Standard Modern 16-60 Lathe chatter problems

Contact SM is the right way to go.

Not your lathe but fairly correct for most machines, look up Grizzly G9249 owners manual. On page 59 is the beginning of how to setup the spindle bearings. The bearings will be loose when the lathe is cold, as the temp moves up the bearings, headstock and spindle change dimensions. You likely have to be warmed up to do the same for your machine.
Pierre
 
Good morning gang.

So this morning I tried a different piece of stock, 2 inch dia. Left it out of the chuck about 2 inches. 320 rpm, .006 per rev, insert tool holder from another lathe that cut nice with the inserts it uses. The herringbone style chatter pattern is still present. Its still making a low frequency sound when it chatters.

This afternoon I plan to revisit the leveling and the jack bolts to make sure I am not missing something, a bolt not touching well or shavings under the pad or whatever could be.

I tightened all the bolts holding the main frame to the base frame. I did get a 1/4 to 1/2 turn on all but 2 of them, but it didn't make any difference with the chatter.

I re-tightened the pre load bearing nut on my machine. It spins freely, but I tightened it with a hammer and punch. I could not tighten it with my spanner wrench, not enough leverage to do so.

Also this morning I set up the dial indicator on the top of the gearbox and positioned it above my 4 jaw chuck. Set it to zero and pried up on it. I could get only .0005 up and down total movement with a 3 foot lever and I'm a 200 pounder.


I did notice my belt look like they could run smoother from motor to the main drive shaft. I tightened them up some yesterday afternoon. I could tell no difference. And 2 of the belts still look floppyish'.Could belts not fit right cause these kind of issues? I have even read about motor out of balance could cause chatter issues. I find it hard to swallow that those belts with everything else in order could vibrate this big ole machine, but I am getting the 3 belts new today so I don't have any question about them.

Ok guys, gotta get back to work now. I just wanted to share these last steps taken and the results.

Thanks,
Dan Reed

EDIT* I am also going to place a call to Standard Modern / Lablond this morning. They said they have a service guy, an old timer who I hope will have some helpful information.
 
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Thanks for the update. I think you may need to revisit the pre load nut once more. My opinion is that you have nothing to lose, although it sounds like you did tighten it up a bit. Other things to consider is the compound and cross slide, and tool post holder, also tool "hang out" . Any slop in those areas can cause chatter too. Rigidity is the name of the game here.
 
A few pics of areas I am going to look into more this afternoon. And one of the chattered work piece.

chatter.JPGbelts.JPGholder setup.JPG

chatter.JPG belts.JPG holder setup.JPG
 
Belts that are "lumpy" due to the machine having been allowed to sit unused for years with them tight can cause quite a bit of vibration.
 
I've got 3 new belts due in an hour. Had to wait for them to pick up the good belts. No generics this time.

Now that the belts are off, My guy asked me to come rotate the motor shaft so he could smooth up the pulley surface on the bottom side. Well, I thought WTH. The motor would lock up at one point, and by hand, you could not have turned it. After some back and forth working of the pulley and shaft it spun freely. Then added a couple shots of lithium grease to the motor bearings and it loosened up some other junk in there. So now you can feel the trash or whatever it is as you spin it.

I now have them pulling the motor and we are getting new motor bearings this afternoon also. I sure hope this will smooth out after these new finds

Also I talked to the service guy at Lablond. He says I should tighten my bearings more. Says without the chuck, it should turn no more than a half a turn or so freely. So I will adjust it again later on today if these new fixes don't do the trick.

Thanks,
Dan Reed
 
I'm guessing that the motor will be full of goop due to having been over-greased.
 
danleereed said:
I've got 3 new belts due in an hour. Had to wait for them to pick up the good belts. No generics this time.

Now that the belts are off, My guy asked me to come rotate the motor shaft so he could smooth up the pulley surface on the bottom side. Well, I thought WTH. The motor would lock up at one point, and by hand, you could not have turned it. After some back and forth working of the pulley and shaft it spun freely. Then added a couple shots of lithium grease to the motor bearings and it loosened up some other junk in there. So now you can feel the trash or whatever it is as you spin it.

I now have them pulling the motor and we are getting new motor bearings this afternoon also. I sure hope this will smooth out after these new finds

Also I talked to the service guy at Lablond. He says I should tighten my bearings more. Says without the chuck, it should turn no more than a half a turn or so freely. So I will adjust it again later on today if these new fixes don't do the trick.

Thanks,
Dan Reed
Click to expand...

Good find Dan. Let us know what you guys find and if it solves the problem. Sounds like it sure might.
 
Well, today I got the motor back on. New belts. The whole drive side is running smooth now. Seems to have improved a little bit, but still chatters.

I am going to tighten on the pre load bearing some more this afternoon.

I was really hoping that the thing would cut smooth now but looks like my adventure isn't over yet hah.

Back soon,
Dan Reed
 
OK guys,
I took advice of a few of you and the repair guy at Leblond. I tightened the main bearings with the chuck off until I could spin it hard and it would not make a full turn. Buttoned up the top and put the chuck back on. This thing cuts nice now. I am still ordering new bearings for it, but I am good now until they go. And I'll have the spares here when/ if there are still issues with the old ones.

I'd like to say thanks to all of you who assisted or advised me while I was working out these issues. The advice was definitely a big help in getting me going in the right directions and give me options to look at to solve the problem.


*Handshakes All Around*

Thanks,
Dan Reed
 
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