Short lived metal lathe :(

[Carl Fisher]

So this little HF 7x10 was used. It had a slight clicking in low gear and a very pronounced one in high gear.

Well today I flipped the switch and didn't notice that the tool post wasn't exactly clear. The jaws caught it and seem to have completely stripped out the transmission. Motor spins but it won't engage the chuck.

Took apart as much as I could find to take apart but there doesn't seem to be any access into the tranny. Not sure what to do now :frown:

 

[walshjp17]

I would immediately contact the previous owner and threaten to sue because he didn't provide more explicit instructions on how to prevent you from making a mistake.:biggrin::wink::biggrin:

 

[jallan]

Carl, did you go to HF web site and download the manual for the lathe. I think you need the mod. number and the manual may help. just an thought.

 

[SteveCG]

Check out littlemachineshop.com, they have everthing you will need and links to other sites for repair instructions.
Good luck
SteveCG

 

[Carl Fisher]

My fault for crashing it. I thought I was clear but I must have moved it again between checks as I was working on checking the overall alignment and was bumping it a bit here and there.

Found some references to a broken key way when it gets crashed, but so far no help figuring out how to actually get into the head stock to see what's in there.

 

[Carl Fisher]

Sigh :frown:

Off to search the web and see if these gears are available for purchase. Hopefully LMS can point me in the right direction if they don't have them.

 

[Ed McDonnell]

LMS should have them in both plastic and metal. I wouldn't upgrade to metal unless you are really sure you won't crash it again. The gears will be a pain to replace, but they aren't that expensive. Using metal gears as a replacement could result in something a lot more expensive breaking if you crash again.

Good luck!

First the dropped blank. Then the lathe crash. If these things come in threes, it may be time to take a break.......

Ed

 

[Ed McDonnell]

One positive out of all this is when you put the headstock back on you can test for alignment and shim/adjust as needed to get it right.

Ed

 

[Carl Fisher]

As I was taking it apart I was noticing just how easy it would be to get the whole thing out of whack on the alignment. For a precision lathe it's not very precise with the methods of adjustment. Kinda take it apart, make a change and then take it on faith that it was a good change.

LMS had everything. I ordered a metal upper and a nylon or plastic lower. I'll leave the lower as the sacrificial since it's easier to remove the intermediate shaft than the main shaft. I'm surprised that the belt didn't give before the gears though. I'd rather replace a skipped belt or pulley gear than take the whole headstock off again.

 

[Ed McDonnell]

The lack of precision adjustment is my biggest complaint with these little chinese lathes. Once you get the headstock repaired and aligned, you will hopefully never have to touch it again.

I like to keep the error on mine to less than 0.001" over 2 inches. It took a lot of work on the tailstock (both adjusting and filing / sanding / grinding) to get mine to that point. Of course, using too light or to tight pressure on the quill lock will change things a couple thousandths. Working with these lathes is really more art than science. But when you get the art just right, they can do some amazing work for such a relatively inexpensive piece of equipment.

Ed

 

[geffre]

Little Machine Shop

When I looked into these Chinese lathes, the Little Machine Shop was an excellent source of information. However, Yahoo Groups has a couple of groups of people who love to work on these machines. I have no doubt that you will be able to find parts for your machine. Whether the parts will be in your price range, that will be a different matter.

 

[Carl Fisher]

Ed, what did you use for an alignment bar to test for your run out or offset? i.e. if I can't grind a perfect cylinder over a length, I have no true point of reference to put the indicator on if that makes sense.

Also what would you use for a dead center on these? It claims MT2 but my MT2 drive centers don't even come close to the side walls of the spindle. I've only been using the 3-jaw to this point.

 

[BRobbins629]

Ed, what did you use for an alignment bar to test for your run out or offset? i.e. if I can't grind a perfect cylinder over a length, I have no true point of reference to put the indicator on if that makes sense.

Also what would you use for a dead center on these? It claims MT2 but my MT2 drive centers don't even come close to the side walls of the spindle. I've only been using the 3-jaw to this point.

Most of these little lathes have a M3 headstock taper.

 

[frank123]

Transmission gear failure can be caused by having the hi/lo shifter poorly engaged or trying to shift it while the lathe is running. It cracks it and eventually it will fail.

Best bet is to shift if (while turned off) and keep a small amount of pressure on it while jiggling the chuck to make sure it fully engages.

