the right or left. Horizontal movement would be adjusted via movement of the tailstock base relative to the main casting. Good luck with whatever you try.
What @addertooth just said. If you bring it in, bring the whole thing! No way can you get it right by just lopping some metal off. You need the whole lathe. Since you haven't posted any pictures, we don't even know if the lathe is assembled correctly, or remotely aligned.
Pretty easy to screw it up badly. Hard, but not totally impossible, for a non-expert to make it good. But, if you have a spare, why not? Maybe you can learn something. If you do try it, please share the experience, both your triumphs, or your (hopefully not,) tragedies. We try to share both triumph and tragedies of a machining sort here, so we can all learn from the experiences of others.
To be successful you will have to measure a lot of stuff, in the correct way, so you can understand what you need to take off and where. You need to correct the height, and make sure the quill stays coaxial with the spindle, not pitching up or down, nor yawing to the right or left. Horizontal movement would be adjusted via movement of the tailstock base relative to the main casting. Good luck with whatever you try.
What @addertooth just said. If you bring it in, bring the whole thing! No way can you get it right by just lopping some metal off. You need the whole lathe. Since you haven't posted any pictures, we don't even know if the lathe is assembled correctly, or remotely aligned.
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- Jul 28, 2017
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You need to post some photos of your tailstock -- at least a side view and bottom view, and one showing how the base sits on the lathe bed. You never know, your problem could be due to something that's a much easier fix than removing .125" somewhere (and perhaps requiring less than $150 to fix).