cruddy finish makes for cruddy attitude

[gerritv]

Hi Zee

I have a KC1022ML lathe, similar to the Grizzly G0602 and your PM1030 (except mine isn't variable speed of course).

I suspect there are several issues at work here, so best to not get too dramatic about spindle play and changing gears int eh gearbox etc until other things are taken out of the equation.

You will need to digest the gear train charts to sort out the feed rate issue. It really sounds as if the default setup is for threading, not feeds. Can you post a link to the manual so we can guide you better. Some photos from your new camera might help as well :-)

The rh lever on your apron is for carriage feed, the small one is for cross slide (facing) feed. So use the RH one for what you are doing at present.

Re: squealing, are there any signs of the material rubbing against the tool? Try marking that face with blue, do a small cut and then look to see if the blueing is gone. It could be clearance

The last thing you want or should need to do is mess with the spindle bearings. From everything I have read PM checks their stuff before shipping. The odds of this being an issue is very slim regardless of where the lathe was made.

Gerrit

[jadge]

Andrew...that was a very helpful and interesting link. Thanks!
Are you the same Andrew as the author?

One and the same - Andrew

[zeeprogrammer]

Still making progress. I got what I consider a good finish on aluminum. After dropping the cutter slightly I also got a real nice finish on brass.
I still have a bit of squealing when I stop feeding and leave the motor on. But it depends on the speed of the spindle. Seems to squeal within a small intermediate range.
Slower or faster is quiet.

A bit troubling though...as I changed the spindle speed I could feel the lathe shake like something is out of balance.
One time, the shaking was what I would consider significant then later could not find the speed where that occurred although some shaking was still noticeable.

I took the chuck off and the shaking reduced considerably. Slight shaking at high speed (over 1500 rpm).
I'm pretty sure the chuck was installed correctly...that is I matched the marking on the chuck to the marking on the flange.

I can try other positions but is this usual? How concerned should I be?

Thanks

[Tennessee Whiskey]

You may have to indicate the chuck true to the spindle. Indicate the OD of the chuck, or, better yet, a known round piece of stock tightened in the chuck.

Cletus

[Jasonb]

You should not get a vibration from the 3-jaw, more common on the 4-jaw when the work is an odd shape

[Vixen]

The Vee belts on some Chinese products are not as good as they could be. Some are distorted out of round, some have bumps on the Vee were they were spliced during manufacture. Observe the belts carefully and check they are running smoothly and not jumping in time with the vibrations. Dont get your nose too close.

Mike

[zeeprogrammer]

You may have to indicate the chuck true to the spindle. Indicate the OD of the chuck, or, better yet, a known round piece of stock tightened in the chuck.

I setup a .0005 test indicator and a piece of 1/2" bar from a printer.
Lowered test indicator and zeroed it.
Turned chuck (by hand) and needle swung just over 5 marks in both directions (0.0025mm)

Seems okay, no?

Since I was set up...I moved the indicator out by 4". Needle swung -3 to 5.5 marks.
Average difference of 1.25 marks or .000625mm.

So that's the tilt in Z (up and down) which doesn't seem too bad. Could be sag too.

At some point I need to measure front to back but I don't think any of that explains the shaking.

It's very noticeable at around 700 rpm. Next to nothing below that and very very slightly above it.
Returns to shaking at around 1500 rpm but not as bad as at 700.

At some point I'll try the 4-jaw chuck too.

Just saw some posts come in...

@Jason - is that also true if the 4-jaw is not holding anything?
@Mike - I switched the belt to high speed yesterday and hadn't noticed anything. I'll take another look. Should probably test with the belt at low speed too.

Thanks everyone.

[gerritv]

If the lathe shakes without the chuck mounted then it must be pulleys or belts, it can't be the chuck. V belts, US or Chinese made are notorious for having lumps. If the belt is too tight the lumpiness will be exacerbated. Too loose you get slippage but that is usually a better thing than too tight.

[Jasonb]

The rh lever on your apron is for carriage feed, the small one is for cross slide (facing) feed. So use the RH one for what you are doing at present.
Gerrit

Sorry gerrit, can't agree with that, Zee's lathe is the Weiss Machine WM250VF as sold by many companies.

From teh manual you will see that the small lever does feeds and the large one on the right is for screwcutting



Also see this thread where someone had the same issues with a coarse feed and finally realised what I was saying was correct

http://www.model-engineer.co.uk/forums/postings.asp?th=125683&p=1

And if you look at page 32 of the manual you can see how the right hand lever engages the half but but the small lever moves a gear that is in constant mesg with the lead screw by a wormwheel and transfers this movement via various gears to move the carrage along via the rack or across via the cross slide screw as I said earlier

http://busybeetools.com/content/product_manuals/CX706.pdf

[Jasonb]

I setup a .0005 test indicator and a piece of 1/2" bar from a printer.
Lowered test indicator and zeroed it.
Turned chuck (by hand) and needle swung just over 5 marks in both directions (0.0025mm)

Zee, check what dial indicator you are using. A 0.0005 indicator is generally an imperial one where one division equals 0.0005" or 5tenths of an inch not 0.0005mm

Provided all jaws are in/out the same amount you should not get vibration from a 4-jaw

[zeeprogrammer]

I setup a .0005 test indicator and a piece of 1/2" bar from a printer.
Lowered test indicator and zeroed it.
Turned chuck (by hand) and needle swung just over 5 marks in both directions (0.0025mm)

Zee, check what dial indicator you are using. A 0.0005 indicator is generally an imperial one where one division equals 0.0005" or 5tenths of an inch not 0.0005mm

Provided all jaws are in/out the same amount you should not get vibration from a 4-jaw

Sorry about that. Units are inches. Numbers are correct.
Thanks.

Seems I've been getting my units mixed up more ever since I got the 3d printer. 

[Allen Smithee]

A 0.0005 indicator is generally an imperial one where one division equals 0.0005" or 5tenths of an inch not 0.0005mm

ITYM "5 tenths of a thou" (half a thou; 0.0125mm)

AS

[Jasonb]

Thanks AS, I went back and  added the "of an inch" after I wrote just 5tenths, should not have bothered maybe I should just have said it's an imperial DTI

[gerritv]

Jasonb, I stand corrected. I would not have known the matching model numbers in EU, (and I have learned to avoid BusyBee for pretty much everything by experience, both price and quality :-)

I guess more important is for Zee to spend some quality time with the manual :-)

Gerrit

[zeeprogrammer]

I guess more important is for Zee to spend some quality time with the manual :-)

Hee hee. Thought I had. But again...what I read isn't necessarily what was meant.

In this case, I thought the small lever was to select feed for cross slide or lead screw and to use the big lever to engage it.
It didn't occur to me that it was 'select AND engage'.