 

[Ed McDonnell]

Ed, what did you use for an alignment bar to test for your run out or offset? i.e. if I can't grind a perfect cylinder over a length, I have no true point of reference to put the indicator on if that makes sense.

Also what would you use for a dead center on these? It claims MT2 but my MT2 drive centers don't even come close to the side walls of the spindle. I've only been using the 3-jaw to this point.

As Bruce answered, it's probably MT3 on the headstock and MT2 on the tailstock. My lathe came with a MT3 center, but I almost always have a collet chuck on it, so I have a ~0.5" straight shank drive center that I mount in a collet when I need it. I suppose it's possible that there is no taper in your spindle and it only works with the chuck? Maybe the taper guy was having a bad day when your lathe passed by. Rick Herrel sells a straight shank dead center for $12 shipped that would work in your chuck. You can pick up a MT3 center at grizzly for less than $10.

I used a length of drill rod (enco) for alignment of the head stock. If you have an old inkjet printer laying around you are willing to sacrifice, you can pull the rods out that the inkjet heads ride on and use them.

Get your chuck dialed in first. You would think it wouldn't matter which way you mount the chuck, but it makes a difference in my lathe. Also which way you push the chuck as you tighten it up will make a difference. With a lot of fussing I can get my chuck mounted with minimal runout. Once you have your chuck mounted satisfactorily, mark the chuck and the faceplate on the lathe so you don't have to play the "which way is up?" game next time.

To align the tailstock after the headstock was good I initially used the razor blade test, but then I bought this:

Amazon.com: Anytime Tools CO-AX COAXIAL TEST CENTERING INDICATOR COMPLETE SET: Home Improvement

For home shop work the razor blade test is probably adequate, but it was fun playing with a new tool. Don't try to adjust the tailstock unless you are really relaxed. After 30 mins of futzing with tailstock adjustments and overshooting both ways, I was ready to throw the thing through the wall.

Ed

 

[Carl Fisher]

I have a magnetic base mount and a dial indicator I use when I setup or move my CNC so I'm covered on the tools to measure the run out but what's missing is a dead straight rod to mount between the two. The printer rods aren't a bad idea but I'm not sure if I have any spares around anymore. I'll have to do some digging.

It doesn't feel like there is a noticeable taper in the main shaft. I'll have to measure the front and back openings and see if there is a variance.

And there was definitely run out in the chuck while it was running.

 

[frank123]

I have a magnetic base mount and a dial indicator I use when I setup or move my CNC so I'm covered on the tools to measure the run out but what's missing is a dead straight rod to mount between the two. The printer rods aren't a bad idea but I'm not sure if I have any spares around anymore. I'll have to do some digging.

It doesn't feel like there is a noticeable taper in the main shaft. I'll have to measure the front and back openings and see if there is a variance.

And there was definitely run out in the chuck while it was running.

TGP rod works pretty well and is available in a variety of diameters.

IMO, more accurate than drill rod or printer parts.

 

[Penultimate]

Adding to Ed's advice, check chuck runout by testing each tightening position. When you find the lowest runout always tighten at that chuck position.

 

[randyrls]

Carl; Do a search on the net for "Rollie Dad's Method" (Yep no typos!) you will find many articles, and a few YouTube videos that show how to align the headstock and tail stock.

 

[KBs Pensnmore]

Sigh :frown:

Off to search the web and see if these gears are available for purchase. Hopefully LMS can point me in the right direction if they don't have them.

Every time mine stops, it is usually the drive gear on the motor that gets stripped, the key inside the toothed pulley rotates, but the pulley doesn't.
Every time that happens it's a 2-3 week wait for LMS to supply and post/deliver to down under. I fixed that problem by super gluing the pulley and key way, next time it happened it sheared the shaft in the motor Nearly 9 months for another motor from China, excuses were, boss forgot to order it, in next container, same again several times over. Unfortunately Australia runs a different voltage, so LMS were no help there. You are lucky in that you have a good supplier of parts and tools for the small lathes and mills, wish we had someone like that here.
Fantastic little lathes for small work, provided that you take small cuts.
Now to try to remember how it all goes back together:frown:
Kryn

 

[Carl Fisher]

Yeah, that would be rough to wait on.

The only thing I'm not sure on reassembly so far is the positions of the 4 wires to the control panel. I know which side is motor vs power, but what I don't recall is which way the white and black wires went on each individual switch.

 

[ironman123]

Carl, what model number 7X10 do you have? Something like a 93212?