HF 9x20 Lathe Manual Sucks. Some Help?

[Cartierusm]

I just got my new Harbor Freight 9x20 Lathe Home and cleaned it up and got it running. Of course the manual is not fit to wipe my behind, it really sucks. So I have some quick questions which I'm sure I know the answers but want to make sure.

1. The half nut is only for threading operations? I should use the auto feed for feeding during regular turning?

2. Very important question: The manual says to never disengage the half nut during threading operations but to move the tool out with the cross slide and then reverse feed to my starting position. How is this done? When it gets to the correct point do I flip the switch to reverse the motor, this seems as it would do damage the machine, or do I turn it off and let it coast to a stop then reverse? I thought this was the point of the threading dial to keep it aligned when moving the carrige otherwise the dial indicator would be useless if you kept it engaged with the halfnut during the entire operation. I mean if you kept the half nut engaged the entire time and just reversed with the motor in reverse then you could start the threading operation at anytime no matter where the line on the threading dial was becuase the dial is nothing more than a gear and some lines?

3. I measured the runout with a dial test indicator on a 6” piece of drill rod (drill blank). I’m not sure how accurate a drill rod is but over the entire length, near the chuck and at the end of the rod, about 4”, the reading is the same it’s off by .0015”. Should I just remove the chuck and reset and see how much off it is?

Thanks. I had a lot more questions but figured it out. Man, those manuals really sucks. Very little information.

[SCzEngrgGroup]

I just got my new Harbor Freight 9x20 Lathe Home and cleaned it up and got it running. Of course the manual is not fit to wipe my behind, it really sucks. So I have some quick questions which I'm sure I know the answers but want to make sure.

1. The half nut is only for threading operations? I should use the auto feed for feeding during regular turning?

2. Very important question: The manual says to never disengage the half nut during threading operations but to move the tool out with the cross slide and then reverse feed to my starting position. How is this done? When it gets to the correct point do I flip the switch to reverse the motor, this seems as it would do damage the machine, or do I turn it off and let it coast to a stop then reverse? I thought this was the point of the threading dial to keep it aligned when moving the carrige otherwise the dial indicator would be useless if you kept it engaged with the halfnut during the entire operation. I mean if you kept the half nut engaged the entire time and just reversed with the motor in reverse then you could start the threading operation at anytime no matter where the line on the threading dial was becuase the dial is nothing more than a gear and some lines?

3. I measured the runout with a dial test indicator on a 6” piece of drill rod (drill blank). I’m not sure how accurate a drill rod is but over the entire length, near the chuck and at the end of the rod, about 4”, the reading is the same it’s off by .0015”. Should I just remove the chuck and reset and see how much off it is?

Thanks. I had a lot more questions but figured it out. Man, those manuals really sucks. Very little information.

1. Yes
2. Doesn't it have a threading dial? If so, then you can disengage the half-nut and move the carriage back, being sure to re-engage at the same setting on the threading dial. Otherwise, you turn off the spindle at the end of the thread, retract the tool a few thou, then turn it back on in reverse to move back to the start of the thread.
3. 0.0015" runout it pretty darned good for out of the box! If you want better than that, you'll probably need to use a 4-jaw chuck.

Regards,
Ray L.

[Cartierusm]

I was just messing with it and when you flip on the half nut the threading dial disengages, not sure how as it doesn't look like it's moving away from the screw but it does. I'm very confused. If the dial disengages when the half nut is on and you have to keep the half nut engaged when threaded the entire time then the threading dial is useless, you can start at any point becuase it's just a dial that rotates and doesn't sync up with anything else? Am I missing something?
So I removed the chuck and put it back on after cleaning and it's now worse. I then deceided to measrue the runout on the body of the chuck near the back. That measures .0005", I think. My dial test indicator says .0005" in the middle of the face. But then there are numbers around the dial. At position 5 there are acutally 10 lines, so Im assuming that those are half lines, but then wouldn't the accuracy of it be .00025". Here is a pic of the dial test indicator. Anyway the drill rod now is twice as much off. I took the jaws out, and yes I did put them back correctly lining up the numbers with the jaw numbers. I don't have anything else that I think is accuratly round to test. Maybe I'll pick somthing up tomrrow. Any suggestions? I have machine shop supply right near me, DTC tool.

[SCzEngrgGroup]

I was just messing with it and when you flip on the half nut the threading dial disengages, not sure how as it doesn't look like it's moving away from the screw but it does. I'm very confused. If the dial disengages when the half nut is on and you have to keep the half nut engaged when threaded the entire time then the threading dial is useless, you can start at any point becuase it's just a dial that rotates and doesn't sync up with anything else? Am I missing something?
So I removed the chuck and put it back on after cleaning and it's now worse. I then deceided to measrue the runout on the body of the chuck near the back. That measures .0005", I think. My dial test indicator says .0005" in the middle of the face. But then there are numbers around the dial. At position 5 there are acutally 10 lines, so Im assuming that those are half lines, but then wouldn't the accuracy of it be .00025". Here is a pic of the dial test indicator. Anyway the drill rod now is twice as much off. I took the jaws out, and yes I did put them back correctly lining up the numbers with the jaw numbers. I don't have anything else that I think is accuratly round to test. Maybe I'll pick somthing up tomrrow. Any suggestions? I have machine shop supply right near me, DTC tool.

