enco 13x40 lathe vibrations andnhowmto eliminate

[richl]

enco 13x40 lathe vibrations and how to eliminate

I finally had the time and some money to make a 3x2 rect tubing base to mount my lathe to. Problem is, the tork from the motor startup vibrates the lathe, while the initial is far less after a few seconds i am still getting a slight vibration in the lathe. It appears (though i am not 100% sure) to be the connection of the lathe bed and the cabinets. My plan is to add rubber grommets where the motor attaches to the lathe to help isolate it, but i am looking for any other ideas that will reduce the vibrations to nothing.

On another matter, i bought a harbor freight magnetic base di stand and the dial indicator. After squaring the base and checking the front and rear ways with the dial indicator ridingnon the carriage, the front ways has a crown of about 5 thousandths. Is this an accurate way to check the ways, and if so, what is acceptable? If this is not an accesptable way, what should i do to test it?

thanks formthe help

rich

 

[richl]

well...errrr... 40 hits:whistle:thanks to those that it least took a look)
the vibration issue i am going to try to isolate the motor from the bed, and i am going to look into something like rubber sheets to isolate the bed from the cabinets. hopefully i can get this working very smoothly.

Not sure what to do about the ways, hopefully the next nj hobbyist machinist meeting someone will take pity on me and offer some suggestions.

best of luck finding your answers enco users)

rich

 

[Ray C]

I'd advise that you see if the vibration occurrs under all (or just a few) conditions. That is, does it happen in all gears? Does it happen w/o a chuck mounted? etc...

Is the lathe mounted on level or uneven ground and do you have a sub-base of any sort?

As for measuring the flatness of the ways... I can't really help you there but, the proof is in the pudding. If you cut a shaft using the two-collar method and if you're able to spin a shaft between centers and get acceptable results -then leave it alone; otherwise, the lathe probably needs to be sitting on a proper bench and it must be properly aligned.

Ray

well...errrr... 40 hits:whistle:thanks to those that it least took a look)
the vibration issue i am going to try to isolate the motor from the bed, and i am going to look into something like rubber sheets to isolate the bed from the cabinets. hopefully i can get this working very smoothly.

Not sure what to do about the ways, hopefully the next nj hobbyist machinist meeting someone will take pity on me and offer some suggestions.

best of luck finding your answers enco users)

rich

 

[richl]

Thank you for replying ray, much appreciated.
The lathe is mounted to a rectangular 2x3 frame. It is a I shape ,the center is 16" wide and the 2 ends are 36" wide in an effort to increase the contact points to the floor. That helped the vibrations a lot. I tested the machine in 3 different speeds , 50 rpm (the slowest) 750 rpm and 1400 rpm all have vibration at the head and the chuck. I removed the chuck to verify it was not the cause. I rechecked all the connection points to the motor and the lathe. Bernie suggested changing the belt , it looks OK, but it can't hurt.

Lathe was set with h a carpenters level, its all I have to check with for right now. Machine is level in the y direction, not in the x. Before I started to spin material and check for taper I'm thinking I need to remove the vibration...

Thanks for the help! ;-)

Rich

 

[RandyM]

Unfortunately Rich, I think this one of those issues you just have to work through. By the sounds of it you have something that is not balanced. You'll have to find the cause. Your idea of using isolators will only put a bandaid on the problem and not solve it. Sometimes posting a photo will help others diagnose also. They tend to see things you don't. Good luck, not sure I was much help.

 

[Ray C]

I agree with changing the belts. Flat spots in the belts will cause problems. Check the key on the motor pulley shaft and make sure that pulley is a proper fit and not wiggling.

Also, it would be best to see a picture of the bench setup but, it sounds like a fairly small bench underneath a fairly large lathe. Wide and deep bases will help a lot. Lathes tend to be very top heavy and they need all the bottom-side support and stability they can get. BTW: My base is about 8" deeper than the distance from the front dials to the back of the motor and it's 6" longer from the left side of the gearbox to the end of the bed. This puts ALL the weight in the center of the boundary of the bench. How much additional weight do you have on the shelves of the bench? -The more the better. My bench alone is 350lbs and there's another 300lbs or so of stuff on the lower shelves.

There is probably a main hub about 6" diameter that the drive belts connect to. That hub is probably made of cast iron and it could be out of balance. Check all the other things before taking that hub off and checking balance.


Ray

 

[richl]

Thanks for he input randy! I'm shooting g in the dark myself, I'm hoping others can give me suggestions of things to try, I'm a bit short on ideas here.

Thanks ray

 

[richl]

The base I made is probably about 80lbs , I'm not too sure how much the cabinets weigh, the grizzly 4003 is basically the same machine... 300lbs. The more I loom at it though the more I am thinking pulleys and belts. Now I am hearing ticking in the gearbox lol , good thing this LA he was free)
Thanks for the suggestions. I'll look into this some more.
Rich

 

[pdentrem]

Could be pulley out of round, flat spot on the belt as suggested, even the seam can cause a vibration if the belt is worn and running on the bottom of the groove. I would look at Fenner Powertwist belts, works wonders to make equipment run smoother.

Motor mount is not solid?

Is the motor mounted on a pivoted plate to make tensioning automatic? These are a problem known to cause vibrations with the belt changing length due to out of round pulleys or hardened old belt.

Look inside the head for a loose gear on one of the shafts?

Improper preload on a bearing?

Unbalanced gear due to accumulation of dried out grease in the bottom of the teeth?

Unbalanced motor? Run with belt off to check. Not likely but try it just to be sure.
Pierre

 

[richl]

Could be pulley out of round, flat spot on the belt as suggested, even the seam can cause a vibration if the belt is worn and running on the bottom of the groove. I would look at Fenner Powertwist belts, works wonders to make equipment run smoother.

Motor mount is not solid?

Is the motor mounted on a pivoted plate to make tensioning automatic? These are a problem known to cause vibrations with the belt changing length due to out of round pulleys or hardened old belt.

Look inside the head for a loose gear on one of the shafts?

Improper preload on a bearing?

Unbalanced gear due to accumulation of dried out grease in the bottom of the teeth?

Unbalanced motor? Run with belt off to check. Not likely but try it just to be sure.
Pierre

You win the prize Pierre! One of the gears in the gearhead wass wabbling, on closer inspection only 2 of the allen screws were left and they were almost off) Tigtened them up tapped the gear in place than started her up. No torque spin, no vibration and the tick in the gear head was gone) i'll purchase allen screws tomorrow for the missing ones and align thengear better, but i think that should just about make her perfect, or close enough for me.

Thanks for all the help guys, I think we got this one:allgood:

rich