The dial stops turning when you engage the halfnut because the dial is moving at the same speed as the carriage. So, it's working exactly as it should. The dial shows you, in effect, the rotational position of the leadscrew, so you use it to determine when to engage the halfnut. Once engaged, you don't care about the dial, until you back up and have to re-engage the halfnut to continue the same thread.

The dial indicator is number in thousandths, and each line represents half a thousandth.

The chuck should be "registered" by a shoulder on the back, which mates with a mating one on the spindle. You might want to join the 9x20Lathe group on Yahoo. There are several guys there that know those machines inside and out, and can tell you how to get the very most out of it.

Regards,
Ray L.

[Cartierusm]

Cool, thanks.

[escott76]

A thou and a half in a 3 jaw isn't half bad. There's only so accurate you are going to get with this sort of chuck. For better centering you really want to rely on a 4 jaw, collet set up, or set tru style chuck. My own 9x20 wasn't any better in the runout department with the 3 jaw.
When I thread on this lathe I have a handle that I clamp on the spindle and I rotate it by hand. I never disengage the half nuts, and simply back the tool out, reverse turn to a little while past the part to allow for the lash in my half nuts. The hand feel allows you to get threads close to things, and to just go slowly. Obviously isn't for production.

[SScnc]

Here's a lathe VIDEO Hoss posted a while back. At about 32:00 into it it shows threading procedures. All the videos are interesting.


escott76,

I have the same HF 9x20 and I use a handle for threading on it too, removes all the stress I used to get trying to turn the motor off just in time. I'm going to switch the handle I'm using now to the arm from a bicycle pedal.


HimyKabibble, I tried to PM you regarding your finish media and your PM box is full. If you will, please PM me when you have a minute, I need your advice.

Steve

[SCzEngrgGroup]

Here's a lathe VIDEO Hoss posted a while back. At about 32:00 into it it shows threading procedures. All the videos are interesting.


escott76,

I have the same HF 9x20 and I use a handle for threading on it too, removes all the stress I used to get trying to turn the motor off just in time. I'm going to switch the handle I'm using now to the arm from a bicycle pedal.


HimyKabibble, I tried to PM you regarding your finish media and your PM box is full. If you will, please PM me when you have a minute, I need your advice.

Steve

Steve,

Sorry 'bout that. I've emptied my box, or you can e-mail me at Jagboy -at- pacbell.net

I do threading with a big-ass handle I made - about a foot long, with a 5" long baseball-bat-shaped (well, more like something else I can't mention here...) "knob" on it. Makes threading really easy, even for really large threads (> 1").

Regards,
Ray L.

[Crevice Reamer]

Try THIS manual from a nearly identical lathe:

http://grizzly.com/images/manuals/g4000_m.pdf

CR.

[Cartierusm]

Thanks for all the help guys, I appreciate it. I plan on using it to just do the 3 spacers I need for my BP conversion and then convert it to CNC as well. I was going to start a new post buy as I've got some of the regulars on this post I'll aks here first.

So the screws for the cross slide and X are pretty tight on my machine. I'm going to use 425 oz/in. stepper with a 72VDC PS, I use quick disconnects so I can use the same electronics for my BP, CNC Router and Lathe, it's cheaper. If I only feed in the same direction and when moving the cutter back to the start position if I come back enough to take up the backlash once it goes forward are ballscrews necessary for a Lathe Conversion?

For a Lathe CNC conversion I take it I only need to put a stepper on the X (longitudinal), the Z (the cross slide), and a C3 board from CNC4PC to let Mach know the RPMs of the spindle so I can cut threads?

P.S. I have some 1/2-5 2 Start McMaster Carr Acme Lead Screws with DumpsterCNC antibacklash nuts that I could use if I need to convert the screws. These were on my CNC Router originally but changed over to ballscrews, they are in perfect condition.

[SScnc]

For a Lathe CNC conversion I take it I only need to put a stepper on the X (longitudinal), the Z (the cross slide), and a C3 board from CNC4PC to let Mach know the RPMs of the spindle so I can cut threads?

If you didn't already read it, THIS POST by a guy here on the zone converted his HF 9x20 may be of some help to you.

Steve

[Crevice Reamer]

For a Lathe CNC conversion I take it I only need to put a stepper on the X (longitudinal), the Z (the cross slide)

On a Lathe, the longitudinal is Z and the cross slide is X.

CR.